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Wu X, Ni S, Wang CH, Zhu W, Chou PT. Comprehensive Review on the Structural Diversity and Versatility of Multi-Resonance Fluorescence Emitters: Advance, Challenges, and Prospects toward OLEDs. Chem Rev 2025. [PMID: 40344420 DOI: 10.1021/acs.chemrev.5c00021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2025]
Abstract
Fluorescence emitters with a multiple-resonant (MR) effect have become a research hotspot. These MR emitters mainly consist of polycyclic aromatic hydrocarbons with boron/nitrogen, nitrogen/carbonyl, and indolocarbazole frameworks. The staggered arrangement of the highest occupied molecular orbital and the lowest unoccupied molecular orbital facilitates MR, resulting in smaller internal reorganization energy and a narrower emission bandwidth. Optimal charge separation suppresses the energy gap between singlet and triplet excited states, favoring thermally activated delayed fluorescence (TADF). These MR-TADF materials, due to color purity and high emission efficiency, are excellent candidates for organic light-emitting diodes. Nevertheless, significant challenges remain; in particular, the limitation imposed by the alternated core configuration hinders their diversity and versatility. Most existing MR-TADF materials are concentrated in the blue-green range, with only a few in red and near-infrared spectra. This review provides a timely and comprehensive screening of MR emitters from their pioneering work to the present. Our goal is to gain understandings of the MR-TADF structure-performance relationship from both basic and advanced perspectives. Special emphasis is placed on exploring the correlations between chemical structure, photophysical properties and electroluminescent performance in both depth and breadth with an aim to promote the future development of MR emitters.
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Affiliation(s)
- Xiugang Wu
- School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou 213164, China
| | - Songqian Ni
- School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou 213164, China
| | - Chih-Hsing Wang
- National Taiwan University, Department of Chemistry, Taipei 10617, Taiwan
| | - Weiguo Zhu
- School of Materials Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou 213164, China
| | - Pi-Tai Chou
- National Taiwan University, Department of Chemistry, Taipei 10617, Taiwan
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2
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Yang Z, Liu D, Cheng X, Wang T, Li Z, Yang GX, Chen Z, Hu J, Fu Y, Nie X, Ren Y, Zeng Y, Chen Y, Liu K, Li M, Su SJ. Delocalized Nonbonding Orbitals of Thioxanthone in Polycyclic Aromatic Hydrocarbons for Reduced Energy Gap and Narrowband Emission. Angew Chem Int Ed Engl 2025; 64:e202423602. [PMID: 39779478 DOI: 10.1002/anie.202423602] [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: 12/03/2024] [Revised: 01/03/2025] [Accepted: 01/08/2025] [Indexed: 01/11/2025]
Abstract
Chalcogen-containing carbonyls, specifically thioxanthone (TX), hold great potential in organic light-emitting diodes (OLEDs). While the development of narrowband OLEDs with chalcogen-containing carbonyls remains challenging due to difficulties in achieving both high device efficiency and narrow emission spectra. Herein, via a strategic incorporation of the TX moiety, two orange-red narrowband emitters, 2TXBN and BNTXBN, are designed and synthesized for the first time. Both 2TXBN and BNTXBN exhibit bright orange-red emissions with peaks at 582 and 585 nm, respectively, along with narrow full widths at half maxima of 30 and 32 nm. Notably, 2TXBN demonstrates delocalization of the nonbonding orbital within the TX segment, which raises the first triplet energy level and reduces the singlet-triplet energy gap. This electronic structural adjustment effectively shortens the delayed fluorescence lifetime, leading to enhanced device performance. Accordingly, OLED employing 2TXBN as the emitter achieves remarkable performance, with a maximum external quantum efficiency of 31.0 %, a current efficiency of 69.0 cd A-1, and a power efficiency of 76.0 lm W-1, highlighting the efficacy of the nonbonding orbital delocalization strategy in achieving bathochromic-shifted narrowband OLED materials.
