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Guo Z, Liu P, Sha Y, Gao Y, Yu G, Lv HH, Wang Y, Han Y, Yang W, Wang XY, Ma X. Resolving the Vibronic Effect on Dark Processes of Conjugation Extended Diketopyrrolopyrrole with Red/NIR Emitting. J Phys Chem Lett 2025; 16:4615-4625. [PMID: 40312138 DOI: 10.1021/acs.jpclett.5c00585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2025]
Abstract
The conjugation extended emitters with bright red/NIR emission are of high interest due to potential bioapplications, while they might be plagued from fluorescence quenching associated with the rapid dark decay channels of excited states. In this work, we employed diketopyrrolopyrrole (DPP) and conjugation extended derivatives as a model system and attempted to resolve the excited-state dynamics by using ultrafast spectroscopy. Further vibrational analysis on electronic states (S0, S1, T1, and T2) allowed us to evaluate vibronic effects on dark processes of the model system, including S1 state nonradiative decay (kNRS) and plausible ISC (kISC) channels. By identification of vibrational modes involved in corresponding dark processes, the relationship between excited-state structure relaxation, vibronic coupling, and the rate constant of dark processes was revealed. Our work indicated that the vibronic effect can greatly affect fluorescent emission by promoting dark processes and should be taken into consideration in molecular design of red/NIR emitters.
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Affiliation(s)
- Zilong Guo
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P. R. China
| | - Pengcai Liu
- State Key Laboratory of Elemento-Organic Chemistry, Frontier Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Yulin Sha
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P. R. China
| | - Yixuan Gao
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P. R. China
| | - Guo Yu
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P. R. China
| | - Hao-Han Lv
- State Key Laboratory of Elemento-Organic Chemistry, Frontier Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Yaxin Wang
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P. R. China
| | - Yandong Han
- Engineering Research Center for Nanomaterials, Henan University, Kaifeng 475004, P. R. China
| | - Wensheng Yang
- Engineering Research Center for Nanomaterials, Henan University, Kaifeng 475004, P. R. China
| | - Xiao-Ye Wang
- State Key Laboratory of Elemento-Organic Chemistry, Frontier Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Xiaonan Ma
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P. R. China
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2
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Ullah Q, Rahman A, Jahan A, Khan I, Ahmer MF, Khan PAA. Carbazole-Based Colorimetric and Fluorescent Chemosensors for Metal Ions Detection : A Comprehensive Review ( 2012 to till date ). J Fluoresc 2025:10.1007/s10895-025-04142-z. [PMID: 40314888 DOI: 10.1007/s10895-025-04142-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2024] [Accepted: 01/10/2025] [Indexed: 05/03/2025]
Abstract
This review focuses on the development of carbazole based colorimetric and fluorescent chemosensors for the detection of metal ions including, mercury (Hg), iron (Fe), aluminium (Al) chromium (Cr) zinc (Zn), cobalt (Co) and copper (Cu) ions detection. Traditional analytical methods for detecting these metal ions, while widely used, present several draw backs such as high cost, low sensitivity, time consuming and the requirement for skilled technician. To overcome these limitations, more efficient alternatives such as colorimetric and fluorescent chemosensors have been developed. These sensors offer advantages like cost effectiveness, high sensitivity, rapid detection, and ease of use without requiring specialized technical expertise. In this review, we emphasize the applications of carbazole based colorimetric and fluorescence chemosensors. Carbazole and its derivatives are well-suited for this purpose due to their unique properties including excellent solubility, a highly conjugated structure, chemical stability, intramolecular charge transfer capabilities, and sensitivity to structural changes. These features make them ideal candidates for use as optical materials and fluorescence chemosensors in metal ion detection. The applications of carbazole- based colorimetric and fluorescent chemosensors. are summarized in tabular format for clarity.
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Affiliation(s)
- Qasim Ullah
- Chemistry Section, School of Sciences, Maulana Azad National Urdu University, Gachibowli, Hyderabad, 500032, TS, India.
| | - Aram Rahman
- Chemistry Section, School of Sciences, Maulana Azad National Urdu University, Gachibowli, Hyderabad, 500032, TS, India
| | - Anzar Jahan
- Chemistry Section, School of Sciences, Maulana Azad National Urdu University, Gachibowli, Hyderabad, 500032, TS, India
| | - Ira Khan
- Botany Section, School of Sciences, Maulana Azad National Urdu University, Gachibowli, Hyderabad, 500032, TS, India
| | - Mohammad Faraz Ahmer
- Electrical and Electronics Engineering, Mewat Engineering College, Gurugram University, Nuh, 122107, Haryana, India
| | - Pathan Arif Ali Khan
- Post graduate and Research Centre, Maulana Azad College of Arts,Science and Commere, Dr Rafiq Zakaria Campus, Rauza Bagh, PB NO 27 Aurangabad, Aurangabad, 431001 , MH, India.
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3
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Sivanarayanan J, Vinod K, Benoy A, Hariharan M. Unlocking the Room Temperature Phosphorescence through Halogen Engineering in Carbazole Dimer. Chemistry 2025:e202500635. [PMID: 40235125 DOI: 10.1002/chem.202500635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2025] [Revised: 04/09/2025] [Accepted: 04/15/2025] [Indexed: 04/17/2025]
Abstract
Room-temperature phosphorescence (RTP) in metal-free organic materials offers immense potential for advanced optoelectronic applications. However, the rational design and fine-tuning of RTP remain challenging due to the complex correlation between molecular structure and photophysical processes. Herein, we explored the impact of intersystem crossing (ISC), spin-orbit coupling (SOC), and halogen interactions to promote RTP in crystalline brominated carbazole dimer (BrCz-D). In contrast, the unsubstituted analogue, carbazole dimer (Cz-D) exhibits thermally activated delayed fluorescence (TADF) under ambient conditions. Femtosecond transient absorption (fsTA) spectroscopy measurements confirmed the population of triplet manifolds in both dimers. Bromine substitution significantly enhances spin-orbit coupling (VSOC = 14.94 cm⁻¹), enabling efficient ISC and robust RTP in BrCz-D. Enhanced RTP in crystalline BrCz-D is attributed to unique halogen interactions, including Br···Br, C···Br, and H···Br, within the crystal lattice. Such halogen interactions are negligible in the solution state, accounting for the lack of RTP under ambient conditions. The present work highlights the critical role of SOC and halogen bonding in achieving efficient RTP for designing high-performance organic phosphorescent materials through crystallochemistry.
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Affiliation(s)
- Jibin Sivanarayanan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala-P. O., Vithura, Thiruvananthapuram, 695551, India
| | - Kavya Vinod
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala-P. O., Vithura, Thiruvananthapuram, 695551, India
| | - Anitta Benoy
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala-P. O., Vithura, Thiruvananthapuram, 695551, India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala-P. O., Vithura, Thiruvananthapuram, 695551, India
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4
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Li J, Shi Y, Cui C, Li Y, Ruan C, Cheng T. Unveiling Quantum Coherence Effects in Modulating Electron Transfer in Platinum (II) Donor-Acceptor-Donor Systems. Chemistry 2025; 31:e202404512. [PMID: 39929777 DOI: 10.1002/chem.202404512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2024] [Accepted: 02/10/2025] [Indexed: 02/20/2025]
Abstract
Quantum coherence effects (QCEs), arising from the interference of wave-like amplitudes, are crucial in controlling the electron transfer function of molecular systems. Here, we report a coherence phenomenon associated with charge separation (CS) in a range of Pt (II) cis-acetylide donor-acceptor-donor (D-A-D) systems, where the photogenerated Pt (III) center acts as an acceptor connecting two (R)phenothiazine (R = H or tBu) donors. Femtosecond transient absorption spectroscopy revealed that CS rates in D-A-D systems with double CS paths were accelerated by 4-8 times compared to their donor-acceptor (D-A) counterparts with a single path. An enhancement factor of 2-3 in electronic coupling, within the context of interference between CS paths, is derived, providing a clear signature of QCEs. This enhancementin CS processes closely correlates with the strength of coupling between donors. This study highlights the significant impact of QCEs on the photophysical properties of molecular systems and offers insights into charge and energy transport mechanisms in both natural and artificial systems.
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Affiliation(s)
- Juanjuan Li
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
| | - Yuqing Shi
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
| | - Can Cui
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
| | - Yefan Li
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
| | - Chenluwei Ruan
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
| | - Tao Cheng
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
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Xiao Z, Zou Y, Chen Z, Miao J, Qiu Y, Huang Z, Cao X, Peng X, Yang C. Deep-Blue OLEDs with BT. 2020 Blue Gamut, External Quantum Efficiency Approaching 40. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2025; 37:e2419601. [PMID: 39935145 DOI: 10.1002/adma.202419601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2024] [Revised: 02/03/2025] [Indexed: 02/13/2025]
Abstract
The hyperfluorescence (HF) technology holds great promise for the development of high-quality organic light-emitting diodes (OLEDs) for their excellent color purity, high efficiency, and low-efficiency roll-off. Sensitizer plays a crucial role in the performance of HF devices. However, designing sensitizers with simultaneous high photoluminescence quantum yield (PLQY), rapid radiative decay (kr), and fast reverse intersystem crossing rate (kRISC) poses a great challenge, particularly for the thermally activated delayed fluorescence (TADF) sensitizers targeting deep-blue HF device. Herein, by introducing a boron-containing multi-resonance-type acceptor into the multi-tert-butyl-carbazole encapsulated benzene molecular skeleton, two TADF emitters featuring hybridized multi-channel charge-transfer pathways, including short-range multi-resonance, weakened through-bond, and compact face-to-face through-space charge-transfer. Benefiting from the rational molecular design, the proof-of-concept sensitizers exhibit simultaneous rapid kr of 5.3 × 107 s-1, fast kRISC up to 5.9 × 105 s-1, a PQLY of near-unity, as well as ideal deep-blue emission in both solution and film. Consequently, the corresponding deep-blue HF devices not only achieve chromaticity coordinates that fully comply with the latest BT. 2020 standards, but also showcase record-high maximum external quantum efficiencies nearing 40%, along with suppressed efficiency roll-off.
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Affiliation(s)
- Zhengqi Xiao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024, China
| | - Yang Zou
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Zhanxiang Chen
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Jingsheng Miao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Yuntao Qiu
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Zhongyan Huang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Xiaosong Cao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Xiaojun Peng
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 116024, China
| | - Chuluo Yang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
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6
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Qu YK, Zheng Q, Zhou DY, Cui LS, Liao LS, Jiang ZQ. Unraveling the Configuration Modulation in Spiro-Based Through-Space Charge Transfer Materials. Angew Chem Int Ed Engl 2025; 64:e202418008. [PMID: 39582255 DOI: 10.1002/anie.202418008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2024] [Revised: 11/15/2024] [Accepted: 11/21/2024] [Indexed: 11/26/2024]
Abstract
Thermally activated delayed fluorescence (TADF) materials hold promise for optoelectronic applications. Among various design strategies, through-space charge transfer (TSCT) systems offer the potential for enhanced performance. However, the relationship between molecular configuration and TSCT properties remains unclear compared to traditional through-band charge transfer materials. In this study, we investigated the influence of spatial configuration on TSCT features and electronic properties of triplet excited states in these TSCT materials. By manipulating the spatial arrangement between donor and acceptor segments using different spiro skeletons, a series of TSCT materials (DMB2-DMB5) was synthesized. Together with the parent molecule, DM-B, these materials exhibited completely different TADF characteristics, demonstrating the impact of spatial arrangements on their optoelectronic properties. Thus, the external quantum efficiency of these materials ranged from as high as 28.0 % (DMB2) to as low as 3.6 % (DMB5) due to variations in their TADF characteristics. Our findings highlight the significance of spatial configuration, beyond distance alone, in influencing TSCT properties when donor and acceptor segments are sufficiently close. This insight provides valuable guidance for developing advanced TSCT materials and advancing TADF systems with improved performance and functionality.
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Affiliation(s)
- Yang-Kun Qu
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
| | - Qi Zheng
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
| | - Dong-Ying Zhou
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
| | - Lin-Song Cui
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Liang-Sheng Liao
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
- Macao Institute of Materials Science and Engineering, Macau University of Science and Technology, Taipa, 999078, Macau SAR, China
| | - Zuo-Quan Jiang
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
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7
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Pei Y, Sukhanov AA, Chen X, Iagatti A, Doria S, Dong X, Zhao J, Li Y, Chi W, Voronkova VK, Di Donato M, Dick B. The Photophysics of Naphthalimide-Phenoselenazine Electron Donor-Acceptor Dyads: Revisiting the Heavy-Atom Effect in Thermally Activated Delayed Fluorescence. Chemistry 2025; 31:e202403542. [PMID: 39607385 DOI: 10.1002/chem.202403542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2024] [Indexed: 11/29/2024]
Abstract
We prepared thermally activated delayed fluorescence (TADF) emitter dyads, NI-PTZ, NI-PTZ-2Br and NI-PSeZ, with naphthalimide (NI) as electron acceptor and 10H-phenothiazine (PTZ) or 10H-phenoselenazine (PSeZ) as electron donor to study the heavy-atom effect on the intersystem crossing (ISC) and reverse ISC (rISC) in the TADF emitters. The delayed fluorescence lifetimes of the dyads containing heavy atoms (τ D F ${{\tau }_{{\rm D}{\rm F}}}$ =5.9 μs for NI-PSeZ andτ D F ${{\tau }_{{\rm D}{\rm F}}}$ =16.5 μs for NI-PTZ-2Br, respectively) are longer than the heavy atom-free counterpart NI-PTZ (τ D F ${{\tau }_{{\rm D}{\rm F}}}$ =2.0 μs). Nanosecond transient absorption (ns-TA) spectral study and the time-resolved electron paramagnetic resonance (TREPR) spectra show the presence of both 3LE and 3CS states. These findings represent solid experimental evidences for the spin-vibronic coupling mechanism of TADF. Moreover, the ns-TA spectra show that the heavy atoms don't have a significant effect since the lifetime of the triplet transient species (1.3 μs for NI-PTZ) is not shortened in their presence (4.5 μs for NI-PSeZ and 5.3 μs for NI-PTZ-2Br). These results show that the previously claimed heavy-atom effect on rISC and TADF is not a universal principle. The femtosecond transient absorption (fs-TA) spectra of the compounds indicate the occurrence of fast charge separation within 1-2 ps, and the charge recombination is slow (>4 ns).
