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Liu M, Li H, Ma H, Yao C, Zhao F, Han S, Zhang Z, Wang N, Yin X. Triarylboron-Based Dual Thermally Activated Delayed Fluorescence Emitter for Single Molecule White Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2025; 17:21509-21520. [PMID: 40136050 DOI: 10.1021/acsami.4c20583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2025]
Abstract
Single-molecule emitters with dual thermally activated delayed fluorescence (TADF) characteristics are very promising for application in organic light-emitting diodes (OLEDs). Rarely reported, organic dual-TADF materials, especially mechanochromic materials, are in demand. We present two donor-acceptor emitters, Mes*BA-Ac and FXylBA-Ac, which exhibit dual-TADF in the solid state due to the separation of HOMO and LUMO and strong intermolecular interactions. Their phase transition from amorphous to crystalline under stimuli leads to switchable TADF emissions. By blending Mes*BA-Ac with poly(methyl methacrylate), we achieve pure white light with Commission Internationale de l'Eclairage (CIE) coordinates of (0.33, 0.32). Furthermore, single-molecule white organic light-emitting diodes (SM-WOLEDs) using Mes*BA-Ac have been fabricated, reaching a maximum external quantum efficiency (EQEmax) of 1.65% with CIE coordinates of (0.30, 0.31). More importantly, the dual-TADF emission mechanism enables the devices to maintain stable white-light emission across a relatively wide voltage range, providing valuable insights for the advancement of pure organic SM-WOLEDs.
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Affiliation(s)
- Meiyan Liu
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, P. R. China
| | - Hongbo Li
- Institute of Organic Luminescent Materials (IOLM), College of Chemistry, Liaoning University, Shenyang 110036, PR China
| | - Hongwei Ma
- Analysis and Testing Center, Beijing Institute of Technology, Beijing 102488, P. R. China
| | - Chunxia Yao
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, P. R. China
| | - Fenggui Zhao
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, P. R. China
| | - Shuai Han
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, P. R. China
| | - Ziqian Zhang
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, P. R. China
| | - Nan Wang
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, P. R. China
| | - Xiaodong Yin
- Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, P. R. China
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Huang M, Chen Z, Miao J, He S, Yang W, Huang Z, Zou Y, Gong S, Tan Y, Yang C. Harmonization of rapid triplet up-conversion and singlet radiation enables efficient and stable white OLEDs. Nat Commun 2024; 15:8048. [PMID: 39277619 PMCID: PMC11401840 DOI: 10.1038/s41467-024-52401-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 09/05/2024] [Indexed: 09/17/2024] Open
Abstract
White organic light-emitting diodes (WOLEDs) hold significant promise in illumination and displays, but achieving high efficiency while maintaining stability is an ongoing challenge. Here, we strategically combine a blue donor-acceptor thermally activated delayed fluorescence (TADF) emitter featuring rapid reverse intersystem crossing rate and a yellow multi-resonance TADF emitter renowned for the fast radiative transition process to achieve warm WOLEDs with exceptional power efficiency exceeding 190 lm W-1 and external quantum efficiency (EQE) of 39%, setting records for WOLEDs. Meanwhile, these devices also exhibit an extended operational lifetime (LT80) of 446 h at an initial luminance of 1000 cd m-2. Another group of blue and yellow emitters based on our strategy achieves a standard white emission and a high EQE of 35.6%, confirming the universality of our strategy. This work presents a versatile strategy to harmonize singlet exciton radiation and triplet exciton up-conversion, thus achieving a win-win situation of efficiency and stability.
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Affiliation(s)
- Manli Huang
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, P. R. China
- Shenzhen Key Laboratory of New Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, P. R. China
| | - Zhanxiang Chen
- Shenzhen Key Laboratory of New Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, P. R. China
| | - Jingsheng Miao
- Shenzhen Key Laboratory of New Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, P. R. China
| | - Siyuan He
- Shenzhen Key Laboratory of New Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, P. R. China
| | - Wei Yang
- Shenzhen Key Laboratory of New Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, P. R. China
| | - Zhongyan Huang
- Shenzhen Key Laboratory of New Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, P. R. China
| | - Yang Zou
- Shenzhen Key Laboratory of New Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, P. R. China
| | - Shaolong Gong
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, P. R. China
| | - Yao Tan
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, P. R. China
| | - Chuluo Yang
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, P. R. China.
- Shenzhen Key Laboratory of New Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, P. R. China.
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Zhu Z, Wei X, Liang W. A theoretical investigation of benzothiadiazole derivatives for high efficiency OLEDs. J Comput Chem 2024; 45:1603-1613. [PMID: 38520729 DOI: 10.1002/jcc.27352] [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: 12/04/2023] [Revised: 03/07/2024] [Accepted: 03/12/2024] [Indexed: 03/25/2024]
Abstract
It is of great importance and worthy of efforts to give a clear structure-property relationship and microscopic mechanism of fluorescence emitters with high quantum yield. In this work, we perform a detailed computational investigation to give an explanation to the high efficiency of a fluorescence emitter XBTD-NPh based TADF sensitized fluorescence (TSF) OLEDs, and construct a symmetry structure DSBNA-BTD. Theoretical calculations show that XBTD-NPh is a long-time phosphorescent material at 77 K and TADF is attributed to the RISC of T1 to S1 state. For DSBNA-BTD, excitons arrived at T1 state comes to a large rate of nonradiatively path to the ground state, meaning it is may not be an efficient TADF molecule. For both molecules, the fast IC between T2 and T1 state results in that the hot exciton channel T1-Tn-S1 makes no contribution to the TADF.
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Affiliation(s)
- Zhiye Zhu
- Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, College of Chemical and Materials Engineering, Xuchang University, Henan, People's Republic of China
| | - Xiaoqing Wei
- Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, College of Chemical and Materials Engineering, Xuchang University, Henan, People's Republic of China
| | - Wanzhen Liang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, People's Republic of China
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Lou J, Li G, Guo X, Li B, Yang D, Zhang H, Wang Z, Tang BZ. Creation of High-Quality Deep-Blue AIE Emitter with a Crossed Long-Short Axis Structure for Efficient and Versatile OLEDs. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2308468. [PMID: 38009497 DOI: 10.1002/smll.202308468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 11/06/2023] [Indexed: 11/29/2023]
Abstract
Developing deep-blue emitters for organic light-emitting diodes (OLEDs) is critical but challenging, which requires a good balance between light color, exciton utilization, and photoluminescence quantum yield (PLQY) of solid film. Herein, a high-quality deep-blue emitter, abbreviated 2TriPE-CzMCN, is designed by introducing an aggregation-induced emission (AIE) group into a crossed long-short axis (CLSA) skeleton. Theoretical and experimental investigations reveal that the CLSA molecular design can achieve a balance between deep-blue emission and triplet-excitons utilization, while the high PLQY of the solid film resulting from the AIE feature helps to improve the performance of OLEDs. Consequently, when 2TriPE-CzMCN is used as the emitting dopant, the OLED exhibits a deep-blue emission at 430 nm with a record-high maximum external quantum efficiency (EQE) of 8.84%. When 2TriPE-CzMCN serves as the host material, the sensitized monochrome orange and two-color white OLEDs (WOLEDs) realize high EL performances that exceed the efficiency limit of conventional fluorescent OLEDs. Moreover, high-performance three-color WOLEDs with a color rendering index (CRI) exceeding 90 and EQE up to 18.08% are achieved by using 2TriPE-CzMCN as the blue-emitting source. This work demonstrates that endowing CLSA molecule with AIE feature is an effective strategy for developing high-quality deep-blue emitters, and high-performance versatile OLEDs can be realized through rational device engineering.