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Affiliation(s)
- Zhihai Yang
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Denghui Liu
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Xiangyi Cheng
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Tong Wang
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Zhizhi Li
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Guo-Xi Yang
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Zijian Chen
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Juntao Hu
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Yu Fu
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Xuewei Nie
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Yongxia Ren
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Yitong Zeng
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Yuling Chen
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Kunkun Liu
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Mengke Li
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
| | - Shi-Jian Su
- Institute of Polymer Optoelectronic Materials and Devices, Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Wushan Road 381, Guangzhou, 510640, P. R. China
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3
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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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4
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Kim H, Lee K, Kim JH, Kim WY. Deep Learning-Based Chemical Similarity for Accelerated Organic Light-Emitting Diode Materials Discovery. J Chem Inf Model 2024; 64:677-689. [PMID: 38270063 DOI: 10.1021/acs.jcim.3c01747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
Thermally activated delayed fluorescence (TADF) material has attracted great attention as a promising metal-free organic light-emitting diode material with a high theoretical efficiency. To accelerate the discovery of novel TADF materials, computer-aided material design strategies have been developed. However, they have clear limitations due to the accessibility of only a few computationally tractable properties. Here, we propose TADF-likeness, a quantitative score to evaluate the TADF potential of molecules based on a data-driven concept of chemical similarity to existing TADF molecules. We used a deep autoencoder to characterize the common features of existing TADF molecules with common chemical descriptors. The score was highly correlated with the four essential electronic properties of TADF molecules and had a high success rate in large-scale virtual screening of millions of molecules to identify promising candidates at almost no cost, validating its feasibility for accelerating TADF discovery. The concept of TADF-likeness can be extended to other fields of materials discovery.
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Affiliation(s)
- Hyeonsu Kim
- Department of Chemistry, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Kyunghoon Lee
- Department of Chemistry, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jun Hyeong Kim
- Department of Chemistry, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Woo Youn Kim
- Department of Chemistry, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
- AI Institute, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
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5
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Zender E, Karger S, Neubaur R, Virovets A, Lerner HW, Wagner M. Green-Emitting Extended B 3,N 2-Doped Polycyclic Aromatic Hydrocarbon with Multiple Resonance Structure. Org Lett 2024; 26:939-944. [PMID: 38266241 DOI: 10.1021/acs.orglett.3c04283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
An air-stable B3,N2-PAH (B3N2; nine annulated six-membered rings) was synthesized from 1-X-2,6-di(azasilaanthryl)benzenes (X = Cl, I) via lithiation/borylation, electrophilic aromatic borylation, and Si/B exchange. The heteroatom distribution in B3N2 meets the requirements for multiple resonance thermally activated delayed fluorescence (MR-TADF). Indeed, B3N2 emits green light (λem = 523 nm; ΦPL = 85%; CHCl3) with a small fwhm of 0.15 eV. Lifetimes for prompt (7.8 ns) and delayed (60 μs) fluorescence were measured in PMMA.
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Affiliation(s)
- Elena Zender
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Sebastian Karger
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Robert Neubaur
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Alexander Virovets
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Hans-Wolfram Lerner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Matthias Wagner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
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6
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Chen J, Liu Z, Chen L, Zou P, Tang BZ, Zhao Z. Exploring Robust Delayed Fluorescence Materials via Structural Rigidification for Realizing Organic Light-Emitting Diodes with High Efficiencies and Small Roll-Offs. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306800. [PMID: 37823676 DOI: 10.1002/smll.202306800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/22/2023] [Indexed: 10/13/2023]
Abstract
Thermally activated delayed fluorescence (TADF) materials have been widely studied for the fabrication of high-performance organic light-emitting diodes (OLEDs), but the serious efficiency roll-offs still remain unsolved in most cases. Herein, it is wish to report a series of robust green TADF compounds containing rigid xanthenone acceptor and acridine-based spiro donors. The enhancement in molecular rigidity not only endows the compounds with improved thermal stability but also results in reduced geometric vibrations and thus lowered reorganization energies. These compounds exhibit distinct merits of high thermal stabilities, excellent photoluminescence quantum efficiencies (96%-97%), large horizontal dipole orientation ratios (87.4%-92.1%) and fast TADF rates (1.4-1.5 × 106 s-1 ). The OLEDs using them as emitters furnish superb electroluminescence performances with outstanding external quantum efficiencies (ηext s) of up to 37.4% and very small efficiency roll-offs. Moreover, highly efficient hyperfluorescence OLEDs are obtained by using them as sensitizers for the green mutilresonance TADF emitter BN2, delivering excellent ηext s of up to 34.2% and improved color purity. These results disclose the high potential of these TADF compounds as emitters and sensitizers for OLEDs.