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Affiliation(s)
- Yuying Pei
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Rd., Dalian, 116024, P. R. China
- School of Chemistry, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Andrey A Sukhanov
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of Russian Academy of Sciences, Sibirsky Tract 10/7, Kazan, 420029, Russia
| | - Xi Chen
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Rd., Dalian, 116024, P. R. China
| | - Alessandro Iagatti
- LENS (European Laboratory for Non-Linear Spectroscopy), via Nello Carrara n. Firenze, 1, 50019, Sesto Fiorentino (Florence), Italy
- INO-CNR Istituto Nazionale di Ottica, Largo Enrico Fermi 6, 50125, Florence (FI), Italy
| | - Sandra Doria
- LENS (European Laboratory for Non-Linear Spectroscopy), via Nello Carrara n. Firenze, 1, 50019, Sesto Fiorentino (Florence), Italy
- ICCOM-CNR, Via Madonna del Piano 10, 50019, Sesto Fiorentino, FI, Italy
| | - Xin Dong
- Ningbo Sunny Automotive Optech Co. Ltd., No. 27-29 Shunke Road, Ning Bo Shi, Yuyao, 315400, P. R. China
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Rd., Dalian, 116024, P. R. China
| | - Yanqin Li
- School of Chemistry, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Weijie Chi
- School of Chemistry and Chemical Engineering, Hainan University, No. 58 Renmin Avenue, Meilan District, Haikou, 570228, China
| | - Violeta K Voronkova
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of Russian Academy of Sciences, Sibirsky Tract 10/7, Kazan, 420029, Russia
| | - Mariangela Di Donato
- LENS (European Laboratory for Non-Linear Spectroscopy), via Nello Carrara n. Firenze, 1, 50019, Sesto Fiorentino (Florence), Italy
- ICCOM-CNR, Via Madonna del Piano 10, 50019, Sesto Fiorentino, FI, Italy
| | - Bernhard Dick
- Lehrstuhl für Physikalische Chemie, Institut für Physikalische und Theoretische Chemie, Universität Regensburg, D, 93053, Regensburg, Germany
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8
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Ye K, Sukhanov AA, Pang Y, Mambetov A, Li M, Cao L, Zhao J, Voronkova VK, Peng Q, Wan Y. Time-resolved transient optical and electron paramagnetic resonance spectroscopic studies of electron donor-acceptor thermally activated delayed fluorescence emitters based on naphthalimide-phenothiazine dyads. Phys Chem Chem Phys 2025; 27:813-823. [PMID: 39660403 DOI: 10.1039/d4cp03629h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2024]
Abstract
The photophysics of naphthalimide (NI)-phenothiazine (PTZ) dyads were investigated as electron donor-acceptor (D-A) thermally activated delayed fluorescence (TADF) emitters. Femtosecond transient absorption (fs-TA) spectra show that the photophysical processes in non-polar solvents are in singlet localized state (1LE, τ = 0.8 ps) → Franck-Condon singlet charge separation state (1CS, τ = 7.8 ps) → 1CS state (τ = 2.2 ns) → triplet state (3LE, τ = 16 μs). The 3LE state is formed via the spin-orbit charge transfer-intersystem crossing (SOCT-ISC) mechanism rather than the spin-orbit (SO)-ISC mechanism. In a polar solvent, the CS state has a much lower energy than the 3LE state; thus, the 3LE state is absent from the photophysical processes and no TADF was observed. Moreover, we found that the delayed fluorescence lifetime is related to the low-lying triplet state (3LE or 3CS states). When the 3CS state is the low-lying triplet state, the TADF lifetime is shorter than that of the 3LE state as the low-lying triplet state. In the time-resolved electron paramagnetic resonance (TREPR) spectra, both 3LE (zero field splitting parameter D = 2250 MHz, E = -150 MHz) and 3CS (D = 430 MHz, E = 0 MHz) states were observed. It is noteworthy that the electron spin polarization (ESP) phase pattern of the 3CS state was inverted at longer delay times as a consequence of the selective transition between the 3LE and 3CS states and a faster decay of one sublevel of the 3CS state. These results are strong and direct experimental evidence for the spin-vibronic coupling mechanism of TADF.
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Affiliation(s)
- Kaiyue Ye
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
| | - Andrey A Sukhanov
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of Russian Academy of Sciences, Kazan 420029, Russia.
| | - Yu Pang
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
| | - Aidar Mambetov
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of Russian Academy of Sciences, Kazan 420029, Russia.
| | - Minjie Li
- College of Chemistry Beijing Normal University, Beijing 100875, P. R. China.
| | - Liyuan Cao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
| | - Violeta K Voronkova
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of Russian Academy of Sciences, Kazan 420029, Russia.
| | - Qian Peng
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
| | - Yan Wan
- College of Chemistry Beijing Normal University, Beijing 100875, P. R. China.
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9
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Dos Santos JM, Hall D, Basumatary B, Bryden M, Chen D, Choudhary P, Comerford T, Crovini E, Danos A, De J, Diesing S, Fatahi M, Griffin M, Gupta AK, Hafeez H, Hämmerling L, Hanover E, Haug J, Heil T, Karthik D, Kumar S, Lee O, Li H, Lucas F, Mackenzie CFR, Mariko A, Matulaitis T, Millward F, Olivier Y, Qi Q, Samuel IDW, Sharma N, Si C, Spierling L, Sudhakar P, Sun D, Tankelevičiu Tė E, Duarte Tonet M, Wang J, Wang T, Wu S, Xu Y, Zhang L, Zysman-Colman E. The Golden Age of Thermally Activated Delayed Fluorescence Materials: Design and Exploitation. Chem Rev 2024; 124:13736-14110. [PMID: 39666979 DOI: 10.1021/acs.chemrev.3c00755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2024]
Abstract
Since the seminal report by Adachi and co-workers in 2012, there has been a veritable explosion of interest in the design of thermally activated delayed fluorescence (TADF) compounds, particularly as emitters for organic light-emitting diodes (OLEDs). With rapid advancements and innovation in materials design, the efficiencies of TADF OLEDs for each of the primary color points as well as for white devices now rival those of state-of-the-art phosphorescent emitters. Beyond electroluminescent devices, TADF compounds have also found increasing utility and applications in numerous related fields, from photocatalysis, to sensing, to imaging and beyond. Following from our previous review in 2017 ( Adv. Mater. 2017, 1605444), we here comprehensively document subsequent advances made in TADF materials design and their uses from 2017-2022. Correlations highlighted between structure and properties as well as detailed comparisons and analyses should assist future TADF materials development. The necessarily broadened breadth and scope of this review attests to the bustling activity in this field. We note that the rapidly expanding and accelerating research activity in TADF material development is indicative of a field that has reached adolescence, with an exciting maturity still yet to come.
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Affiliation(s)
- John Marques Dos Santos
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - David Hall
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Biju Basumatary
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Megan Bryden
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Dongyang Chen
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Praveen Choudhary
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Thomas Comerford
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Ettore Crovini
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Andrew Danos
- Department of Physics, Durham University, Durham DH1 3LE, UK
| | - Joydip De
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Stefan Diesing
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY169SS, UK
| | - Mahni Fatahi
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Máire Griffin
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Abhishek Kumar Gupta
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Hassan Hafeez
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY169SS, UK
| | - Lea Hämmerling
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Emily Hanover
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
- EaStCHEM School of Chemistry, The University of Edinburgh, Edinburgh, EH9 3FJ, UK
| | - Janine Haug
- Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Tabea Heil
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Durai Karthik
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Shiv Kumar
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
- Department of Chemistry, University of Delhi, Delhi 110007, India
| | - Oliver Lee
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY169SS, UK
| | - Haoyang Li
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Fabien Lucas
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | | | - Aminata Mariko
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Tomas Matulaitis
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Francis Millward
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Yoann Olivier
- Laboratory for Computational Modeling of Functional Materials, Namur Institute of Structured Matter, Université de Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium
| | - Quan Qi
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Ifor D W Samuel
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY169SS, UK
| | - Nidhi Sharma
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY169SS, UK
| | - Changfeng Si
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Leander Spierling
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Pagidi Sudhakar
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Dianming Sun
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Eglė Tankelevičiu Tė
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY169SS, UK
| | - Michele Duarte Tonet
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY169SS, UK
| | - Jingxiang Wang
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Tao Wang
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Sen Wu
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Yan Xu
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
| | - Le Zhang
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY169SS, UK
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY169ST, UK
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10
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Zhang J, Xiao TF, Zhao H, Kong J, Kuang Z, Zhou M, Xu GQ, Li Y, Xia A. Photocatalytic Mechanisms of Organic Thermally Activated Delayed Fluorescence Compounds. J Phys Chem Lett 2024; 15:11784-11791. [PMID: 39556232 DOI: 10.1021/acs.jpclett.4c02670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2024]
Abstract
Reverse intersystem crossing (RISC) has become possible by minimizing the energy gap between the first excited singlet (S1) and triplet state (T1), which facilitates the thermally activated delayed fluorescence (TADF). Due to the small singlet-triplet energy gap, the S1 and T1 states exhibit comparable redox reactivity, leading organic TADF compounds to be potent photocatalysts. Here, we report such TADF compounds with multiple donor units designed as an efficient photocatalyst for the direct C(sp3)-H carbamoylation of saturated aza-heterocycles. The results obtained by photophysical investigations and chemical calculations confirm that both the S1 and T1 states are involved in the photocatalysis cycle, with the fast spin-flip from the S1 to triplet states being a crucial factor in the enhancement of catalytic performance. The findings will be beneficial for the design of novel, efficient organic photocatalysis with TADF characteristics and aid in the development of organic photocatalysis.
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Affiliation(s)
- Jiawen Zhang
- State Key Laboratory of Information Photonic and Optical Communications, and School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, P. R. China
| | - Teng-Fei Xiao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, MOE Frontiers Science Center for Rare Isotopes, Lanzhou Magnetic Resonance Center, Lanzhou University, 730000 Lanzhou, Gansu, China
| | - Hongmei Zhao
- State Key Laboratory of Information Photonic and Optical Communications, and School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, P. R. China
| | - Jie Kong
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhuoran Kuang
- State Key Laboratory of Information Photonic and Optical Communications, and School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, P. R. China
| | - Meng Zhou
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guo-Qiang Xu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, MOE Frontiers Science Center for Rare Isotopes, Lanzhou Magnetic Resonance Center, Lanzhou University, 730000 Lanzhou, Gansu, China
| | - Yang Li
- State Key Laboratory of Information Photonic and Optical Communications, and School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, P. R. China
| | - Andong Xia
- State Key Laboratory of Information Photonic and Optical Communications, and School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, P. R. China
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11
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Kuila S, Miranda-Salinas H, Eng J, Li C, Bryce MR, Penfold TJ, Monkman AP. Rigid and planar π-conjugated molecules leading to long-lived intramolecular charge-transfer states exhibiting thermally activated delayed fluorescence. Nat Commun 2024; 15:9611. [PMID: 39511188 PMCID: PMC11544105 DOI: 10.1038/s41467-024-53740-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2024] [Accepted: 10/21/2024] [Indexed: 11/15/2024] Open
Abstract
Intramolecular charge transfer (ICT) occurs when photoexcitation causes electron transfer from an electron donor to an electron acceptor within the same molecule and is usually stabilized by decoupling of the donor and acceptor through an orthogonal twist between them. Thermally activated delayed fluorescence (TADF) exploits such twisted ICT states to harvest triplet excitons in OLEDs. However, the highly twisted conformation of TADF molecules results in limited device lifetimes. Rigid molecules offer increased stability, yet their typical planarity and π-conjugated structures impedes ICT. Herein, we achieve dispersion-free triplet harvesting using fused indolocarbazole-phthalimide molecules that have remarkably stable co-planar ICT states, yielding blue/green-TADF with good photoluminescence quantum yield and small singlet-triplet energy gap < 50 meV. ICT formation is dictated by the bonding connectivity and excited-state conjugation breaking between the donor and acceptor fragments, that stabilises the planar ICT excited state, revealing a new criterion for designing efficient TADF materials.
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Affiliation(s)
- Suman Kuila
- Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK.
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK.
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado, 80309, US.
| | | | - Julien Eng
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Chunyong Li
- Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
| | - Martin R Bryce
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | - Thomas J Penfold
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Andrew P Monkman
- Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK.
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12
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Uji M, Kondo J, Hara-Miyauchi C, Akimoto S, Haruki R, Sasaki Y, Kimizuka N, Ajioka I, Yanai N. In Vivo Optogenetics Based on Heavy Metal-Free Photon Upconversion Nanoparticles. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2405509. [PMID: 39308228 DOI: 10.1002/adma.202405509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 09/14/2024] [Indexed: 11/16/2024]
Abstract
Photon upconversion (UC) from red or near-infrared (NIR) light to blue light is promising for in vivo optogenetics. However, the examples of in vivo optogenetics have been limited to lanthanide inorganic UC nanoparticles, and there have been no examples of optogenetics without using heavy metals. Here the first example of in vivo optogenetics using biocompatible heavy metal-free TTA-UC nanoemulsions is shown. A new organic TADF sensitizer, a boron difluoride curcuminoid derivative modified with a bromo group, can promote intersystem crossing to the excited triplet state, significantly improving TTA-UC efficiency. The TTA-UC nanoparticles formed from biocompatible surfactants and methyl oleate acquire water dispersibility and remarkable oxygen tolerance. By combining with genome engineering technology using the blue light-responding photoactivatable Cre-recombinase (PA-Cre), TTA-UC nanoparticles promote Cre-reporter EGFP expression in neurons in vitro and in vivo. The results open new opportunities toward deep-tissue control of neural activities based on heavy metal-free fully organic UC systems.
