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Wu Y, Xin Y, Pan Y, Yiu S, Yan J, Lau KC, Duan L, Chi Y. Ir(III) Metal Emitters with Cyano-Modified Imidazo[4,5-b]pyridin-2-ylidene Chelates for Deep-Blue Organic Light-Emitting Diodes. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309389. [PMID: 38689505 PMCID: PMC11234470 DOI: 10.1002/advs.202309389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 03/15/2024] [Indexed: 05/02/2024]
Abstract
Ir(III) carbene complexes have been explored as one of the best blue phosphors for their high performance. Herein, the authors designed and synthesized a series of blue-emitting Ir(III) phosphors (f-ct9a-c), featuring fac-coordinated cyano-imidazo[4,5-b]pyridin-2-ylidene cyclometalates. These Ir(III) complexes exhibit true-blue emission with a peak maximum spanning 448-467 nm, with high photoluminescence quantum yields of 81-88% recorded in degassed toluene. Moreover, OLED devices bearing phosphors f-ct9a and f-ct9b deliver maximum external quantum efficiencies (EQEmax) of 25.9% and 30.3%, together with Commission Internationale de L'Eclairage (CIEx,y) coordinates of (0.157, 0.225) and (0.142, 0.169), respectively. Remarkably, the f-ct9b-based device displays an incredible EQE of 29.0% at 5000 cd·m-2. The hyper-OLED device based on f-ct9b and ν-DABNA exhibits an EQEmax of 34.7% and CIEx,y coordinates of (0.122, 0.131), affirming high potentials in achieving efficient blue electroluminescence.
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Affiliation(s)
- Yixin Wu
- Department of ChemistryDepartment of Materials Science and EngineeringCenter of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongHong KongSAR999077China
| | - Yangyang Xin
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of EducationDepartment of ChemistryTsinghua UniversityBeijing100084China
| | - Yi Pan
- Department of ChemistryDepartment of Materials Science and EngineeringCenter of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongHong KongSAR999077China
| | - Shek‐Man Yiu
- Department of ChemistryDepartment of Materials Science and EngineeringCenter of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongHong KongSAR999077China
| | - Jie Yan
- Department of ChemistryDepartment of Materials Science and EngineeringCenter of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongHong KongSAR999077China
| | - Kai Chung Lau
- Department of ChemistryDepartment of Materials Science and EngineeringCenter of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongHong KongSAR999077China
| | - Lian Duan
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of EducationDepartment of ChemistryTsinghua UniversityBeijing100084China
| | - Yun Chi
- Department of ChemistryDepartment of Materials Science and EngineeringCenter of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongHong KongSAR999077China
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Wei F, Chen J, Zhao X, Wu Y, Wang H, Chen X, Xiong Z. High-Performance Hot-Exciton OLEDs via Fully Harvesting Triplet Excited States from Both the Exciplex Co-Host and the TBRb Emitter. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303192. [PMID: 37587760 PMCID: PMC10582462 DOI: 10.1002/advs.202303192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/12/2023] [Indexed: 08/18/2023]
Abstract
The high-level reverse intersystem crossing (HL-RISC, T2 → S1 ) process from triplet to singlet exciton, namely the "hot exciton" channel, has recently been demonstrated in the traditional fluorescent emitter of TBRb. Although it is a potential pathway to improve the utilization of non-radiative triplet exciton energy, highly efficient fluorescent organic light emitting diodes (FOLEDs) based on this "hot exciton" channel have not been developed. Herein, high-efficiency and low-efficiency roll-off FOLEDs are achieved through doping TBRb molecules into an energy-level matched exciplex co-host. Combining the low-level RISC (LL-RISC, EX3 → EX1 ) process in the exciplex co-host with the HL-RISC process of hot excitons in TBRb to fully harvest the triplet energy, a record-high external quantum efficiency (EQE) of 20.4% is obtained via a proper Dexter energy transfer of triplet excitons, realizing the efficiency breakthrough from fully fluorescent material-based OLEDs with TBRb as an end emitter. Furthermore, the fingerprint Magneto-electroluminescence (MEL) as a sensitive measuring tool is employed to visualize the "hot exciton" channel in TBRb, which also directly verifies the effective energy confinement and the full utilization of hot excitons. Obviously, this work paves a promising way for further fabricating high-efficiency TBRb-based FOLEDs for lighting and flat-panel display applications.
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Affiliation(s)
- Fuxian Wei
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Jing Chen
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Xi Zhao
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Yuting Wu
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Huiyao Wang
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Xiaoli Chen
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Zuhong Xiong
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
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3
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Xue Q, Huo M, Xie G. Thermally activated delayed fluorescent small molecule sensitized fluorescent polymers with reduced concentration-quenching for efficient electroluminescence. FRONTIERS OF OPTOELECTRONICS 2023; 16:2. [PMID: 36941509 PMCID: PMC10027968 DOI: 10.1007/s12200-022-00056-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 12/11/2022] [Indexed: 05/25/2023]
Abstract
Thermally activated delayed fluorescence (TADF) small molecule bis-[3-(9,9-dimethyl-9,10-dihydroacridine)-phenyl]-sulfone (m-ACSO2) was used as a universal host to sensitize three conventional fluorescent polymers for maximizing the electroluminescent performance. The excitons were utilized via inter-molecular energy transfer and the non-radiative decays were successfully refrained in the condensed states. Therefore, the significant enhancement of the electroluminescent efficiencies was demonstrated. For instance, after doping poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) into m-ACSO2, the external quantum efficiency (EQE) was improved by a factor of 17.0 in the solution-processed organic light-emitting device (OLED), as compared with the device with neat F8BT. In terms of the other well-known fluorescent polymers, i.e., poly (para-phenylene vinylene) copolymer (Super Yellow, SY) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), their EQEs in the devices were respectively enhanced by 70% and 270%, compared with the reference devices based on the conventional host 1,3-di(9H-carbazol-9-yl) benzene (mCP). Besides the improved charge balance in the bipolar TADF host, these were partially ascribed to reduced fluorescence quenching in the mixed films.
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Affiliation(s)
- Qin Xue
- Department of Physical Science and Technology, Central China Normal University, Wuhan, 430079, China
| | - Mingfang Huo
- Department of Physical Science and Technology, Central China Normal University, Wuhan, 430079, China
| | - Guohua Xie
- Sauvage Center for Molecular Sciences, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, China.
