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Wang J, Yang Y, Gu F, Zhai X, Yao C, Zhang J, Jiang C, Xi X. Molecular Engineering Modulating the Singlet-Triplet Energy Splitting of Indolocarbazole-Based TADF Emitters Exhibiting AIE Properties for Nondoped Blue OLEDs with EQE of Nearly 20. ACS APPLIED MATERIALS & INTERFACES 2023; 15:59643-59654. [PMID: 38090754 DOI: 10.1021/acsami.3c14230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
The development of efficient blue thermally activated delayed fluorescence (TADF) emitters with an aggregation-induced emission (AIE) nature, for the construction of organic light-emitting diodes (OLEDs), is still insufficient. This can be attributed to the challenges encountered in molecular design, including the inherent trade-off between radiative decay and reverse intersystem crossing (RISC), as well as small singlet-triplet energy splitting (ΔEST) and the requirement for high photoluminescence quantum yields (ΦPL). Herein, we present the design of three highly efficient blue TADF molecules with AIE characteristics by combining π-extended donors with different acceptors to modulate the differences in the electron-donating and electron-withdrawing abilities. This approach not only ensures high emission efficiency by suppressing close π-π stacking, weakening nonradiative relaxation, and enhancing radiative transition but also maintains the equilibrium ratio between the triplet and singlet excitons by facilitating the process of RISC. These emitters exhibit AIE and TADF properties, featuring quick radiative rates and low nonradiative rates. The ΦPL of these emitters reached an impressive 88%. Based on their excellent comprehensive performance, nondoped PICzPMO and PICzPMO OLEDs achieved excellent electroluminescence performance, exhibiting maximum external quantum efficiency (EQEmax) of up to 19.5%, while the doped device achieved a higher EQEmax of 20.8%. This work demonstrated that by fusing π-extended large rigid donors with different acceptors, it is possible to regulate the difference in electron-donating and electron-withdrawing abilities, resulting in a small ΔEST, high ΦPL, and fast RISC process, which is a highly feasible strategy for designing efficient TADF molecules.
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Affiliation(s)
- Jinshan Wang
- Jiangsu Provincial Key Laboratory of Eco-Environmental Materials, School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Yuguang Yang
- Jiangsu Provincial Key Laboratory of Eco-Environmental Materials, School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Fei Gu
- Jiangsu Provincial Key Laboratory of Eco-Environmental Materials, School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Xuesong Zhai
- Jiangsu Provincial Key Laboratory of Eco-Environmental Materials, School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Chuang Yao
- Chongqing Key Laboratory of Extraordinary Bond Engineering and Advance Materials Technology (EBEAM), Yangtze Normal University, Chongqing 408100, China
| | - Jianfeng Zhang
- School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Cuifeng Jiang
- Jiangsu Provincial Key Laboratory of Eco-Environmental Materials, School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Xinguo Xi
- Jiangsu Provincial Key Laboratory of Eco-Environmental Materials, School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
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Park SW, Kim D, Rhee YM. Overcoming the Limitation of Spin Statistics in Organic Light Emitting Diodes (OLEDs): Hot Exciton Mechanism and Its Characterization. Int J Mol Sci 2023; 24:12362. [PMID: 37569740 PMCID: PMC10418923 DOI: 10.3390/ijms241512362] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
Triplet harvesting processes are essential for enhancing efficiencies of fluorescent organic light-emitting diodes. Besides more conventional thermally activated delayed fluorescence and triplet-triplet annihilation, the hot exciton mechanism has been recently noticed because it helps reduce the efficiency roll-off and improve device stability. Hot exciton materials enable the conversion of triplet excitons to singlet ones via reverse inter-system crossing from high-lying triplet states and thereby the depopulation of long-lived triplet excitons that are prone to chemical and/or efficiency degradation. Although their anti-Kasha characteristics have not been clearly explained, numerous molecules with behaviors assigned to the hot exciton mechanism have been reported. Indeed, the related developments appear to have just passed the stage of infancy now, and there will likely be more roles that computational elucidations can play. With this perspective in mind, we review some selected experimental studies on the mechanism and the related designs and then on computational studies. On the computational side, we examine what has been found and what is still missing with regard to properly understanding this interesting mechanism. We further discuss potential future points of computational interests toward aiming for eventually presenting in silico design guides.