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Affiliation(s)
- Jinke Chen
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Zhangshan Liu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Letian Chen
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Peng Zou
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Ben Zhong Tang
- School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, Guangdong
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
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7
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Liu Z, Chen J, Chen L, Liu H, Yang D, Ma D, Tang BZ, Zhao Z. Simultaneously Realizing High Efficiency and High Color Rendering Index for Hybrid White Organic Light-Emitting Diodes by Ultra-Thin Design of Delayed Fluorescence Sensitized Phosphorescent Layers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2305589. [PMID: 37828633 DOI: 10.1002/smll.202305589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/25/2023] [Indexed: 10/14/2023]
Abstract
In consideration of energy economization and light quality, concurrently attaining high external quantum efficiency (ηext ) and high color rendering index (CRI) is of high significance for the commercialization of hybrid white organic light-emitting diodes (WOLEDs) but is challenging. Herein, a blue luminescent molecule (2PCz-XT) consisting of a xanthone acceptor and two 3,6-diphenylcarbazole donors is prepared, which exhibits strong delayed fluorescence, short delayed fluorescence lifetime, and excellent electroluminescence property, and can sensitize green, orange, and red phosphorescent emitters efficiently. By employing 2PCz-XT as sensitizer and phosphorescent emitters as dopants, efficient two-color and three-color WOLED architectures with ultra-thin phosphorescent emitting layers (EMLs) are proposed and constructed. By incorporating a thin interlayer to modulate exciton recombination zone and reduce exciton loss, high-performance three-color hybrid WOLEDs are finally achieved, providing a high ηext of 26.8% and a high CRI value 83 simultaneously. Further configuration optimization realizes a long device operational lifetime. These WOLEDs with ultra-thin phosphorescent EMLs are among the state-of-the-art hybrid WOLEDs in the literature, demonstrating the success and applicability of the proposed device design for developing robust hybrid WOLEDs with superb efficiency and color quality.
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Affiliation(s)
- Zhangshan Liu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Jinke Chen
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Letian Chen
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Hao Liu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Dezhi Yang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Ben Zhong Tang
- School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
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8
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Han W, Liu J, Ran C, Huang Z, Gao G, You J, Bin Z. Alignment of Heptagonal Diimide and Triazine Enables Narrowband Pure-Blue Organic Light-Emitting Diodes with Low Efficiency Roll-Off. Angew Chem Int Ed Engl 2023; 62:e202312297. [PMID: 37815880 DOI: 10.1002/anie.202312297] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/28/2023] [Accepted: 10/10/2023] [Indexed: 10/12/2023]
Abstract
The endeavor to develop high-performance narrowband blue organic light-emitting diodes (OLEDs) with low efficiency roll-off represents an attractive challenge. Herein, we introduce a hetero-acceptor design strategy centered around the heptagonal diimide (BPI) building block to create an efficient thermally activated delayed fluorescence (TADF) sensitizer. The alignment of a twisted BPI unit and a planar diphenyltriazine (TRZ) fragment imparts remarkable exciton dynamic properties to 26tCz-TRZBPI, including a fast radiative decay rate (kR ) of 1.0×107 s-1 and a swift reverse intersystem crossing rate (kRISC ) of 1.8×106 s-1 , complemented by a slow non-radiative decay rate (kNR ) of 6.0×103 s-1 . Consequently, 26tCz-TRZBPI facilitates the fabrication of high-performance narrowband pure-blue TADF-sensitized fluorescence OLEDs (TSF-OLEDs) with a maximum external quantum efficiency (EQEmax ) of 24.3 % and low efficiency roll-off even at a high brightness level of 10000 cd m-2 (EQE10000 : 16.8 %). This showcases a record-breaking external quantum efficiency at a high luminance level of 10000 cd m-2 for narrowband blue TSF-OLEDs.
