1
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Chen YS, Lin IH, Huang HY, Liu SW, Hung WY, Wong KT. Exciplex-forming cohost systems with 2,7-dicyanofluorene acceptors for high efficiency red and deep-red OLEDs. Sci Rep 2024; 14:2458. [PMID: 38291066 PMCID: PMC10827723 DOI: 10.1038/s41598-024-52680-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 01/21/2024] [Indexed: 02/01/2024] Open
Abstract
Two 2,7-dicyaonfluorene-based molecules 27-DCN and 27-tDCN are utilized as acceptors (A) to combine with hexaphenylbenzene-centered donors (D) TATT and DDT-HPB for probing the exciplex formation. The photophysical characteristics reveal that the steric hindered 27-tDCN not only can increase the distance of D and A, resulting in a hypsochromic emission, but also dilute the concentration of triplet excitons to suppress non-radiative process. The 27-tDCN-based exciplex-forming blends exhibit better photoluminescence quantum yield (PLQY) as compared to those of 27-DCN-based pairs. In consequence, among these D:A blends, the device employing DDT-HPB:27-tDCN blend as the emissiom layer (EML) exhibits the best EQE of 3.0% with electroluminescence (EL) λmax of 542 nm. To further utilize the exciton electrically generated in exciplex-forming system, two D-A-D-configurated fluorescence emitter DTPNT and DTPNBT are doped into the DDT-HPB:27-tDCN blend. The nice spectral overlap ensures fast and efficient Förster energy transfer (FRET) process between the exciplex-forming host and the fluorescent quests. The red device adopting DDT-HPB:27-tDCN:10 wt% DTPNT as the EML gives EL λmax of 660 nm and maximum external quantum efficiency (EQEmax) of 5.8%, while EL λmax of 685 nm and EQE of 5.0% for the EML of DDT-HPB:27-tDCN:10 wt% DTPNBT. This work manifests a potential strategy to achieve high efficiency red and deep red OLED devices by incorporating the highly fluorescent emitters to extract the excitons generated by the exciplex-forming blend with bulky acceptor for suppressing non-radiative process.
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Affiliation(s)
- Yi-Sheng Chen
- Organic Electronic Research Center, Ming Chi University of Technology, New Taipei City, 24031, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - I-Hung Lin
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan
| | - Hsin-Yuan Huang
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan
| | - Shun-Wei Liu
- Organic Electronic Research Center, Ming Chi University of Technology, New Taipei City, 24031, Taiwan
| | - Wen-Yi Hung
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan.
| | - Ken-Tsung Wong
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan.
- Institute of Atomic and Molecular Science Academia Sinica, Taipei, 10617, Taiwan.
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Gu J, Shi W, Zheng H, Chen G, Wei B, Wong WY. The Novel Organic Emitters for High-Performance Narrow-Band Deep Blue OLEDs. Top Curr Chem (Cham) 2023; 381:26. [PMID: 37632653 DOI: 10.1007/s41061-023-00436-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 08/15/2023] [Indexed: 08/28/2023]
Abstract
Narrow-band deep-blue organic light-emitting diodes (OLEDs) have played a key role in the field of high-quality full-color displays. However, because of the considerable challenges of inherent band gaps, unbalanced carrier injection and the lack of molecular structures, narrow-band deep-blue emitters develop slowly compared with red- and green-emitting materials. Encouragingly, with the continuous efforts of scientists in recent years, great progress has been made in the molecule design and material synthesis of highly efficient narrow-band deep-blue emitters. The typical deep-blue emitters which exhibit narrow emission with a full width at half maximum of < 50 nm are summarized in this article. They are divided into the three categories: fluorescence, phosphorescence and thermally activated delayed fluorescence. The methods of molecular design for realizing narrow-band deep-blue emission are described in detail and future research directions are also discussed in this article.
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Affiliation(s)
- Jialu Gu
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200444, China
| | - Wei Shi
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200444, China
| | - Haixia Zheng
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200444, China
| | - Guo Chen
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200444, China
| | - Bin Wei
- School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200444, China.
| | - Wai-Yeung Wong
- Department of Applied Biology and Chemical Technology and Research Institute for Smart Energy, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 100872, China.
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen, 518057, Guangdong, China.
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Cao HT, Hou PF, Yu WJ, Gao Y, Li B, Feng QY, Zhang H, Wang SS, Su ZM, Xie LH. Enhanced Efficiency of Exciplex Emission from a 9-Phenylfluorene Derivative. ACS APPLIED MATERIALS & INTERFACES 2023; 15:7236-7246. [PMID: 36700822 DOI: 10.1021/acsami.2c22266] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The exciplex-thermally activated delayed fluorescence (exciplex-TADF) system is an excellent candidate for the fabrication of high-efficiency organic light-emitting diodes (OLEDs) because of its more easily achieved small singlet-triplet energy splitting (ΔEST) and doping control. However, exciplex-TADF is still faced with the problems of low external quantum efficiency (ηext) and unclear effect of structure modification in electron acceptors. Herein, we provide a steric hindrance increase strategy to obtain high-efficiency exciplex emissions. Through introducing a 9-phenylfluorene group into N-ethylcarbazole of the dicyano-substituted 9-phenylfluorene, an electron acceptor material with increased steric hindrance is obtained, which helps the exciplex harvest a larger driving force and higher emission efficiencies. Encouragingly, the obtained OLED displays a maximum ηext of 25.8%, which is one of the best efficiency values among reported exciplex-OLEDs, simultaneously possessing excellent current efficiency of 83.6 cd A-1 and power efficiency of 93.7 lm W-1. It is expected that this work will offer a new avenue for designing electron acceptors for highly efficient exciplex emissions.
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Affiliation(s)
- Hong-Tao Cao
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Peng-Fei Hou
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Wen-Jing Yu
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Ying Gao
- Institute of Biomass Functional Materials Interdisciplinary Studies, Jilin Engineering Normal University, 3050 Kaixuan Road, Changchun 130052, P.R. China
| | - Bo Li
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Quan-You Feng
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - He Zhang
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Sha-Sha Wang
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Zhong-Min Su
- College of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun 130024, P.R. China
| | - Ling-Hai Xie
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
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Liu GC, Huang TH, Wang HW, Hsu CH, Chou PT, Hung WY, Wong KT. Exciplex-Forming Cohost Systems with 2,3-Dicyanopyrazinophenanthrene-based Acceptors to Achieve Efficient Near Infrared OLEDs. Chemistry 2023; 29:e202203660. [PMID: 36650716 DOI: 10.1002/chem.202203660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/26/2022] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Two new 2,3-dicyanopyrazinophenanthrene-based acceptors (A) p-QCN and m-QCN were synthesized to blend with a donor (D) CPTBF for the exciplex formation. The energy levels of p-QCN and m-QCN are modulated by the peripheral substituents 4- and 3-benzonitrile, respectively. Exciplex-forming blends were identified by the observation of the red-shifted emissions from various D : A blends with higher ratios of donor for suppressing the aggregation of acceptor. The two-component relaxation processes observed by time-resolved photoluminescence support the thermally activated delayed fluorescence (TADF) character of the exciplex-forming blends. The device employing CPTBF : p-QCN and (2 : 1) and CPTBF : m-QCN (2 : 1) blend as the emitting layer (EML) gave EQEmax of 1.76 % and 5.12 %, and electroluminescence (EL) λmax of 629 nm and 618 nm, respectively. The device efficiency can be further improved to 4.32 % and 5.57 % with CPTBF : p-QCN and (4 : 1) and CPTBF : m-QCN (4 : 1) as the EML, which is consistent with their improved photoluminescence quantum yields (PLQYs). A new fluorescent emitter BPBBT with photoluminescence (PL) λmax of 726 nm and a high PLQY of 67 % was synthesized and utilized as the dopant of CPTBF : m-QCN (4 : 1) cohost system. The device employing CPTBF : m-QCN (4 : 1): 5 wt.% BPBBT as the EML gave an EQEmax of 5.02 % and EL λmax centered at 735 nm, however, the weak residual exciplex emission remains. By reducing the donor ratio, the exciplex emission can be completely transferred to BPBBT and the corresponding device with CPTBF : m-QCN (2 : 1): 5 wt.% BPBBT as the EML can achieve EL λmax of 743 nm and EQEmax of 4.79 %. This work manifests the high efficiency near infrared (NIR) OLED can be realized by triplet excitons harvesting of exciplex-forming cohost system, followed by the effective energy transfer to an NIR fluorescent dopant.