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Affiliation(s)
- Soo Wan Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Dongwook Kim
- Department of Chemistry, Kyonggi University, Suwon 16227, Republic of Korea
| | - Young Min Rhee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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Liu X, Wang L, Feng Y, Cui D, Liu Z. Crystal structure of 8-hexyloxy-2-[( Z)-2-(naphthalen-2-yl)ethenyl]quinoline. Acta Crystallogr E Crystallogr Commun 2022; 78:770-773. [PMID: 35974831 PMCID: PMC9361378 DOI: 10.1107/s2056989022006740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 06/30/2022] [Indexed: 11/10/2022]
Abstract
In the title molecule, C27H27NO, the naphthalene and quinoline groups are both planar and subtend a dihedral angle of 15.47 (7)°. They are nearly coplanar with the cis-vinyl bridge and the hexyloxy chain, which adopts an all-trans conformation, resulting in transannular bifurcated intramolecular C—H⋯N,O contact. The crystal structure features γ-packing of the aromatic moieties, while the parallel packing of alkyl chains resembles that of alkanes. In the title molecule, C27H27NO, the naphthalene and quinoline groups are both planar and subtend a dihedral angle of 15.47 (7)°. They are nearly coplanar with the cis-vinyl bridge and the hexyloxy chain, which adopts an all-trans conformation, resulting in transannular bifurcated intramolecular C—H⋯N,O contact. The crystal structure features γ-packing of the aromatic moieties, while the parallel packing of alkyl chains resembles that of alkanes.
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Wang J, Jiang X, Liang T, Pan Y, Yang B. Theoretical study on the mechanism of hot excitons combined with aggregation-induced emission in efficient red fluorescent molecules. Phys Chem Chem Phys 2022; 24:17632-17640. [PMID: 35833615 DOI: 10.1039/d2cp02552c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorescent emitters with the hot exciton mechanism combined with aggregation induced emission (AIE) character show prospective applications in organic light emitting diodes (OLEDs). However, theoretical studies on amorphous states are limited. In this work, a theoretical study is performed on the photophysical properties of the reported compound 4-(7-(10-ethyl-10H-phenothiazin-3-yl)benzo[c][1,2,5]thiadiazol-4-yl)-N,N-diphenylaniline (PBTPA), which possesses a hot exciton mechanism and AIE. The aggregation states of this molecule in a film are given by molecular dynamics (MD) simulations, and then the photophysical properties are studied by using the QM/MM method with the consideration of the solid-state effect (SSE). The results explain the hot exciton and AIE mechanism of the molecule. First, there is a hot exciton channel between the S1 and T2 state of the PBTPA. Second, the conformational changes of PBTPA between the ground state and the excited state are restricted in the aggregate state. Last, in the low frequency region, the rotation motion is suppressed, and then the reorganization energy and Huang-Rhys (HR) factor in the aggregate state are much smaller. Therefore, the molecules show strong fluorescence efficiency in the aggregated state.
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Affiliation(s)
- Jiao Wang
- School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China.
| | - Xinnan Jiang
- School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China.
| | - Tingdong Liang
- School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China.
| | - Yuyu Pan
- School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China.