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Affiliation(s)
- Weiguo Han
- Key Laboratory of Green Chemistry, 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, Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, People's Republic of China
| | - Chunhao Ran
- Key Laboratory of Green Chemistry, Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, People's Republic of China
| | - Zhenmei Huang
- Key Laboratory of Green Chemistry, Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, People's Republic of China
| | - Ge Gao
- Key Laboratory of Green Chemistry, 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, 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, Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, People's Republic of China
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9
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Fu Y, Ye Z, Liu D, Mu Y, Xiao J, Hu D, Ji S, Huo Y, Su SJ. Macrocyclic Engineering of Thermally Activated Delayed Fluorescent Emitters for High-Efficiency Organic Light-Emitting Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2301929. [PMID: 37178057 DOI: 10.1002/adma.202301929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/29/2023] [Indexed: 05/15/2023]
Abstract
Several thermally activated delayed fluorescence (TADF) materials have been studied and developed to realize high-performance organic light-emitting diodes (OLEDs). However, TADF macrocycles have not been sufficiently investigated owing to the synthetic challenges, resulting in limited exploration of their luminescent properties and the corresponding highly efficient OLEDs. In this study, a series of TADF macrocycles is synthesized using a modularly tunable strategy by introducing xanthones as acceptors and phenylamine derivatives as donors. A detailed analysis of their photophysical properties combined with fragment molecules reveals characteristics of high-performance macrocycles. The results indicate that: a) the ideal structure decreases the energy loss, which in turn reduces the non-radiative transitions; b) reasonable building blocks increase the oscillator strength providing a higher radiation transition rate; c) the horizontal dipole orientation (Θ) of the extended macrocyclic emitters is increased. Owing to the high photoluminescence quantum yields of ≈100% and 92% and excellent Θ of 80 and 79% for macrocycles MC-X and MC-XT in 5 wt% doped films, the corresponding devices exhibit record-high external quantum efficiencies of 31.6% and 26.9%, respectively, in the field of TADF macrocycles.
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Affiliation(s)
- Yu Fu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Zecong Ye
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Denghui Liu
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Yingxiao Mu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Jingping Xiao
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Dehua Hu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Shaomin Ji
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Yanping Huo
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
- Analytical & Testing Center, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Shi-Jian Su
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
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10
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Wu Y, Liu X, Liu J, Yang G, Han S, Yang D, Cao X, Ma D, Bin Z, You J. Geometry engineering of a multiple resonance core via a phenyl-embedded strategy toward highly efficient narrowband blue OLEDs. MATERIALS HORIZONS 2023; 10:3785-3790. [PMID: 37409621 DOI: 10.1039/d3mh00617d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
The geometry of the molecular skeleton is of importance for the property regulation of organic electronic materials. Herein, we present a phenyl-embedded molecular design strategy to adjust the molecular curvature and achieve the improvement of blue multiple resonance (MR)-emitters. The introduction of a bridged phenyl contributes to a highly twisted saddle skeleton and the separation of frontier molecular orbitals, which are beneficial for the increase of photoluminescence quantum yield (PLQY) as well as the decrease of singlet-triplet energy gap (ΔEST). Consequently, hp-BQAO features an accelerated reverse intersystem crossing rate and suppressed non-radiative decay rate simultaneously, which enables the assembly of high-performance narrowband blue OLEDs with a record-high external quantum efficiency (EQE) of 24.1% for the blue OLED devices exploiting nitrogen-carbonyl-containing MR-emitters without sensitizers.