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Affiliation(s)
- Guan-Cheng Liu
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Tzu-Hao Huang
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 202, Taiwan
| | - Hao-Wen Wang
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Chao-Hsien Hsu
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Wen-Yi Hung
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 202, Taiwan
| | - Ken-Tsung Wong
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan.,Institute of Atomic and Molecular Science, Academia Sinica, Taipei, 10617, Taiwan
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5
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Wei J, Yang Y, Liu X, Li R, Li S. 2,3‐Disubstituted Fluorene Scaffold for Efficient Green Phosphorescent Organic Light‐Emitting Diodes. Chemistry 2022; 28:e202200756. [DOI: 10.1002/chem.202200756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Jia‐Jia Wei
- School of Environment and Chemical Engineering Jiangsu Ocean University 59 Cangwu Road, Haizhou District Lianyungang 222005 P. R. China
| | - Yong‐Jian Yang
- School of Environment and Chemical Engineering Jiangsu Ocean University 59 Cangwu Road, Haizhou District Lianyungang 222005 P. R. China
| | - Xiang‐Yang Liu
- WISPO Advanced Materials (Suzhou) Co., Ltd. 200 Xingpu Road, Shengpu Street, Suzhou Industrial Park (SIP) Suzhou 215126 P. R. China
| | - Runlai Li
- College of Polymer Science & Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Shu‐an Li
- School of Environment and Chemical Engineering Jiangsu Ocean University 59 Cangwu Road, Haizhou District Lianyungang 222005 P. R. China
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6
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Hu Y, Chen L, Lin Z, Lee J, Wei W, Ko T, Lo C, Hung W, Wong K. Suppressing intermolecular interactions for enhancing the performance of exciplex‐based OLEDs. J CHIN CHEM SOC-TAIP 2022. [DOI: 10.1002/jccs.202200094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yuan‐Cheng Hu
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Li‐Ming Chen
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Zong‐Liang Lin
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Jhih‐Wei Lee
- Department of Optoelectronics and Materials Technology National Taiwan Ocean University Keelung Taiwan
| | - Wei‐Chih Wei
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Tzu‐Yu Ko
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Chun‐Yuan Lo
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Wen‐Yi Hung
- Department of Optoelectronics and Materials Technology National Taiwan Ocean University Keelung Taiwan
| | - Ken‐Tsung Wong
- Department of Chemistry National Taiwan University Taipei Taiwan
- Institute of Atomic and Molecular Science Academia Sinica Taipei Taiwan
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7
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Cho S, Kwon NY, Kim CW, Lee H, Ha JM, Kim HJ, Woo HY, Park S, Cho MJ, Choi DH. High Efficiency Solution-Processed Green Thermally Activated Delayed Fluorescence OLEDs using Polymer-Small Molecule Mixed Host. Polym Chem 2022. [DOI: 10.1039/d1py01700d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Development of suitable host materials for application to an emitter is of significant importance for the high-efficiency organic light-emitting diodes (OLEDs). In this study, we successfully synthesized poly(9,9-diphenyl-10-(4-vinylbenzyl)-9,10-dihydroacridine) (P(Bn-DPAc)) as...
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8
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Chen WL, Chen SY, Huang DC, Luo D, Chen HW, Wang CY, Chang CH. A Method to Realize Efficient Deep-Red Phosphorescent OLEDs with a Broad Spectral Profile and Low Operating Voltages. MATERIALS (BASEL, SWITZERLAND) 2021; 14:5723. [PMID: 34640113 PMCID: PMC8510200 DOI: 10.3390/ma14195723] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/25/2021] [Accepted: 09/27/2021] [Indexed: 12/02/2022]
Abstract
Organic light-emitting diodes (OLEDs) used as phototherapy light sources require sufficient spectral distribution in the effective wavelength ranges and low operating voltages. Herein, a double emitting layer structure consisting of a red-emitting Ir(piq)2acac and a deep-red Ir(fliq)2acac was designed to generate a broad electroluminescence spectrum. An efficient TCTA:CN-T2T exciplex system was used as the host of the emitting layer, facilitating effective energy transfer from the exciplex host to the red and deep-red phosphors. The materials used in the exciplex host were also used as the carrier transport layers to eliminate the energy barriers and thus increase the current density. The hole injection layer structures were varied to examine the hole injection capabilities and the carrier balance. The resulting optimized phosphorescent OLEDs with a broad spectral profile exhibit a 90% coverage ratio in the target ranges from 630 to 690 nm, together with a high peak efficiency of 19.1% (10.2 cd/A and 13.8 lm/W). The proposed device only needs 5.2 V to achieve a power density of 5 mW/cm2, implying that the device could be driven via two series-connected button cell batteries. These results illustrate the feasibility of our design concepts and demonstrate the realization of a portable and lightweight OLED phototherapy light source.
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Affiliation(s)
- Wei-Ling Chen
- Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan; (W.-L.C.); (S.-Y.C.); (D.-C.H.)
| | - Shan-Yu Chen
- Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan; (W.-L.C.); (S.-Y.C.); (D.-C.H.)
| | - Dun-Cheng Huang
- Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan; (W.-L.C.); (S.-Y.C.); (D.-C.H.)
| | - Dian Luo
- Institute of Lighting and Energy Photonics, National Yang Ming Chiao Tung University, Tainan 71150, Taiwan;
| | - Hsueh-Wen Chen
- Raystar Optronic, Inc., Taichung 42881, Taiwan; (H.-W.C.); (C.-Y.W.)
| | - Chih-Yuan Wang
- Raystar Optronic, Inc., Taichung 42881, Taiwan; (H.-W.C.); (C.-Y.W.)
| | - Chih-Hao Chang
- Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan; (W.-L.C.); (S.-Y.C.); (D.-C.H.)