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Affiliation(s)
- Masanori Uji
- Department of Applied Chemistry, Graduate School of Engineering and Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Jumpei Kondo
- Department of Applied Chemistry, Graduate School of Engineering and Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Chikako Hara-Miyauchi
- Center for Brain Integration Research (CBIR), Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
- Kanagawa Institute of Industrial Science and Technology (KISTEC), 3-2-1 Sakato, Takatsu-ku, Kawasaki-shi, Kanagawa, 213-0012, Japan
| | - Saori Akimoto
- Center for Brain Integration Research (CBIR), Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
- Kanagawa Institute of Industrial Science and Technology (KISTEC), 3-2-1 Sakato, Takatsu-ku, Kawasaki-shi, Kanagawa, 213-0012, Japan
| | - Rena Haruki
- Department of Applied Chemistry, Graduate School of Engineering and Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Yoichi Sasaki
- Department of Applied Chemistry, Graduate School of Engineering and Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Nobuo Kimizuka
- Department of Applied Chemistry, Graduate School of Engineering and Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Itsuki Ajioka
- Center for Brain Integration Research (CBIR), Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
- Kanagawa Institute of Industrial Science and Technology (KISTEC), 3-2-1 Sakato, Takatsu-ku, Kawasaki-shi, Kanagawa, 213-0012, Japan
- Research Center for Autonomous Systems Materialogy (AsMAT), Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama-shi, Kanagawa, 226-8501, Japan
| | - Nobuhiro Yanai
- Department of Applied Chemistry, Graduate School of Engineering and Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
- CREST, JST, 4-1-8 Honcho, Kawaguchi-shi, Saitama, 332-0012, Japan
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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13
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Chen WC, Su Y, Wu X, Wang R, Jin JM, Zheng F, Liu XL, Zhang Y, He N, Sun Y, Zeng Q, Huo Y. An Azaryl-Ketone-Based Thermally Activated Delayed Fluorophore with Aggregation-Induced Emission for Efficient Organic Light-Emitting Diodes with Slow Efficiency Roll-Offs. Chem Asian J 2024; 19:e202400741. [PMID: 39058306 DOI: 10.1002/asia.202400741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 07/20/2024] [Accepted: 07/26/2024] [Indexed: 07/28/2024]
Abstract
Achieving the concurrent manifestation of thermally activated delayed fluorescence (TADF) and aggregation-induced emission (AIE) within a single molecular system is highly sought after for organic light-emitting diodes (OLEDs), yet remains rare. In this study, we present a novel TADF-AIE dye, named PQMO-PXZ, which has been designed, synthesized, and systematically characterized. Our comprehensive investigation, which includes structural analysis, theoretical calculations, and optical studies, evaluates the potential of PQMO-PXZ for integration into OLEDs. Unlike existing azaryl-ketone-based emitters, PQMO-PXZ exhibits red-shifted emission and enhanced luminescence efficiency, due to its rigid structure and strong intramolecular charge transfer characteristics. Significantly, PQMO-PXZ demonstrates pronounced AIE properties and TADF with a short delayed lifetime. When utilized as the emissive core, OLED devices based on PQMO-PXZ achieve a respectable external quantum efficiency of up to 11.8 % with minimal efficiency roll-off, underscoring PQMO-PXZ's promise as a highly efficient candidate for OLED applications.
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Affiliation(s)
- Wen-Cheng Chen
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang, 515200, People's Republic of China
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China
| | - Yaozu Su
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang, 515200, People's Republic of China
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China
| | - Xiaohui Wu
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang, 515200, People's Republic of China
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China
| | - Ruicheng Wang
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang, 515200, People's Republic of China
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China
| | - Jia-Ming Jin
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang, 515200, People's Republic of China
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China
| | - Fan Zheng
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang, 515200, People's Republic of China
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China
| | - Xiao-Long Liu
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang, 515200, People's Republic of China
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China
| | - Yuzhen Zhang
- School of Chemistry and Chemical Engineering, Guangxi Minzu University, Nanning, People's Republic of China
| | - Nian He
- Guangdong Shuo Cheng Technology Co. Ltd., Shaoguan, 512600, People's Republic of China
| | - Yuxi Sun
- Guangdong Shuo Cheng Technology Co. Ltd., Shaoguan, 512600, People's Republic of China
| | - Qingming Zeng
- Guangdong Shuo Cheng Technology Co. Ltd., Shaoguan, 512600, People's Republic of China
| | - Yanping Huo
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang, 515200, People's Republic of China
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China
- Analytical & Testing Center, Guangdong University of Technology, Guangzhou, 510006, People's Republic of China
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14
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Qu YK, Zhou DY, Zheng Q, Zuo P, Che ZL, Liao LS, Jiang ZQ. Linearly Arranged Multi-π-Stacked Structure for Efficient Through-Space Charge-Transfer Emitters. Angew Chem Int Ed Engl 2024; 63:e202408712. [PMID: 38962896 DOI: 10.1002/anie.202408712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 06/24/2024] [Accepted: 07/02/2024] [Indexed: 07/05/2024]
Abstract
Noncovalent spatial interaction has become an intriguing and important tool for constructing optoelectronic molecules. In this study, we linearly attached three conjugated units in a multi π-stacked manner by using just one trident bridge based on indeno[2,1-b]fluorene. To achieve this structure, we improved the synthetic approach through double C-H activation, significantly simplifying the preparation process. Due to the proximity of the C10, C11, and C12 sites in indeno[2,1-b]fluorene, we derived two novel donor|acceptor|donor (D|A|D) type molecules, 2DMB and 2DMFB, which exhibited closely packed intramolecular stacking, enabling efficient through-space charge transfer. This molecular construction is particularly suitable for developing high-performance thermally activated delayed fluorescence materials. With donor(s) and acceptor(s) constrained and separated within this spatially rigid structure, elevated radiative transition rates, and high photoluminescence quantum yields were achieved. Organic light-emitting diodes incorporating 2DMB and 2DMFB demonstrated superior efficiency, achieving maximum external quantum efficiencies of 28.6 % and 16.2 %, respectively.
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Affiliation(s)
- Yang-Kun Qu
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
| | - Dong-Ying Zhou
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
| | - Qi Zheng
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
| | - Peng Zuo
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
| | - Zong-Lu Che
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
| | - Liang-Sheng Liao
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
- Macao Institute of Materials Science and Engineering, Macau University of Science and Technology, Taipa, 999078, Macau SAR, China
| | - Zuo-Quan Jiang
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou, 215123, Jiangsu, PR China
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15
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Li P, Lai SL, Chen Z, Tang WK, Leung MY, Ng M, Kwok WK, Chan MY, Yam VWW. Achieving efficient and stable blue thermally activated delayed fluorescence organic light-emitting diodes based on four-coordinate fluoroboron emitters by simple substitution molecular engineering. Chem Sci 2024; 15:12606-12615. [PMID: 39118634 PMCID: PMC11304800 DOI: 10.1039/d3sc06989c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 06/18/2024] [Indexed: 08/10/2024] Open
Abstract
Achieving both high efficiency and high stability in blue thermally activated delayed fluorescence organic light-emitting diodes (TADF-OLEDs) is challenging for practical displays and lighting. Here, we have successfully developed a series of sky-blue to pure-blue emitting donor-acceptor (D-A) type TADF materials featuring a four-coordinated boron with 2,2'-(pyridine-2,6-diyl)diphenolate (dppy) ligands, i.e.1-8. Synergistic engineering of substituents on the phenyl bridge as well as the electronic properties and the attached positions of heteroatom N-donors not only enables fine-tuning of the emission colors, but also modulates the nature and energies of their triplet excited states that are important for the reverse intersystem crossing (RISC). Particularly for the compound with two methyl substituents on the phenyl bridge (compound 8), RISC is significantly facilitated through the vibronic coupling of the energetically close-lying triplet charge transfer (3CT) and the triplet local excited (3LE) states, when compared to analogue 7. Efficient sky-blue to pure-blue OLEDs with electroluminescence peaks (λ EL) at 460-492 nm have been obtained, in which ca. five-fold higher external quantum efficiencies (EQEs) of 18.9% have been demonstrated by 8 than that by 7. Moreover, ca. thirty times longer device operational half-lifetimes (LT50) of 9113 hours for 8 than that for 7 as well as satisfactory LT50 reaching 26 643 hours for 6 at an initial luminance of 100 cd m-2 have also been demonstrated. To the best of our knowledge, these results represent one of the best high-performance blue OLEDs based on tetracoordinated boron TADF emitters. Moreover, the design strategy presented here has provided an attractive strategy for enhancing the device performance of blue TADF-OLEDs.
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Affiliation(s)
- Panpan Li
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
- Hong Kong Quantum AI Lab Limited 17 Science Park West Avenue Pak Shek Kok Hong Kong P. R. China
| | - Shiu-Lun Lai
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
| | - Ziyong Chen
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
| | - Wai Kit Tang
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
| | - Ming-Yi Leung
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
- Hong Kong Quantum AI Lab Limited 17 Science Park West Avenue Pak Shek Kok Hong Kong P. R. China
| | - Maggie Ng
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
| | - Wing-Kei Kwok
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
- Hong Kong Quantum AI Lab Limited 17 Science Park West Avenue Pak Shek Kok Hong Kong P. R. China
| | - Mei-Yee Chan
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
- Hong Kong Quantum AI Lab Limited 17 Science Park West Avenue Pak Shek Kok Hong Kong P. R. China
| | - Vivian Wing-Wah Yam
- Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
- Hong Kong Quantum AI Lab Limited 17 Science Park West Avenue Pak Shek Kok Hong Kong P. R. China
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16
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Stuart AN, Bergmann K, Cho I, Kendrick WJ, Hudson ZM, Wong WWH, Lakhwani G. Triplet dynamics reveal loss pathways in multi-resonance thermally activated delayed fluorescence emitters. Chem Sci 2024:d4sc03649b. [PMID: 39144466 PMCID: PMC11318651 DOI: 10.1039/d4sc03649b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Accepted: 07/25/2024] [Indexed: 08/16/2024] Open
Abstract
Multi-resonance thermally activated delayed fluorescence (MR-TADF) materials are of interest for light-emitting applications due to their narrow emission bandwidths and high photoluminescence quantum yields. Whilst there have been numerous examples of multi-resonance molecules exhibiting efficient TADF, the photophysics and mechanism of TADF in multi-resonance emitters have not been investigated to the same extent as the more conventional spatially separated donor-acceptor TADF materials, limiting the development of MR-TADF devices. Here we study the photophysics of a multi-resonance TADF material, OQAO(mes)2, using transient absorption spectroscopy to spectrally resolve the triplet population(s). We identify multiple triplet populations with distinct spectral contributions, and resolve the dynamics between them. Unlike conventional donor-acceptor TADF materials that have previously been studied, we find these triplet states are not formed in equilibrium, instead exhibiting a slow evolution from a high-energy triplet to a low-energy triplet. Delayed fluorescence predominantly reflects the lifetime of the high-energy triplet state, indicating that the formation of the low-energy triplet is a loss pathway for TADF. We also find that greater amounts of the low-energy triplet are formed in a higher dielectric environment, which leads to less delayed fluorescence. These triplet dynamics have significant implications for TADF in devices, as depending on the identity of the triplet formed by electrical excitation, there will either be a significant barrier to TADF, or a competing nonradiative decay pathway.
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Affiliation(s)
- Alexandra N Stuart
- Department of Chemistry, The University of Sydney Camperdown New South Wales 2000 Australia
- Australian Research Council Centre of Excellence in Exciton Science Parkville 3010 Australia
| | - Katrina Bergmann
- Department of Chemistry, The University of British Columbia Vancouver British Columbia V6T 1Z1 Canada
| | - Inseong Cho
- Department of Chemistry, The University of Sydney Camperdown New South Wales 2000 Australia
- Australian Research Council Centre of Excellence in Exciton Science Parkville 3010 Australia
| | - William J Kendrick
- Australian Research Council Centre of Excellence in Exciton Science Parkville 3010 Australia
- School of Chemistry, The University of Melbourne Parkville 3010 VIC Australia
| | - Zachary M Hudson
- Department of Chemistry, The University of British Columbia Vancouver British Columbia V6T 1Z1 Canada
| | - Wallace W H Wong
- Australian Research Council Centre of Excellence in Exciton Science Parkville 3010 Australia
- School of Chemistry, The University of Melbourne Parkville 3010 VIC Australia
| | - Girish Lakhwani
- Department of Chemistry, The University of Sydney Camperdown New South Wales 2000 Australia
- Australian Research Council Centre of Excellence in Exciton Science Parkville 3010 Australia
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17
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Wei J, Yang N, Li F, Cai S, Zhang B, Cai Z. Direct Comparative Studies Revealing the Contribution of TADF Activity of Organic Emitters Towards Efficient Electrochemiluminescence. Chemistry 2024; 30:e202401036. [PMID: 38742490 DOI: 10.1002/chem.202401036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/16/2024]
Abstract
Electrochemiluminescence (ECL) featuring thermally activated delayed fluorescence (TADF) properties has attracted considerable interest, showcasing their potential for 100 % exciton harvesting, which marks a significant advancement in the realm of organic ECL. However, the challenge of elucidating the precise contribution of TADF to the enhanced ECL efficiency arises due to the lack of comparative studies of organic compounds with or without efficient TADF properties. In this study, we present four carbazole-benzonitrile molecules possessing similar chemical structures and comparable exchange energy (ΔEST). Despite their comparable properties, these compounds exhibited varying TADF efficiencies, warranting a closer examination of their underlying structural and electronic characteristics governing the optical properties. Consequently, intense ECL emission was only observed from 4CzBN with a remarkable TADF efficiency, underscoring the substantial difference in the ECL signal among molecules with comparable ΔEST and similar spectral properties but varying TADF activity.
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Affiliation(s)
- Jinliu Wei
- College of Chemistry, Chemical Engineering and Environment, Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, Fujian, 363000, China
| | - Nairong Yang
- College of Chemistry, Chemical Engineering and Environment, Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, Fujian, 363000, China
| | - Feiming Li
- College of Chemistry, Chemical Engineering and Environment, Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, Fujian, 363000, China
| | - Shunyou Cai
- College of Chemistry, Chemical Engineering and Environment, Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, Fujian, 363000, China
| | - Baohua Zhang
- School of Chemistry and Chemical Engineering, Center for Advanced Analytical Science, Guangzhou Key Laboratory of Sensing Materials and Devices, Guangdong Engineering Technology Research Center for Photoelectric Sensing Materials and Devices, Guangzhou University, Guangzhou, Guangdong, 510006, China
| | - Zhixiong Cai
- College of Chemistry, Chemical Engineering and Environment, Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou, Fujian, 363000, China
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18
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Mohammadian-Sabet F, Shayesteh A. Multireference Ab Initio Calculations on Excited Electronic States of Carbazole-Based Organic Compounds for Thermally Activated Delayed Fluorescence. J Phys Chem A 2024; 128:4937-4949. [PMID: 38864150 DOI: 10.1021/acs.jpca.4c00427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
The emerging technology of organic light-emitting diodes takes advantage of the thermally activated delayed fluorescence (TADF) mechanism for improved efficiency. Carbazole-based organic molecules are suitable for TADF emission because of charge transfer excitations between the electron-donor carbazole and an electron-acceptor unit. Computational design of new TADF molecules with the desired properties is challenging because charge-transfer excitations cannot be predicted accurately by time-dependent density functional theory. Four groups of carbazole-based donor-acceptor molecules have been studied using multireference ab initio methods to understand the nature of excited electronic states. The state-averaged complete active space self-consistent field (SA-CASSCF) and the N-electron valence state perturbation theory (NEVPT2) were used to calculate energies and oscillator strengths for multiple excited electronic states. The number of active electrons and orbitals and the number of excited states included in state-averaged CASSCF were selected such that the accuracy of ab initio predictions could be improved systematically. The procedure introduced here for the calculation of multiple excited electronic states of TADF candidates can be used to accelerate the computational search for efficient TADF materials.