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
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Ahn TJ, Choi BH, Yu JW, Kim YB, Yu YS. Effects of Thermal Treatment on DC Voltage-Driven Color Conversion in Organic Light-Emitting Diode. MICROMACHINES 2022; 14:30. [PMID: 36677091 PMCID: PMC9864168 DOI: 10.3390/mi14010030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/16/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
A DC voltage-dependent color-tunable organic light-emitting diode (CTOLED) was proposed for lighting applications. The CTOLED consists of six consecutive organic layers: the hole injection layer, the hole transport layer (HTL), two emission layers (EMLs), a hole blocking layer (HBL), and an electron transport layer (ETL). Only one metal-free phthalocyanine (H2Pc) layer with a thickness of 5 nm was employed as the EML in the CTOLED on a green organic light-emitting diode (OLED) structure using tris (8-hydroxyquinoline) aluminum (III) (Alq3). The current density-voltage-luminance characteristics of the CTOLEDs before and after thermal treatment were characterized and analyzed. Several Gaussian peaks were also extracted by multipeak fitting analysis of the electroluminescent spectra. In the CTOLED before thermal treatment, green emission was dominant in the entire voltage range from low to high voltages, and blue and infrared were emitted simultaneously and at relatively low intensities at low and high voltages, respectively. In the CTOLED after thermal treatment, the dominant color conversion from blue to green was observed as the applied voltage increased, and the infrared emission was relatively low over the entire voltage range. By simulating the CTOLED with and without traps at the H2Pc interface using a technology computer-aided design simulator, we observed the following: 1. After thermal treatment, the CTOLED emitted blue light by exciton generation at the H2Pc-HBL interface because of the small electron transport through the H2Pc thin film due to the dramatic reduction of traps in the low-voltage regime. 2. In the high-voltage regime, electrons reaching the HBL were transferred to Alq3 by resonant tunneling in two quantum wells; thus, green light was emitted by exciton generation at the HTL-Alq3 interface.
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Affiliation(s)
- Tae Jun Ahn
- Department of Electrical, Electronic and Control Engineering, AISPC Laboratory, IITC, Hankyong National University, 327 Jungang-ro, Anseong-si 17579, Republic of Korea
- Green Energy Nano Research Group, Korea Institute of Industrial Technology, 6, Cheomdangwagi-ro 208 beon-gil, Buk-gu, Gwangju 61012, Republic of Korea
| | - Bum Ho Choi
- PJPTECH, 36-2, Hagal-ro 86, Giheung-gu, Yongin-si 17096, Republic of Korea
| | - Jae-Woong Yu
- Department of Advanced Materials Engineering for Information & Electronics, Kyung Hee University, Deogyeong-daro 1732, Giheung-gu, Yongin-si 17104, Republic of Korea
| | - Young Baek Kim
- Green Energy Nano Research Group, Korea Institute of Industrial Technology, 6, Cheomdangwagi-ro 208 beon-gil, Buk-gu, Gwangju 61012, Republic of Korea
| | - Yun Seop Yu
- Department of Electrical, Electronic and Control Engineering, AISPC Laboratory, IITC, Hankyong National University, 327 Jungang-ro, Anseong-si 17579, Republic of Korea
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5
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Bai P, Hu A, Deng Y, Tang Z, Yu W, Hao Y, Yang S, Zhu Y, Xiao L, Jin Y, Gao Y. CdSe/CdSeS Nanoplatelet Light-Emitting Diodes with Ultrapure Green Color and High External Quantum Efficiency. J Phys Chem Lett 2022; 13:9051-9057. [PMID: 36153736 DOI: 10.1021/acs.jpclett.2c02633] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Colloidal II-VI group nanoplatelets (NPLs) possess ultranarrow emission line widths, for which they have great promise in achieving the purest display color in solution-processed light-emitting diodes (LEDs). Red NPL-LEDs have shown extremely saturated red color with high efficiency, while the green and blue ones lag far behind. Herein, we report green NPL-LEDs with the purest color in accordance with the Rec. 2020 standard and the peak external quantum efficiency (EQE) of 9.78%. By carefully controlling the aspect ratio, capping ligands, and purifications of CdSe/CdSeS core/alloyed-crown NPLs, NPL films with excellent flatness and unity photoluminescence quantum yields (PLQYs) are realized, laying a solid foundation for improving LED performance. Furthermore, via tuning the carrier injection balance, the record-high EQE for green NPL-LEDs is achieved. The electroluminescence (EL) exhibits an extremely saturated green color with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.163 0.786), which demonstrates their great potential in applications of ultrahigh-definition display technology. Our findings would help to further improve the performance of all NPL-LEDs.
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Affiliation(s)
- Peng Bai
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - An Hu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yunzhou Deng
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zhenyu Tang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Wenjin Yu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yanlei Hao
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Shuang Yang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yunke Zhu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Lixin Xiao
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yizheng Jin
- Key Laboratory of Excited-State Materials of Zhejiang Province, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Yunan Gao
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Frontiers Science Center for Nano-optoelectronics, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
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6
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Yang X, Zhou X, Zhang Y, Li D, Li C, You C, Chou T, Su S, Chou P, Chi Y. Blue Phosphorescence and Hyperluminescence Generated from Imidazo[4,5-b]pyridin-2-ylidene-Based Iridium(III) Phosphors. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201150. [PMID: 35822668 PMCID: PMC9443441 DOI: 10.1002/advs.202201150] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/02/2022] [Indexed: 05/19/2023]
Abstract
Four isomeric, homoleptic iridium(III) metal complexes bearing 5-(trifluoromethyl)imidazo[4,5-b]pyridin-2-ylidene and 6-(trifluoromethyl)imidazo[4,5-b]pyridin-2-ylidene-based cyclometalating chelates are successfully synthesized. The meridional isomers can be converted to facial isomers through acid induced isomerization. The m-isomers display a relatively broadened and red-shifted emission, while f-isomers exhibit narrowed blue emission band, together with higher photoluminescent quantum yields and reduced radiative lifetime relative to the mer-counterparts. Maximum external quantum efficiencies of 13.5% and 22.8% are achieved for the electrophosphorescent devices based on f-tpb1 and m-tpb1 as dopant emitter together with CIE coordinates of (0.15, 0.23) and (0.22, 0.45), respectively. By using f-tpb1 as the sensitizing phosphor and t-DABNA as thermally activated delayed fluorescence (TADF) terminal emitter, hyperluminescent OLEDs are successfully fabricated, giving high efficiency of 29.6%, full width at half maximum (FWHM) of 30 nm, and CIE coordinates of (0.13, 0.11), confirming the efficient Förster resonance energy transfer (FRET) process.
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Affiliation(s)
- Xilin Yang
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640China
| | - Xiuwen Zhou
- School of Mathematics and PhysicsThe University of QueenslandBrisbaneQueensland4072Australia
| | - Ye‐Xin Zhang
- Suzhou Joysun Advanced Materials Co., Ltd. SuzhouJiangsu215126China
| | - Deli Li
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640China
| | - Chensen Li
- Department of ChemistryDepartment of Materials Sciences and Engineeringand Center of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongHong Kong SAR999077China
| | - Caifa You
- Department of ChemistryDepartment of Materials Sciences and Engineeringand Center of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongHong Kong SAR999077China
| | - Tai‐Che Chou
- Department of ChemistryNational Taiwan UniversityTaipei10617Taiwan
| | - Shi‐Jian Su
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou510640China
| | - Pi‐Tai Chou
- Department of ChemistryNational Taiwan UniversityTaipei10617Taiwan
| | - Yun Chi
- Department of ChemistryDepartment of Materials Sciences and Engineeringand Center of Super‐Diamond and Advanced Films (COSDAF)City University of Hong KongHong Kong SAR999077China
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7
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Park HJ, Jang JH, Lee JH, Hwang DH. Highly Efficient Deep-Blue Phosphorescent OLEDs Based on a Trimethylsilyl-Substituted Tetradentate Pt(II) Complex. ACS APPLIED MATERIALS & INTERFACES 2022; 14:34901-34908. [PMID: 35867806 DOI: 10.1021/acsami.2c06891] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Compared to Ir(III) complexes with octahedral geometries, Pt(II) complexes with square planar geometries show superior optical properties because their flat shapes lead to an orientation that enhances the outcoupling of organic light-emitting diodes (OLEDs). However, the flat shapes of Pt(II) complexes typically induce a bathochromic shift, limiting their application in high-performance deep-blue phosphorescent OLEDs with high color purity. In this study, bulky trimethylsilyl (TMS)-substituted blue phosphorescent Pt(II) complex (PtON7-TMS) is successfully synthesized to improve color purity. The TMS substituent containing Si atom effectively suppresses intermolecular interaction and aggregation even when the complex concentration in the film state is higher than 30 wt %. As a result, the PtON7-TMS-based OLEDs exhibit a maximum external quantum efficiency of 21.4%, along with a pure-blue color of CIE (0.14, 0.09) at 20 wt % doping concentration and a full-width at half maximum of 30 nm. The pure blue color is maintained at a higher doping concentration (>30 wt %).