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Dai G, Zhang M, Wang K, Fan X, Shi Y, Sun D, Liu W, Chen J, Yu J, Ou X, Xiong S, Zheng C, Zhang X. Nonconjugated Triptycene-Spaced Donor-Acceptor-Type Emitters Showing Thermally Activated Delayed Fluorescence via Both Intra- and Intermolecular Charge-Transfer Transitions. ACS APPLIED MATERIALS & INTERFACES 2021; 13:25193-25201. [PMID: 34013735 DOI: 10.1021/acsami.1c05646] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Thermally activated delayed fluorescence (TADF) emitters have aroused considerable attention, particularly for their great potential in organic light-emitting diodes (OLEDs). In typical TADF molecules, intramolecular charge transfer (CT) between electron-donor (D) and electron-acceptor (A) moieties is the dominant transition. Actually, CT transitions can possibly occur between different molecules as well. Herein, we used a nonconjugated triptycene (TPE) moiety to space D and A moieties and developed two novel emitters tBuDMAC-TPE-TRZ and tBuDMAC-TPE-TTR to explore the roles of intra- and intermolecular CT transitions. Along with weak intramolecular CT transitions, intermolecular CT transitions are dominant for tBuDMAC-TPE-TRZ and tBuDMAC-TPE-TTR neat films. Particularly, tBuDMAC-TPE-TRZ showed a high maximum external quantum efficiency of 10.0% in a nondoped solution-processed OLED, which was evidently higher than that of a corresponding 10 wt % tBuDMAC-TPE-TRZ-doped OLED with 4,4',4″-tris(carbazol-9-yl)triphenylamine (TCTA) as the host matrix. The results prove that intermolecular CT transitions indeed participate in the CT transition process in these systems and they are helpful to enhance the electroluminescence performance of emitting systems with weak intramolecular CT transitions.
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Affiliation(s)
- Gaole Dai
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Ming Zhang
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, Sichuan 610054, P. R. China
| | - Kai Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Xiaochun Fan
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Yizhong Shi
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Dianming Sun
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Wei Liu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Jiaxiong Chen
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Jia Yu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Xuemei Ou
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Shiyun Xiong
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
| | - Caijun Zheng
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, Sichuan 610054, P. R. China
| | - Xiaohong Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China
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Chen C, Cheng J, Ding W, Lin Z, Chen Y, Chiu T, Lo Y, Lee J, Wong K. New carboline‐based donors for green exciplex‐forming systems. J CHIN CHEM SOC-TAIP 2021. [DOI: 10.1002/jccs.202000456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Chia‐Hsun Chen
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Ju‐Ting Cheng
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Wen‐Cheng Ding
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei Taiwan
| | - Zong‐Liang Lin
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Yi‐Sheng Chen
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Tien‐Lung Chiu
- Department of Electrical Engineering Yuan Ze University Taoyuan Taiwan
| | - Yuan‐Chih Lo
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Jiun‐Haw Lee
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei Taiwan
| | - Ken‐Tsung Wong
- Department of Chemistry National Taiwan University Taipei Taiwan
- Institute of Atomic and Molecular Science, Academia Sinica Taipei Taiwan
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11
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Zhang M, Zheng CJ, Lin H, Tao SL. Thermally activated delayed fluorescence exciplex emitters for high-performance organic light-emitting diodes. MATERIALS HORIZONS 2021; 8:401-425. [PMID: 34821262 DOI: 10.1039/d0mh01245a] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Owing to their natural thermally activated delayed fluorescence (TADF) characteristics, the development of exciplex emitters for organic light-emitting diodes (OLEDs) has witnessed booming progress in recent years. Formed between electron-donating and electron-accepting molecules, exciplexes with intermolecular charge transfer processes have unique advantages compared with unimolecular TADF materials, offering a new way to develop high-performance TADF emitters. In this review, a comprehensive overview of TADF exciplex emitters is presented with a focus on the relationship between the constituents of exciplexes and their electroluminescence performance. We summarize and discuss the latest and most significant developments of TADF exciplex emitters. Notably, the design principles of efficient TADF exciplex emitters are systematically categorized into three systems within this review. These progressive achievements of TADF exciplex emitters point out future challenges to trigger more research endeavors in this growing field.
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Affiliation(s)
- Ming Zhang
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, 610054, P. R. China.
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12
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Zhang M, Liu W, Zheng C, Wang K, Shi Y, Li X, Lin H, Tao S, Zhang X. Tricomponent Exciplex Emitter Realizing over 20% External Quantum Efficiency in Organic Light-Emitting Diode with Multiple Reverse Intersystem Crossing Channels. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1801938. [PMID: 31380198 PMCID: PMC6661936 DOI: 10.1002/advs.201801938] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 04/11/2019] [Indexed: 06/10/2023]
Abstract
With the naturally separated frontier molecular orbitals, exciplexes are capable of thermally activated delayed fluorescence emitters for organic light-emitting diodes (OLEDs). And, the current key issue for exciplex emitters is improving their exciton utilization. In this work, a strategy of building exciplex emitters with three components is proposed to realize multiple reverse intersystem crossing (RISC) channels, improving their exciton utilization by enhancing upconversion of nonradiative triplet excitons. Accordingly, a tricomponent exciplex DBT-SADF:PO-T2T:CDBP is constructed with three RISC channels respectively on DBT-SADF, DBT-SADF:PO-T2T, and CDBP:PO-T2T. Furthermore, its photoluminescence quantum yield and rate constant of the RISC process are successfully improved. In the OLED, DBT-SADF:PO-T2T:CDBP exhibits a remarkably high maximum external quantum efficiency (EQE) of 20.5%, which is the first report with an EQE over 20% for the OLEDs based on exciplex emitters to the best of our knowledge. This work not only demonstrates that introducing multiple RISC channels can effectively improve the exciton utilization of exciplex emitters, but also proves the superiority of the tricomponent exciplex strategy for further development of exciplex emitters.
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Affiliation(s)
- Ming Zhang
- School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of China (UESTC)Chengdu610054P. R. China
- Institute of Functional Nano & Soft Materials (FUNSOM)Soochow UniversitySuzhou215123P. R. China
| | - Wei Liu
- Institute of Functional Nano & Soft Materials (FUNSOM)Soochow UniversitySuzhou215123P. R. China
| | - Cai‐Jun Zheng
- School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of China (UESTC)Chengdu610054P. R. China
| | - Kai Wang
- Institute of Functional Nano & Soft Materials (FUNSOM)Soochow UniversitySuzhou215123P. R. China
| | - Yi‐Zhong Shi
- Institute of Functional Nano & Soft Materials (FUNSOM)Soochow UniversitySuzhou215123P. R. China
| | - Xing Li
- Institute of Functional Nano & Soft Materials (FUNSOM)Soochow UniversitySuzhou215123P. R. China
| | - Hui Lin
- School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of China (UESTC)Chengdu610054P. R. China
| | - Si‐Lu Tao
- School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of China (UESTC)Chengdu610054P. R. China
| | - Xiao‐Hong Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM)Soochow UniversitySuzhou215123P. R. China
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13
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Song X, Zhang D, Li H, Cai M, Huang T, Duan L. Exciplex System with Increased Donor-Acceptor Distance as the Sensitizing Host for Conventional Fluorescent OLEDs with High Efficiency and Extremely Low Roll-Off. ACS APPLIED MATERIALS & INTERFACES 2019; 11:22595-22602. [PMID: 31198026 DOI: 10.1021/acsami.9b05963] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Exciplex systems with efficient thermally activated delayed fluorescence as the sensitizing hosts for fluorescent organic light-emitting diodes (OLEDs) have been flourished recently, while the device performances are still lagging behind. Here, a donor molecule sterically encapsulated with tert-butyl units is designed and synthesized to increase the donor-acceptor separation in an exciplex system, leading to reduced singlet-triplet energy gap (Δ ESTs) and improved reverse intersystem crossing (RISC) efficiency. OLEDs utilizing exciplexes with increased donor-acceptor distance ( rDA) as the hosts for conventional fluorescent dopants exhibit a maximum external quantum efficiency (EQEmax) as high as 16.5%, benefiting from the enhanced RISC process and suppressed exciton loss by the Dexter interaction. Furthermore, extremely low efficiency roll-off is obtained with EQEs of 16.2% at 5000 cd/m2 and 15.2% at 10 000 cd/m2. The results here represent the state-of-the-art performances for devices based on exciplexes as the hosts for conventional fluorescent dopants, manifesting the superiority of exciplexes with increased rDA as the sensitizing hosts for fluorescent dopants.