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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.
| | - Songyan Han
- 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.
| | - Dezhi Yang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China
| | - Xiaosong Cao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Dongge Ma
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, 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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11
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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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12
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Meng QY, Wang R, Wang YL, Guo XW, Liu YQ, Wen XL, Yao CY, Qiao J. Longevity gene responsible for robust blue organic materials employing thermally activated delayed fluorescence. Nat Commun 2023; 14:3927. [PMID: 37400475 DOI: 10.1038/s41467-023-39697-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 06/23/2023] [Indexed: 07/05/2023] Open
Abstract
The 3rd-Gen OLED materials employing thermally-activated delayed fluorescence (TADF) combine advantages of first two for high-efficiency and low-cost devices. Though urgently needed, blue TADF emitters have not met stability requirement for applications. It is essential to elucidate the degradation mechanism and identify the tailored descriptor for material stability and device lifetime. Here, via in-material chemistry, we demonstrate chemical degradation of TADF materials involves critical role of bond cleavage at triplet state rather than singlet, and disclose the difference between bond dissociation energy of fragile bonds and first triplet state energy (BDE-ET1) is linearly correlated with logarithm of reported device lifetime for various blue TADF emitters. This significant quantitative correlation strongly reveals the degradation mechanism of TADF materials have general characteristic in essence and BDE-ET1 could be the shared "longevity gene". Our findings provide a critical molecular descriptor for high-throughput-virtual-screening and rational design to unlock the full potential of TADF materials and devices.
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Affiliation(s)
- Qing-Yu Meng
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, China
| | - Rui Wang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, China
| | - Yi-Lei Wang
- Department of Chemistry, Tsinghua University, Beijing, China
| | - Xing-Wei Guo
- Department of Chemistry, Tsinghua University, Beijing, China
- Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing, China
| | - Yu-Qi Liu
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, China
| | - Xue-Liang Wen
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, China
| | - Cheng-Yu Yao
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, China
| | - Juan Qiao
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, China.
- Laboratory for Flexible Electronics Technology, Tsinghua University, Beijing, China.
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13
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Zhang YL, He TF, Zhao ZK, Shen A, Gao Q, Ren AM, Su ZM, Li H, Chu HY, Zou LY. Self-Consistent Quantum Mechanics/Embedded Charge Study on Aggregation-Enhanced Delayed Fluorescence of Cu(I) Complexes: Luminescence Mechanism and Molecular Design Strategy. Inorg Chem 2023; 62:7753-7763. [PMID: 37154416 DOI: 10.1021/acs.inorgchem.3c00383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
To elucidate the luminescence mechanism of highly efficient blue Cu(N^N)(POP)+-type thermally activated delayed fluorescence (TADF) materials, we have selected Cu(pytfmpz)(POP)+ (1) and Cu(pympz)(POP)+ (2) as targets to investigate the photophysical properties in both solution and solid phases. The self-consistent electrostatic potential (ESP) embedded charge within the quantum mechanics/molecular mechanics (QM/MM) method demonstrates a greater advantage over the charge equilibrium (QEQ) in accurately calculating atomic charges and reasonably describing the polarization effect, ultimately resulting in a favorable consistency between simulation and experimental measurements. After systematic and quantitative simulation, it has been found that complex 2, with an electron-donating group of -CH3, exhibits a much more blue-shifted spectrum and a significantly enhanced efficiency in comparison to complex 1 with -CF3. This is due to the widened HOMO-LUMO gap as well as the narrowed energy gap between the lowest singlet and triplet excited states (ΔEST), respectively. Then, the designed complex 3 is introduced with a stronger electron donor and larger tert-butyl group, which plays a key role in simultaneously suppressing the structural distortion and reducing the ΔEST. This leads to a faster reverse intersystem crossing process than that of the two experimental complexes in solution, turning out to be a new deep-blue-emitting material with excellent TADF performance.