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Affiliation(s)
- Hea Jung Park
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 46241, Republic of Korea
| | - Jee-Hun Jang
- Department of Materials Science and Engineering, 3D Convergence Center, Inha University, Incheon 22212, Republic of Korea
| | - Jeong-Hwan Lee
- Department of Materials Science and Engineering, 3D Convergence Center, Inha University, Incheon 22212, Republic of Korea
| | - Do-Hoon Hwang
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 46241, Republic of Korea
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8
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Yin C, Zhang Y, Huang T, Liu Z, Duan L, Zhang D. Highly efficient and nearly roll-off-free electrofluorescent devices via multiple sensitizations. SCIENCE ADVANCES 2022; 8:eabp9203. [PMID: 35895814 PMCID: PMC9328673 DOI: 10.1126/sciadv.abp9203] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The efficiency roll-off at high luminance has hindered the wide application of organic light-emitting diodes (OLEDs) for decades. To circumvent this issue, both high exciton utilization and short exciton residence should be satisfied, which, however, faces formidable challenges. Here, we propose an advanced approach of phosphor-assisted thermally activated delayed fluorophor (TADF)-sensitized fluorescence, abbreviated as TPSF. It is proved to be a rational strategy that can realize high quantum efficiency and elaborately accelerated radiative exciton consumption simultaneously by breaking singlet-triplet spin-flip cycles on a TADF host via multiple sensitizations. On the basis of a TADF molecule exhibiting anti-accumulation-caused quenching character, a proof-of-concept device exhibits a maximum external quantum efficiency (EQEmax) of 24.2% with an ultrahigh L90% (the luminance at which EQE drops to 90% of its maximum value) of 190,500 cd m-2 and a greatly improved operational stability, unlocking the full potential of OLEDs for ultrahigh-luminance applications.
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Affiliation(s)
- Chen Yin
- Key Laboratory of Organic Optoelectronics, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yuewei Zhang
- Key Laboratory of Organic Optoelectronics, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Tianyu Huang
- Key Laboratory of Organic Optoelectronics, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Ziyang Liu
- Key Laboratory of Organic Optoelectronics, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Lian Duan
- Key Laboratory of Organic Optoelectronics, Department of Chemistry, Tsinghua University, Beijing 100084, China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, China
| | - Dongdong Zhang
- Key Laboratory of Organic Optoelectronics, Department of Chemistry, Tsinghua University, Beijing 100084, China
- Corresponding author.
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9
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Zhang W, Ren F, Wen Y, Xu Z, Sun J, Yan Z, Ding L, Hai X, Zhang Q. Enhancing Hole Transport of Quantum-Dot Light-Emitting Diodes by a Cruciform Oligothiophene for Effective p-Type Doping. Macromol Rapid Commun 2022; 43:e2200187. [PMID: 35451198 DOI: 10.1002/marc.202200187] [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: 02/26/2022] [Revised: 04/06/2022] [Indexed: 11/07/2022]
Abstract
Effective p-type doping is essential to enhance hole transport and balance electron-hole injection in quantum dot light-emitting diodes (QLEDs). Here, an oligothiophene material is adopted as a p-type dopant in the hole-transport layer, considering its cruciform cross-centre structure, precise molecular weight, and high purity. Compared with the dopant-free counterpart, hole transport capability at the optimal doping level exhibits a significant improvement, producing a boosted external quantum efficiency (EQE) and luminance up to 20.8%, 213,439 cd m-2 , respectively, among the highest reported on the red-light emission. The work indicates the potential applications of oligothiophene material in red light-emitting devices. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Wenjing Zhang
- Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, P. R. China.,Key Laboratory for Special Functional Materials of Ministry of Education, School of Materials, Henan University, Kaifeng, Henan, 475004, P. R. China
| | - Fumeng Ren
- Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, P. R. China.,Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China
| | - Yu Wen
- Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, P. R. China
| | - Zhangwang Xu
- Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, P. R. China
| | - Juan Sun
- Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, P. R. China
| | - Zhenzhen Yan
- Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, P. R. China
| | - Lei Ding
- Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, P. R. China
| | - Xia Hai
- Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, P. R. China
| | - Qin Zhang
- Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang, Jiangxi, 330063, P. R. China
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10
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Chen J, Zhao X, Tang X, Ning Y, Wu F, Chen X, Zhu H, Xiong Z. An unprecedented spike of the electroluminescence turn-on transience from guest-doped OLEDs with strong electron-donating abilities of host carbazole groups. MATERIALS HORIZONS 2021; 8:2785-2796. [PMID: 34605830 DOI: 10.1039/d1mh00941a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
An unreported unprecedented spike of ∼μs line-width, followed by an overshoot, was discovered at the rising edge of transient electroluminescence (TEL) from guest-doped organic light-emitting diodes with strong electron-donating abilities from the host carbazole groups. By changing the device structures and TEL measurement parameters, a series of experimental results demonstrate that this TEL spike is not related to exciton interactions such as singlet-triplet and triplet-triplet annihilations but originated from the radiative recombination of pre-stored electrons with injected holes. Surprisingly, these pre-stored guest electrons do not come from the energy-level traps in the host-guest systems; instead, the guest molecules receive the electrons transferred from the host carbazole groups due to their strong electron-donating abilities. Moreover, the observed spikes show rich and extraordinary temperature dependences. Based on the detailed understanding of the spike formation mechanism, we have proposed the requirements for the occurrence of spike and realized the artificial adjustments of the spike intensity. For instance, the instantaneous luminescent intensity of this spike can reach over 80 times the magnitude of the TEL plateau. Accordingly, this work deepens the physical understanding of this novel spike in TEL and paves the way for fabricating an electro-optic sensor to detect instantaneous weak current signals.
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Affiliation(s)
- Jing Chen
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China.
| | - Xi Zhao
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China.
| | - Xiantong Tang
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China.
| | - Yaru Ning
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China.
| | - Fengjiao Wu
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China.
| | - Xiaoli Chen
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China.
| | - Hongqiang Zhu
- Chongqing Key Laboratory of Photo-Electric Functional Materials, Chongqing Normal University, Chongqing 401331, People's Republic of China
| | - Zuhong Xiong
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China.