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Affiliation(s)
| | | | - Haoyuan Li
- School of Chemistry and Biochemistry, Center for Organic Photonics and Electronics (COPE) , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
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14
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Wu TL, Liao SY, Huang PY, Hong ZS, Huang MP, Lin CC, Cheng MJ, Cheng CH. Exciplex Organic Light-Emitting Diodes with Nearly 20% External Quantum Efficiency: Effect of Intermolecular Steric Hindrance between the Donor and Acceptor Pair. ACS APPLIED MATERIALS & INTERFACES 2019; 11:19294-19300. [PMID: 31046225 DOI: 10.1021/acsami.9b04365] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Exciplex emitters have emerged as an important class of thermally activated delayed fluorescence (TADF) materials for highly efficient OLEDs. A TADF exciplex emitter requires an intermolecular donor/acceptor pair. We have synthesized a bipolar donor-type material, DPSTPA, which was used to pair with known acceptor materials (2CzPN, 4CzIPN, or CzDBA). The OLEDs based on the exciplex emitters, DPSTPA/X, where X = 2CzPN and CzDBA, give green and orange-red colors with record-high external quantum efficiencies (EQEs) of 19.0 ± 0.6 and 14.6 ± 0.4%, respectively. In contrast, the exciplex pair DPSTPA/4CzIPN gave a very low photoluminescence quantum yield (PLQY) and a very low EQE value of the device. The DFT calculations indicate that the intermolecular distance between the donor and the acceptor plays a key factor for the PLQY and EQE. The observed low PLQY and the poor device performance for the DPSTPA/4CzIPN pair are probably because of the relatively long distance between the DPSTPA and 4CzIPN in the thin film caused by the four congested carbazole (Cz) groups of 4CzIPN, which effectively block the interaction of the nitrile acceptor with the triphenylamino donor of DPSTPA.
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Affiliation(s)
- Tien-Lin Wu
- Department of Chemistry , National Tsing Hua University , No. 101, Section 2, Kuang-Fu Road , Hsinchu 30013 , Taiwan
| | - Ssu-Yu Liao
- Department of Chemistry , National Tsing Hua University , No. 101, Section 2, Kuang-Fu Road , Hsinchu 30013 , Taiwan
| | - Pei-Yun Huang
- Department of Chemistry , National Tsing Hua University , No. 101, Section 2, Kuang-Fu Road , Hsinchu 30013 , Taiwan
| | - Zih-Siang Hong
- Department of Chemistry , National Cheng Kung University No. 1, Daxue Road , East District, Tainan 70101 , Taiwan
| | - Man-Ping Huang
- Department of Chemistry , National Tsing Hua University , No. 101, Section 2, Kuang-Fu Road , Hsinchu 30013 , Taiwan
| | - Chih-Chun Lin
- Department of Chemistry , National Tsing Hua University , No. 101, Section 2, Kuang-Fu Road , Hsinchu 30013 , Taiwan
| | - Mu-Jeng Cheng
- Department of Chemistry , National Cheng Kung University No. 1, Daxue Road , East District, Tainan 70101 , Taiwan
| | - Chien-Hong Cheng
- Department of Chemistry , National Tsing Hua University , No. 101, Section 2, Kuang-Fu Road , Hsinchu 30013 , Taiwan
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15
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Chapran M, Pander P, Vasylieva M, Wiosna-Salyga G, Ulanski J, Dias FB, Data P. Realizing 20% External Quantum Efficiency in Electroluminescence with Efficient Thermally Activated Delayed Fluorescence from an Exciplex. ACS APPLIED MATERIALS & INTERFACES 2019; 11:13460-13471. [PMID: 30864778 DOI: 10.1021/acsami.8b18284] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The investigation of nondoped exciplex blends of 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine (PO-T2T), working as the one-electron acceptor molecule, with different electron donors is reported. The emissions of these exciplexes span from the blue to orange-red regions, showing clear contribution from thermally activated delayed fluorescence (TADF) and delayed fluorescence originated from nongeminate recombination of charge carriers created by the dissociation of optically generated exciplexes. We focus our studies on the properties of TADF in these systems, covering in particular the physical meaning of the different transient components observed in their luminescence decays. Our results unravel the intricate role of reverse intersystem crossing due to spin-orbit coupling and possibly also due to hyperfine interactions and internal conversion, which affect the efficiency of the TADF mechanism. Remarkable performances are obtained in prototype organic light-emitting diodes fabricated with some of these blends. Green exciplex blends, in particular, exhibited the current efficiency of 60 cd A-1, power efficiency of 71 lm W-1, and external quantum efficiency of 20%. We believe that our results will contribute significantly to highlight the potential advantages of intermolecular exciplexes in the area of organic light-emitting diodes.