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Affiliation(s)
- Jingli Lou
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, P. R. China
| | - Ganggang Li
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, P. R. China
| | - Xuecheng Guo
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, P. R. China
| | - Baoxi Li
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, P. R. China
| | - Dezhi Yang
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, P. R. China
| | - Han Zhang
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, P. R. China
| | - Zhiming Wang
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, P. R. China
| | - Ben Zhong Tang
- Shenzhen Institute of Aggregate Science and Technology, School of Science and Engineering, The Chinese University of Hong Kong (Shenzhen), Shenzhen, 518172, P. R. China
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Dey S, Deka R, Upadhyay M, Peethambaran S, Ray D. White Light Emission via Dual Thermally Activated Delayed Fluorescence from a Single-Component Phenothiazines-Diphenyl Quinoline Conjugate. J Phys Chem Lett 2024; 15:3135-3141. [PMID: 38477646 DOI: 10.1021/acs.jpclett.4c00185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
White light emission (WLE) via dual thermally activated delayed fluorescence (TADF) from a single-component-based organic system remains challenging as a result of the difficulty in design. Here, we introduce a conformational isomerization approach to achieve WLE from a twisted donor-acceptor (PTzQP1) that comprises two phenothiazines covalently attached to the 6,8-isomeric positions of 2,4-diphenyl quinoline via two C-N single bonds. Spectroscopic studies and quantum chemistry calculations revealed that PTzQP1 shows WLE via simultaneous blue TADF and orange TADF covering the visible range (420-800 nm) with a photoluminescence quantum yield of 45 ± 2% and Commission Internationale de l'Éclairage (CIE) coordinates of 0.30, 0.33. The dual TADF features with high rates of reverse intersystem crossing (kRISC1 = 1.38 × 107 ± 0.24 s-1 and kRISC2 = 5.04 × 106 ± 0.32 s-1) are realized as a result of the low singlet-triplet gaps (S1EQ-T1EQ = 0.04 eV and S1QA-T1QA = 0.05 eV) of the quasi-axial (QA) and quasi-equatorial (QE) conformers. This finding is expected to provide a new direction for designing high-energy-efficient WLE emitters.
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Affiliation(s)
- Suvendu Dey
- Advanced Photofunctional Materials Laboratory, Department of Chemistry, Shiv Nadar Institution of Eminence, Delhi National Capital Region (NCR), NH-91, Tehsil Dadri, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Raktim Deka
- Advanced Photofunctional Materials Laboratory, Department of Chemistry, Shiv Nadar Institution of Eminence, Delhi National Capital Region (NCR), NH-91, Tehsil Dadri, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Manoj Upadhyay
- Advanced Photofunctional Materials Laboratory, Department of Chemistry, Shiv Nadar Institution of Eminence, Delhi National Capital Region (NCR), NH-91, Tehsil Dadri, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Sreerang Peethambaran
- Advanced Photofunctional Materials Laboratory, Department of Chemistry, Shiv Nadar Institution of Eminence, Delhi National Capital Region (NCR), NH-91, Tehsil Dadri, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Debdas Ray
- Advanced Photofunctional Materials Laboratory, Department of Chemistry, Shiv Nadar Institution of Eminence, Delhi National Capital Region (NCR), NH-91, Tehsil Dadri, Gautam Buddha Nagar, Uttar Pradesh 201314, India
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6
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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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Jang EB, Choi GS, Bae EJ, Ju BK, Park YW. Doping-Free Phosphorescent and Thermally Activated Delayed Fluorescent Organic Light-Emitting Diodes with an Ultra-Thin Emission Layer. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2366. [PMID: 37630950 PMCID: PMC10458739 DOI: 10.3390/nano13162366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023]
Abstract
We report the electroluminescence (EL) characteristics of blue ultra-thin emissive layer (U-EML) phosphorescent (PH) organic light-emitting diodes (OLED) and thermally activated delayed fluorescence (TADF) OLED. A variety of transport layer (TL) materials were used in the fabricated OLEDs. The well-known FIrpic and DMAC-DPS were used with a thickness of 0.3 nm, which is relatively thicker than the optimal thickness (0.15 nm) of the blue phosphorescent ultra-thin emissive layer to ensure sufficient energy transfer. While FIrpic showed overall high efficiency in various TLs, DMAC-DPS exhibited three times lower efficiency in limited TLs. To clarify/identify low efficiency and to improve the EL, the thickness of DMAC-DPS was varied. A significantly higher and comparable efficiency was observed with a thickness of 4.5 nm, which is 15 times thicker. This thickness was oriented from the TADF itself, which reduces quenching in a triplet-triplet annihilation compared to the PH process. The thinner optimal thickness compared with ~30 nm of fluorescent OLEDs suggests that there still is quenching taking place. We expect that the efficiency of TADF U-EML OLEDs can be enhanced through further research on controlling the exciton quenching using multiple U-EMLs with spacers and a novel material with a high energy transfer rate (ΔES-T).
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Affiliation(s)
- Eun-Bi Jang
- Nano and Organic-Electronics Laboratory, SunMoon University, Asan 31460, Republic of Korea; (E.-B.J.); (G.-S.C.)
| | - Geun-Su Choi
- Nano and Organic-Electronics Laboratory, SunMoon University, Asan 31460, Republic of Korea; (E.-B.J.); (G.-S.C.)
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, 145, Anam-ro, Seoul 02841, Republic of Korea
| | - Eun-Jeong Bae
- Nano and Organic-Electronics Laboratory, SunMoon University, Asan 31460, Republic of Korea; (E.-B.J.); (G.-S.C.)
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, 145, Anam-ro, Seoul 02841, Republic of Korea
| | - Byeong-Kwon Ju
- Display and Nanosystem Laboratory, Department of Electrical Engineering, Korea University, 145, Anam-ro, Seoul 02841, Republic of Korea
| | - Young-Wook Park
- Nano and Organic-Electronics Laboratory, SunMoon University, Asan 31460, Republic of Korea; (E.-B.J.); (G.-S.C.)
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Fang P, Huo P, Wang L, Zhao Z, Yu G, Huang Y, Bian Z, Liu Z. Lanthanide complexes with d-f transition: new emitters for single-emitting-layer white organic light-emitting diodes. LIGHT, SCIENCE & APPLICATIONS 2023; 12:170. [PMID: 37419880 DOI: 10.1038/s41377-023-01211-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/13/2023] [Accepted: 06/13/2023] [Indexed: 07/09/2023]
Abstract
White organic light-emitting diodes (WOLEDs) is a new generation of lighting technology and has stimulated wide-ranging studies. Despite the advantage of simple device structure, single-emitting-layer WOLEDs (SEL-WOLEDs) still face the challenges of difficult material screening and fine energy level regulation. Herein, we report efficient SEL-WOLEDs with a sky-blue emitting cerium(III) complex Ce-TBO2Et and an orange-red emitting europium(II) complex Eu(Tp2Et)2 as the emitters, showing a maximum external quantum efficiency of 15.9% and Commission Internationale de l'Eclairage coordinates of (0.33, 0.39) at various luminances. Most importantly, the electroluminescence mechanism of direct hole capture and hindered energy transfer between the two emitters facilitate a manageable weight doping concentration of 5% for Eu(Tp2Et)2, avoiding the low concentration (<1%) of the low-energy emitter in typical SEL-WOLEDs. Our results indicate that d-f transition emitters may circumvent fine energy level regulation and provide development potential for SEL-WOLEDs.
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Affiliation(s)
- Peiyu Fang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Peihao Huo
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Liding Wang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Zifeng Zhao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Gang Yu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Yanyi Huang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Zuqiang Bian
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Zhiwei Liu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China.