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Affiliation(s)
| | - Alireza Shayesteh
- School of Chemistry, College of Science, University of Tehran, Tehran 14176, Iran
- Department of Chemistry, State University of New York at Oswego, Oswego, New York 13126, United States
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19
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Wu Y, Liu X, Liu J, Yang G, Deng Y, Bin Z, You J. Nitrogen Effects Endowed by Doping Electron-Withdrawing Nitrogen Atoms into Polycyclic Aromatic Hydrocarbon Fluorescence Emitters. J Am Chem Soc 2024; 146:15977-15985. [PMID: 38713009 DOI: 10.1021/jacs.4c02872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Unveiling innovative mechanisms to design new highly efficient fluorescent materials and, thereby, fabricate high-performance organic light-emitting diodes (OLEDs) is a concerted endeavor in both academic and industrial circles. Polycyclic aromatic hydrocarbons (PAHs) have been widely used as fluorescent emitters in blue OLEDs, but device performances are far from satisfactory. In response, we propose the concept of "nitrogen effects" endowed by doping electron-withdrawing nitrogen atoms into PAH fluorescence emitters. The presence of the n orbital on the imine nitrogen is conducive to promoting electron coupling, which leads to increased molar absorptivity and an accelerated radiative decay rate of emitters, thereby facilitating the Förster energy transfer (FET) process in the OLEDs. Additionally, electronically withdrawing nitrogen atoms enhances host-guest interactions, thereby positively affecting the FET process and the horizontal orientation factor of the emitting layer. To validate the "nitrogen effects" concept, cobalt-catalyzed multiple C-H annulation has been utilized to incorporate alkynes into the imine-based frameworks, which enables various imine-embedded PAH (IE-PAH) fluorescence emitters. The cyclization demonstrates notable regioselectivity, thereby offering a practical tool to precisely introduce peripheral groups at desired positions with bulky alkyl units positioned adjacent to the nitrogen atoms, which were previously beyond reach through the Friedel-Crafts reaction. Blue OLEDs fabricated with IE-PAHs exhibit outstanding performance with a maximum external quantum efficiency (EQEmax) of 32.7%. This achievement sets a groundbreaking record for conventional blue PAH-based fluorescent emitters, which have an EQEmax of 24.0%.
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Affiliation(s)
- Yimin Wu
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Xiaoyu Liu
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Junjie Liu
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Ge Yang
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Yayin Deng
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Zhengyang Bin
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
| | - Jingsong You
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, People's Republic of China
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20
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Zhao W, Tan K, Guo W, Guo C, Li M, Chen C. Acceptor Copolymerized Axially Chiral Conjugated Polymers with TADF Properties for Efficient Circularly Polarized Electroluminescence. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309031. [PMID: 38553794 PMCID: PMC11186117 DOI: 10.1002/advs.202309031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/29/2023] [Indexed: 06/20/2024]
Abstract
Chiral conjugated polymer has promoted the development of the efficient circularly polarized electroluminescence (CPEL) device, nevertheless, it remains a challenge to develop chiral polymers with high electroluminescence performance. Herein, by the acceptor copolymerization of axially chiral biphenyl emitting skeleton and benzophenone, a pair of axially chiral conjugated polymers namely R-PAC and S-PAC are synthesized. The target polymers exhibit obvious thermally activated delayed fluorescence (TADF) activities with high photoluminescence quantum yields of 81%. Moreover, the chiral polymers display significant circularly polarized luminescence features, with luminescence dissymmetry factor (|glum|) of nearly 3 × 10-3. By using the chiral polymers as emitters, the corresponding circularly polarized organic light-emitting diodes (CP-OLEDs) exhibit efficient CPEL signals with electroluminescence dissymmetry factor |gEL| of 3.4 × 10-3 and high maximum external quantum efficiency (EQEmax) of 17.8%. Notably, considering both EQEmax and |gEL| comprehensively, the device performance of R-PAC and S-PAC is the best among all the reported CP-OLEDs with chiral conjugated polymers as emitters. This work provides a facile approach to constructing chiral conjugated TADF polymers and discloses the potential of axially chiral conjugated luminescent skeletons in architecting high-performance CP-OLEDs.
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Affiliation(s)
- Wen‐Long Zhao
- Beijing National Laboratory for Molecular SciencesCAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China
- School of Chemical SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Ke‐Ke Tan
- Beijing National Laboratory for Molecular SciencesCAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China
- School of Chemical SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Wei‐Chen Guo
- Beijing National Laboratory for Molecular SciencesCAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China
- School of Chemical SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Chen‐Hao Guo
- College of Chemistry and Chemical EngineeringShanxi UniversityTaiyuan030006China
| | - Meng Li
- Beijing National Laboratory for Molecular SciencesCAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China
- School of Chemical SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Chuan‐Feng Chen
- Beijing National Laboratory for Molecular SciencesCAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China
- School of Chemical SciencesUniversity of Chinese Academy of SciencesBeijing100049China
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21
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Jodra A, Marazzi M, Frutos LM, García-Iriepa C. Modulating Efficiency and Color of Thermally Activated Delayed Fluorescence by Rationalizing the Substitution Effect. J Chem Theory Comput 2024; 20:4239-4253. [PMID: 38738688 PMCID: PMC11137832 DOI: 10.1021/acs.jctc.4c00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 04/22/2024] [Accepted: 04/25/2024] [Indexed: 05/14/2024]
Abstract
Thermally activated delayed fluorescence (TADF) constitutes the process by which third-generation organic light-emitting diodes (OLEDs) are being designed and produced. Despite several years of trial-and-error attempts, mainly driven by chemical intuition about how to improve a certain aspect of the process, few studies focused on the in-depth description of its two key properties: efficiency of the T1 → S1 intersystem crossing and further S1 → S0 emission. Here, by means of a newly developed theoretical formalism, we propose a systematic rationalization of the substituent effect in a paradigmatic class of OLED compounds, based on phenothiazine-dibenzothiophene-S,S-dioxide, known as PTZ-DBTO2. Our methodology allows to discern among geometrical and electronic effects induced by the substituent, deeply understanding the relationships existing between charge transfer, spin density, geometrical deformations, and energy modulations between electronic states. By our results, we can finally elucidate, depending on the substituent, the fate of the overall TADF process, quantitatively assessing its efficiency and predicting the color emission. Moreover, the general terms by which this methodology was developed allow its application to any chromophore of interest.
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Affiliation(s)
- Alejandro Jodra
- Departamento
de Química Analítica, Química Física e
Ingeniería Química, Grupo de Reactividad y Estructura
Molecular (RESMOL), Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid 28871, Spain
| | - Marco Marazzi
- Departamento
de Química Analítica, Química Física e
Ingeniería Química, Grupo de Reactividad y Estructura
Molecular (RESMOL), Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid 28871, Spain
- Instituto
de Investigación Química “Andrés M. del
Río” (IQAR), Universidad de
Alcalá, Ctra.
Madrid-Barcelona, Km 33.600, Alcalá
de Henares, Madrid 28871, Spain
| | - Luis Manuel Frutos
- Departamento
de Química Analítica, Química Física e
Ingeniería Química, Grupo de Reactividad y Estructura
Molecular (RESMOL), Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid 28871, Spain
- Instituto
de Investigación Química “Andrés M. del
Río” (IQAR), Universidad de
Alcalá, Ctra.
Madrid-Barcelona, Km 33.600, Alcalá
de Henares, Madrid 28871, Spain
| | - Cristina García-Iriepa
- Departamento
de Química Analítica, Química Física e
Ingeniería Química, Grupo de Reactividad y Estructura
Molecular (RESMOL), Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid 28871, Spain
- Instituto
de Investigación Química “Andrés M. del
Río” (IQAR), Universidad de
Alcalá, Ctra.
Madrid-Barcelona, Km 33.600, Alcalá
de Henares, Madrid 28871, Spain
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22
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Zhang X, Song JX, Chang X, Li K, Chen Y. Thermally Activated Delayed Fluorescent Binuclear Copper(I) Alkynyl Complexes with Cuprophilic Interactions. Chemistry 2024; 30:e202304224. [PMID: 38414117 DOI: 10.1002/chem.202304224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/06/2024] [Accepted: 02/27/2024] [Indexed: 02/29/2024]
Abstract
Copper(I)-based thermally activated delayed fluorescence (TADF) emitters have been conceived to be promising candidates for display and lighting applications because of their multifarious structures and strong photoluminescence. Herein a string of binuclear Cu(I) complexes bearing pronounced cuprophilic interactions have been designed and synthesized. [Cu2(dppb)2(μ2-η1-C≡C-Ph)2] (1 a) and [Cu2(dppb)2(μ2-η1-C≡C-PPXZ)2] (1 b) display photoluminescence quantum yields of up to 67 % in doped films and solid states via TADF and exhibit reversible bicolor luminescence switching upon mechanical stimuli. Computational studies manifest that the metal-to-ligand charge transfer predominant transitions ensure a small energy splitting (ΔEST) between the lowest singlet (S1) and triplet (T1) excited states and cuprophilic interactions promote the spin-orbit coupling (SOC), favoring the reverse intersystem crossing (RISC) process. This study provides a new strategy for the construction of stimuli-responsive metal-based TADF materials.
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Affiliation(s)
- Xi Zhang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & CAS-HKU Joint Laboratory on New Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Jia-Xi Song
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & CAS-HKU Joint Laboratory on New Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Xiaoyong Chang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, P.R. China
| | - Kai Li
- College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P.R. China
| | - Yong Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials & CAS-HKU Joint Laboratory on New Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
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23
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Gao Y, Wang Y, Guo Z, Wan Y, Xue Z, Han Y, Yang W, Ma X. Ultrafast photophysics of an orange-red thermally activated delayed fluorescence emitter: the role of external structural restraint. Chem Sci 2024; 15:6410-6420. [PMID: 38699269 PMCID: PMC11062098 DOI: 10.1039/d4sc00460d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/21/2024] [Indexed: 05/05/2024] Open
Abstract
The application of thermally activated delay fluorescence (TADF) emitters in the orange-red regime usually suffers from the fast non-radiative decay of emissive singlet states (kSNR), leading to low emitting efficiency in corresponding organic light-emitting diode (OLED) devices. Although kSNR has been quantitatively described by energy gap law, how ultrafast molecular motions are associated with the kSNR of TADF emitters remains largely unknown, which limits the development of new strategies for improving the emitting efficiency of corresponding OLED devices. In this work, we employed two commercial TADF emitters (TDBA-Ac and PzTDBA) as a model system and attempted to clarify the relationship between ultrafast excited-state structural relaxation (ES-SR) and kSNR. Spectroscopic and theoretical investigations indicated that S1/S0 ES-SR is directly associated with promoting vibrational modes, which are considerably involved in electronic-vibrational coupling through the Huang-Rhys factor, while kSNR is largely affected by the reorganization energy of the promoting modes. By restraining S1/S0 ES-SR in doping films, the kSNR of TADF emitters can be greatly reduced, resulting in high emitting efficiency. Therefore, by establishing the connection among S1/S0 ES-SR, promoting modes and kSNR of TADF emitters, our work clarified the key role of external structural restraint for achieving high emitting efficiency in TADF-based OLED devices.
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Affiliation(s)
- Yixuan Gao
- Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China
| | - Yaxin Wang
- Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China
| | - Zilong Guo
- Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China
| | - Yan Wan
- College of Chemistry, Beijing Normal University Beijing 100875 P. R. China
| | - Zheng Xue
- Engineering Research Center for Nanomaterials, Henan University Kaifeng 475004 P. R. China
| | - Yandong Han
- Engineering Research Center for Nanomaterials, Henan University Kaifeng 475004 P. R. China
| | - Wensheng Yang
- Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China
- Engineering Research Center for Nanomaterials, Henan University Kaifeng 475004 P. R. China
| | - Xiaonan Ma
- Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China
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24
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Shi Y, Zhang Y, Wang Z, Yuan T, Meng T, Li Y, Li X, Yuan F, Tan Z, Fan L. Onion-like multicolor thermally activated delayed fluorescent carbon quantum dots for efficient electroluminescent light-emitting diodes. Nat Commun 2024; 15:3043. [PMID: 38589394 PMCID: PMC11001924 DOI: 10.1038/s41467-024-47372-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 03/27/2024] [Indexed: 04/10/2024] Open
Abstract
Carbon quantum dots are emerging as promising nanomaterials for next-generation displays. The elaborate structural design is crucial for achieving thermally activated delayed fluorescence, particularly for improving external quantum efficiency of electroluminescent light-emitting diodes. Here, we report the synthesis of onion-like multicolor thermally activated delayed fluorescence carbon quantum dots with quantum yields of 42.3-61.0%. Structural, spectroscopic characterization and computational studies reveal that onion-like structures assembled from monomer carbon quantum dots of different sizes account for the decreased singlet-triplet energy gap, thereby achieving efficient multicolor thermally activated delayed fluorescence. The devices exhibit maximum luminances of 3785-7550 cd m-2 and maximum external quantum efficiency of 6.0-9.9%. Importantly, owing to the weak van der Waals interactions and adequate solution processability, flexible devices with a maximum luminance of 2554 cd m-2 are realized. These findings facilitate the development of high-performance carbon quantum dots-based electroluminescent light-emitting diodes that are promising for practical applications.
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Affiliation(s)
- Yuxin Shi
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China
| | - Yang Zhang
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China.
| | - Zhibin Wang
- College of Physics and Energy, Fujian Normal University, Fuzhou, 350117, China
| | - Ting Yuan
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China
| | - Ting Meng
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China
| | - Yunchao Li
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China
| | - Xiaohong Li
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China
| | - Fanglong Yuan
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China.
| | - Zhan'ao Tan
- Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
| | - Louzhen Fan
- Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China.