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Affiliation(s)
- Marian Chapran
- Department of Molecular Physics , Lodz University of Technology , Zeromskiego 116 , 90-924 Lodz , Poland
| | - Piotr Pander
- Physics Department , Durham University , South Road, Durham DH1 3LE , United Kingdom
| | - Marharyta Vasylieva
- Faculty of Chemistry , Silesian University of Technology , M. Strzody 9 , 44-100 Gliwice , Poland
| | - Gabriela Wiosna-Salyga
- Department of Molecular Physics , Lodz University of Technology , Zeromskiego 116 , 90-924 Lodz , Poland
| | - Jacek Ulanski
- Department of Molecular Physics , Lodz University of Technology , Zeromskiego 116 , 90-924 Lodz , Poland
| | - Fernando B Dias
- Physics Department , Durham University , South Road, Durham DH1 3LE , United Kingdom
| | - Przemyslaw Data
- Physics Department , Durham University , South Road, Durham DH1 3LE , United Kingdom
- Faculty of Chemistry , Silesian University of Technology , M. Strzody 9 , 44-100 Gliwice , Poland
- Centre of Polymer and Carbon Materials , Polish Academy of Science , M. Curie-Sklodowskiej 34 , 41-819 Zabrze , Poland
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16
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Yuan W, Yang H, Zhang M, Hu D, Sun N, Tao Y. N-Benzoimidazole/Oxadiazole Hybrid Universal Electron Acceptors for Highly Efficient Exciplex-Type Thermally Activated Delayed Fluorescence OLEDs. Front Chem 2019; 7:187. [PMID: 31001516 PMCID: PMC6457096 DOI: 10.3389/fchem.2019.00187] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/11/2019] [Indexed: 11/29/2022] Open
Abstract
Recently, donor/acceptor type exciplex have attracted considerable interests due to the low driving voltages and small singlet-triplet bandgaps for efficient reverse intersystem crossing to achieve 100% excitons for high efficiency thermally activated delayed fluorescence (TADF) OLEDs. Herein, two N-linked benzoimidazole/oxadiazole hybrid electron acceptors were designed and synthesized through simple catalyst-free C-N coupling reaction. 24iPBIOXD and iTPBIOXD exhibited deep-blue emission with peak at 421 and 459 nm in solution, 397 and 419 nm at film state, respectively. The HOMO/LUMO energy levels were −6.14/−2.80 for 24iPBIOXD and −6.17/−2.95 eV for iTPBIOXD. Both compounds could form exciplex with conventional electron donors such as TAPC, TCTA, and mCP. It is found that the electroluminescent performance for exciplex-type OLEDs as well as the delayed lifetime was dependent with the driving force of both HOMO and LUMO energy offsets on exciplex formation. The delayed lifetime from 579 to 2,045 ns was achieved at driving forces close to or larger than 1 eV. Two TAPC based devices possessing large HOMO/LUMO offsets of 1.09–1.34 eV exhibited the best EL performance, with maximum external quantum efficiency (EQE) of 9.3% for 24iPBIOXD and 7.0% for iTPBIOXD acceptor. The TCTA containing exciplex demonstrated moderate energy offsets (0.88–1.03 eV) and EL efficiency (~4%), while mCP systems showed the poorest EL performance (EQE <1%) and shortest delayed lifetime of <100 ns due to inadequate driving force of 0.47–0.75 eV for efficient exciplex formation.
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Affiliation(s)
- Wenbo Yuan
- Key Lab for Flexible Electronics and Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing, China
| | - Hannan Yang
- Department of Physics, Yunnan University, Kunming, China
| | - Mucan Zhang
- Key Lab for Flexible Electronics and Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing, China
| | - Die Hu
- Key Lab for Flexible Electronics and Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing, China
| | - Ning Sun
- Department of Physics, Yunnan University, Kunming, China
| | - Youtian Tao
- Key Lab for Flexible Electronics and Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing, China
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17
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Wang Z, Li M, Gan L, Cai X, Li B, Chen D, Su S. Predicting Operational Stability for Organic Light-Emitting Diodes with Exciplex Cohosts. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1802246. [PMID: 30989033 PMCID: PMC6446740 DOI: 10.1002/advs.201802246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/27/2019] [Indexed: 05/06/2023]
Abstract
Organic light-emitting diodes (OLEDs) employing exciplex cohosts have gained attractive interest due to the promising high efficiency, low driving voltage, and potential low cost in future solid-state lighting sources and full-color displays. However, their device lifetime is still the most challenging weakness and rarely studied, which is regarded as a time consuming and complicated work. Therefore, a simplified but effective and comprehensive approach is demonstrated to give prediction for the exciplex cohosts operating lifespan and analyze their possible degradation mechanisms by considering molecular dissociated activation energy with internal exciton dynamics correlations. As a consequence, strong chemical bond stability for the hole transport moieties and rapid reactive exciton relaxation have the intrinsic talent to access potentially long-lived exciplex cohosts, achieving an extended lifetime of 10169 h for the predicted long-lived exciplex cohost OLEDs. Degradation behaviors further confirm that the deteriorated source is attributed to the formation of exciton quenchers and hole traps from excited states and charged-excited states, respectively. The current findings establish a universal technique to screen the stable exciplex cohost candidates with economic time consumption and expenses.
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Affiliation(s)
- Zhiheng Wang
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640P. R. China
| | - Mengke Li
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640P. R. China
| | - Lin Gan
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640P. R. China
| | - Xinyi Cai
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640P. R. China
| | - Binbin Li
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640P. R. China
| | - Dongcheng Chen
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640P. R. China
| | - Shi‐Jian Su
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640P. R. China
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18
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Sarma M, Wong KT. Development of Materials for Blue Organic Light Emitting Devices. CHEM REC 2019; 19:1667-1692. [PMID: 30835939 DOI: 10.1002/tcr.201800156] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 01/29/2019] [Indexed: 01/20/2023]
Abstract
The success of organic light emitting diodes (OLED) has been witnessed by the commercialization of this technology for manufacturing the vivid and colorful displays used in our daily life now. The prospective growth of OLED technology on display industry will be optimistic. Over the last three decades, many different approaches on material and device designs have been implemented for improving the efficiency and stability of OLED devices. These efforts install main cornerstones to support the great achievement of OLED technology. However, until now, the performance and stability of blue OLEDs still have some concerns. This troublesome issue should be totally conquered before the large-scale manufactures dominated over other display technologies, particularly liquid crystal-based displays, takes place. Though significant progress has already been made to achieve high performance and long lifetime blue OLEDs, this topic still remains as one of the hot researches in OLEDs. We have been working on this area for about two decades and made some notable contributions. Consequently, in this personal account we have outlined our efforts to obtain better performing blue OLEDs by utilizing a range of emitters based on fluorescence, phosphorescence, delayed fluorescence and exciplex systems. We have also developed some novel host materials for blue OLEDs, which are worth mentioning in this account.
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Affiliation(s)
- Monima Sarma
- Department of Chemistry National Taiwan University, Taipei, 10617, Taiwan.,Department of Chemistry, KL University (KLEF), Vaddeswaram, Andhra Pradesh, 522502, India
| | - Ken-Tsung Wong
- Department of Chemistry National Taiwan University, Taipei, 10617, Taiwan.,Institute of Atomic and Molecular Science Academia Sinica, Taipei, 10617, Taiwan
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19
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Wang X, Guo L, Feng L. A multi stimuli responsive material with rhodamine B and carbazole groups. NEW J CHEM 2019. [DOI: 10.1039/c8nj05716h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A facile material with multi stimuli responsive behaviors was developed. The chromic properties of the material can be observed by stimulating it with light, electricity and ions.