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11
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Nam S, Kim JW, Bae HJ, Maruyama YM, Jeong D, Kim J, Kim JS, Son W, Jeong H, Lee J, Ihn S, Choi H. Improved Efficiency and Lifetime of Deep-Blue Hyperfluorescent Organic Light-Emitting Diode using Pt(II) Complex as Phosphorescent Sensitizer. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100586. [PMID: 34137208 PMCID: PMC8373157 DOI: 10.1002/advs.202100586] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/20/2021] [Indexed: 05/19/2023]
Abstract
Although the organic light-emitting diode (OLED) has been successfully commercialized, the development of deep-blue OLEDs with high efficiency and long lifetime remains a challenge. Here, a novel hyperfluorescent OLED that incorporates the Pt(II) complex (PtON7-dtb) as a phosphorescent sensitizer and a hydrocarbon-based and multiple resonance-based fluorophore as an emitter (TBPDP and ν-DABNA) in the device emissive layer (EML), is proposed. Such an EML system can promote efficient energy transfer from the triplet excited states of the sensitizer to the singlet excited states of the fluorophore, thus significantly improving the efficiency and lifetime of the device. As a result, a deep-blue hyperfluorescent OLED using a multiple resonance-based fluorophore (ν-DABNA) with Commission Internationale de L'Eclairage chromaticity coordinate y below 0.1 is demonstrated, which attains a narrow full width at half maximum of ≈17 nm, fourfold increased maximum current efficiency of 48.9 cd A-1 , and 19-fold improved half-lifetime of 253.8 h at 1000 cd m-2 compared to a conventional phosphorescent OLED. The findings can lead to better understanding of the hyperfluorescent OLEDs with high performance.
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Affiliation(s)
- Sungho Nam
- Samsung Advanced Institute of TechnologySamsung Electronics Co., Ltd.130 Samsung‐roSuwon‐siGyeonggi‐do16678Republic of Korea
| | - Ji Whan Kim
- Samsung Advanced Institute of TechnologySamsung Electronics Co., Ltd.130 Samsung‐roSuwon‐siGyeonggi‐do16678Republic of Korea
| | - Hye Jin Bae
- Samsung Advanced Institute of TechnologySamsung Electronics Co., Ltd.130 Samsung‐roSuwon‐siGyeonggi‐do16678Republic of Korea
| | - Yusuke Makida Maruyama
- Samsung Advanced Institute of TechnologySamsung Electronics Co., Ltd.130 Samsung‐roSuwon‐siGyeonggi‐do16678Republic of Korea
| | - Daun Jeong
- Data and Information Technology CenterSamsung Electronics Co., Ltd.1 Samsungjeonja‐roHwaseong‐siGyeonggi‐do18448Republic of Korea
| | - Joonghyuk Kim
- Samsung Advanced Institute of TechnologySamsung Electronics Co., Ltd.130 Samsung‐roSuwon‐siGyeonggi‐do16678Republic of Korea
| | - Jong Soo Kim
- Samsung Advanced Institute of TechnologySamsung Electronics Co., Ltd.130 Samsung‐roSuwon‐siGyeonggi‐do16678Republic of Korea
| | - Won‐Joon Son
- Data and Information Technology CenterSamsung Electronics Co., Ltd.1 Samsungjeonja‐roHwaseong‐siGyeonggi‐do18448Republic of Korea
| | - Hyein Jeong
- Display Research CenterSamsung Display Co.1 Samsung‐roYongin‐siGyeonggi‐do17113Republic of Korea
| | - Jaesang Lee
- Department of Electrical and Computer EngineeringInter‐University Semiconductor Research CenterSeoul National UniversitySeoul08826Republic of Korea
| | - Soo‐Ghang Ihn
- Samsung Advanced Institute of TechnologySamsung Electronics Co., Ltd.130 Samsung‐roSuwon‐siGyeonggi‐do16678Republic of Korea
| | - Hyeonho Choi
- Samsung Advanced Institute of TechnologySamsung Electronics Co., Ltd.130 Samsung‐roSuwon‐siGyeonggi‐do16678Republic of Korea
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12
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Wang J, Liang B, Wei J, Li Z, Xu Y, Yang T, Li C, Wang Y. Highly Efficient Electrofluorescence Material Based on Pure Organic Phosphor Sensitization**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Jiaxuan Wang
- State Key Laboratory of Supramolecular Structure and Materials College of Chemistry Jilin University Changchun 130012 P. R. China
| | - Baoyan Liang
- Jihua Laboratory 28 Huandao South Road Foshan 528200 Guangdong Province P. R. China
| | - Jinbei Wei
- State Key Laboratory of Supramolecular Structure and Materials College of Chemistry Jilin University Changchun 130012 P. R. China
| | - Zhiqiang Li
- Jihua Laboratory 28 Huandao South Road Foshan 528200 Guangdong Province P. R. China
| | - Yincai Xu
- State Key Laboratory of Supramolecular Structure and Materials College of Chemistry Jilin University Changchun 130012 P. R. China
| | - Tong Yang
- State Key Laboratory of Supramolecular Structure and Materials College of Chemistry Jilin University Changchun 130012 P. R. China
| | - Chenglong Li
- State Key Laboratory of Supramolecular Structure and Materials College of Chemistry Jilin University Changchun 130012 P. R. China
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials College of Chemistry Jilin University Changchun 130012 P. R. China
- Jihua Laboratory 28 Huandao South Road Foshan 528200 Guangdong Province P. R. China
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13
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Wang J, Liang B, Wei J, Li Z, Xu Y, Yang T, Li C, Wang Y. Highly Efficient Electrofluorescence Material Based on Pure Organic Phosphor Sensitization*. Angew Chem Int Ed Engl 2021; 60:15335-15339. [PMID: 33904242 DOI: 10.1002/anie.202104755] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 11/07/2022]
Abstract
Pure organic room-temperature phosphorescence (RTP) materials are considered as potential candidates for replacing precious metal complexes to fabricate highly efficient organic light-emitting devices (OLEDs). However, applications of the reported RTP materials in OLEDs are seriously impeded by their low photoluminescence quantum yields (PLQYs) in a thin film state. To overcome these obstacles, we established a new strategy to construct highly efficient OLEDs based on a pure organic RTP material sensitized fluorescence emitter by selecting benzimidazole-triazine molecules (PIM-TRZ), 2,6-di(phenothiazinyl)naphthalene (β-DPTZN), and 5,6,11,12-tetraphenylnaphthacene (rubrene) as host, phosphor sensitizer, and fluorescent emitter, respectively. The perfect combination of host, phosphorescent sensitizer, and fluorescent emitter in the emitting layer ensure the outstanding performance of the devices with an external quantum efficiency (EQE) of 15.7 %.