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Affiliation(s)
- Yun-Li Zhang
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China
| | - Teng-Fei He
- College of Chemistry, National Institute for Advanced Materials, Renewable Energy Conversion and Storage Center (RECAST), Nankai University, 300350 Tianjin, China
| | - Zi-Kang Zhao
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China
| | - Ao Shen
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China
| | - Qiang Gao
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China
| | - Ai-Min Ren
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China
| | - Zhong-Min Su
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China
| | - Hui Li
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China
| | - Hui-Ying Chu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian 116023, P. R. China
| | - Lu-Yi Zou
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, P. R. China
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14
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Nguyen TB, Nakanotani H, Chan CY, Kakumachi S, Adachi C. Enhancing Triplet-Triplet Upconversion Efficiency and Operational Lifetime in Blue Organic Light-Emitting Diodes by Utilizing Thermally Activated Delayed Fluorescence Materials. ACS APPLIED MATERIALS & INTERFACES 2023; 15:23557-23563. [PMID: 37146232 DOI: 10.1021/acsami.3c02855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
In the process of triplet-triplet upconversion (TTU), a bright excited singlet can be generated because of the collision of two dark excited triplets. In particular, the efficiency of TTU is crucial for achieving a high exciton production yield in blue fluorescence organic light-emitting diodes (OLEDs) beyond the theoretical limit. While the theoretical upper limit of TTU contribution yield is expected to be 60%, blue OLEDs with the maximum TTU contribution are still scarce. Herein, we present a proof of concept for realizing the maximum TTU contribution yield in blue OLEDs, achieved through the doping of thermally activated delayed fluorescence (TADF) molecules in the carrier recombination zone. The bipolar carrier transport ability of TADF materials enables direct carrier recombination on the molecules, resulting in the expansion of the recombination zone. Although the external electroluminescence quantum efficiency of OLEDs is slightly lower than that of conventional TTU-OLEDs due to the low photoluminescence quantum yield of the doped layer, the TTU efficiency approaches the upper limit. Furthermore, the operational device lifetime of OLEDs employing TADF molecules increased by five times compared to the conventional ones, highlighting the expansion of the recombination zone as a crucial factor for enhancing overall OLED performance in TTU-OLEDs.
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Affiliation(s)
- Thanh B Nguyen
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Hajime Nakanotani
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Chin-Yiu Chan
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Shunta Kakumachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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15
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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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16
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Zhang B, Xu H, Xia Y, Wen J, Zhu M. Effect of void-carbon on blue-shifted luminescence in TADF molecules by theoretical simulations. Front Chem 2023; 11:1094574. [PMID: 36778032 PMCID: PMC9908751 DOI: 10.3389/fchem.2023.1094574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/16/2023] [Indexed: 01/27/2023] Open
Abstract
Thermally activated delayed fluorescence (TADF) molecules have a theoretical 100% photoluminescence quantum yield in comparison with traditional fluorescent materials, leading to broad application in organic light-emitting diode (OLED). However, the application of TADF molecules with conjugated donor-acceptor structures in blue OLED remains a challenge due to their generally narrow energy gap between frontier molecular orbitals. Recently, a strategy has been approved in the improvement of the performance in TADF, in which void-carbon atoms between donor and acceptor fragments (donor-void-acceptor (D-v-A)) could regulate blue light emission. In this study, we first select three reported isomers followed by two proposed D-v-A TADF isomers to verify the feasibility of the void-carbon strategy through evaluation of the electronic structures in the excited state and photophysical properties. We further proposed a series of TADF molecules by replacing different donor and acceptor fragments to assess the applicability of the void-carbon strategy from the aspect of simulations in electronic structures, different properties of donor and acceptor fragments, photophysical properties, and analysis in the molecular conjugation. The results indicate that void-carbon strategy has conditional feasibility and applicability. Donor-acceptor molecular properties could be tuned through void-carbon strategy on aromatic acceptor fragments during the selection of promising candidates of TADF molecules. However, the void-carbon strategy does not work for the molecules with antiaromatic acceptor fragments, where the steric hindrance of the molecules plays a dominant role. Our work provides insightful guidance for the design of the blue-emission TADF molecules.