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Affiliation(s)
- Xiaoju Wang
- Institute of Molecular Science
- Chemical Biology and Molecular Engineering
- Laboratory of Education Ministry
- Shanxi University
- Taiyuan 030006
| | - Lixia Guo
- School of Chemistry and Chemical Engineering
- Shanxi University
- Taiyuan
- P. R. China
| | - Liheng Feng
- School of Chemistry and Chemical Engineering
- Shanxi University
- Taiyuan
- P. R. China
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20
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Dou D, Wu P, Liao Z, Hao J, Zhang J, Wang Z. A thermally activated delayed fluorescence exciplex to achieve highly efficient and stable blue and green phosphorescent organic light-emitting diodes. RSC Adv 2019; 9:23810-23817. [PMID: 35530600 PMCID: PMC9069484 DOI: 10.1039/c9ra02875g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/22/2019] [Indexed: 12/26/2022] Open
Abstract
The development of a thermally activated delayed fluorescence (TADF) exciplex with high energy is of great significance in achieving highly efficient blue, green, and red organic light-emitting diodes (OLEDs) for use in full-color displays and white lighting. Highly efficient and stable blue and green phosphorescent OLEDs were demonstrated by employing a TADF exciplex (energy: 2.9 eV) based on 4-substituted aza-9,9′-spirobifluorenes (aza-SBFs). Blue PhOLEDs demonstrated a maximum current efficiency (CE) of 47.9 cd A−1 and an external quantum efficiency (EQE) of 22.5% at 1300 cd m−2 (2.5 times the values of aza-SBF-based systems), with the best blue PhOLED demonstrating a CE, power efficiency (PE) and EQE of 60.3 cd A−1, 52.7 lm W−1, and 26.2%, respectively. Green PhOLEDs exhibited a CE of 78.1 cd A−1 and EQE of 22.5% at 9360 cd m−2, with the best green PhOLED exhibiting a maximum CE, PE, and EQE of 87.4 cd A−1, 101.6 lm W−1, and 24.5%, respectively. The device operational lifetime was improved over 17-fold compared to reference devices because of the high thermal stability of the materials and full utilization of the TADF exciplex energy, indicating their potential for application in commercial OLEDs. A high energy TADF exciplex (415 nm) based on aza-spirobifluorene derivatives was demonstrated to achieve efficient and stable PhOLEDs.![]()
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Affiliation(s)
- Dehai Dou
- Key Laboratory of Advanced Display and System Applications
- Ministry of Education
- Shanghai University
- 200072 P. R. China
- Department of Chemistry
| | - Peng Wu
- Key Laboratory of Advanced Display and System Applications
- Ministry of Education
- Shanghai University
- 200072 P. R. China
- Department of Chemistry
| | - Zhangcheng Liao
- Key Laboratory of Advanced Display and System Applications
- Ministry of Education
- Shanghai University
- 200072 P. R. China
- Department of Chemistry
| | - Jian Hao
- Department of Chemistry
- Shanghai University
- 200072 P. R. China
| | - Jianhua Zhang
- Key Laboratory of Advanced Display and System Applications
- Ministry of Education
- Shanghai University
- 200072 P. R. China
| | - Zixing Wang
- Key Laboratory of Advanced Display and System Applications
- Ministry of Education
- Shanghai University
- 200072 P. R. China
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21
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Wang S, Qiao M, Ye Z, Dou D, Chen M, Peng Y, Shi Y, Yang X, Cui L, Li J, Li C, Wei B, Wong WY. Efficient Deep-Blue Electrofluorescence with an External Quantum Efficiency Beyond 10. iScience 2018; 9:532-541. [PMID: 30497025 PMCID: PMC6258878 DOI: 10.1016/j.isci.2018.10.026] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/30/2018] [Accepted: 10/25/2018] [Indexed: 11/26/2022] Open
Abstract
The design of blue fluorescent materials combining both deep-blue emission (CIEy<0.06) and high-efficiency climbing over the typically limited exciton production efficiency of 25% is a challenge for organic light-emitting diodes (OLEDs). In this work, we have synthesized two blue luminogens, trans-9,10-bis(2-butoxyphenyl)anthracene (BBPA) and trans-9,10-bis (2,4-dimethoxyphenyl)anthracene with high photoluminescence quantum yields (PLQYs) of 89.5% and 87.0%, respectively. Intriguingly, we have proposed a strategy to avoid aggregation-caused quenching, which can effectively reduce the undesirable excimeric emission by introducing two host matrices with twisted molecular structure, 9,10-di(naphth-2-yl) anthracene and 10,10′-bis-(4-fluorophenyl)-3,3′-dimethyl-9,9′-bianthracene (MBAn-(4)-F), in the BBPA emission layer. The device containing the EML of BBPA-doped MBAn-(4)-F exhibited a high external quantum efficiency of 10.27% for deep-blue emission with the Commission International de L'Eclairage CIE coordinates of (0.15, 0.05) via the steric effect. Importantly, this represents an advance in deep-blue-emitting fluorescent OLED architectures and materials that meet the requirements of high-definition display. Highly efficient deep-blue luminogens BBPA and DMPA are synthesized Low-efficiency roll-off deep-blue OLEDs with CIE coordinate Y < 0.06 Record-high external quantum efficiency of 10.27% for deep-blue fluorescent OLEDs Host matrix of twisted structure showing steric effect reduces intermolecular aggregation
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Affiliation(s)
- Shuanglong Wang
- School of Mechatronic Engineering and Automation, Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, P. R. China
| | - Mengya Qiao
- Department of Chemistry, Center for Supramolecular Chemistry and Catalysis, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China
| | - Zhonghua Ye
- School of Materials Science and Engineering, Shanghai University, Shanghai 200444, P. R. China
| | - Dehai Dou
- School of Mechatronic Engineering and Automation, Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, P. R. China
| | - Minyu Chen
- School of Mechatronic Engineering and Automation, Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, P. R. China
| | - Yan Peng
- School of Mechatronic Engineering and Automation, Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, P. R. China
| | - Ying Shi
- School of Materials Science and Engineering, Shanghai University, Shanghai 200444, P. R. China
| | - Xuyong Yang
- School of Mechatronic Engineering and Automation, Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, P. R. China
| | - Lei Cui
- Department of Chemistry, Center for Supramolecular Chemistry and Catalysis, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China
| | - Jiuyan Li
- School of Chemical Engineering, Dalian University of Technology, Liaoning 116024, P.R. China
| | - Chunju Li
- Department of Chemistry, Center for Supramolecular Chemistry and Catalysis, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China.
| | - Bin Wei
- School of Mechatronic Engineering and Automation, Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University, 149 Yanchang Road, Shanghai, 200072, P. R. China.
| | - Wai-Yeung Wong
- Institute of Molecular Functional Materials and Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China.
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22
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Pander P, Gogoc S, Colella M, Data P, Dias FB. Thermally Activated Delayed Fluorescence in Polymer-Small-Molecule Exciplex Blends for Solution-Processed Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2018; 10:28796-28802. [PMID: 30044613 DOI: 10.1021/acsami.8b07554] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The photophysics of an exciplex state formed between a small molecule and a polymer is investigated in this work. The results obtained with this blend show the strong potential of polymer-small-molecule blends for triplet harvesting in organic light-emitting diodes (OLEDs) via thermally activated delayed fluorescence. The exciplex formed between poly( N-vinylcarbazole) (PVK) and 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine (PO-T2T) shows yellow-green emission and is applied in solution-processed OLEDs. The excellent film-forming properties in this blend allow easy spin coating and potential use in other solution-processing techniques, such as slot die coating. In this work, we critically address the reverse intersystem crossing mechanism in the presented exciplex system, including the role of local triplet states. Moreover, we bring a clear physical meaning to the decay components of the exciplex emission, including the decay occurring in a power-law fashion that is often ignored in the literature.