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9
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Jacob JM, Jennifer G A, Varathan E, Ravva MK. Improving the TADF in Corannulene‐Based Emitters via Tuning the Strength of Donor and Acceptor Groups. ADVANCED THEORY AND SIMULATIONS 2023. [DOI: 10.1002/adts.202200850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Affiliation(s)
- Jesni M. Jacob
- Department of Chemistry SRM University‐AP Guntur Andhra Pradesh 522240 India
| | - Abigail Jennifer G
- Department of Chemistry SRM Institute of Science and Technology Kattankulathur Chennai Tamil Nadu 603203 India
| | - Elumalai Varathan
- Department of Chemistry SRM Institute of Science and Technology Kattankulathur Chennai Tamil Nadu 603203 India
| | - Mahesh Kumar Ravva
- Department of Chemistry SRM University‐AP Guntur Andhra Pradesh 522240 India
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10
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Arshad MA. Kinetics of crystallization mechanisms in poly(3-hexylthiophene) and poly(9,9-dihexylfluorene-alt-2,5-didodecyloxybenzene) conjugated polymers. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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11
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Ding D, Wang Z, Duan C, Han C, Zhang J, Chen S, Wei Y, Xu H. White Fluorescent Organic Light-Emitting Diodes with 100% Power Conversion. RESEARCH (WASHINGTON, D.C.) 2022; 2022:0009. [PMID: 39290967 PMCID: PMC11407583 DOI: 10.34133/research.0009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/21/2022] [Indexed: 09/19/2024]
Abstract
Energy-efficient lighting sources are desired to provide another solution of carbon emission reduction. White organic light-emitting diodes are promising, because of theoretical internal quantum efficiencies for 100% electric-to-light conversion. However, pure organic fluorescent materials still face a challenge in harvesting triplet excitons for radiation. Herein, we report a white fluorescent organic light-emitting diode having an external quantum efficiency of 30.7% and a power efficiency of 120.2 lm W-1. In the single emissive layers, we use blue thermally activated delayed fluorescent emitters to sensitize a yellow fluorescent emitter. Transient photoluminescence and electroluminescence analyses suggest that a blue thermally activated delayed fluorescent molecule with ~100% reverse intersystem crossing efficiency and negligible triplet nonradiative rate constant completely converts triplet to singlet, suppressing triplet quenching by a yellow fluorescent emitter and ensuring 100% power conversion.
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Affiliation(s)
- Dongxue Ding
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials, Heilongjiang University, Harbin, Heilongjiang, China
| | - Zicheng Wang
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials, Heilongjiang University, Harbin, Heilongjiang, China
| | - Chunbo Duan
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials, Heilongjiang University, Harbin, Heilongjiang, China
| | - Chunmiao Han
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials, Heilongjiang University, Harbin, Heilongjiang, China
| | - Jing Zhang
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials, Heilongjiang University, Harbin, Heilongjiang, China
| | - Shuo Chen
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials, Heilongjiang University, Harbin, Heilongjiang, China
| | - Ying Wei
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials, Heilongjiang University, Harbin, Heilongjiang, China
| | - Hui Xu
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials, Heilongjiang University, Harbin, Heilongjiang, China
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12
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All-fluorescence white organic light-emitting diodes with record-beating power efficiencies over 130 lm W ‒1 and small roll-offs. Nat Commun 2022; 13:5154. [PMID: 36056014 PMCID: PMC9440051 DOI: 10.1038/s41467-022-32967-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 08/25/2022] [Indexed: 11/22/2022] Open
Abstract
Improving power efficiency (PE) and reducing roll-off are of significant importance for the commercialization of white organic light-emitting diodes (WOLEDs) in consideration of energy conservation. Herein, record-beating PE of 130.7 lm W−1 and outstanding external quantum efficiency (EQE) of 31.1% are achieved in all-fluorescence two-color WOLEDs based on a simple sandwich configuration of emitting layer consisting of sky-blue and orange delayed fluorescence materials. By introducing a red fluorescence dopant, all-fluorescence three-color WOLEDs with high color rendering index are constructed based on an interlayer sensitization configuration, furnishing ultrahigh PE of 110.7 lm W−1 and EQE of 30.8%. More importantly, both two-color and three-color WOLEDs maintain excellent PEs at operating luminance with smaller roll-offs than the reported state-of-the-art WOLEDs, and further device optimization realizes outstanding comprehensive performances of low driving voltages, large luminance, high PEs and long operational lifetimes. The underlying mechanisms of the impressive device performances are elucidated by host-tuning effect and electron-trapping effect, providing useful guidance for the development of energy-conserving all-fluorescence WOLEDs. High power efficiency and low roll-off values are essential to the commercialization of white organic light-emitting diodes. Here, the authors construct all-fluorescence devices with an orange emitting layer sandwiched between two sky-blue emitting layers, achieving figure-of-merit of 130.7 lm/W.
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13
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Lin C, Han P, Qu F, Xiao S, Li Y, Xie D, Qiao X, Yang D, Dai Y, Sun Q, Qin A, Tang BZ, Ma D. Suppressing singlet-triplet annihilation processes to achieve highly efficient deep-blue AIE-based OLEDs. MATERIALS HORIZONS 2022; 9:2376-2383. [PMID: 35789246 DOI: 10.1039/d2mh00627h] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Aggregation-induced emission (AIE) materials are attractive for the fabrication of high efficiency organic light-emitting diodes (OLEDs) by harnessing "hot excitons" from the high-lying triplet exciton states (Tn, n ≥ 2) and high photoluminescence (PL) quantum efficiency in solid films. However, the electroluminescence (EL) efficiency of most AIE-based OLEDs does not meet our expectation due to some unrevealed exciton loss processes. Herein, we further enhance the efficiency of blue AIE-based OLEDs, and find experimentally and theoretically that the serious exciton loss is caused by the quenching of radiative singlet excitons and long-lived triplet excitons [singlet-triplet annihilation (STA)]. In order to suppress the STA process, 1-(2,5-dimethyl-4-(1-pyrenyl)phenyl)pyrene (DMPPP) with triplet-triplet annihilation up-conversion was doped in two AIE emitters to reduce the triplet excitons on the lowest triplet excited state (T1) of AIE molecules. It can be seen that the external quantum efficiency (EQE) of the resulting blue OLEDs was enhanced to 11.8% with CIE coordinates of (0.15, 0.07) and a negligible efficiency roll-off, realizing the efficiency breakthrough of deep-blue AIE-based OLEDs. This work establishes a physical insight in revealing the exciton loss processes and the fabrication of high-performance AIE-based OLEDs.
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Affiliation(s)
- Chengwei Lin
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Pengbo Han
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Fenlan Qu
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Shu Xiao
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Yuanzhao Li
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Dian Xie
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Xianfeng Qiao
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Dezhi Yang
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Yanfeng Dai
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Qian Sun
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Anjun Qin
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Ben Zhong Tang
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
- Shenzhen Institute of Molecular Aggregate Science and Engineering, School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 2001 Longxiang Boulevard, Longgang District, Shenzhen City, Guangdong 518172, China
| | - Dongge Ma
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
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14
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Germino JC, Duarte LGTA, Mendes RA, Faleiros MM, de Morais A, de Freitas JN, Pereira L, Atvars TDZ. All-Solution Processed Single-Layer WOLEDs Using [Pt(salicylidenes)] as Guests in a PFO Matrix. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:2497. [PMID: 35889721 PMCID: PMC9316125 DOI: 10.3390/nano12142497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/06/2022] [Accepted: 07/12/2022] [Indexed: 02/01/2023]
Abstract
Herein, we report the synthesis and characterization of two Pt(II) coordination compounds, the new platinum(II)[N,N'-bis(salicylidene)-3,4-diaminobenzophenone)] ([Pt(sal-3,4-ben)]) and the already well-known platinum(II)[N,N'-bis(salicylidene)-o-phenylenediamine] ([Pt(salophen)]), along with their application as guests in a poly [9,9-dioctylfluorenyl-2,7-diyl] (PFO) conjugated polymer in all-solution processed single-layer white organic light-emitting diodes. Completely different performances were achieved: 2.2% and 15.3% of external quantum efficiencies; 2.8 cd A-1 and 12.1 cd A-1 of current efficiencies; and 3103 cd m-2 and 6224 cd m-2 of luminance for the [Pt(salophen)] and [Pt(sal-3,4-ben)] complexes, respectively. The Commission Internationale de l'Eclairage (CIE 1931) chromaticity color coordinates are (0.33, 0.33) for both 0.1% mol/mol Pt(II):PFO composites at between approximately 3.2 and 8 V. The optoelectronic properties of doped and neat PFO films have been investigated, using steady-state and time-resolved photoluminescence. Theoretical calculations at the level of relativistic density functional theory explained these results, based on the presence of the Pt(II) central ion's phosphorescence emission, considering spin-orbit coupling relationships. The overall results are explained, taking into account the active layer morphological properties, along with the device's electric balance and the emitter's efficiencies, according to deep-trap space-charge models. Considering the very simple structure of the device and the ease of synthesis of such compounds, the developed framework can offer a good trade-off for solution-deposited white organic light-emitting diodes (WOLEDs), with further applications in the field of lighting and signage.