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Affiliation(s)
- Jiaxuan Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Baoyan Liang
- Jihua Laboratory, 28 Huandao South Road, Foshan, 528200, Guangdong Province, P. R. China
| | - Jinbei Wei
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Zhiqiang Li
- Jihua Laboratory, 28 Huandao South Road, Foshan, 528200, Guangdong Province, P. R. China
| | - Yincai Xu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Tong Yang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Chenglong Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.,Jihua Laboratory, 28 Huandao South Road, Foshan, 528200, Guangdong Province, P. R. China
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14
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Kumar K, Kesavan KK, Thakur D, Banik S, Jayakumar J, Cheng CH, Jou JH, Ghosh S. Functional Pyrene-Pyridine-Integrated Hole-Transporting Materials for Solution-Processed OLEDs with Reduced Efficiency Roll-Off. ACS OMEGA 2021; 6:10515-10526. [PMID: 34056206 PMCID: PMC8153793 DOI: 10.1021/acsomega.0c04080] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
A series of new functional pyridine-appended pyrene derivatives, viz., 2,6-diphenyl-4-(pyren-1-yl)pyridine (Py-03), 2,6-bis(4-methoxyphenyl)-4-(pyren-1-yl)pyridine (Py-MeO), 4-(pyren-1-yl)-2,6-di-p-tolylpyridine (Py-Me), and 2,6-bis(4-bromophenyl)-4-(pyren-1-yl)pyridine (Py-Br) were designed, developed, and studied as the hole-transporting materials (HTMs) for organic light-emitting diode (OLED) application. The crystal structures of two molecules revealed to have a large dihedral angle between the pyrene and pyridine units, indicating poor π-electronic communication between them due to ineffective orbital overlap across the pyrene-pyridine systems as the two p-orbitals of pivotal atoms are twisted at 66.80° and 68.75° angles to each other in Py-03 and Py-Me, respectively. The influence of variedly functionalized pyridine units on the electro-optical properties and device performance of the present integrated system for OLED application was investigated. All of the materials have suitable HOMO values (5.6 eV) for hole injection by closely matching the HOMOs of indium tin oxide (ITO) and the light-emitting layer. All of the synthesized molecules have suitable triplet energies, glass transition temperatures, and melting temperatures, which are highly desirable for good HTMs. The pyrene-pyridine-based devices demonstrated stable performance with low-efficiency roll-off. The device with Py-Br as HTM showed a maximum luminance of 17300 cd/m2 with a maximum current efficiency of 22.4 cd/A and an EQE of 9% at 3500 cd/m2 with 7% roll-off from 1000 to 10 000 cd/m2. Also, the devices with Py-Me and Py-03 showed performance roll-up while moving from 1000 to 10 000 cd/m2.
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Affiliation(s)
- Krishan Kumar
- School
of Basic Sciences, IIT Mandi, Mandi, Himachal Pradesh 175005, India
| | - Kiran Kishore Kesavan
- Department
of Materials Science and Engineering, National
Tsing Hua University, 101, Sec. 2, Guang-Fu Road, Hsinchu 30013, Taiwan, R.O.C.
| | - Diksha Thakur
- School
of Basic Sciences, IIT Mandi, Mandi, Himachal Pradesh 175005, India
| | - Subrata Banik
- Department
of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | | | - Chien-Hong Cheng
- Department
of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan, R.O.C.
| | - Jwo-Huei Jou
- Department
of Materials Science and Engineering, National
Tsing Hua University, 101, Sec. 2, Guang-Fu Road, Hsinchu 30013, Taiwan, R.O.C.
| | - Subrata Ghosh
- School
of Basic Sciences, IIT Mandi, Mandi, Himachal Pradesh 175005, India
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15
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Zhang C, Lu Y, Liu Z, Zhang Y, Wang X, Zhang D, Duan L. A π-D and π-A Exciplex-Forming Host for High-Efficiency and Long-Lifetime Single-Emissive-Layer Fluorescent White Organic Light-Emitting Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2004040. [PMID: 32893390 DOI: 10.1002/adma.202004040] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Exciplex-forming hosts with thermally activated delayed fluorescence (TADF) provide a viable opportunity to unlock the full potential of the yet-to-be improved power efficiencies (PEs) and stabilities of all-fluorescent white organic light-emitting diodes (WOLEDs), but this, however, is hindered by the lack of stable blue exciplexes. Here, an advanced exciplex system is proposed by incorporating bipolar charge-transport π-spacers into both the electron-donor (D) and the electron-accepter (A) to increase their distance for hypsochromic-shifted emission while maintaining the superior transporting ability. By using spirofluorene as the π-spacer, 3,3'-bicarbazole as the D-unit, and 2,4,6-triphenyl-1,3,5-triazine as the A-unit, a π-D and π-A exciplex with sky-blue emission and fast reverse intersystem crossing process is thereof constructed. Combining this exciplex-forming host, a blue TADF-sensitizer, and a yellow conventional fluorescent dopant in a single-emissive-layer, the fabricated warm-white-emissive device simultaneously exhibits a low driving voltage of 3.08 V, an external quantum efficiency of 21.4%, and a remarkable T80 (time to 80% of the initial luminance) of >8200 h at 1000 cd m-2 , accompanied by a new benchmark PE of 69.6 lm W-1 among all-fluorescent WOLEDs.
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Affiliation(s)
- Chen Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Yang Lu
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Ziyang Liu
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Yuewei Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Xuewen Wang
- Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory, Xianhu Hydrogen Valley, Foshan, 528200, P. R. China
| | - Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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16
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Jiang Y, Liu YY, Liu X, Lin H, Gao K, Lai WY, Huang W. Organic solid-state lasers: a materials view and future development. Chem Soc Rev 2020; 49:5885-5944. [PMID: 32672260 DOI: 10.1039/d0cs00037j] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Lasing applications have spread over various aspects of human life. To meet the developing trends of the laser industry towards being miniature, portable, and highly integrated, new laser technologies are in urgent demand. Organic semiconductors are promising gain medium candidates for novel laser devices, due to their convenient processing techniques, ease of spectral and chemical tuning, low refractive indexes, mechanical flexibilities, and low thresholds, etc. organic solid-state lasers (OSSLs) open up a new horizon of simple, low-cost, time-saving, versatile and environmental-friendly manufacturing technologies for new and desirable laser structures (micro-, asymmetric, flexible, etc.) to unleash the full potential of semiconductor lasers for future electronics. Besides the development of optical feedback structures, the design and synthesis of robust organic gain media is critical as a vigorous aspect of OSSLs. Herein, we provide a comprehensive review of recent advances in organic gain materials, mainly focused on organic semiconductors for OSSLs. The significant breakthroughs toward electrical pumping of OSSLs are emphasized. Opportunities, challenges and future research directions for the design of organic gain media are also discussed.
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Affiliation(s)
- Yi Jiang
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Yuan-Yuan Liu
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Xu Liu
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - He Lin
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Kun Gao
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Wen-Yong Lai
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China. and Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an 710072, China
| | - Wei Huang
- Key Laboratory for Organic Electronics and Information Displays (KLOEID), Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China. and Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an 710072, China
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17
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Kang S, Moon JH, Kim T, Lee JY. Design of efficient non-doped blue emitters: toward the improvement of charge transport. RSC Adv 2019; 9:27807-27816. [PMID: 35530480 PMCID: PMC9070764 DOI: 10.1039/c9ra04918e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 08/16/2019] [Indexed: 11/25/2022] Open
Abstract
Charge transport and electronic transition properties of a series of newly designed anthracene-based non-doped blue emitters were investigated by density functional theory calculations. For a highly efficient non-doped device, Cz3PhAn-based emitters were designed to suppress the hole and electron reorganization energies required for structural relaxation with respect to the changes of charged states. As a result, the hole hopping rates of triphenylamine (TPA) and phenylbenzimidazole (PBI) substituted Cz3PhAn derivatives (1, 4, and 5-7) were tremendously enhanced as compared to that of Cz3PhAn due to the suppression of the reorganization energy of holes, λ h. Moreover, 1 and 4 emitters showed almost identical hopping rates of holes and electrons, which can possibly lead to a perfect charge balance and high efficiency. The photo-physical properties showed that the emission energy of all 1-10 emitters is in 439-473 nm range. It is expected that our rational design strategy can help develop non-doped blue fluorescent emitters for high efficiency.