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Affiliation(s)
- Piotr Pander
- Department of Physics , Durham University , South Road , Durham DH1 3LE , United Kingdom
| | - Szymon Gogoc
- Faculty of Chemistry , Silesian University of Technology , Ks. M. Strzody 9 , 44-100 Gliwice , Poland
| | - Marco Colella
- Department of Physics , Durham University , South Road , Durham DH1 3LE , United Kingdom
| | - Przemyslaw Data
- Department of Physics , Durham University , South Road , Durham DH1 3LE , United Kingdom
- Faculty of Chemistry , Silesian University of Technology , Ks. M. Strzody 9 , 44-100 Gliwice , Poland
- Centre of Polymer and Carbon Materials , Polish Academy of Sciences , M. Sklodowskiej-Curie 34 , 41-819 Zabrze , Poland
| | - Fernando B Dias
- Department of Physics , Durham University , South Road , Durham DH1 3LE , United Kingdom
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23
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Mamada M, Tian G, Nakanotani H, Su J, Adachi C. The Importance of Excited‐State Energy Alignment for Efficient Exciplex Systems Based on a Study of Phenylpyridinato Boron Derivatives. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804218] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Masashi Mamada
- Center for Organic Photonics and Electronics Research (OPERA) Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
- JST, ERATO Adachi Molecular Exciton Engineering Project 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Guojian Tian
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals East China University of Science and Technology 130 Meilong Road Shanghai 200237 China
| | - Hajime Nakanotani
- Center for Organic Photonics and Electronics Research (OPERA) Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
- JST, ERATO Adachi Molecular Exciton Engineering Project 744 Motooka, Nishi Fukuoka 819-0395 Japan
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER) Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Jianhua Su
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals East China University of Science and Technology 130 Meilong Road Shanghai 200237 China
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA) Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
- JST, ERATO Adachi Molecular Exciton Engineering Project 744 Motooka, Nishi Fukuoka 819-0395 Japan
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER) Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
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Mamada M, Tian G, Nakanotani H, Su J, Adachi C. The Importance of Excited-State Energy Alignment for Efficient Exciplex Systems Based on a Study of Phenylpyridinato Boron Derivatives. Angew Chem Int Ed Engl 2018; 57:12380-12384. [PMID: 30062688 DOI: 10.1002/anie.201804218] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/06/2018] [Indexed: 12/31/2022]
Abstract
Understanding excited-state dynamics is critical for improving the photoluminescence (PL) efficiency of exciplexes. A series of exciplexes based on conventional hole-transporting materials as donor and newly developed phenylpyridinato boron derivatives as acceptor were investigated. High PL efficiencies were achieved in only some combinations, and a large difference in performance among combinations provided insight into nonradiative processes in exciplex systems. Furthermore, the triplet local excited states (3 LE) of each donor and acceptor were found play an important role in triplet exciplex harvesting. Significant contributions from triplets were clearly observed when the charge-transfer excited states (1 CT and 3 CT) and 3 LE were ideally aligned. We also demonstrated fine control of relative energy alignment via the concentration to improve the PL efficiency.
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Affiliation(s)
- Masashi Mamada
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.,JST, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Guojian Tian
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Hajime Nakanotani
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.,JST, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.,International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Jianhua Su
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.,JST, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.,International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
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25
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Luo D, Hsieh CT, Wang YP, Chuang TC, Chang HH, Chang CH. Pure exciplex-based white organic light-emitting diodes with imitation daylight emissions. RSC Adv 2018; 8:30582-30588. [PMID: 35546845 PMCID: PMC9085475 DOI: 10.1039/c8ra04986f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 08/24/2018] [Indexed: 12/16/2022] Open
Abstract
An exciplex could be formed by blending a selected hole-transporting material (HTM)/electron-transporting material (ETM) pair, and the corresponding energy band gap is roughly determined by the energy difference between the lowest unoccupied molecular orbital (LUMO) of the ETM and the highest occupied molecular orbital (HOMO) of the HTM. In this study, three HTM/ETM combinations are adopted to generate blue, green, and red exciplexes, allowing us to design precise device architectures for the fabrication of exciplex-based white OLEDs (WOLEDs) with daylight-like emissions. The CIE coordinates of this WOLED varied close to the Planckian locus as the biases increase, with a high color rendering index of about 96. This high performance suggests this exciplex-based WOLED can provide high-quality white-light illumination. Photoluminance and lifetime measurements of the exciplex behavior of the HTM/ETM combinations indicate that the HTM and ETM selected should possess higher triplet energy bandgaps than those of their corresponding exciplex to avoid energy loss.
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Affiliation(s)
- Dian Luo
- Department of Electrical Engineering, Yuan Ze University Chung-Li Taiwan 32003 +886 34638800 ext. 7517 +886 34514281
| | - Chung-Tsung Hsieh
- Department of Electrical Engineering, Yuan Ze University Chung-Li Taiwan 32003 +886 34638800 ext. 7517 +886 34514281
| | - Yen-Po Wang
- Department of Electrical Engineering, Yuan Ze University Chung-Li Taiwan 32003 +886 34638800 ext. 7517 +886 34514281
| | - Thomas C Chuang
- Department of Information Science and Technology, Vanung University Chung-Li Taiwan 32061
| | - Hsin-Hua Chang
- Department of Aeronautical and Opto-Mechatronic Engineering, Vanung University Chung-Li Taiwan 32061
| | - Chih-Hao Chang
- Department of Electrical Engineering, Yuan Ze University Chung-Li Taiwan 32003 +886 34638800 ext. 7517 +886 34514281
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26
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Shih CJ, Lee CC, Yeh TH, Biring S, Kesavan KK, Amin NRA, Chen MH, Tang WC, Liu SW, Wong KT. Versatile Exciplex-Forming Co-Host for Improving Efficiency and Lifetime of Fluorescent and Phosphorescent Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2018; 10:24090-24098. [PMID: 29943574 DOI: 10.1021/acsami.8b08281] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report a new efficient exciplex-forming system consisting of a biscarbazole donor and a triazine-based acceptor. The new exciplex was characterized with a high photoluminescence quantum yield up to 68% and effective thermally activated delayed fluorescence behavior. The BCzPh:3P-T2T (2:1, 30 nm) blend was examined not only as an emitting layer (device D1) but also a reliable co-host of fluorescent and phosphorescent emitters for giving highly efficient exciplex-based organic light-emitting diodes (OLEDs) with a high maximum external quantum efficiency of 15.5 and 29.7% for devices doped with 1 wt % C545T (device D2) and 8 wt % Ir(ppy)2(acac) (device D4), respectively. More strikingly, a strongly enhanced lifetime ( T75 = 16 927 min.) of the C545T-doped device was obtained. The transient electroluminescence measurement as well as capacitance-voltage and impedance-voltage correlations were utilized to explore the factors governing the high efficiency and stability. The obtained results clearly show that the energy transfer and charge transport is highly efficient; they also show the photoelectric semiconducting characteristics of exciplex-based OLEDs, which are significantly different from those of unipolar host-based reference devices D3 (Alq3: 1 wt % C545T) and D5 (CBP: 8 wt % Ir(ppy)2(acac)). Our works have established a systematic protocol to shed light on the mechanisms behind exciplex-based devices. The combined results also confirm the bright prospect of the exciplex-forming system as the co-host for highly efficient and stable OLEDs.