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Affiliation(s)
- José Carlos Germino
- Chemistry Institute, University of Campinas—UNICAMP, Campinas 13083-862, Brazil; (L.G.T.A.D.); (M.M.F.); (T.D.Z.A.)
- Department of Physics and i3N—Institute for Nanostructures, Nanomodelling and Nanofabrication, University of Aveiro, 3810-193 Aveiro, Portugal
| | | | - Rodrigo Araújo Mendes
- São Carlos Institute of Chemistry, University of São Paulo—USP, São Carlos 13566-590, Brazil;
| | - Marcelo Meira Faleiros
- Chemistry Institute, University of Campinas—UNICAMP, Campinas 13083-862, Brazil; (L.G.T.A.D.); (M.M.F.); (T.D.Z.A.)
| | - Andreia de Morais
- Center for Information Technology Renato Archer—CTI, Campinas 13069-901, Brazil; (A.d.M.); (J.N.d.F.)
| | - Jilian Nei de Freitas
- Center for Information Technology Renato Archer—CTI, Campinas 13069-901, Brazil; (A.d.M.); (J.N.d.F.)
| | - Luiz Pereira
- Department of Physics and i3N—Institute for Nanostructures, Nanomodelling and Nanofabrication, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Teresa Dib Zambon Atvars
- Chemistry Institute, University of Campinas—UNICAMP, Campinas 13083-862, Brazil; (L.G.T.A.D.); (M.M.F.); (T.D.Z.A.)
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15
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Yang M, Zhao TX, Ji SC, Tao XD, Chen XL, Meng L, Liang D, Lu CZ. Voltage-Dependent Emission Varying from Blue to Orange–Red from a Nondoped Organic Light-Emitting Diode with a Single Emitter. NANOMATERIALS 2022; 12:nano12142333. [PMID: 35889558 PMCID: PMC9320025 DOI: 10.3390/nano12142333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 11/29/2022]
Abstract
Organic light-emitting diodes (OLEDs) with tunable emission colors, especially white OLEDs, have rarely been observed with a single emitter in a single emissive layer. In this paper, we report a new compound featuring a D–A–D structure, 9,9′-(pyrimidine-2,5-diylbis(2,1-phenylene))bis(3,6-di-tert-butyl-9H-carbazole) (PDPC). A nondoped OLED using this compound as a single emitter exhibits unique voltage-dependent dual emission. The emission colors range from blue to orange–red with an increase in voltage, during which white electroluminescence with a Commission Internationale De L’Eclairage (CIE) coordinate of (0.35, 0.29) and a color render index (CRI) value of 93 was observed. A comparative study revealed that the dual emission simultaneously originates from the monomers and excimers of the emitter. This study provides insight into understanding the multimer-excited mechanism and developing novel color-tunable OLEDs.
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Affiliation(s)
- Mingxue Yang
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (M.Y.); (T.-X.Z.); (S.-C.J.); (X.-D.T.); (X.-L.C.); (L.M.); (D.L.)
- Xiamen Institute of Rare Earth Materials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Xiamen 361021, China
| | - Tian-Xiang Zhao
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (M.Y.); (T.-X.Z.); (S.-C.J.); (X.-D.T.); (X.-L.C.); (L.M.); (D.L.)
- Xiamen Institute of Rare Earth Materials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Xiamen 361021, China
| | - Si-Chao Ji
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (M.Y.); (T.-X.Z.); (S.-C.J.); (X.-D.T.); (X.-L.C.); (L.M.); (D.L.)
- Xiamen Institute of Rare Earth Materials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xiao-Dong Tao
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (M.Y.); (T.-X.Z.); (S.-C.J.); (X.-D.T.); (X.-L.C.); (L.M.); (D.L.)
- Xiamen Institute of Rare Earth Materials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xu-Lin Chen
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (M.Y.); (T.-X.Z.); (S.-C.J.); (X.-D.T.); (X.-L.C.); (L.M.); (D.L.)
- Xiamen Institute of Rare Earth Materials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Xiamen 361021, China
| | - Lingyi Meng
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (M.Y.); (T.-X.Z.); (S.-C.J.); (X.-D.T.); (X.-L.C.); (L.M.); (D.L.)
- Xiamen Institute of Rare Earth Materials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Xiamen 361021, China
| | - Dong Liang
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (M.Y.); (T.-X.Z.); (S.-C.J.); (X.-D.T.); (X.-L.C.); (L.M.); (D.L.)
| | - Can-Zhong Lu
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (M.Y.); (T.-X.Z.); (S.-C.J.); (X.-D.T.); (X.-L.C.); (L.M.); (D.L.)
- Xiamen Institute of Rare Earth Materials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Xiamen 361021, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence:
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16
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Zhang C, Zhang D, Bin Z, Liu Z, Zhang Y, Lee H, Kwon JH, Duan L. Color-Tunable All-Fluorescent White Organic Light-Emitting Diodes with a High External Quantum Efficiency Over 30% and Extended Device Lifetime. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2103102. [PMID: 34293225 DOI: 10.1002/adma.202103102] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/20/2021] [Indexed: 06/13/2023]
Abstract
White organic light-emitting diodes (WOLEDs) with high efficiencies and tunable colors attracts considerable interest from the industry and academia. Thermally activated delayed-fluorescence (TADF) emitters can revolutionize such WOLED devices; however, they still suffer from poor performances. In this study, an advanced double-emissive-layer device architecture capable of hole-trapping TADF-sensitized emissions is proposed to not only achieve a recombination zone shift for the tunable colors but also accelerate exciton emission dynamics for high efficiency and alleviated roll-off. The proof-of-concept WOLEDs exhibit significant shifts in their Commission Internationale de l'Eclairage (CIE) coordinates and correlated color temperatures from (0.40, 0.47) and 4088 K at 100 cd m-2 to (0.27, 0.33) and 9269 K at 5000 cd m-2 . Additionally, the maximum external quantum efficiency (EQE) reaches 30.7% and remains >25% over a wide luminance range of 500-5000 cd m-2 , along with an extended LT80 of over 20 000 h at an initial luminance of 100 cd m-2 . This is the first time that all-fluorescent WOLEDs have been used to realize an EQE exceeding 30%, thereby establishing a new benchmark in this field.