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25
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Shi Q, Ding N, Wang Z, Gou X, Peng L, Ma J, Fang Y. Room-Temperature Phosphorescence Materials Featuring Triplet Hybrid Local Charge Transfer Emission. J Phys Chem Lett 2024; 15:2995-3001. [PMID: 38457284 DOI: 10.1021/acs.jpclett.4c00359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
Abstract
Room-temperature phosphorescence materials have found important applications in dissolved oxygen sensing, temperature monitoring, anticounterfeiting, etc., because of their prolonged phosphorescence lifetime. However, the known systems mainly utilize the triplet local excited state emission, which is generally less sensitive to microenvironment perturbation. In this work, we designed a series of 4-phenyl-1,8-naphthalimide (NMI) derivatives containing different numbers of carbazole (Cz) units (denoted as NMI-Cz, NMI-2Cz, and NMI-3Cz). Steady state and time-resolved spectroscopy studies determined that the compounds undergo intramolecular through-space charge transfer in solution, yielding a triplet hybrid local charge transfer state. Room-temperature phosphorescence emission was observed in compound-doped poly(methyl methacrylate) thin films upon ammonia treatment. Interestingly, emission from different films exhibited different persistence times. We believe a film-based, time-resolved luminescent ammonia sensor could be developed by making a device of the emissive films as fabricated.
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Affiliation(s)
- Qiyuan Shi
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Nannan Ding
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Zhaolong Wang
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Xinyu Gou
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Lingya Peng
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Jiani Ma
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
| | - Yu Fang
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, P. R. China
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26
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Kim HS, Lee SH, Yoo S, Adachi C. Understanding of complex spin up-conversion processes in charge-transfer-type organic molecules. Nat Commun 2024; 15:2267. [PMID: 38480706 PMCID: PMC10937997 DOI: 10.1038/s41467-024-46406-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 02/13/2024] [Indexed: 03/17/2024] Open
Abstract
Despite significant progress made over the past decade in thermally activated delayed fluorescence (TADF) molecules as a material paradigm for enhancing the performance of organic light-emitting diodes, the underlying spin-flip mechanism in these charge-transfer (CT)-type molecular systems remains an enigma, even since its initial report in 2012. While the initial and final electronic states involved in spin-flip between the lowest singlet and lowest triplet excited states are well understood, the exact dynamic processes and the role of intermediate high-lying triplet (T) states are still not fully comprehended. In this context, we propose a comprehensive model to describe the spin-flip processes applicable for a typical CT-type molecule, revealing the origin of the high-lying T state in a partial molecular framework in CT-type molecules. This work provides experimental and theoretical insights into the understanding of intersystem crossing for CT-type molecules, facilitating more precise control over spin-flip rates and thus advancing toward developing the next-generation platform for purely organic luminescent candidates.
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Affiliation(s)
- Hyung Suk Kim
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Sang Hoon Lee
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Seunghyup Yoo
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.
- International Institute for Carbon Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.
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27
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Zhang S, Zhou Z, Qu Z. Diradical-Based Strategy in Designing Narrowband Thermally Activated Delayed Fluorescence Molecules with Tunable Emission Wavelengths. J Phys Chem Lett 2024:2723-2731. [PMID: 38437846 DOI: 10.1021/acs.jpclett.4c00146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
In the design of thermally activated delayed fluorescence (TADF) materials, narrow-band emission is of particular importance for the development of organic light-emitting diodes (OLEDs). In this work, we proposed a new strategy for designing TADF molecules utilizing degenerate nonbonding (NB) orbitals of diradical parent molecules, and these designed molecules are termed NB-TADF molecules. Based on this strategy, a series of NB-TADF molecules is finely designed and systematically studied by theoretical calculations. Taking advantage of the nonbonding properties, these NB-TADF molecules exhibit desirable narrowband emissions and high quantum yields. More importantly, the emission bands can be easily tuned from blue to near-infrared by changing the conjugate length of the parent group in the NB-TADF molecules. We hope that this new strategy can open a new door for the design of novel TADF materials.
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Affiliation(s)
- Shaoqin Zhang
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, China
| | - Zhongjun Zhou
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, China
| | - Zexing Qu
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, China
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28
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Chen YS, Lin IH, Huang HY, Liu SW, Hung WY, Wong KT. Exciplex-forming cohost systems with 2,7-dicyanofluorene acceptors for high efficiency red and deep-red OLEDs. Sci Rep 2024; 14:2458. [PMID: 38291066 PMCID: PMC10827723 DOI: 10.1038/s41598-024-52680-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 01/21/2024] [Indexed: 02/01/2024] Open
Abstract
Two 2,7-dicyaonfluorene-based molecules 27-DCN and 27-tDCN are utilized as acceptors (A) to combine with hexaphenylbenzene-centered donors (D) TATT and DDT-HPB for probing the exciplex formation. The photophysical characteristics reveal that the steric hindered 27-tDCN not only can increase the distance of D and A, resulting in a hypsochromic emission, but also dilute the concentration of triplet excitons to suppress non-radiative process. The 27-tDCN-based exciplex-forming blends exhibit better photoluminescence quantum yield (PLQY) as compared to those of 27-DCN-based pairs. In consequence, among these D:A blends, the device employing DDT-HPB:27-tDCN blend as the emissiom layer (EML) exhibits the best EQE of 3.0% with electroluminescence (EL) λmax of 542 nm. To further utilize the exciton electrically generated in exciplex-forming system, two D-A-D-configurated fluorescence emitter DTPNT and DTPNBT are doped into the DDT-HPB:27-tDCN blend. The nice spectral overlap ensures fast and efficient Förster energy transfer (FRET) process between the exciplex-forming host and the fluorescent quests. The red device adopting DDT-HPB:27-tDCN:10 wt% DTPNT as the EML gives EL λmax of 660 nm and maximum external quantum efficiency (EQEmax) of 5.8%, while EL λmax of 685 nm and EQE of 5.0% for the EML of DDT-HPB:27-tDCN:10 wt% DTPNBT. This work manifests a potential strategy to achieve high efficiency red and deep red OLED devices by incorporating the highly fluorescent emitters to extract the excitons generated by the exciplex-forming blend with bulky acceptor for suppressing non-radiative process.
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Affiliation(s)
- Yi-Sheng Chen
- Organic Electronic Research Center, Ming Chi University of Technology, New Taipei City, 24031, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - I-Hung Lin
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan
| | - Hsin-Yuan Huang
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan
| | - Shun-Wei Liu
- Organic Electronic Research Center, Ming Chi University of Technology, New Taipei City, 24031, Taiwan
| | - Wen-Yi Hung
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan.
| | - Ken-Tsung Wong
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan.
- Institute of Atomic and Molecular Science Academia Sinica, Taipei, 10617, Taiwan.
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29
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Busch J, Rehak FR, Ferraro V, Nieger M, Kemell M, Fuhr O, Klopper W, Bräse S. From Mono- to Polynuclear 2-(Diphenylphosphino)pyridine-Based Cu(I) and Ag(I) Complexes: Synthesis, Structural Characterization, and DFT Calculations. ACS OMEGA 2024; 9:2220-2233. [PMID: 38250424 PMCID: PMC10795044 DOI: 10.1021/acsomega.3c05755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 10/21/2023] [Accepted: 10/25/2023] [Indexed: 01/23/2024]
Abstract
A series of monometallic Ag(I) and Cu(I) halide complexes bearing 2-(diphenylphosphino)pyridine (PyrPhos, L) as a ligand were synthesized and spectroscopically characterized. The structure of most of the derivatives was unambiguously established by X-ray diffraction analysis, revealing the formation of mono-, di-, and tetranuclear complexes having general formulas MXL3 (M = Cu, X = Cl, Br; M = Ag, X = Cl, Br, I), Ag2X2L3 (X = Cl, Br), and Ag4X4L4 (X = Cl, Br, I). The Ag(I) species were compared to the corresponding Cu(I) analogues from a structural point of view. The formation of Cu(I)/Ag(I) heterobimetallic complexes MM'X2L3 (M/M' = Cu, Ag; X = Cl, Br, I) was also investigated. The X-ray structure of the bromo-derivatives revealed the formation of two possible MM'Br2L3 complexes with Cu/Ag ratios, respectively, of 7:1 and 1:7. The ratio between Cu and Ag was studied by scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDX) measurements. The structure of the binuclear homo- and heterometallic derivatives was investigated using density functional theory (DFT) calculations, revealing the tendency of the PyrPhos ligands not to maintain the bridging motif in the presence of Ag(I) as the metal center.
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Affiliation(s)
- Jasmin
M. Busch
- Institute
of Organic Chemistry (IOC), Karlsruhe Institute
of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Florian R. Rehak
- Institute
of Physical Chemistry (IPC), Karlsruhe Institute
of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Valentina Ferraro
- Institute
of Organic Chemistry (IOC), Karlsruhe Institute
of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Martin Nieger
- Department
of Chemistry, University of Helsinki, A.I. Virtasen Aukio 1, P.O. Box 55, FI 00014 Helsinki, Finland
| | - Marianna Kemell
- Department
of Chemistry, University of Helsinki, A.I. Virtasen Aukio 1, P.O. Box 55, FI 00014 Helsinki, Finland
| | - Olaf Fuhr
- Institute
of Nanotechnology (INT), Karlsruhe Institute
of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany
- Karlsruhe
Nano-Micro Facility (KNMFi), Karlsruhe Institute
of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Wim Klopper
- Institute
of Physical Chemistry (IPC), Karlsruhe Institute
of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany
- Institute
of Nanotechnology (INT), Karlsruhe Institute
of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Stefan Bräse
- Institute
of Organic Chemistry (IOC), Karlsruhe Institute
of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany
- Institute
of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, 76131 Karlsruhe, Germany
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30
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Zheng R, Cheng M, Ma R, Schipper D, Pichugin K, Sciaini G. Solvent effects on the intramolecular charge transfer excited state of 3CzClIPN: a broadband transient absorption study. Phys Chem Chem Phys 2024; 26:1039-1045. [PMID: 38093689 DOI: 10.1039/d3cp04975b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
The prediction of solvent properties using molecular probes often relies on correlating steady-state absorption and fluorescence measurements, as well as determining absorption maxima and/or Stokes shifts. In this study, we employ femtosecond broadband transient absorption (fs-bb-TA) spectroscopy to investigate the spectroscopic behaviour of the intramolecular charge transfer (ICT) excited state of 3CzClIPN (2,4,6-tri(9H-carbazol-9-yl)-5-chloroisophthalonitrile), a representative ICT organic molecule, in both aromatic and non-aromatic solvents. Unlike observations in non-aromatic media, fs-bb-TA spectra of 3CzClIPN in aromatic solvents exhibit enhanced spectral broadening that strongly correlates with the solvent's polarity. We hypothesise that this spectral broadening originates from a wider configurational energy landscape experienced by the positively charged carbazole Cz+ group, owing to the larger size and, consequently, reduced solvation effectiveness of aromatic solvent molecules.
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Affiliation(s)
- Ruofei Zheng
- The Ultrafast Electron Imaging Laboratory, University of Waterloo, Waterloo, Canada.
- Department of Chemistry, University of Waterloo, Waterloo, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Canada
| | - Meixin Cheng
- Department of Chemistry, University of Waterloo, Waterloo, Canada
| | - Ruishu Ma
- The Ultrafast Electron Imaging Laboratory, University of Waterloo, Waterloo, Canada.
- Department of Chemistry, University of Waterloo, Waterloo, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Canada
| | - Derek Schipper
- Department of Chemistry, University of Waterloo, Waterloo, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Canada
| | - Kostyantyn Pichugin
- The Ultrafast Electron Imaging Laboratory, University of Waterloo, Waterloo, Canada.
- Department of Chemistry, University of Waterloo, Waterloo, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Canada
| | - Germán Sciaini
- The Ultrafast Electron Imaging Laboratory, University of Waterloo, Waterloo, Canada.
- Department of Chemistry, University of Waterloo, Waterloo, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Canada
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31
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Whitaker W, Sazanovich IV, Kwon Y, Jeon W, Kwon MS, Orr-Ewing AJ. Characterization of the Reversible Intersystem Crossing Dynamics of Organic Photocatalysts Using Transient Absorption Spectroscopy and Time-Resolved Fluorescence Spectroscopy. J Phys Chem A 2023; 127:10775-10788. [PMID: 38096377 PMCID: PMC10758116 DOI: 10.1021/acs.jpca.3c04780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 12/01/2023] [Accepted: 12/01/2023] [Indexed: 12/29/2023]
Abstract
Thermally activated delayed fluorescence (TADF) emitters are molecules of interest as homogeneous organic photocatalysts (OPCs) for photoredox chemistry. Here, three classes of OPC candidates are studied in dichloromethane (DCM) or N,N-dimethylformamide (DMF) solutions, using transient absorption spectroscopy and time-resolved fluorescence spectroscopy. These OPCs are benzophenones with either carbazole (2Cz-BP and 2tCz-BP) or phenoxazine/phenothiazine (2PXZ-BP and 2PTZ-BP) appended groups and the dicyanobenzene derivative 4DP-IPN. Dual lifetimes of the S1 state populations are observed, consistent with reverse intersystem crossing (RISC) and TADF emission. Example fluorescence lifetimes in DCM are (5.18 ± 0.01) ns and (6.22 ± 1.27) μs for 2Cz-BP, (1.38 ± 0.01) ns and (0.32 ± 0.01) μs for 2PXZ-BP, and (2.97 ± 0.01) ns and (62.0 ± 5.8) μs for 4DP-IPN. From ground state bleach recoveries and time-correlated single photon counting measurements, triplet quantum yields in DCM are estimated to be 0.62 ± 0.16, 0.04 ± 0.01, and 0.83 ± 0.02 for 2Cz-BP, 2PXZ-BP, and 4DP-IPN, respectively. 4DP-IPN displays similar photophysical behavior to the previously studied OPC 4Cz-IPN. Independent of the choice of solvent, 4DP-IPN, 2Cz-BP, and 2tCz-BP are shown to be TADF emitters, whereas emission by 2PXZ-BP and 2PTZ-BP depends on the molecular environment, with TADF emission enhanced in aggregates compared to monomers. Behavior of this type is representative of aggregation-induced emission luminogens (AIEgens).