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Affiliation(s)
| | | | - Yumin Xia
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, China
| | - Jin Wen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, China
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17
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Zhou D, Tong GSM, Cheng G, Tang YK, Liu W, Ma D, Du L, Chen JR, Che CM. Stable Tetradentate Gold(III)-TADF Emitters with Close to Unity Quantum Yield and Radiative Decay Rate Constant of up to 2 × 10 6 s -1 : High-Efficiency Green OLEDs with Operational Lifetime (LT 90 ) Longer than 1800 h at 1000 cd m -2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2206598. [PMID: 36208071 DOI: 10.1002/adma.202206598] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/23/2022] [Indexed: 06/16/2023]
Abstract
High maximum external quantum efficiency (EQEmax ), small efficiency roll-offs, and long operational lifetime at practical luminances are three crucial parameters for commercialization of organic light-emitting diodes (OLEDs). To simultaneously achieve these goals, it is desirable to have the radiative decay rate constant (kr ) as large as possible, which, for a thermally activated delayed fluorescent (TADF) emitter, requires both a large S1 →S0 radiative decay rate constant (kr S ) and a small singlet-triplet energy gap (ΔEST ). Here, the design of a class of tetradentate gold(III) TADF complexes for narrowing the ΔEST while keeping the kr S large is reported. The as-synthesized complexes display green emission with close to unity emission quantum yields, and kr approaching 2 × 106 s-1 in thin films. The vacuum-deposited green OLEDs based on 1 and 4 demonstrate maximum EQEs of up to 24 and 27% with efficiency roll-offs of 5.5 and 2.2% at 1000 cd m-2 , respectively; the EQEs maintain high at 10 000 cd m-2 (19% (1) and 24% (4)). A long LT90 device lifetime of 1820 h at 1000 cd m-2 for complex 1 is achieved, which is one of the longest device lifetimes of TADF-OLEDs reported in the literature.
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Affiliation(s)
- Dongling Zhou
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Glenna So Ming Tong
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Gang Cheng
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- Chemistry and Chemical Engineering Guangdong Laboratory, Shantou, Guangdong, 515041, China
| | - Yu-Kan Tang
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Wei Liu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology Guangzhou, Guangzhou, 510640, China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology Guangzhou, Guangzhou, 510640, China
| | - Lili Du
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- School of Life Science, Jiangsu University, Zhenjiang, 212013, China
| | - Jian-Rui Chen
- Chemistry and Chemical Engineering Guangdong Laboratory, Shantou, Guangdong, 515041, China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- Chemistry and Chemical Engineering Guangdong Laboratory, Shantou, Guangdong, 515041, China
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Liu X, Li J, Qiu X, Pan Y. Organic Electroluminescent Materials Possessing Intra- and Intermolecular Hydrogen Bond Interactions: A Mini-Review. Front Chem 2022; 10:954419. [PMID: 35936093 PMCID: PMC9353211 DOI: 10.3389/fchem.2022.954419] [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: 05/27/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
Organic light-emitting diodes (OLEDs) have become the predominant technology in display applications because of their superior light weight, flexibility, power conservation, and environmental friendliness, among other reasons. The device’s performance is determined by the intrinsic properties of organic emitters. The aggregation structure of emitters, in particular, is crucial for color purity and efficiency. Intra- and intermolecular interactions, such as hydrogen bonds (H-bonds), can reduce structural vibrations and torsions, which affect the stability of emitting layer films and optoelectronic properties of emitting materials. Hence, by regulating the H-bond interaction, the desired properties could be obtained. This mini-review focuses on the influence of intra- and intermolecular H-bond interactions on the optoelectronic properties of high-performance emitters.
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Affiliation(s)
- Xinyong Liu
- College of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Jingwei Li
- College of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Xu Qiu
- College of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao, China
- *Correspondence: Xu Qiu, ; Yuyu Pan,
| | - Yuyu Pan
- School of Petrochemical Engineering, Shenyang University of Technology, Liaoyang, China
- *Correspondence: Xu Qiu, ; Yuyu Pan,
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