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Affiliation(s)
- Chen Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Zhengyang Bin
- College of Chemistry, Sichuan University, Chengdu, 610064, P. R. China
| | - Ziyang Liu
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Yuewei Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Hyuna Lee
- Department of Information Display, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Jang Hyuk Kwon
- Department of Information Display, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
- Center for Flexible Electronics Technology Tsinghua University, Beijing, 100084, P. R. China
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17
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Yadav IS, Jang Y, Rout Y, Thomas MB, Misra R, D'Souza F. Near-IR Intramolecular Charge Transfer in Strongly Interacting Diphenothiazene-TCBD and Diphenothiazene-DCNQ Push-Pull Triads. Chemistry 2022; 28:e202200348. [PMID: 35275434 DOI: 10.1002/chem.202200348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Indexed: 12/15/2022]
Abstract
Three types of phenothiazines dimers (PTZ-PTZ, 1-3), covalently linked with one or two acetylene linkers, were synthesized by copper-mediated Eglinton and Pd-catalyzed Sonogashira coupling reactions in excellent yields. The dimers 1-3 were further engaged in [2+2] cycloaddition-retroelectrocyclization reactions with strong electron acceptors, tetracyanoethylene (TCNE) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) to yield tetracyanobutadiene (TCBD, 1 a-3 a), and dicyanoquinodimethane (DCNQ, 1 b-3 b) functionalized donor-acceptor (D-A) conjugates, respectively. The conjugates were examined by a series of spectral, computational, and electrochemical studies. Strong ground state polarization leading to new optical transitions was witnessed in both series of D-A conjugates. In the case of DCNQ derived D-A system 1 b, the optical coverage extended until 1200 nm in benzonitrile, making this a rare class of D-A ICT system. Multiple redox processes were witnessed in these D-A systems, and the frontier orbitals generated on DFT optimized structures further supported the ICT phenomenon. Photochemical studies performed using femtosecond pump-probe studies confirmed solvent polarity dependent excited state charge transfer and separation in these novel multi-modular D-A conjugates. The charge-separated states lasted up to 70 ps in benzonitrile while in toluene slightly prolonged lifetime of up to 100 ps was witnessed. The significance of phenothiazine dimer in wide-band optical capture all the way into the near-IR region and promoting ultrafast photoinduced charge transfer in the D-A-D configured multi-modular systems, and the effect of donor-acceptor distance and the solvent polarity was the direct outcome of the present study.
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Affiliation(s)
- Indresh S Yadav
- Department of Chemistry, Indian Institute of Technology, 453552, Indore, India
| | - Youngwoo Jang
- Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203-5017, USA
| | - Yogajivan Rout
- Department of Chemistry, Indian Institute of Technology, 453552, Indore, India
| | - Michael B Thomas
- Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203-5017, USA
| | - Rajneesh Misra
- Department of Chemistry, Indian Institute of Technology, 453552, Indore, India
| | - Francis D'Souza
- Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, TX 76203-5017, USA
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18
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Liu S, Zhang J, Zang C, Zhang L, Xie W, Lee CS. Centimeter-scale hole diffusion and its application in organic light-emitting diodes. SCIENCE ADVANCES 2022; 8:eabm1999. [PMID: 35486728 PMCID: PMC9054018 DOI: 10.1126/sciadv.abm1999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 03/14/2022] [Indexed: 06/14/2023]
Abstract
In conventional organic light-emitting diodes (OLEDs), current balance between electron and hole transport regions is typically achieved by leakage of the major carrier through the devices or by accumulation of the major carrier inside the devices. Both of these are known to reduce performances leading to reduction of efficiency and operation stability due to exciton-polaron annihilation, etc. We found that hole diffusion in a centimeter-scale can be achieved in a PEDOT:PSS layer via composition and interface engineering. This ultralong distance hole diffusion enables substantially enhanced hole diffusion current in the lateral direction perpendicular to the applied electric field in typical organic optoelectronic devices. By introducing this lateral hole diffusion layer (LHDL) at the anode side of OLEDs, reduced carrier accumulation, improved efficiency, and enhanced operation stability are demonstrated. The application of the LHDL provides a third strategy for current balancing with much reduced harmful effects from the previous two approaches.
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Affiliation(s)
- Shihao Liu
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong SAR 999077, People’s Republic of China
| | - Jiaming Zhang
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
| | - Chunxiu Zang
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
| | - Letian Zhang
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
| | - Wenfa Xie
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong SAR 999077, People’s Republic of China
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19
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Duan C, Xin Y, Wang Z, Zhang J, Han C, Xu H. High-efficiency hyperfluorescent white light-emitting diodes based on high-concentration-doped TADF sensitizer matrices via spatial and energy gap effects. Chem Sci 2021; 13:159-169. [PMID: 35059164 PMCID: PMC8694281 DOI: 10.1039/d1sc05753g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/24/2021] [Indexed: 01/05/2023] Open
Abstract
Despite the success of monochromatic hyperfluorescent (HF) organic light-emitting diodes (OLEDs), high-efficiency HF white OLEDs (WOLEDs) are still a big challenge. Herein, we demonstrate HF WOLEDs with state-of-the-art efficiencies, featuring a quasi-bilayer emissive layer (EML) composed of an ultrathin (0.1 nm) blue fluorescence (FL) emitter (TBPe) layer and a layer of thermally activated delayed fluorescence (TADF) sensitizer matrix heavily doped with a yellow FL emitter (TBRb, 3%). Based on an asymmetric high-energy-gap TADF sensitizer host (PhCzSPOTz), such an “ultrathin blue emitting layer (UTBL)” strategy endowed the HF WOLEDs with a record power efficiency of ∼80 lm W−1, approaching the level of fluorescent tubes. Transient photoluminescence (PL) and electroluminescence (EL) kinetics demonstrate that the spatial separation of TBPe from the TADF sensitizer and TBRb, and the large energy gap between the latter two effectively suppress triplet leakage, in addition to suppressing triplet diffusion in the PhCzSPOTz matrix with anisotropic intermolecular interactions. These results provide a new insight into the exciton allocation process in HF white light-emitting systems. A thermally activated delayed fluorescence host was developed to realize high-efficiency fluorescence white organic light-emitting diodes (WOLED) through spatial and energy gap effects.![]()
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Affiliation(s)
- Chunbo Duan
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Ying Xin
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Zicheng Wang
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Jing Zhang
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Chunmiao Han
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Hui Xu
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
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Li W, Tang J, Zheng Y, Peng J, Zhang J, Wei B, Li X. Improved stability of blue TADF organic electroluminescent diodes via OXD-7 based mixed host. FRONTIERS OF OPTOELECTRONICS 2021; 14:491-498. [PMID: 36637756 PMCID: PMC9743841 DOI: 10.1007/s12200-020-1069-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/22/2020] [Indexed: 06/17/2023]
Abstract
Thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have been demonstrated in applications such as displays and solid-state lightings. However, weak stability and inefficient emission of blue TADF OLEDs are two key bottlenecks limiting the development of solution processable displays and white light sources. This work presents a solution-processed OLED using a blue-emitting TADF small molecule bis[4-(9,9-dimethyl-9,10-dihydroacridine) phenyl]sulfone (DMAC-DPS) as an emitter. We comparatively investigated the effects of single host poly(N-vinylcarbazole) (PVK) and a co-host of 60% PVK and 30% 2,2'-(1,3-phenylene)-bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole] (OXD-7) on the device performance (the last 10% is emitter DMAC-DPS). The co-host device shows lower turn-on voltage, similar maximum luminance, and much slower external quantum efficiency (EQE) rolloff. In other words, device stability improved by doping OXD-7 into PVK, and the device impedance simultaneously and significantly reduced from 8.6 × 103 to 4.2 × 103 Ω at 1000 Hz. Finally, the electroluminescent stability of the co-host device was significantly enhanced by adjusting the annealing temperature.