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Affiliation(s)
- William Whitaker
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Igor V. Sazanovich
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, U.K.
| | - Yonghwan Kwon
- Department
of Materials Science and Engineering, Seoul
National University, Seoul 08826, Republic
of Korea
| | - Woojin Jeon
- Department
of Materials Science and Engineering, Seoul
National University, Seoul 08826, Republic
of Korea
| | - Min Sang Kwon
- Department
of Materials Science and Engineering, Seoul
National University, Seoul 08826, Republic
of Korea
| | - Andrew J. Orr-Ewing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
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32
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Drwal D, Matousek M, Golub P, Tucholska A, Hapka M, Brabec J, Veis L, Pernal K. Role of Spin Polarization and Dynamic Correlation in Singlet-Triplet Gap Inversion of Heptazine Derivatives. J Chem Theory Comput 2023; 19:7606-7616. [PMID: 37864544 PMCID: PMC10653106 DOI: 10.1021/acs.jctc.3c00781] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Indexed: 10/23/2023]
Abstract
The new generation of proposed light-emitting molecules for organic light-emitting diodes (OLEDs) has raised considerable research interest due to its exceptional feature─a negative singlet-triplet (ST) gap violating Hund's multiplicity rule in the excited S1 and T1 states. We investigate the role of spin polarization in the mechanism of ST gap inversion. Spin polarization is associated with doubly excited determinants of certain types, whose presence in the wave function expansion favors the energy of the singlet state more than that of the triplet. Using a perturbation theory-based model for spin polarization, we propose a simple descriptor for prescreening of candidate molecules with negative ST gaps and prove its usefulness for heptazine-type molecules. Numerical results show that the quantitative effect of spin polarization decreases linearly with the increasing highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) exchange integral. Comparison of single- and multireference coupled-cluster predictions of ST gaps shows that the former methods provide good accuracy by correctly balancing the effects of doubly excited determinants and dynamic correlation. We also show that accurate ST gaps may be obtained using a complete active space model supplemented with dynamic correlation from multireference adiabatic connection theory.
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Affiliation(s)
- Daria Drwal
- Institute
of Physics, Lodz University of Technology, ul. Wolczanska 219, 90-924 Lodz, Poland
| | - Mikulas Matousek
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences
of the Czech Republic, v.v.i., Dolejškova 3, 18223 Prague 8, Czech Republic
- Faculty
of Mathematics and Physics, Charles University, 12116 Prague, Czech Republic
| | - Pavlo Golub
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences
of the Czech Republic, v.v.i., Dolejškova 3, 18223 Prague 8, Czech Republic
| | - Aleksandra Tucholska
- Institute
of Physics, Lodz University of Technology, ul. Wolczanska 219, 90-924 Lodz, Poland
| | - Michał Hapka
- Faculty
of Chemistry, University of Warsaw, ul. L. Pasteura 1, 02-093 Warsaw, Poland
| | - Jiri Brabec
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences
of the Czech Republic, v.v.i., Dolejškova 3, 18223 Prague 8, Czech Republic
| | - Libor Veis
- J.
Heyrovský Institute of Physical Chemistry, Academy of Sciences
of the Czech Republic, v.v.i., Dolejškova 3, 18223 Prague 8, Czech Republic
| | - Katarzyna Pernal
- Institute
of Physics, Lodz University of Technology, ul. Wolczanska 219, 90-924 Lodz, Poland
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33
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Kant C, Shukla A, McGregor SKM, Lo SC, Namdas EB, Katiyar M. Large area inkjet-printed OLED fabrication with solution-processed TADF ink. Nat Commun 2023; 14:7220. [PMID: 37940640 PMCID: PMC10632475 DOI: 10.1038/s41467-023-43014-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 10/28/2023] [Indexed: 11/10/2023] Open
Abstract
This work demonstrates successful large area inkjet printing of a thermally activated delayed fluorescence (TADF) material as the emitting layer of organic light-emitting diodes (OLEDs). TADF materials enable efficient light emission without relying on heavy metals such as platinum or iridium. However, low-cost manufacturing of large-scale TADF OLEDs has been restricted due to their incompatibility with solution processing techniques. In this study, we develop ink formulation for a TADF material and show successful ink jet printing of intricate patterns over a large area (6400 mm2) without the use of any lithography. The stable ink is successfully achieved using a non-chlorinated binary solvent mixture for a solution processable TADF material, 3-(9,9-dimethylacridin-10(9H)-yl)-9H-xanthen-9-one dispersed in 4,4'-bis-(N-carbazolyl)-1,1'-biphenyl host. Using this ink, large area ink jet printed OLEDs with performance comparable to the control spin coated OLEDs are successfully achieved. In this work, we also show the impact of ink viscosity, density, and surface tension on the droplet formation and film quality as well as its potential for large-area roll-to-roll printing on a flexible substrate. The results represent a major step towards the use of TADF materials for large-area OLEDs without employing any lithography.
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Affiliation(s)
- Chandra Kant
- Materials Science and Engineering Department, Indian Institute of Technology Kanpur, Kanpur, India
- National Centre for Flexible Electronics, Indian Institute of Technology Kanpur, Kanpur, India
| | - Atul Shukla
- Centre for Organic Photonics & Electronics, The University of Queensland, Brisbane, Australia
- School of Mathematics and Physics, The University of Queensland, Brisbane, Australia
| | - Sarah K M McGregor
- Centre for Organic Photonics & Electronics, The University of Queensland, Brisbane, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Shih-Chun Lo
- Centre for Organic Photonics & Electronics, The University of Queensland, Brisbane, Australia.
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia.
| | - Ebinazar B Namdas
- Centre for Organic Photonics & Electronics, The University of Queensland, Brisbane, Australia.
- School of Mathematics and Physics, The University of Queensland, Brisbane, Australia.
| | - Monica Katiyar
- Materials Science and Engineering Department, Indian Institute of Technology Kanpur, Kanpur, India.
- National Centre for Flexible Electronics, Indian Institute of Technology Kanpur, Kanpur, India.
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34
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Liu J, Perez OM, Lavergne D, Rasu L, Murphy E, Galvez-Rodriguez A, Bergens SH. One-Step Electropolymerization of a Dicyanobenzene-Carbazole-Imidazole Dye to Prepare Photoactive Redox Polymer Films. Polymers (Basel) 2023; 15:3340. [PMID: 37631397 PMCID: PMC10457835 DOI: 10.3390/polym15163340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/25/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
To the best of our knowledge, this study reports the first direct electropolymerization of a dicyanobenzene-carbazole dye functionalized with an imidazole group to prepare redox- and photoactive porous organic polymer (POP) films in controlled amounts. The POP films were grown on indium-doped tin oxide (ITO) and carbon surfaces using a new monomer, 1-imidazole-2,4,6-tri(carbazol-9-yl)-3,5-dicyanobenzene (1, 3CzImIPN), through a simple one-step process. The structure and activities of the POP films were investigated as photoelectrodes for electrooxidations, as heterogeneous photocatalysts for photosynthetic olefin isomerizations, and for solid-state photoluminescence behavior tunable by lithium-ion concentrations in solution. The results demonstrate that the photoredox-POPs can be used as efficient photocatalysts, and they have potential applications in sensing.
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Affiliation(s)
| | | | | | | | | | | | - Steven H. Bergens
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada
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35
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Ma B, Ding Z, Liu D, Zhou Z, Zhang K, Dang D, Zhang S, Su SJ, Zhu W, Liu Y. A Feasible Strategy for a Highly Efficient Thermally Activated Delayed Fluorescence Emitter Over 900 nm Based on Phenalenone Derivatives. Chemistry 2023; 29:e202301197. [PMID: 37154226 DOI: 10.1002/chem.202301197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/05/2023] [Accepted: 05/08/2023] [Indexed: 05/10/2023]
Abstract
Near-infrared (NIR) organic light-emitting diodes (OLEDs) suffer from the low external electroluminescence (EL) quantum efficiency (EQE), which is a critical obstacle for potential applications. Herein, 1-oxo-1-phenalene-2,3-dicarbonitrile (OPDC) is employed as an electron-withdrawing aromatic ring, and by incorporating with triphenylamine (TPA) and biphenylphenylamine (BBPA) donors, two novel NIR emitters with thermally activated delayed fluorescence (TADF) characteristics, namely OPDC-DTPA and OPDC-DBBPA, are first developed and compared in parallel. Intense NIR emission peaks at 962 and 1003 nm are observed in their pure films, respectively. Contributed by the local excited (LE) characteristics in the triplet (T1 ) state in synergy with the charge transfer (CT) characteristics for the singlet (S1 ) state to activate TADF emission, the solution processable doped NIR OLEDs based on OPDC-DTPA and OPDC-DBBPA yield EL peaks at 834 and 906 nm, accompanied with maximum EQEs of 0.457 and 0.103 %, respectively, representing the state-of-the-art EL performances in the TADF emitter-based NIR-OLEDs in the similar EL emission regions so far. This work manifests a simple and effective strategy for the development of NIR TADF emitters with long wavelength and efficiency synchronously.
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Affiliation(s)
- Bin Ma
- School of Materials Science and Engineering, Jiangsu Engineering Research Center of Light-Electricity-Heat Energy-Converting Materials and Applications, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Key Laboratories of Environment-Friendly Polymers, National Experimental Demonstration Center for Materials Science and Engineering, Changzhou University, Changzhou, 213164, P. R. China
| | - Zhenming Ding
- School of Materials Science and Engineering, Jiangsu Engineering Research Center of Light-Electricity-Heat Energy-Converting Materials and Applications, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Key Laboratories of Environment-Friendly Polymers, National Experimental Demonstration Center for Materials Science and Engineering, Changzhou University, Changzhou, 213164, P. R. China
| | - Denghui Liu
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Zhongxin Zhou
- School of Materials Science and Engineering, Jiangsu Engineering Research Center of Light-Electricity-Heat Energy-Converting Materials and Applications, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Key Laboratories of Environment-Friendly Polymers, National Experimental Demonstration Center for Materials Science and Engineering, Changzhou University, Changzhou, 213164, P. R. China
| | - Kai Zhang
- School of Materials Science and Engineering, Jiangsu Engineering Research Center of Light-Electricity-Heat Energy-Converting Materials and Applications, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Key Laboratories of Environment-Friendly Polymers, National Experimental Demonstration Center for Materials Science and Engineering, Changzhou University, Changzhou, 213164, P. R. China
| | - Dongfeng Dang
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Shiyue Zhang
- School of Materials Science and Engineering, Jiangsu Engineering Research Center of Light-Electricity-Heat Energy-Converting Materials and Applications, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Key Laboratories of Environment-Friendly Polymers, National Experimental Demonstration Center for Materials Science and Engineering, Changzhou University, Changzhou, 213164, P. R. China
| | - Shi-Jian Su
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Weiguo Zhu
- School of Materials Science and Engineering, Jiangsu Engineering Research Center of Light-Electricity-Heat Energy-Converting Materials and Applications, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Key Laboratories of Environment-Friendly Polymers, National Experimental Demonstration Center for Materials Science and Engineering, Changzhou University, Changzhou, 213164, P. R. China
| | - Yu Liu
- School of Materials Science and Engineering, Jiangsu Engineering Research Center of Light-Electricity-Heat Energy-Converting Materials and Applications, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Key Laboratories of Environment-Friendly Polymers, National Experimental Demonstration Center for Materials Science and Engineering, Changzhou University, Changzhou, 213164, P. R. China
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36
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Cao L, Liu X, Zhang X, Zhao J, Yu F, Wan Y. The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads. Beilstein J Org Chem 2023; 19:1028-1046. [PMID: 37497052 PMCID: PMC10366440 DOI: 10.3762/bjoc.19.79] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/07/2023] [Indexed: 07/28/2023] Open
Abstract
A series of 1,8-naphthalimide (NI)-phenothiazine (PTZ) electron donor-acceptor dyads were prepared to study the thermally activated delayed fluorescence (TADF) properties of the dyads, from a point of view of detection of the various transient species. The photophysical properties of the dyads were tuned by changing the electron-donating and the electron-withdrawing capability of the PTZ and NI moieties, respectively, by oxidation of the PTZ unit, or by using different aryl substituents attached to the NI unit. This tuning effect was manifested in the UV-vis absorption and fluorescence emission spectra, e.g., in the change of the charge transfer absorption bands. TADF was observed for the dyads containing the native PTZ unit, and the prompt and delayed fluorescence lifetimes changed with different aryl substituents on the imide part. In polar solvents, no TADF was observed. For the dyads with the PTZ unit oxidized, no TADF was observed as well. Femtosecond transient absorption spectra showed that the charge separation takes ca. 0.6 ps, and admixtures of locally excited (3LE) state and charge separated (1CS/3CS) states formed (in n-hexane). The subsequent charge recombination from the 1CS state takes ca. 7.92 ns. Upon oxidation of the PTZ unit, the beginning of charge separation is at 178 fs and formation of 3LE state takes 4.53 ns. Nanosecond transient absorption (ns-TA) spectra showed that both 3CS and 3LE states were observed for the dyads showing TADF, whereas only 3LE or 3CS states were observed for the systems lacking TADF. This is a rare but unambiguous experimental evidence that the spin-vibronic coupling of 3CS/3LE states is crucial for TADF. Without the mediating effect of the 3LE state, no TADF is resulted, even if the long-lived 3CS state is populated (lifetime τCS ≈ 140 ns). This experimental result confirms the 3CS → 1CS reverse intersystem crossing (rISC) is slow, without coupling with an approximate 3LE state. These studies are useful for an in-depth understanding of the photophysical mechanisms of the TADF emitters, as well as for molecular structure design of new electron donor-acceptor TADF emitters.