| | - Bing Yang
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, 130012, P. R. China
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Zhang C, Li X, Li Z, Wang Y, Lu J, Zhu L, Zhang F. Two-Stage Three-Dimensional Luminescent Sensing Strategy for Precisely Detecting a Wide Range of Water Content in Tetrahydrofuran. Anal Chem 2022; 94:7004-7011. [PMID: 35500230 DOI: 10.1021/acs.analchem.1c05600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of efficient sensors for detecting water content in organic solvents is highly desirable for various cases in the chemical industry. Relevant sensors based on luminescent materials are promising due to their superior sensitivity and visualization. However, reported luminescent probes are either aggregation-caused quenching-type molecules, which present an emission quenching effect in high water content, or aggregation induced emission-type luminogens, which exhibit weak emission in organic solvents. This factor narrows the targeted water-content sensing range. Herein, we developed a series of indoline-based donor-acceptor-donor luminogens involving twist intramolecular charge transfer and an aggregation-induced emission effect, which exhibited a unique "on-off-on" emission behavior in tetrahydrofuran with the continuous increase of water content from 0% to 99%. Simultaneously, the emission wavelength underwent a process of first red-shift and then blue-shift. Three-dimensional working curves based upon the log value of wavelength and emission intensity ratio versus water content in tetrahydrofuran were established with two-stage characteristics, aiming to visually detect a wide range of water content in organic solvents. Such a sensing method offers extra sensitivity, convenience, and accuracy.
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Affiliation(s)
- Chenchen Zhang
- State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Xuping Li
- State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan, 030024, China.,Department of Macromolecular Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200433, China.,Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, China
| | - Ziqi Li
- State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Yan Wang
- State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Jianjun Lu
- State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Liangliang Zhu
- Department of Macromolecular Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200433, China
| | - Fan Zhang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, China
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Bai X, Wu SX, Duan YC, Pan QQ, Gao FW, Kan YH, Su ZM. Turning conventional non-TADF units into high-lying reverse intersystem crossing TADF emitters: different symmetric D–A–D-type modified donor units. NEW J CHEM 2022. [DOI: 10.1039/d2nj02484e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DFT and TD-DFT calculations were performed to turn conventional non-TADF units into high-lying reverse intersystem crossing D–A–D-type TADF emitters.
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Affiliation(s)
- Xue Bai
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Shui-xing Wu
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province, School of Chemistry & Chemical Engineering, Hainan Normal University, Haikou 571158, China
| | - Ying-chen Duan
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Qing-qing Pan
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Feng-wei Gao
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
- Chongqing Research Institute, Changchun University of Science and Technology, No. 618 Liangjiang Avenue, Longxing Town, Yubei District, Chongqing City 401135, China
| | - Yu-he Kan
- Jiangsu Province Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai’an 223300, China
| | - Zhong-min Su
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
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Sudyoadsuk T, Funchien P, Petdee S, Loythaworn T, Chasing P, Waengdongbung W, Saenubol A, Hadsadee S, Jungsuttiwong S, Promarak V. Benzothiadiazole-based fluorophores as efficient non-doped emitters for solution-processed organic light-emitting diodes. NEW J CHEM 2022. [DOI: 10.1039/d2nj04354h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
New HLCT fluorophores are synthesized and successfully applied as non-doped emissive layers in solution-processed double-layered OLEDs. These devices exhibit intense yellow-green emission colors with superior performance.
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Affiliation(s)
- Taweesak Sudyoadsuk
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Patteera Funchien
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Sujinda Petdee
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Thidarat Loythaworn
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Pongsakorn Chasing
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Wijitra Waengdongbung
- Research Network of NANOTEC-VISTEC on Nanotechnology for Energy, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Atthapon Saenubol
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Sarinya Hadsadee
- Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Warinchumrap, Ubon Ratchathani 34190, Thailand
| | - Siriporn Jungsuttiwong
- Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Warinchumrap, Ubon Ratchathani 34190, Thailand
| | - Vinich Promarak
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
- Research Network of NANOTEC-VISTEC on Nanotechnology for Energy, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
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Tang X, Liu H, Xu L, Xu X, He X, Liu F, Chen J, Peng Q. Achieving High Efficiency at High Luminance in Fluorescent Organic Light-Emitting Diodes through Triplet-Triplet Fusion Based on Phenanthroimidazole-Benzothiadiazole Derivatives. Chemistry 2021; 27:13828-13839. [PMID: 34291514 DOI: 10.1002/chem.202102136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Indexed: 11/09/2022]
Abstract
Achieving high efficiency at high luminance is one of the most important prerequisites towards practical application of any kind of light-emitting diode (LED). Herein, we report highly emissive organic fluorescent molecules based on phenanthroimidazole-benzothiadiazole derivatives capable of maintaining high external quantum efficiency (EQE) at high luminance enabled by triplet-triplet fusion (TTF) in doped organic LEDs. The PIBzP-, PIBzPCN-, and PIBzTPA-based devices showed EQEs of 8.27, 9.15, and 8.64 %, respectively, at luminance of higher than 1000 cd m-2 , with little efficiency roll-off.