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Affiliation(s)
- Weiguang Li
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200072, China
- School of Materials Science and Engineering, Shanghai University, Shanghai, 200072, China
| | - Jie Tang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200072, China
- School of Materials Science and Engineering, Shanghai University, Shanghai, 200072, China
| | - Yanqiong Zheng
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200072, China.
| | - Junbiao Peng
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Jianhua Zhang
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200072, China
| | - Bin Wei
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200072, China.
| | - Xifeng Li
- Key Laboratory of Advanced Display and System Applications of Ministry of Education, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200072, China
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21
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Tian Y, Wang H, Man Y, Zhang N, Zhang J, Li Y, Han C, Xu H. Weaving host matrices with intermolecular hydrogen bonds for high-efficiency white thermally activated delayed fluorescence. Chem Sci 2021; 12:14519-14530. [PMID: 34881003 PMCID: PMC8580069 DOI: 10.1039/d1sc04188f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 10/07/2021] [Indexed: 01/14/2023] Open
Abstract
A thermally activated delayed fluorescence (TADF) white organic light-emitting diode (WOLED) holds great promise for low-cost, large-scale lighting applications. Nevertheless, manipulating exciton allocation in a white TADF single layer is still a challenge. Herein, we demonstrate that the exciton kinetic process of dually doped white TADF films is strongly dependent on the grid regularity of the host matrix. Intermolecular hydrogen bonds (IHBs) are used to weave the matrices of two host molecules DPEQPO and DPSQPO featuring four phosphine oxide (PO) groups and different IHB orientations. The DPSQPO matrix forms regular grids to uniformly disperse and separate dopants, while DPEQPO exhibits chaotic IHBs, in turn inducing a heterogeneous dopant distribution. As a consequence, in both photoluminescence and electroluminescence processes, in contrast to DPEQPO hosted systems with comparable singlet Förster resonance energy transfer and triplet Dexter energy transfer, DPSQPO provides a FRET-predominant exciton allocation between blue and yellow dopants, which markedly suppresses triplet quenching and improves the white color purity, resulting in a state-of-the-art external quantum efficiency up to 24.2% of its single-emissive-layer pure-white TADF diode, in contrast to 16.0% for DPEQPO based analogs. These results indicate the significance of host engineering for exciton kinetics and suggest the feasibility of host grid design for developing high-performance TADF lighting. A thermally activated delayed fluorescence (TADF) white organic light-emitting diode (WOLED) holds great promise for low-cost, large-scale lighting applications.![]()
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Affiliation(s)
- Yuee Tian
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Huiqin Wang
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Yi Man
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Nan Zhang
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Jing Zhang
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Ying Li
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Chunmiao Han
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
| | - Hui Xu
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education & School of Chemistry and Material Science, Heilongjiang University 74 Xuefu Road Harbin 150080 P. R. China
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22
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Fu Y, Liu H, Yang D, Ma D, Zhao Z, Tang BZ. Boosting external quantum efficiency to 38.6% of sky-blue delayed fluorescence molecules by optimizing horizontal dipole orientation. SCIENCE ADVANCES 2021; 7:eabj2504. [PMID: 34669483 PMCID: PMC8528420 DOI: 10.1126/sciadv.abj2504] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/30/2021] [Indexed: 06/02/2023]
Abstract
To achieve high electroluminescence efficiency, great efforts are devoted to enhancing photoluminescence quantum yield (ΦPL) and exciton utilization of luminescent molecule, while another important factor, light out-coupling efficiency (ηout), receives less attention in molecule design. Here, we focus on horizontal dipole orientation engineering of the molecule to increase ηout and external quantum efficiency (ηext). A series of tailor-made luminescent molecules consisting of an electron-accepting carbonyl core plus double electron-donating groups of spiro[acridine-9,9′-fluorene] and carbazole derivatives [e.g., 1,3,5-tri(carbazol-9-yl)benzene] are developed and systematically investigated. These molecules hold distinguished merits of strong sky-blue delayed fluorescence with excellent ΦPL values, large horizontal dipole ratios, and balanced bipolar carrier transport, which furnish record-high ηext values of up to 26.1 and 38.6% in nondoped and doped sky-blue organic light-emitting diodes (OLEDs), respectively. Moreover, the state-of-the-art nondoped hybrid white OLED and all-fluorescence single-emitting layer white OLED are also realized, demonstrating great potentials in OLED industry of these molecules.
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Affiliation(s)
- Yan Fu
- 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
| | - 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
| | - Ben Zhong Tang
- 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
- Shenzhen Institute of Aggregate Science and Technology, School of Science and Engineering, Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
- AIE Institute, Guangzhou Development District, Huangpu, Guangzhou 510530, China
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23
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Han C, Du R, Xu H, Han S, Ma P, Bian J, Duan C, Wei Y, Sun M, Liu X, Huang W. Ladder-like energy-relaying exciplex enables 100% internal quantum efficiency of white TADF-based diodes in a single emissive layer. Nat Commun 2021; 12:3640. [PMID: 34131127 PMCID: PMC8206214 DOI: 10.1038/s41467-021-23941-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/14/2021] [Indexed: 11/17/2022] Open
Abstract
Development of white organic light-emitting diodes based on purely thermally activated delayed fluorescence with a single-emissive-layer configuration has been a formidable challenge. Here, we report the rational design of a donor-acceptor energy-relaying exciplex and its utility in fabricating single-emissive-layer, thermally activated delayed fluorescence-based white organic light-emitting diodes that exhibit 100% internal quantum efficiency, 108.2 lm W−1 power efficiency, and 32.7% external quantum efficiency. This strategy enables thin-film fabrication of an 8 cm × 8 cm thermally activated delayed fluorescence white organic light-emitting diodes (10 inch2) prototype with 82.7 lm W−1 power efficiency and 25.0% external quantum efficiency. Introduction of a phosphine oxide-based acceptor with a steric group to the exciplex limits donor-acceptor triplet coupling, providing dual levels of high-lying and low-lying triplet energy. Transient spectroscopic characterizations confirm that a ladder-like energy relaying occurs from the high-lying triplet level of the exciplex to a blue emitter, then to the low-lying triplet level of the phosphine oxide acceptor, and ultimately to the yellow emitter. Our results demonstrate the broad applicability of energy relaying in multicomponent systems for exciton harvesting, providing opportunities for the development of third-generation white organic light-emitting diode light sources. Realizing efficient white organic light-emitting diodes (WOLEDs) with a single thermally-activated delayed fluorescence (TADF) emissive layer remains a challenge. Here, the authors design energy-relaying exciplex hosts with multi-triplet excited states for efficient single-emissive-layer TADF WOLEDs.
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Affiliation(s)
- Chunmiao Han
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) & School of Chemistry and Material Science, Heilongjiang University, Harbin, PR China
| | - Ruiming Du
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) & School of Chemistry and Material Science, Heilongjiang University, Harbin, PR China
| | - Hui Xu
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) & School of Chemistry and Material Science, Heilongjiang University, Harbin, PR China.
| | - Sanyang Han
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Peng Ma
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) & School of Chemistry and Material Science, Heilongjiang University, Harbin, PR China
| | - Jinkun Bian
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) & School of Chemistry and Material Science, Heilongjiang University, Harbin, PR China
| | - Chunbo Duan
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) & School of Chemistry and Material Science, Heilongjiang University, Harbin, PR China
| | - Ying Wei
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) & School of Chemistry and Material Science, Heilongjiang University, Harbin, PR China
| | - Mingzhi Sun
- Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) & School of Chemistry and Material Science, Heilongjiang University, Harbin, PR China
| | - Xiaogang Liu
- Department of Chemistry, National University of Singapore, Singapore, Singapore.
| | - Wei Huang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Nanjing Tech University, Nanjing, China. .,Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), Xi'an, China.