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Affiliation(s)
- Sunwoo Kang
- Display Research Center, Samsung Display Co. 1 Giheung-gu Gyunggi South Korea
| | - Jong Hun Moon
- Department of Chemistry, Sungkyunkwan University Suwon 16419 South Korea
| | - Taekyung Kim
- Department of Materials Science and Engineering, Hongik University Sejongsi 30016 South Korea
| | - Jin Yong Lee
- Department of Chemistry, Sungkyunkwan University Suwon 16419 South Korea
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18
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Song X, Zhang D, Lu Y, Yin C, Duan L. Understanding and Manipulating the Interplay of Wide-Energy-Gap Host and TADF Sensitizer in High-Performance Fluorescence OLEDs. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1901923. [PMID: 31265200 DOI: 10.1002/adma.201901923] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/16/2019] [Indexed: 06/09/2023]
Abstract
Comprising an emitting layer (EML) constituting a wide-energy-gap host, a thermally activated delayed fluorescence (TADF) sensitizer and a conventional fluorescent dopant, TADF-sensitizing-fluorescence organic light-emitting diodes (TSF-OLEDs) highly depend on component interplay to maximize their performance, which, however, is still under-researched. Taking the host type (TADF or non-TADF) and the recombination position (on the host or on the TADF sensitizer) into consideration, the interplay of host and TADF sensitizer is comprehensively studied and manipulated. A wide-energy-gap host with TADF and recombination of charges on it are both required to maximize device performances by triggering multiple sensitizing processes to eliminate exciton losses. Based on those findings, a maximum external quantum efficiency (EQE)/power efficiency (PE) of 23.2%/76.9 lm W-1 is realized with a newly developed TADF host, significantly outperforming the reference devices. Further device optimization leads to unprecedently high EQE/PE of 24.2%/89.5 lm W-1 and a half-lifetime of over 400 h at an initial luminance of 2000 cd m-2 , with the peak PE being the highest value among the reported TSF-OLEDs. This work reveals the importance of manipulating the component interplay in EMLs, opening a new avenue toward highly efficient TSF-OLEDs.
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Affiliation(s)
- Xiaozeng Song
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Yang Lu
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Chen Yin
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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19
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Byeon SY, Lee DR, Yook KS, Lee JY. Recent Progress of Singlet-Exciton-Harvesting Fluorescent Organic Light-Emitting Diodes by Energy Transfer Processes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1803714. [PMID: 30761642 DOI: 10.1002/adma.201803714] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/30/2018] [Indexed: 05/21/2023]
Abstract
The external quantum efficiency (EQE) of organic light-emitting diodes (OLEDs) has been dramatically improved by developing highly efficient organic emitters such as phosphorescent emitters and thermally activated delayed fluorescent (TADF) emitters. However, high-EQE OLED technologies suffer from relatively poor device lifetimes in spite of their high EQEs. In particular, the short lifetimes of blue phosphorescent and TADF OLEDs remain a big hurdle to overcome. Therefore, the high-EQE approach harvesting singlet excitons of fluorescent emitters by energy transfer processes from the host or sensitizer has been explored as an alternative for high-EQE OLED strategies. Recently, there has been a big jump in the EQE and device lifetime of singlet-exciton-harvesting fluorescent OLEDs. Recent progress on the materials and device structure is discussed herein.
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Affiliation(s)
- Sung Yong Byeon
- School of Chemical and Engineering, Sunkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 446-740, South Korea
| | - Dong Ryun Lee
- School of Chemical and Engineering, Sunkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 446-740, South Korea
| | - Kyoung Soo Yook
- School of Chemical and Engineering, Sunkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 446-740, South Korea
| | - Jun Yeob Lee
- School of Chemical and Engineering, Sunkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 446-740, South Korea
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20
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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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21
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Liang B, Wang J, Cheng Z, Wei J, Wang Y. Exciplex-Based Electroluminescence: Over 21% External Quantum Efficiency and Approaching 100 lm/W Power Efficiency. J Phys Chem Lett 2019; 10:2811-2816. [PMID: 31082247 DOI: 10.1021/acs.jpclett.9b01140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Benzimidazole-triazine-based electron acceptor PIM-TRZ with high triplet exited-state energy and strong electron-transport ability was newly developed. A series of highly efficient exciplex emitters have been fabricated. The TAPC:PIM-TRZ (TAPC: di-[4-( N, N-ditoly amino)-phenyl]cyclohexane) film shows a high photoluminescence (PL) quantum yields (PLQY, Φf) of 93.4%, and the device based on TAPC:PIM-TRZ exhibits a low turn-on voltage of 2.3 V, high maximum efficiency of 71.2 cd A-1 (current efficiency, CE), 97.3 lm W-1 (power efficiency, PE), and 21.7% (external quantum efficiency, EQE), as well as a high EQE of 16.2% at a luminance of 5000 cd m-2. The device displays the highest efficiency among reported organic light-emitting devices with an exciplex film as the emitting layer. Furthermore, a green device is also fabricated with a TAPC:PIM-TRZ cohost using C545T (C545T: (10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1 H,5 H,11 H-benzopyrano[6,7-8- I, j]quinolizin-11-one)) as the dopant, and the highest CE, PE, and EQE are 68.3 cd A-1, 86.6 lm W-1, and 20.2%, respectively.
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Affiliation(s)
- Baoyan Liang
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Jiaxuan Wang
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Zong Cheng
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Jinbei Wei
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , People's Republic of China
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22
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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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23
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Liu N, Mei S, Sun D, Shi W, Feng J, Zhou Y, Mei F, Xu J, Jiang Y, Cao X. Effects of Charge Transport Materials on Blue Fluorescent Organic Light-Emitting Diodes with a Host-Dopant System. MICROMACHINES 2019; 10:mi10050344. [PMID: 31130630 PMCID: PMC6562655 DOI: 10.3390/mi10050344] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/14/2019] [Accepted: 05/23/2019] [Indexed: 11/16/2022]
Abstract
High efficiency blue fluorescent organic light-emitting diodes (OLEDs), based on 1,3-bis(carbazol-9-yl)benzene (mCP) doped with 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl (BCzVBi), were fabricated using four different hole transport layers (HTLs) and two different electron transport layers (ETLs). Fixing the electron transport material TPBi, four hole transport materials, including 1,1-Bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4'-diamine(NPB), 4,4'-Bis(N-carbazolyl)-1,1,-biphenyl (CBP) and molybdenum trioxide (MoO3), were selected to be HTLs, and the blue OLED with TAPC HTL exhibited a maximum luminance of 2955 cd/m2 and current efficiency (CE) of 5.75 cd/A at 50 mA/cm2, which are 68% and 62% higher, respectively, than those of the minimum values found in the device with MoO3 HTL. Fixing the hole transport material TAPC, the replacement of TPBi ETL with Bphen ETL can further improve the performance of the device, in which the maximum luminance can reach 3640 cd/m2 at 50 mA/cm2, which is 23% higher than that of the TPBi device. Furthermore, the lifetime of the device is also optimized by the change of ETL. These results indicate that the carrier mobility of transport materials and energy level alignment of different functional layers play important roles in the performance of the blue OLEDs. The findings suggest that selecting well-matched electron and hole transport materials is essential and beneficial for the device engineering of high-efficiency blue OLEDs.