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Affiliation(s)
- Liyuan Cao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Road, Dalian, 116024, P. R. China
| | - Xi Liu
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Xue Zhang
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Road, Dalian, 116024, P. R. China
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Road, Dalian, 116024, P. R. China
| | - Fabiao Yu
- Key Laboratory of Hainan Trauma and Disaster Rescue, The First Affiliated Hospital of Hainan Medical University, Hainan Medical University, Haikou 571199, P. R. China
| | - Yan Wan
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
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37
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Yumoto S, Katsumata J, Osawa F, Wada Y, Suzuki K, Kaji H, Marumoto K. Operando ESR observation in thermally activated delayed fluorescent organic light-emitting diodes. Sci Rep 2023; 13:11109. [PMID: 37429886 DOI: 10.1038/s41598-023-38063-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/02/2023] [Indexed: 07/12/2023] Open
Abstract
Organic light-emitting diodes (OLEDs) using thermally activated delayed fluorescence (TADF) materials have advantages over OLEDs using conventional fluorescent materials or high-cost phosphorescent materials, including higher efficiency and lower cost. To attain further high device performance, clarifying internal charge states in OLEDs at a microscopic viewpoint is crucial; however, only a few such studies have been performed. Here, we report a microscopic investigation into internal charge states in OLEDs with a TADF material by electron spin resonance (ESR) at a molecular level. We observed operando ESR signals of the OLEDs and identified their origins due to a hole-transport material PEDOT:PSS, gap states at an electron-injection layer, and a host material CBP in the light-emitting layer by performing density functional theory calculation and studying thin films used in the OLEDs. The ESR intensity varied with increasing applied bias before and after the light emission. We find leakage electrons in the OLED at a molecular level, which is suppressed by a further electron-blocking layer MoO3 between the PEDOT:PSS and light-emitting layer, resulting in the enhancement of luminance with a low-voltage drive. Such microscopic information and applying our method to other OLEDs will further improve the OLED performance from the microscopic viewpoint.
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Affiliation(s)
- Shintaro Yumoto
- Department of Materials Science, Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573, Japan
| | - Junya Katsumata
- Department of Materials Science, Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573, Japan
| | - Fumiya Osawa
- Department of Materials Science, Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573, Japan
| | - Yoshimasa Wada
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Katsuaki Suzuki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Hironori Kaji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Kazuhiro Marumoto
- Department of Materials Science, Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573, Japan.
- Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, Ibaraki, 305-8571, Japan.
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38
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Sneha M, Thornton GL, Lewis-Borrell L, Ryder ASH, Espley SG, Clark IP, Cresswell AJ, Grayson MN, Orr-Ewing AJ. Photoredox-HAT Catalysis for Primary Amine α-C-H Alkylation: Mechanistic Insight with Transient Absorption Spectroscopy. ACS Catal 2023; 13:8004-8013. [PMID: 37342833 PMCID: PMC10278065 DOI: 10.1021/acscatal.3c01474] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/17/2023] [Indexed: 06/23/2023]
Abstract
The synergistic use of (organo)photoredox catalysts with hydrogen-atom transfer (HAT) cocatalysts has emerged as a powerful strategy for innate C(sp3)-H bond functionalization, particularly for C-H bonds α- to nitrogen. Azide ion (N3-) was recently identified as an effective HAT catalyst for the challenging α-C-H alkylation of unprotected, primary alkylamines, in combination with dicyanoarene photocatalysts such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN). Here, time-resolved transient absorption spectroscopy over sub-picosecond to microsecond timescales provides kinetic and mechanistic details of the photoredox catalytic cycle in acetonitrile solution. Direct observation of the electron transfer from N3- to photoexcited 4CzIPN reveals the participation of the S1 excited electronic state of the organic photocatalyst as an electron acceptor, but the N3• radical product of this reaction is not observed. Instead, both time-resolved infrared and UV-visible spectroscopic measurements implicate rapid association of N3• with N3- (a favorable process in acetonitrile) to form the N6•- radical anion. Electronic structure calculations indicate that N3• is the active participant in the HAT reaction, suggesting a role for N6•- as a reservoir that regulates the concentration of N3•.
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Affiliation(s)
- Mahima Sneha
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
- Department
of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Georgia L. Thornton
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Luke Lewis-Borrell
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Alison S. H. Ryder
- Centre
for Sustainable Chemical Technologies, University
of Bath, 1 South, Claverton Down, Bath BA2 7AY, U.K.
| | - Samuel G. Espley
- Department
of Chemistry, University of Bath, 1 South, Claverton Down, Bath BA2 7AY, U.K.
| | - Ian P. Clark
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton
Laboratory, Harwell Oxford, Didcot OX11 0QX, U.K.
| | - Alexander J. Cresswell
- Department
of Chemistry, University of Bath, 1 South, Claverton Down, Bath BA2 7AY, U.K.
| | - Matthew N. Grayson
- Department
of Chemistry, University of Bath, 1 South, Claverton Down, Bath BA2 7AY, U.K.
| | - Andrew J. Orr-Ewing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
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39
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Nguyen HA, Dixon G, Dou FY, Gallagher S, Gibbs S, Ladd DM, Marino E, Ondry JC, Shanahan JP, Vasileiadou ES, Barlow S, Gamelin DR, Ginger DS, Jonas DM, Kanatzidis MG, Marder SR, Morton D, Murray CB, Owen JS, Talapin DV, Toney MF, Cossairt BM. Design Rules for Obtaining Narrow Luminescence from Semiconductors Made in Solution. Chem Rev 2023. [PMID: 37311205 DOI: 10.1021/acs.chemrev.3c00097] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Solution-processed semiconductors are in demand for present and next-generation optoelectronic technologies ranging from displays to quantum light sources because of their scalability and ease of integration into devices with diverse form factors. One of the central requirements for semiconductors used in these applications is a narrow photoluminescence (PL) line width. Narrow emission line widths are needed to ensure both color and single-photon purity, raising the question of what design rules are needed to obtain narrow emission from semiconductors made in solution. In this review, we first examine the requirements for colloidal emitters for a variety of applications including light-emitting diodes, photodetectors, lasers, and quantum information science. Next, we will delve into the sources of spectral broadening, including "homogeneous" broadening from dynamical broadening mechanisms in single-particle spectra, heterogeneous broadening from static structural differences in ensemble spectra, and spectral diffusion. Then, we compare the current state of the art in terms of emission line width for a variety of colloidal materials including II-VI quantum dots (QDs) and nanoplatelets, III-V QDs, alloyed QDs, metal-halide perovskites including nanocrystals and 2D structures, doped nanocrystals, and, finally, as a point of comparison, organic molecules. We end with some conclusions and connections, including an outline of promising paths forward.
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Affiliation(s)
- Hao A Nguyen
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Grant Dixon
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Florence Y Dou
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Shaun Gallagher
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Stephen Gibbs
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Dylan M Ladd
- Department of Materials Science and Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Emanuele Marino
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo, Italy
| | - Justin C Ondry
- Department of Chemistry, James Franck Institute, and Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - James P Shanahan
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Eugenia S Vasileiadou
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Stephen Barlow
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - David S Ginger
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - David M Jonas
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Mercouri G Kanatzidis
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Seth R Marder
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Daniel Morton
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Christopher B Murray
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jonathan S Owen
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Dmitri V Talapin
- Department of Chemistry, James Franck Institute, and Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Michael F Toney
- Department of Materials Science and Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Brandi M Cossairt
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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40
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Gawale Y, Ansari R, Naveen KR, Kwon JH. Forthcoming hyperfluorescence display technology: relevant factors to achieve high-performance stable organic light emitting diodes. Front Chem 2023; 11:1211345. [PMID: 37377883 PMCID: PMC10291061 DOI: 10.3389/fchem.2023.1211345] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023] Open
Abstract
Over the decade, there have been developments in purely organic thermally activated delayed fluorescent (TADF) materials for organic light-emitting diodes (OLEDs). However, achieving narrow full width at half maximum (FWHM) and high external quantum efficiency (EQE) is crucial for real display industries. To overcome these hurdles, hyperfluorescence (HF) technology was proposed for next-generation OLEDs. In this technology, the TADF material was considered a sensitizing host, the so-called TADF sensitized host (TSH), for use of triplet excitons via the reverse intersystem crossing (RISC) pathway. Since most of the TADF materials show bipolar characteristics, electrically generated singlet and triplet exciton energies can be transported to the final fluorescent emitter (FE) through Förster resonance energy transfer (FRET) rather than Dexter energy transfer (DET). This mechanism is possible from the S1 state of the TSH to the S1 state of the final fluorescent dopant (FD) as a long-range energy transfer. Considering this, some reports are available based on hyperfluorescence OLEDs, but the detailed analysis for highly efficient and stable devices for commercialization was unclear. So herein, we reviewed the relevant factors based on recent advancements to build a highly efficient and stable hyperfluorescence system. The factors include an energy transfer mechanism based on spectral overlapping, TSH requirements, electroluminescence study based on exciplex and polarity system, shielding effect, DET suppression, and FD orientation. Furthermore, the outlook and future positives with new directions were discussed to build high-performance OLEDs.
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Affiliation(s)
| | | | | | - Jang Hyuk Kwon
- *Correspondence: Kenkera Rayappa Naveen, ; Jang Hyuk Kwon,
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41
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Matsubara R, Kuang H, Yabuta T, Xie W, Hayashi M, Sakuda E. Photophysical and electrochemical properties of 9-naphthyl-3,6-diaminocarbazole derivatives and their application as photosensitizers. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2023. [DOI: 10.1016/j.jpap.2023.100176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
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42
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Zhang D, Jiang S, Tao X, Lin F, Meng L, Chen XL, Lu CZ. Efficient Spin-Flip between Charge-Transfer States for High-Performance Electroluminescence, without an Intermediate Locally Excited State. RESEARCH (WASHINGTON, D.C.) 2023; 6:0155. [PMID: 37250955 PMCID: PMC10214979 DOI: 10.34133/research.0155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/04/2023] [Indexed: 05/31/2023]
Abstract
Thermally activated delayed fluorescence (TADF) materials with both high photoluminescence quantum yield (PLQY) and fast reverse intersystem crossing (RISC) are strongly desired to realize efficient and stable organic light-emitting diodes (OLEDs). Control of excited-state dynamics via molecular design plays a central role in optimizing the PLQY and RISC rate of TADF materials but remains challenging. Here, 3 TADF emitters possessing similar molecular structures, similar high PLQYs (89.5% to 96.3%), and approximate energy levels of the lowest excited singlet states (S1), but significantly different spin-flipping RISC rates (0.03 × 106 s-1 vs. 2.26 × 106 s-1) and exciton lifetime (297.1 to 332.8 μs vs. 6.0 μs) were systematically synthesized to deeply investigate the feasibility of spin-flip between charge-transfer excited states (3CT-1CT) transition. Experimental and theoretical studies reveal that the small singlet-triplet energy gap together with low RISC reorganization energy between the 3CT and 1CT states could provide an efficient RISC through fast spin-flip 3CT-1CT transition, without the participation of an intermediate locally excited state, which has previously been recognized as being necessary for realizing fast RISC. Finally, the OLED based on the champion TADF emitter achieves a maximum external quantum efficiency of 27.1%, a tiny efficiency roll-off of 4.1% at 1,000 cd/m2, and a high luminance of 28,150 cd/m2, which are markedly superior to those of the OLEDs employing the other 2 TADF emitters.
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Affiliation(s)
- Donghai Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter,
Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, Fujian 350108, China
- Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institutes,
Chinese Academy of Sciences, Xiamen, Fujian 361021, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shanshan Jiang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter,
Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institutes,
Chinese Academy of Sciences, Xiamen, Fujian 361021, China
| | - Xiaodong Tao
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter,
Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, Fujian 350108, China
- Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institutes,
Chinese Academy of Sciences, Xiamen, Fujian 361021, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fulin Lin
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter,
Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institutes,
Chinese Academy of Sciences, Xiamen, Fujian 361021, China
| | - Lingyi Meng
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter,
Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institutes,
Chinese Academy of Sciences, Xiamen, Fujian 361021, China
| | - Xu-Lin Chen
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter,
Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, Fujian 350108, China
- Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institutes,
Chinese Academy of Sciences, Xiamen, Fujian 361021, China
| | - Can-Zhong Lu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter,
Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, Fujian 350108, China
- Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials, Xiamen Institute of Rare Earth Materials, Haixi Institutes,
Chinese Academy of Sciences, Xiamen, Fujian 361021, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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43
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Madushani B, Mamada M, Goushi K, Nguyen TB, Nakanotani H, Kaji H, Adachi C. Multiple donor-acceptor design for highly luminescent and stable thermally activated delayed fluorescence emitters. Sci Rep 2023; 13:7644. [PMID: 37169821 PMCID: PMC10175249 DOI: 10.1038/s41598-023-34623-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 05/04/2023] [Indexed: 05/13/2023] Open
Abstract
A considerable variety of donor-acceptor (D-A) combinations offers the potential for realizing highly efficient thermally activated delayed fluorescence (TADF) materials. Multiple D-A type compounds are one of the promising families of TADF materials in terms of stability as well as efficiencies. However, those emitters are always composed of carbazole-based donors despite a wide choice of moieties used in linearly linked single D-A molecules. Herein, we developed a multiple D-A type TADF compound with two distinct donor units of 9,10-dihydro-9,9-dimethylacridine (DMAC) and carbazole as the hetero-donor design. The new emitter exhibits high photoluminescence quantum yield (PLQY) in various conditions including polar media blend and high concentrations. Organic light-emitting diodes (OLEDs) showed a reasonably high external quantum efficiency (EQE). In addition, we revealed that the multiple-D-A type molecules showed better photostability than the single D-A type molecules, while the operational stability in OLEDs involves dominant other factors.
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Affiliation(s)
- Bhagya Madushani
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Masashi Mamada
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan.
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
| | - Kenichi Goushi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Thanh Ba Nguyen
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Hajime Nakanotani
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Hironori Kaji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan.
- International Institute for Carbon Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.
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44
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Qiu W, Liu D, Li M, Cai X, Chen Z, He Y, Liang B, Peng X, Qiao Z, Chen J, Li W, Pu J, Xie W, Wang Z, Li D, Gan Y, Jiao Y, Gu Q, Su SJ. Confining donor conformation distributions for efficient thermally activated delayed fluorescence with fast spin-flipping. Nat Commun 2023; 14:2564. [PMID: 37142564 PMCID: PMC10160101 DOI: 10.1038/s41467-023-38197-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Accepted: 04/19/2023] [Indexed: 05/06/2023] Open
Abstract
Fast spin-flipping is the key to exploit the triplet excitons in thermally activated delayed fluorescence based organic light-emitting diodes toward high efficiency, low efficiency roll-off and long operating lifetime. In common donor-acceptor type thermally activated delayed fluorescence molecules, the distribution of dihedral angles in the film state would have significant influence on the photo-physical properties, which are usually neglected by researches. Herein, we find that the excited state lifetimes of thermally activated delayed fluorescence emitters are subjected to conformation distributions in the host-guest system. Acridine-type flexible donors have a broad conformation distribution or bimodal distribution, in which some conformers feature large singlet-triplet energy gap, leading to long excited state lifetime. Utilization of rigid donors with steric hindrance can restrict the conformation distributions in the film to achieve degenerate singlet and triplet states, which is beneficial to efficient reverse intersystem crossing. Based on this principle, three prototype thermally activated delayed fluorescence emitters with confined conformation distributions are developed, achieving high reverse intersystem crossing rate constants greater than 106 s-1, which enable highly efficient solution-processed organic light-emitting diodes with suppressed efficiency roll-off.