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24
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Jang Y, Rout Y, Misra R, D’Souza F. Symmetric and Asymmetric Push–Pull Conjugates: Significance of Pull Group Strength on Charge Transfer and Separation. J Phys Chem B 2021; 125:4067-4075. [DOI: 10.1021/acs.jpcb.0c09996] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Youngwoo Jang
- Department of Chemistry, University of North Texas, 1155 Union Circle, # 305070, Denton, Texas 76203-5017, United States
| | - Yogajivan Rout
- Department of Chemistry, Indian Institute of Technology, Indore 453552, India
| | - Rajneesh Misra
- Department of Chemistry, Indian Institute of Technology, Indore 453552, India
| | - Francis D’Souza
- Department of Chemistry, University of North Texas, 1155 Union Circle, # 305070, Denton, Texas 76203-5017, United States
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25
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26
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Supramolecular self-assembly of an alkynylpyrene derivative and dye for modulation of white light. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2020.125940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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27
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Li X, Shen S, Zhang C, Liu M, Lu J, Zhu L. Small-molecule based thermally activated delayed fluorescence materials with dual-emission characteristics. Sci China Chem 2021. [DOI: 10.1007/s11426-020-9908-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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28
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Xu Y, Xu P, Hu D, Ma Y. Recent progress in hot exciton materials for organic light-emitting diodes. Chem Soc Rev 2020; 50:1030-1069. [PMID: 33231588 DOI: 10.1039/d0cs00391c] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
According to Kasha's rule, high-lying excited states usually have little effect on fluorescence. However, in some molecular systems, the high-lying excited states partly or even mainly contribute to the photophysical properties, especially in the process of harvesting triplet excitons in organic electroluminescent devices. In the current review, we focus on a type of organic light-emitting diode (OLED) materials called "hot exciton" materials, which can effectively harness the non-radiative triplet excitons via reverse intersystem crossing (RISC) from high-lying triplet states to singlet states (Tn→ Sm; n≥ 2, m≥ 1). Since Ma and Yang proposed the hot exciton mechanism for OLED material design in 2012, there have been many reports aiming at the design and synthesis of novel hot exciton luminogens. Herein, we present a comprehensive review of the recent progress in hot exciton materials. The developments of the hot exciton mechanism are reviewed, the fundamental principles regarding molecular design are discussed, and representative reported hot exciton luminogens are summarized and analyzed, along with their structure-property relationships and OLED applications.
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Affiliation(s)
- Yuwei Xu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China.
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29
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Zhang C, Lu Y, Liu Z, Zhang Y, Wang X, Zhang D, Duan L. A π-D and π-A Exciplex-Forming Host for High-Efficiency and Long-Lifetime Single-Emissive-Layer Fluorescent White Organic Light-Emitting Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2004040. [PMID: 32893390 DOI: 10.1002/adma.202004040] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Exciplex-forming hosts with thermally activated delayed fluorescence (TADF) provide a viable opportunity to unlock the full potential of the yet-to-be improved power efficiencies (PEs) and stabilities of all-fluorescent white organic light-emitting diodes (WOLEDs), but this, however, is hindered by the lack of stable blue exciplexes. Here, an advanced exciplex system is proposed by incorporating bipolar charge-transport π-spacers into both the electron-donor (D) and the electron-accepter (A) to increase their distance for hypsochromic-shifted emission while maintaining the superior transporting ability. By using spirofluorene as the π-spacer, 3,3'-bicarbazole as the D-unit, and 2,4,6-triphenyl-1,3,5-triazine as the A-unit, a π-D and π-A exciplex with sky-blue emission and fast reverse intersystem crossing process is thereof constructed. Combining this exciplex-forming host, a blue TADF-sensitizer, and a yellow conventional fluorescent dopant in a single-emissive-layer, the fabricated warm-white-emissive device simultaneously exhibits a low driving voltage of 3.08 V, an external quantum efficiency of 21.4%, and a remarkable T80 (time to 80% of the initial luminance) of >8200 h at 1000 cd m-2 , accompanied by a new benchmark PE of 69.6 lm W-1 among all-fluorescent WOLEDs.
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Affiliation(s)
- Chen Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Yang Lu
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Ziyang Liu
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Yuewei Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Xuewen Wang
- Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory, Xianhu Hydrogen Valley, Foshan, 528200, P. R. China
| | - Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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30
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Barman D, Gogoi R, Narang K, Iyer PK. Recent Developments on Multi-Functional Metal-Free Mechanochromic Luminescence and Thermally Activated Delayed Fluorescence Organic Materials. Front Chem 2020; 8:483. [PMID: 32695743 PMCID: PMC7338664 DOI: 10.3389/fchem.2020.00483] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/11/2020] [Indexed: 12/12/2022] Open
Abstract
Metal-free organic compounds with highly ordered π-conjugated twisted skeletons are capable of generating brilliant multi-colored light. Additionally, the co-existence of numerous other multi-functional properties have endowed them with the potential to be a promising class of materials for several electronic and photonic applications and next-generation advanced luminescent material-based devices. This review highlights the recent developments made in this fascinating class of multi-property encompassing materials, involving a highly twisted donor-acceptor based single molecular platform with synchronized photophysical behavior such as thermally activated delayed fluorescence (TADF), mechanoresponsive (MR), room-temperature phosphorescence (RTP), and aggregation induced emission (AIE) with associated unique and inherently manifested structure-property relationship investigations. Furthermore, a brief summary of the optoelectronic behavior of TADF materials are also presented by correlating their performances in the organic light-emitting diodes (OLEDs) and corresponding EL devices. In addition to mechanochromic luminescence (MCL) with TADF behavior, new types of emitters are also being developed, with tunable color changes such as blue-green, yellow-orange, yellow-red, etc., with some emitters crossing the entire visible span to produce white OLEDs. These developments have enriched the library of fascinating organic materials in addition to providing new directions of multifunctional material design for solutions processed OLED and several other advanced devices.
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Affiliation(s)
- Debasish Barman
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, India
| | - Rajdikshit Gogoi
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, India
| | - Kavita Narang
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, India
| | - Parameswar Krishnan Iyer
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, India.,Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, India
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31
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Xie FM, Zou SJ, Li Y, Lu LY, Yang R, Zeng XY, Zhang GH, Chen J, Tang JX. Management of Delayed Fluorophor-Sensitized Exciton Harvesting for Stable and Efficient All-Fluorescent White Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2020; 12:16736-16742. [PMID: 32193927 DOI: 10.1021/acsami.0c04251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
White organic light-emitting diodes (WOLEDs) using thermally activated delayed fluorescence (TADF)-based single emissive layer (SEL) have attracted enormous attention because of their simple device structure and full exciton utilization potential for high efficiency. However, WOLEDs made of an all-TADF SEL usually exhibit serious efficiency roll-off and poor color stability due to serious exciton-annihilation and unbalanced radiative decays of different TADF emitters. Herein, a new strategy is proposed to manipulate the TADF-sensitized fluorescence process by combining dual-host systems of high triplet energy with a conventional fluorescent emitter of complementary color. The multiple energy-funneling paths are modulated and short-range Dexter energy transfer is largely suppressed due to the steric effect of peripheral tert-butyl group in the blue TADF sensitizer. The resulting all-fluorescent WOLEDs achieve an unprecedentedly high external quantum efficiency of 21.8% with balanced white emission of Commission Internationale de l'Eclairage coordinate of (0.292, 0.343), accompanied with good color stability, reduced efficiency roll-off, and prolonged operational lifetime. These findings demonstrate the validity of this strategy for precisely allocating the exciton harvesting in SEL WOLEDs.