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Affiliation(s)
- Neng Liu
- Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan 430068, China.
| | - Sijiong Mei
- Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan 430068, China.
| | - Dongwei Sun
- Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan 430068, China.
| | - Wuxing Shi
- Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan 430068, China.
| | - Jiahuan Feng
- Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan 430068, China.
| | - Yuanming Zhou
- Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan 430068, China.
| | - Fei Mei
- Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan 430068, China.
| | - Jinxia Xu
- Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan 430068, China.
| | - Yan Jiang
- Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System, Hubei University of Technology, Wuhan 430068, China.
| | - Xianan Cao
- Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, WV 26506, USA.
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24
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Wei X, Liu Y, Hu T, Li Z, Liu J, Wang R, Gao H, Hu X, Liu G, Wang P, Lee CS, Wang Y. Design of Efficient Exciplex Emitters by Decreasing the Energy Gap Between the Local Excited Triplet ( 3LE) State of the Acceptor and the Charge Transfer (CT) States of the Exciplex. Front Chem 2019; 7:188. [PMID: 31024884 PMCID: PMC6465540 DOI: 10.3389/fchem.2019.00188] [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: 01/27/2019] [Accepted: 03/11/2019] [Indexed: 11/13/2022] Open
Abstract
A series of thermally activated delayed fluorescence (TADF) exciplex based on the TX-TerPy were constructed. The electronic coupling between the triplet local excited states (3LE) of the donors and acceptor and the charge transfer states had a great influence on the triplet exciton harvesting and ΦPL. Herein, based on this strategy, three donor molecules TAPC, TCTA, and m-MTDATA were selected. The local triplet excited state (3LE) of the three donors are 2.93, 2.72 and 2.52 eV in pure films. And the 3LE of TX-TerPy is 2.69 eV in polystyrene film. The energy gap between the singlet charge transfer (1CT) states of TAPC:TX-TerPy (7:1), TCTA:TX-TerPy (7:1) and the 3LE of TX-TerPy are 0.30 eV and 0.20 eV. Finally, the ΦPL of TAPC:TX-TerPy (7:1) and TCTA:TX-TerPy (7:1) are 65.2 and 69.6%. When we changed the doping concentration of the exciplex from 15% to 50%, the ratio of the triplet decreased, and ΦPL decreased by half, perhaps due to the increased energy gap between 1CT and 3LE. Therefore, optimizing the 1CT, 3CT, and 3LE facilitated the efficient exciplex TADF molecules.
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Affiliation(s)
- Xiaofang Wei
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Yanwei Liu
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, China.,Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Taiping Hu
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, China.,Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Zhiyi Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Jianjun Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Ruifang Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Honglei Gao
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoxiao Hu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Guanhao Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Pengfei Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong, Hong Kong
| | - Ying Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.,School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
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25
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Gao F, Du R, Han C, Zhang J, Wei Y, Lu G, Xu H. High-efficiency blue thermally activated delayed fluorescence from donor-acceptor-donor systems via the through-space conjugation effect. Chem Sci 2019; 10:5556-5567. [PMID: 31293740 PMCID: PMC6553033 DOI: 10.1039/c9sc01240k] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/25/2019] [Indexed: 12/11/2022] Open
Abstract
Highly efficient sky-blue TADF donor–acceptor–donor molecules were demonstrated, in which 5,10-diphenyl-5,10-dihydrophosphanthrene oxide (DPDPO2A) with the feature of homoconjugation was used as the acceptor to bridge four carbazolyl or 3,6-di-t-butyl-carbazolyl groups.
The photophysical optimization of donor (D)–acceptor (A) molecules is a real challenge because of the intrinsic limitation of their charger transfer (CT) excited states. Herein, two D–A–D molecules featuring blue thermally activated delayed fluorescence (TADF) are developed, in which a homoconjugated acceptor 5,10-diphenyl-5,10-dihydrophosphanthrene oxide (DPDPO2A) is incorporated to bridge four carbazolyl or 3,6-di-t-butyl-carbazolyl groups for D–A interaction optimization without immoderate conjugation extension. It is shown that the through-space conjugation effect of DPDPO2A can efficiently enhance intramolecular CT (ICT) and simultaneously facilitate the uniform dispersion of the frontier molecular orbitals (FMO), which remarkably reduces the singlet–triplet splitting energy (ΔEST) and increases FMO overlaps for radiation facilitation, resulting in the 4–6 fold increased rate constants of reverse intersystem crossing (RISC) and singlet radiation. The maximum external quantum efficiency beyond 20% and the state-of-the-art efficiency stability from sky-blue TADF OLEDs demonstrate the effectiveness of the “conjugation modulation” strategy for developing high-performance optoelectronic D–A systems.