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Affiliation(s)
- Weidong Qiu
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Denghui Liu
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Mengke Li
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China.
| | - Xinyi Cai
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Zijian Chen
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Yanmei He
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | | | - Xiaomei Peng
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Zhenyang Qiao
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Jiting Chen
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Wei Li
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Junrong Pu
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Wentao Xie
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Zhiheng Wang
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
- Ji Hua Laboratory, Foshan, 528200, P. R. China
| | - Deli Li
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Yiyang Gan
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Yihang Jiao
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Qing Gu
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Shi-Jian Su
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China.
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45
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Qian X, Chu F, Zhou W, Zheng Z, Chen X, Zhao Y. Design of Intramolecular Dihedral Angle between Electronic Donor and Acceptor in Thermally Activated Delayed Fluorescence Molecules. J Phys Chem Lett 2023; 14:3335-3342. [PMID: 36994861 DOI: 10.1021/acs.jpclett.3c00515] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
In order to improve the exciton utilization efficiency (ηexc) of organic light-emitting materials, we addressed the ideal donor-acceptor dihedral angle (θD-A) in the TADF molecule by striking a balance between two photophysical processes. One is the conversion of triplet excitons into singlet excitons, and the other is the radiative process from a low-lying excited state to the ground state. Using a combination of first-principles calculations and molecular dynamics simulations, we investigated the impact of θD-A on the splitting energy and spin-orbit coupling between singlet and triplet excitons as well as the transition dipole moment for carbazole benzonitrile (CzBN) derivatives. By comparison with the reverse intersystem crossing rate (krISC), fluorescence emission rate (kr), and ηexc, we proposed a potential highest ηexc (of 94.4%) with the ideal θD-A of 77° for blue light CzBN derivatives; the calculated results have a good agreement with experimental measurement. The structure-efficiency physical connection between the molecular structure (θD-A) and efficiency provided an ideal parameter for a potential candidate for blue TADF-OLED materials.
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Affiliation(s)
- Xin Qian
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, P. R. China
| | - Feihong Chu
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, P. R. China
| | - Wencai Zhou
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, P. R. China
| | - Zilong Zheng
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, P. R. China
| | - Xiaoqing Chen
- Faculty of Materials and Manufacturing, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, P. R. China
| | - Yi Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Fujian Provincial Key Lab of Theoretical and Computational Chemistry, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
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46
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Naveen KR, Palanisamy P, Chae MY, Kwon JH. Multiresonant TADF materials: triggering the reverse intersystem crossing to alleviate the efficiency roll-off in OLEDs. Chem Commun (Camb) 2023; 59:3685-3702. [PMID: 36857643 DOI: 10.1039/d2cc06802h] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The hunt for narrow-band emissive pure organic molecules capable of harvesting both singlet and triplet excitons for light emission has garnered enormous attention to promote the advancement of organic light-emitting diodes (OLEDs). Over the past decade, organic thermally activated delayed fluorescence (TADF) materials based on donor (D)/acceptor (A) combinations have been researched for OLEDs in wide color gamut (RGB) regions. However, due to the strong intramolecular charge-transfer (CT) state, they exhibit broad emission with full-width-at-half maximum (FWHM) > 70 nm, which deviates from being detrimental to achieving high color purity for future high-end display electronics such as high-definition TVs and ultra-high-definition TVs (UHDTVs). Recently, the new development in the sub-class of TADF emitters called multi-resonant TADF (MR-TADF) emitters based on boron/nitrogen atoms has attracted much interest in ultra-high definition OLEDs. Consequently, MR-TADF emitters are appeal to their potentiality as promising candidates in fabricating the high-efficient OLEDs due to their numerous advantages such as high photoluminescence quantum yield (PLQY), unprecedented color purity, and narrow bandwidth (FWHM ≤ 40 nm). Until now many MR-TADF materials have been developed for ultra-gamut regions with different design concepts. However, most MR-TADF-OLEDs showed ruthless external quantum efficiency (EQE) roll-off characteristics at high brightness. Such EQE roll-off characteristics were derived mainly from the low reverse intersystem crossing (kRISC) rate values. This feature article primarily focuses on the design strategies to improve kRISC for MR-TADF materials with some supportive strategies including extending charge delocalization, heavy atom introduction, multi-donor/acceptor utilization, and a hyperfluorescence system approach. Furthermore, the outlook and prospects for future developments in MR-TADF skeletons are described.
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Affiliation(s)
- Kenkera Rayappa Naveen
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea.
| | - Paramasivam Palanisamy
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea.
| | - Mi Young Chae
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea.
| | - Jang Hyuk Kwon
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea.
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47
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Zhang X, Zhao X, Ye K, Zhao J. Detection of the Dark States in Thermally Activated Delayed Fluorescence (TADF) Process of Electron Donor-Acceptor Dyads: Insights from Optical Transient Absorption Spectroscopy. Chemistry 2023; 29:e202203737. [PMID: 36468907 DOI: 10.1002/chem.202203737] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/07/2022]
Abstract
The photophysical processes involved in the electron donor-acceptor thermally activated delayed fluorescence (TADF) emitters are complicated and controversial. The recent consensus is that at least three states are involved, i. e. the singlet charge transfer state (1 CT), the triplet localized excited state (3 LE) and the triplet CT state (3 CT). It is clear the very often used steady state and time-resolved luminescence spectroscopic methods are unable to present direct evidence for the dark states, i. e. the 3 LE and 3 CT states, as well as the interconversion of these states. Concerning this aspect, the femtosecond-nanosecond transient absorption spectroscopic methods are in particular interests. Both the emissive state and the dark state can be detected in these spectra, and interconversion of the states involved in TADF process can be also revealed. This review article focuses on the recent development of using the transient absorption spectra to study the photophysics of the TADF emitters.
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Affiliation(s)
- Xue Zhang
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Road, Dalian, 116024, P. R. China
| | - Xiaoyu Zhao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Road, Dalian, 116024, P. R. China.,State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, 830017, P. R. China
| | - Kaiyue Ye
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Road, Dalian, 116024, P. R. China
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, 2 Ling Gong Road, Dalian, 116024, P. R. China.,State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, 830017, P. R. China
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48
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Duda E, Madayanad Suresh S, Hall D, Bagnich S, Saxena R, Cordes DB, Slawin AMZ, Beljonne D, Olivier Y, Köhler A, Zysman-Colman E. An Oligomer Approach for Blue Thermally Activated Delayed Fluorescent Emitters Based on Twisted Donor-Acceptor Units. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:2027-2037. [PMID: 36936179 PMCID: PMC10018739 DOI: 10.1021/acs.chemmater.2c03438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/14/2023] [Indexed: 06/18/2023]
Abstract
The development of efficient blue donor-acceptor thermally activated delayed fluorescence (TADF) emitters remains a challenge. To enhance the efficiency of TADF-related processes of the emitter, we targeted a molecular design that would introduce a large number of intermediate triplet states between the lowest energy excited triplet (T1) and singlet (S1) excited states. Here, we introduce an oligomer approach using repetitive donor-acceptor units to gradually increase the number of quasi-degenerate states. In our design, benzonitrile (BN) moieties were selected as acceptors that are connected together via the amine donors, acting as bridges to adjacent BN acceptors. To preserve the photoluminescence emission wavelength across the series, we employed a design based on an ortho substitution pattern of the donors about the BN acceptor that induces a highly twisted conformation of the emitters, limiting the conjugation. Via a systematic photophysical study, we show that increasing the oligomer size allows for enhancement of the intersystem crossing and reverse intersystem crossing rates. We attribute the increasing intersystem crossing rate to the increasing number of intermediate triplet states along the series, confirmed by the time-dependent density functional theory. Overall, we report an approach to enhance the efficiency of TADF-related processes without changing the blue photoluminescence color.
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Affiliation(s)
- Eimantas Duda
- Soft
Matter Optoelectronics, BIMF & BPI, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Subeesh Madayanad Suresh
- Organic
Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK
| | - David Hall
- Organic
Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK
- Laboratory
for Chemistry of Novel Materials, Materials Research Institute, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Sergey Bagnich
- Soft
Matter Optoelectronics, BIMF & BPI, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Rishabh Saxena
- Soft
Matter Optoelectronics, BIMF & BPI, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - David B. Cordes
- Organic
Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK
| | - Alexandra M. Z. Slawin
- Organic
Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK
| | - David Beljonne
- Laboratory
for Chemistry of Novel Materials, Materials Research Institute, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Yoann Olivier
- Laboratory
for Chemistry of Novel Materials, Materials Research Institute, University of Mons, Place du Parc 20, 7000 Mons, Belgium
- Unité
de Chimie Physique Théorique et Structurale & Laboratoire
de Physique du Solide, Namur Institute of Structured Matter, Université de Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium
| | - Anna Köhler
- Soft
Matter Optoelectronics, BIMF & BPI, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Eli Zysman-Colman
- Organic
Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK
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49
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Skhirtladze L, Bezvikonnyi O, Keruckienė R, Dvylys L, Mahmoudi M, Labanauskas L, Ariffin A, Grazulevicius JV. Derivatives of Pyridazine with Phenoxazine and 9,9-Dimethyl-9,10-dihydroacridine Donor Moieties Exhibiting Thermally Activated Delayed Fluorescence. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1294. [PMID: 36770299 PMCID: PMC9919726 DOI: 10.3390/ma16031294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/18/2023] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Two compounds based on pyridazine as the acceptor core and 9,9-dimethyl-9,10-dihydroacridine or phenoxazine donor moieties were designed and synthesized by Buchwald-Hartwig cross-coupling reaction. The electronic, photophysical, and electrochemical properties of the compounds were studied by ultraviolet-visible spectroscopy (UV-vis), photoluminescence spectrometry, differential scanning calorimetry, thermogravimetric analysis, and cyclic voltammetry. The compounds are characterized by high thermal stabilities. Their 5% weight loss temperatures are 314 and 336 °C. Complete weight loss of both pyridazine-based compounds was detected by TGA, indicating sublimation. The derivative of pyridazine and 9,9-dimethyl-9,10-dihydroacridine is capable of glass formation. Its glass transition temperature is 80 °C. The geometries and electronic characteristics of the compounds were substantiated using density functional theory (DFT). The compounds exhibited emission from the intramolecular charge transfer state manifested by positive solvatochromism. The emission in the range of 534-609 nm of the toluene solutions of the compounds is thermally activated delayed fluorescence with lifetimes of 93 and 143 ns, respectively.
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Affiliation(s)
- Levani Skhirtladze
- Department of Polymer Chemistry and Technology, Faculty of Chemical Technology, Kaunas University of Technology, LT-51423 Kaunas, Lithuania
| | - Oleksandr Bezvikonnyi
- Department of Polymer Chemistry and Technology, Faculty of Chemical Technology, Kaunas University of Technology, LT-51423 Kaunas, Lithuania
- Department of Physics, Faculty of Mathematics and Natural Science, Kaunas University of Technology, LT-51369 Kaunas, Lithuania
| | - Rasa Keruckienė
- Department of Polymer Chemistry and Technology, Faculty of Chemical Technology, Kaunas University of Technology, LT-51423 Kaunas, Lithuania
| | - Lukas Dvylys
- Department of Polymer Chemistry and Technology, Faculty of Chemical Technology, Kaunas University of Technology, LT-51423 Kaunas, Lithuania
| | - Malek Mahmoudi
- Department of Polymer Chemistry and Technology, Faculty of Chemical Technology, Kaunas University of Technology, LT-51423 Kaunas, Lithuania
| | - Linas Labanauskas
- Center for Physical Sciences & Technology, Department of Organic Chemistry, LT-10257 Vilnius, Lithuania
| | - Azhar Ariffin
- Department of Chemistry, Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Juozas V. Grazulevicius
- Department of Polymer Chemistry and Technology, Faculty of Chemical Technology, Kaunas University of Technology, LT-51423 Kaunas, Lithuania
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50
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Wang J, Li N, Zhong C, Miao J, Huang Z, Yu M, Hu YX, Luo S, Zou Y, Li K, Yang C. Metal-Perturbed Multiresonance TADF Emitter Enables High-Efficiency and Ultralow Efficiency Roll-Off Nonsensitized OLEDs with Pure Green Gamut. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208378. [PMID: 36534824 DOI: 10.1002/adma.202208378] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/17/2022] [Indexed: 06/17/2023]
Abstract
Multiresonance (MR)-induced thermally activated delayed fluorescence (TADF) emitters based on B- and N-embedded polycyclic aromatics are desirable for ultrahigh-definition organic light-emitting diodes (OLEDs) due to their high photoluminescence quantum yield (PLQY) and narrow bandwidth. But the reverse intersystem crossing (RISC) rates of MR-TADF emitters are usually small, resulting in severe device efficiency roll-off at high brightness. To solve this issue, a sensitizer for the MR-TADF emitter has been required. Herein, a new MR-TADF emitter is developed through coordination of Au with B/N-embedded polycyclic ligand. Benefitting from the Au perturbation, the RISC rate is dramatically accelerated to 2.3 × 107 s-1 , leading to delayed fluorescence lifetime as short as 4.3 µs. Meanwhile, the PLQY of 95% and full width at half maximum of 39 nm (0.18 eV) are essentially unchanged after metal coordination. Therefore, a high PLQY, short delayed fluorescence lifetime, and high color purity are concurrently realized in a single TADF emitter. Accordingly, vacuum-deposited OLEDs exhibit high-performance electroluminescence with a maximum external quantum efficiency (EQE) of 35.8% without sensitization. The EQE is maintained as high as 32.3% at 10 000 cd m-2 . Furthermore, solution-processed OLED based on the emitter also achieves excellent performance with a maximum EQE of 25.7% and a small efficiency roll-off.
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Affiliation(s)
- Junjie Wang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
| | - Nengquan Li
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
| | - Cheng Zhong
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China
| | - Jingsheng Miao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
| | - Zhongyan Huang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
| | - Mingxin Yu
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
| | - Yu Xuan Hu
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
| | - Sai Luo
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
| | - Yang Zou
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
| | - Kai Li
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
| | - Chuluo Yang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518055, P. R. China
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