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Affiliation(s)
- Feng-Ming Xie
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, Jiangsu, China
| | - Shi-Jie Zou
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, Jiangsu, China
| | - Yanqing Li
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, Jiangsu, China
- School of Physics and Electronics Science, Nanophotonics & Advanced Instrument Engineering Research Center, Ministry of Education, East China Normal University, Shanghai 200062, China
| | - Lin-Yang Lu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, Jiangsu, China
| | - Rui Yang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, Jiangsu, China
| | - Xin-Yi Zeng
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, Jiangsu, China
| | - Guang-Hui Zhang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, Jiangsu, China
| | - Jingde Chen
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, Jiangsu, China
| | - Jian-Xin Tang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, Jiangsu, China
- Institute of Organic Optoelectronics (IOO), JITRI, Wujiang, Suzhou 215215, China
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32
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Liu Y, Liu H, Bai Q, Du C, Shang A, Jiang D, Tang X, Lu P. Pyrene[4,5- d]imidazole-Based Derivatives with Hybridized Local and Charge-Transfer State for Highly Efficient Blue and White Organic Light-Emitting Diodes with Low Efficiency Roll-Off. ACS APPLIED MATERIALS & INTERFACES 2020; 12:16715-16725. [PMID: 32180398 DOI: 10.1021/acsami.0c01846] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A family of pyrene[4,5-d]imidazole derivatives, PyPA, PyPPA, PyPPAC, and PyPAC, with different excited states are successfully developed. Among them, PyPPA and PyPPAC possess hybridized local and charge-transfer (HLCT) state, endowing them with pure blue fluorescence as well as high quantum yields. The nondoped organic light-emitting diode (OLED) based on PyPPA displays Commission Internationale de L'Eclairage coordinates of (0.14, 0.13) and achieves a maximum external quantum efficiency (EQE) of 8.47%, which are among the highest value reported to date for nondoped blue HLCT OLEDs. The nondoped OLED based on PyPPAC exhibits a maximum luminance of 50,046 cd m-2 located in the blue region with CIE coordinates of (0.15, 0.21) and an EQE of 6.74% even when the luminance reached over 10,000 cd m-2. In addition, they both reveal ultimate exciton utilizing efficiencies of nearly 100%. The potential of a blue emitter of PyPPA with an HLCT character for application in white OLED (WOLED) is further tested. The efficient two-color hybrid warm WOLED is successfully achieved, which provides the total EQE, power efficiency, and current efficiency of up to 21.19%, 61.46 lm W-1, and 62.13 cd A-1, respectively. The nondoped blue OLEDs and hybrid WOLEDs present good color stabilities with low efficiency roll-offs. Our results prove that taking advantage of the HLCT state, nondoped blue OLEDs as well as hybrid WOLEDs with high performance could be realized, which have a promising prospect for the displays and lightings in the future.
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Affiliation(s)
- Yulong Liu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
- Department of Applied Chemistry, Northeast Agricultural University, Harbin 150030, China
| | - Hui Liu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Qing Bai
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Chunya Du
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Anqi Shang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Dongyan Jiang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Xiangyang Tang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Ping Lu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
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33
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Ding D, Wang Z, Li C, Zhang J, Duan C, Wei Y, Xu H. Highly Efficient and Color-Stable Thermally Activated Delayed Fluorescence White Light-Emitting Diodes Featured with Single-Doped Single Emissive Layers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906950. [PMID: 31990429 DOI: 10.1002/adma.201906950] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/12/2019] [Indexed: 05/15/2023]
Abstract
Despite their merits of environmental friendliness, low cost, and large-scale production, thermally activated delayed fluorescence (TADF) based white organic light-emitting diodes (WOLEDs) for daily lighting applications still face the formidable challenges of structural simplification and controllable exciton allocation. Here, the state-of-the-art full-TADF WOLEDs with features of the single-doped single emissive layers (EMLs) and ultrasimple trilayer structure are demonstrated. The EMLs are binary systems as yellow TADF emitter (4CzTPNBu) doped blue TADF matrix (ptBCzPO2 TPTZ) with the large steric hindrance and mismatched frontier molecular orbital energy levels to effectively restrain excessive blue-to-yellow triplet exciton transfer and host-dopant interaction induced triplet quenching. Simultaneously, Förster resonance energy transfer is utilized to optimize exciton allocation for the balance of blue and yellow emissions, giving rise to the photoluminescence quantum yield beyond 90%. Consequently, these single-doped EMLs endow their cool white, pure white, and warm white diodes with the high-quality and ultrastable white light and the 100% exciton utilization efficiencies through the extremely simple structures, making them competent for the diverse daily lighting applications.
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Affiliation(s)
- Dongxue Ding
- Key Laboratory of Functional Inorganic Material Chemistry, Chinese Ministry of Education & School of Chemistry and Material Science, Heilongjiang University, 74 Xuefu Road, Harbin, 150080, P. R. China
| | - Zicheng Wang
- Key Laboratory of Functional Inorganic Material Chemistry, Chinese Ministry of Education & School of Chemistry and Material Science, Heilongjiang University, 74 Xuefu Road, Harbin, 150080, P. R. China
| | - Chenyu Li
- Key Laboratory of Functional Inorganic Material Chemistry, Chinese Ministry of Education & School of Chemistry and Material Science, Heilongjiang University, 74 Xuefu Road, Harbin, 150080, P. R. China
| | - Jing Zhang
- Key Laboratory of Functional Inorganic Material Chemistry, Chinese Ministry of Education & School of Chemistry and Material Science, Heilongjiang University, 74 Xuefu Road, Harbin, 150080, P. R. China
| | - Chunbo Duan
- Key Laboratory of Functional Inorganic Material Chemistry, Chinese Ministry of Education & School of Chemistry and Material Science, Heilongjiang University, 74 Xuefu Road, Harbin, 150080, P. R. China
| | - Ying Wei
- Key Laboratory of Functional Inorganic Material Chemistry, Chinese Ministry of Education & School of Chemistry and Material Science, Heilongjiang University, 74 Xuefu Road, Harbin, 150080, P. R. China
| | - Hui Xu
- Key Laboratory of Functional Inorganic Material Chemistry, Chinese Ministry of Education & School of Chemistry and Material Science, Heilongjiang University, 74 Xuefu Road, Harbin, 150080, P. R. China
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Xu Y, Liang X, Liang Y, Guo X, Hanif M, Zhou J, Zhou X, Wang C, Yao J, Zhao R, Hu D, Qiao X, Ma D, Ma Y. Efficient Deep-Blue Fluorescent OLEDs with a High Exciton Utilization Efficiency from a Fully Twisted Phenanthroimidazole-Anthracene Emitter. ACS APPLIED MATERIALS & INTERFACES 2019; 11:31139-31146. [PMID: 31368304 DOI: 10.1021/acsami.9b10823] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A novel, efficient, deep-blue fluorescent emitter mPAC, with a meta-connected donor-acceptor structure containing phenanthroimidazole (PPI) as the donor and phenylcarbazole-substituted anthracene (An-CzP) as the acceptor, was designed and synthesized. The meta-linkage provided a highly twisted molecular conformation, which efficiently interrupts the intramolecular π-conjugation, resulting in a deep-blue emission. The optimized nondoped device based on mPAC displayed a deep-blue emission with a narrow full width at half-maximum of 56 nm and Commission Internationale de L'Eclairage coordinates of (0.16, 0.09). The maximum external quantum efficiency (EQEmax) is 6.76%, corresponding to a high exciton utilization efficiency (EUE) of 59.3-88.9%. Experimental results and theoretical analysis indicated that the high EUE is mainly ascribed to the reverse intersystem crossing (RISC) from T2 to S1, a "hot exciton" path in which the large T2-T1 energy gap (1.45 eV) and small T2-S1 energy difference (0.18 eV, T2 > S1) hamper the internal crossing from T2 to T1 and facilitate the RISC process. For the hot exciton path, the T2 state can be feasibly arranged to a high energy level, forming a thermal equilibrium with S1, even slightly higher than the deep-blue S1 to realize an exergonic RISC process, which is usually difficult for the thermally activated delayed fluorescence emitters.
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Affiliation(s)
- Yuwei Xu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Xiaoming Liang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Yiqian Liang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Xiaomin Guo
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Muddasir Hanif
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Jiadong Zhou
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Xuehong Zhou
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Cong Wang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Jingwen Yao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Ruiyang Zhao
- College of Chemical Engineering , Qingdao University of Science and Technology , Qingdao 266042 , P. R. China
| | - Dehua Hu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Xianfeng Qiao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. 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 , P. R. China
| | - Yuguang Ma
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
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