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Affiliation(s)
- Xiangyang Tang
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, 38 Zheda Road, 310027, Hangzhou, P. R. China
| | - Hui Liu
- State Key Lab of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, 2699 Qianjin Avenue, 130012, Changchun, P. R. China
| | - Lei Xu
- Key Laboratory of Flexible Electronics (KLOFE) &, Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, 211816, Nanjing, P. R. China
| | - Xuehui Xu
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, 38 Zheda Road, 310027, Hangzhou, P. R. China
| | - Xin He
- State Key Lab of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, 2699 Qianjin Avenue, 130012, Changchun, P. R. China
| | - Futong Liu
- State Key Lab of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, 2699 Qianjin Avenue, 130012, Changchun, P. R. China
| | - Jianwu Chen
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, 38 Zheda Road, 310027, Hangzhou, P. R. China
| | - Qiming Peng
- Key Laboratory of Flexible Electronics (KLOFE) &, Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, 211816, Nanjing, P. R. China
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Tang X, Liu H, Liu F, He X, Xu X, Chen J, Peng Q, Lu P. Efficient Red Electroluminescence From Phenanthro[9,10-d]imidazole-Naphtho[2,3-c][1,2,5]thiadiazole Donor-Acceptor Derivatives. Chem Asian J 2021; 16:1942-1948. [PMID: 34003594 DOI: 10.1002/asia.202100391] [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: 04/12/2021] [Revised: 05/17/2021] [Indexed: 01/18/2023]
Abstract
Red emission is one of the three primary colors and is indispensable for full color displays. Fluorescent materials that can generate efficient red electroluminescence (EL) are limited and need to be developed. In this work, we report efficient red emitters based on phenanthro[9,10-d]imidazole-naphtho[2,3-c][1,2,5]thiadiazole donor-acceptor derivatives. The molecules, abbreviated as PINzP and PINzPCN, exhibited high photoluminescence quantum yield (PLQY) up to unity in doped films. They can also reach a relatively high PLQY of ∼30% in neat films. PINzP and PINzPCN were capable of generating efficient red EL in doped devices with a maximum external quantum efficiency (EQE) of 6.96% and 5.92%, respectively.
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Affiliation(s)
- Xiangyang Tang
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, 38 Zheda Road, 310027, Hangzhou, P. R. China.,State Key Lab of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, 2699 Qianjin Avenue, 130012, Changchun, P. R. China
| | - Hui Liu
- State Key Lab of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, 2699 Qianjin Avenue, 130012, Changchun, P. R. China
| | - Futong Liu
- State Key Lab of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, 2699 Qianjin Avenue, 130012, Changchun, P. R. China
| | - Xin He
- State Key Lab of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, 2699 Qianjin Avenue, 130012, Changchun, P. R. China
| | - Xuehui Xu
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, 38 Zheda Road, 310027, Hangzhou, P. R. China
| | - Jianwu Chen
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, 38 Zheda Road, 310027, Hangzhou, P. R. China
| | - Qiming Peng
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, 211816, Nanjing, P. R. China
| | - Ping Lu
- State Key Lab of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, 2699 Qianjin Avenue, 130012, Changchun, P. R. China
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