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Affiliation(s)
- Chun-Jen Shih
- Department of Electronic Engineering , National Taiwan University of Science and Technology , Taipei 10617 , Taiwan
| | - Chih-Chien Lee
- Department of Electronic Engineering , National Taiwan University of Science and Technology , Taipei 10617 , Taiwan
| | - Tzu-Hung Yeh
- Department of Electronic Engineering , National Taiwan University of Science and Technology , Taipei 10617 , Taiwan
| | | | | | | | | | - Wei-Chieh Tang
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | | | - Ken-Tsung Wong
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
- Institute of Atomic and Molecular Science , Academia Sinica , Taipei 10617 , Taiwan
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27
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Sarma M, Wong KT. Exciplex: An Intermolecular Charge-Transfer Approach for TADF. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19279-19304. [PMID: 29613766 DOI: 10.1021/acsami.7b18318] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Organic materials that display thermally activated delayed fluorescence (TADF) are a striking class of functional materials that have witnessed a booming progress in recent years. In addition to pure TADF emitters achieved by the subtle manipulations of intramolecular charge transfer processes with sophisticated molecular structures, a new class of efficient TADF-based OLEDs with emitting layer formed by blending electron donor and acceptor molecules that involve intermolecular charge transfer have also been fabricated. In contrast to pure TADF materials, the exciplex-based systems can realize small Δ EST (0-0.05 eV) much more easily since the electron and hole are positioned on two different molecules, thereby giving small exchange energy. Consequently, exciplex-based OLEDs have the prospective to maximize the TADF contribution and achieve theoretical 100% internal quantum efficiency. Therefore, the challenging issue of achieving small Δ EST in organic systems could be solved. In this article, we summarize and discuss the latest and most significant developments regarding these rapidly evolving functional materials, wherein the majority of the reported exciplex forming systems are categorized into two subgroups, viz. (a) exciplex as TADF emitters and (b) those as hosts for fluorescent, phosphorescent and TADF dopants according to their structural features and applications. The working mechanisms of the direct electroluminescence from the donor/acceptor interface and the exciplex-forming systems as cohost for the realization of high efficiency OLEDs are reviewed and discussed. This article delivers a summary of the current progresses and achievements of exciplex-based researches and points out the future challenges to trigger more research endeavors to this growing field.
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Affiliation(s)
- Monima Sarma
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - Ken-Tsung Wong
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
- Institute of Atomic and Molecular Science , Academia Sinica , Taipei 10617 , Taiwan
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28
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Shih CJ, Lee CC, Chen YH, Biring S, Kumar G, Yeh TH, Sen S, Liu SW, Wong KT. Exciplex-Forming Cohost for High Efficiency and High Stability Phosphorescent Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2018; 10:2151-2157. [PMID: 29265796 DOI: 10.1021/acsami.7b15034] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An exciplex forming cohost system is employed to achieve a highly efficient organic light-emitting diode (OLED) with good electroluminescent lifetime. The exciplex is formed at the interfacial contact of a conventional star-shaped carbazole hole-transporting material, 4,4',4″-tris(N-carbazolyl)-triphenylamine (TCTA), and a triazine electron-transporting material, 2,4,6-tris[3-(1H-pyrazol-1-yl)phenyl]-1,3,5-triazine (3P-T2T). The excellent combination of TCTA and 3P-T2T is applied as the cohost of a common green phosphorescent emitter with almost zero energy loss. When Ir(ppy)2(acac) is dispersed in such exciplex cohost system, OLED device with maximum external quantum efficiency of 29.6%, the ultrahigh power efficiency of 147.3 lm/W, and current efficiency of 107 cd/A were successfully achieved. More importantly, the OLED device showed a low-efficiency roll-off and an operational lifetime (τ80) of ∼1020 min with the initial brightness of 2000 cd/m2, which is 56 times longer than the reference device. The significant difference of device stability was attributed to the degradation of exciplex system for energy transfer process, which was investigated by the photoluminescence aging measurement at room temperature and 100 K, respectively.
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Affiliation(s)
- Chun-Jen Shih
- Department of Electronic Engineering, National Taiwan University of Science and Technology , Taipei 10617, Taiwan
| | - Chih-Chien Lee
- Department of Electronic Engineering, National Taiwan University of Science and Technology , Taipei 10617, Taiwan
| | - Ying-Hao Chen
- Department of Electronic Engineering, National Taiwan University of Science and Technology , Taipei 10617, Taiwan
| | | | | | - Tzu-Hung Yeh
- Department of Electronic Engineering, National Taiwan University of Science and Technology , Taipei 10617, Taiwan
| | | | | | - Ken-Tsung Wong
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
- Institute of Atomic and Molecular Science, Academia Sinica , Taipei 10617, Taiwan
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29
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Kamata T, Sasabe H, Igarashi M, Kido J. A Novel Sterically Bulky Hole Transporter to Remarkably Improve the Lifetime of Thermally Activated Delayed Fluorescent OLEDs at High Brightness. Chemistry 2017; 24:4590-4596. [DOI: 10.1002/chem.201705262] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Takahiro Kamata
- Department of Organic Materials ScienceYamagata University 4-3-16 Jonan, Yonezawa Yamagata 992-8510 Japan
| | - Hisahiro Sasabe
- Department of Organic Materials ScienceYamagata University 4-3-16 Jonan, Yonezawa Yamagata 992-8510 Japan
- Research Center of Organic Electronics (ROEL), and Frontier Center for, Organic Materials (FROM)Yamagata University 4-3-16 Jonan, Yonezawa Yamagata 992-8510 Japan
- Flask Corporation 4-3-16 Jonan, Yonezawa Yamagata 992-8510 Japan
| | - Masahiro Igarashi
- Research Center of Organic Electronics (ROEL), and Frontier Center for, Organic Materials (FROM)Yamagata University 4-3-16 Jonan, Yonezawa Yamagata 992-8510 Japan
| | - Junji Kido
- Department of Organic Materials ScienceYamagata University 4-3-16 Jonan, Yonezawa Yamagata 992-8510 Japan
- Research Center of Organic Electronics (ROEL), and Frontier Center for, Organic Materials (FROM)Yamagata University 4-3-16 Jonan, Yonezawa Yamagata 992-8510 Japan
- Flask Corporation 4-3-16 Jonan, Yonezawa Yamagata 992-8510 Japan
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30
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Kim HG, Kim KH, Kim JJ. Highly Efficient, Conventional, Fluorescent Organic Light-Emitting Diodes with Extended Lifetime. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1702159. [PMID: 28850733 DOI: 10.1002/adma.201702159] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/10/2017] [Indexed: 06/07/2023]
Abstract
Highly efficient, yellow-fluorescent organic light-emitting diodes with a maximum external quantum efficiency exceeding 25.0% and extended lifetime are reported using iridium-complex sensitizers doped in an exciplex host. Energy transfer processes reduce the lifetime of the exciplex and excitons on the Ir complexes and enable an excited state to exist in a conventional fluorescent emitter, thereby increasing device lifetime. The device stability depends on the location of the excited state.
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Affiliation(s)
- Hyun-Gu Kim
- Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744, South Korea
| | - Kwon-Hyeon Kim
- Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744, South Korea
| | - Jang-Joo Kim
- Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744, South Korea
- Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul, 151-744, South Korea
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