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Affiliation(s)
- Feifei Gao
- Key Laboratory of Functional Inorganic Material Chemistry , Ministry of Education & School of Chemistry and Material Science , Heilongjiang University , 74 Xuefu Road , Harbin 150080 , People's Republic of China . ;
| | - Ruiming Du
- Key Laboratory of Functional Inorganic Material Chemistry , Ministry of Education & School of Chemistry and Material Science , Heilongjiang University , 74 Xuefu Road , Harbin 150080 , People's Republic of China . ;
| | - Chunmiao Han
- Key Laboratory of Functional Inorganic Material Chemistry , Ministry of Education & School of Chemistry and Material Science , Heilongjiang University , 74 Xuefu Road , Harbin 150080 , People's Republic of China . ;
| | - Jing Zhang
- Key Laboratory of Functional Inorganic Material Chemistry , Ministry of Education & School of Chemistry and Material Science , Heilongjiang University , 74 Xuefu Road , Harbin 150080 , People's Republic of China . ;
| | - Ying Wei
- Key Laboratory of Functional Inorganic Material Chemistry , Ministry of Education & School of Chemistry and Material Science , Heilongjiang University , 74 Xuefu Road , Harbin 150080 , People's Republic of China . ;
| | - Guang Lu
- Key Laboratory of Functional Inorganic Material Chemistry , Ministry of Education & School of Chemistry and Material Science , Heilongjiang University , 74 Xuefu Road , Harbin 150080 , People's Republic of China . ;
| | - Hui Xu
- Key Laboratory of Functional Inorganic Material Chemistry , Ministry of Education & School of Chemistry and Material Science , Heilongjiang University , 74 Xuefu Road , Harbin 150080 , People's Republic of China . ;
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26
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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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27
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Jones LO, Mosquera MA, Fu B, Schatz GC, Ratner MA, Marks TJ. Germanium Fluoride Nanocages as Optically Transparent n-Type Materials and Their Endohedral Metallofullerene Derivatives. J Am Chem Soc 2019; 141:1672-1684. [PMID: 30608154 DOI: 10.1021/jacs.8b11259] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carbon- and silicon-based n-type materials tend to suffer from instability of the corresponding radical anions. With DFT calculations, we explore a promising route to overcome such challenges with molecular nanocages which utilize the heavier element Ge. The addition of fluorine substituents creates large electron affinities in the range 2.5-5.5 eV and HOMO-LUMO gaps between 1.6 and 3.2 eV. The LUMOs envelop the surfaces of these structures, suggesting extensive delocalization of injected electrons, analogous to fullerene acceptors. Moreover, these Ge nF n inorganic cages are found to be transparent in the UV-visible region as probed with their excited states. Their capacitance, linear polarizabilities, and dielectric constants are computed and found to be on the same order of magnitude as saturated oligomers and some extended π-organics (azobenzenes). Furthermore, we explore fullerene-type endohedral isomers, i.e., cages with internal substituents or guest atoms, and find them to be more stable than the parent exohedral isomers by up to -206.45 kcal mol-1. We also consider the addition of Li, He, Cs, and Bi, to probe the utility of the exo/ endo cages as host-guest systems. The endohedral He/Li@F8@Ge60F52 cages are significantly more stable than their parent exohedral isomers He/Li@Ge60F52 by -182.46 and -49.22 kcal mol-1, respectively. The energy of formation of endohedral He@F8@Ge60F52 is exothermic by -10.4 kcal mol-1, while Cs and Bi guests are too large to be accommodated but are stable in the exohedral parent cages. Conceivable applications of these materials include n-type semiconductors and transparent electrodes, with potential for novel energy storage modalities.
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Affiliation(s)
- Leighton O Jones
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Martín A Mosquera
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Bo Fu
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - George C Schatz
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Mark A Ratner
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
| | - Tobin J Marks
- Department of Chemistry and the Materials Research Center , Northwestern University , Evanston , Illinois 60208 , United States
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28
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Kim HG, Shin H, Ha YH, Kim R, Kwon SK, Kim YH, Kim JJ. Triplet Harvesting by a Fluorescent Emitter Using a Phosphorescent Sensitizer for Blue Organic-Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2019; 11:26-30. [PMID: 30543096 DOI: 10.1021/acsami.8b17957] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The development of highly efficient blue organic light-emitting diodes (OLEDs) with good stability is currently the most important issue in OLED displays and lighting. This paper reports an efficient blue fluorescent OLED based on a deep-blue-emitting phosphorescent sensitizer [(dfpysipy)2Ir(mpic)] and a conventional fluorescent emitter (TBPe). Efficient triplet harvesting by the fluorescent emitter occurs in the OLED because of sensitization even though the difference in the emission energy between the phosphorescent and fluorescent emissions was only 0.05 eV. These results clearly demonstrate the potential for realizing highly efficient blue fluorescent OLEDs using phosphorescent sensitizers without requiring ultraviolet-emitting phosphorescent dye.
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29
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Yu R, Wang T, Kang Z, Zhang H, Zhang H, Ji W. Intaglio-type random silver networks as the cathodes for efficient full-solution processed flexible quantum-dot light-emitting diodes. NANOSCALE 2018; 10:22541-22548. [PMID: 30480288 DOI: 10.1039/c8nr05678a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Flexible quantum-dot light-emitting diodes (FQLEDs) hold great promise as a leading display and lighting technology due to their light weight, low-cost, and saturated emission color. However, there remain many challenges in the development of high quality electrodes on flexible substrates for device fabrication and operation. In this work, we present a robust flexible transparent conductive film with embedded random Ag networks in the PET substrate (named PRAN). The PRAN composite film exhibits an average transmittance of 85%, and the sheet resistance reaches near 5.3 Ω sq-1 without any obvious change after bending 3000 times, indicating excellent flexibility of this type of conductive film. A highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer was employed to smooth the surface of the PRAN electrode. Consequently, FQLEDs based on these flexible electrodes are successfully fabricated and the peak power efficiencies of 42.3, 101.9, and 6.4 lm W-1 are achieved for the red, green and blue devices, respectively. To the best of our knowledge, these are the best efficiencies for the FQLEDs reported to date. These results lay the foundation of the realization of ITO-free, high-efficiency FQLEDs for use in flexible lighting and display applications.
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Affiliation(s)
- Rongmei Yu
- Key Lab of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, China.
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30
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Unicolored phosphor-sensitized fluorescence for efficient and stable blue OLEDs. Nat Commun 2018; 9:4990. [PMID: 30478331 PMCID: PMC6255836 DOI: 10.1038/s41467-018-07432-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/29/2018] [Indexed: 11/28/2022] Open
Abstract
Improving lifetimes and efficiencies of blue organic light-emitting diodes is clearly a scientific challenge. Towards solving this challenge, we propose a unicolored phosphor-sensitized fluorescence approach, with phosphorescent and fluorescent emitters tailored to preserve the initial color of phosphorescence. Using this approach, we design an efficient sky-blue light-emitting diode with radiative decay times in the submicrosecond regime. By changing the concentration of fluorescent emitter, we show that the lifetime is proportional to the reduction of the radiative decay time and tune the operational stability to lifetimes of up to 320 h (80% decay, initial luminance of 1000 cd/m2). Unicolored phosphor-sensitized fluorescence provides a clear path towards efficient and stable blue light-emitting diodes, helping to overcome the limitations of thermally activated delayed fluorescence. The potential of organic light-emitting diodes (OLEDs) for solid-state lighting applications is limited by the need to develop efficient blue emitters. Here, the authors utilize a unicolored phosphor-sensitized fluorescence strategy to demonstrate efficient sky-blue OLEDs with enhanced lifetime.
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31
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Kim KH, Kim JJ. Origin and Control of Orientation of Phosphorescent and TADF Dyes for High-Efficiency OLEDs. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1705600. [PMID: 29707823 DOI: 10.1002/adma.201705600] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/29/2017] [Indexed: 06/08/2023]
Abstract
It has been known for decades that the emitting dipole orientation (EDO) of emitting dyes influences the outcoupling efficiency of organic light-emitting diodes (OLEDs). However, the EDO of dopants, especially phosphorescent dopants, has been studied less than that of neat films and polymer emitting layers (EMLs) due to the lack of an apparent driving force for aligning the dopants in amorphous host films. Recently, however, even globular-shaped Ir complexes have been reported to have a preferred orientation in doped films and OLEDs. External quantum efficiencies (EQEs) higher than 30% have also been demonstrated using phosphorescent and thermally activated delayed fluorescent dyes (TADF) doped in EMLs. Here, recent results on the EDO of phosphorescent and TADF dyes doped in host films, and highly efficient OLEDs using these dyes are reviewed. The origin and control of the orientation of phosphors are discussed, followed by a discussion of future strategies to achieve EQEs of over 60% without a light extraction layer, from the material point of view.
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Affiliation(s)
- Kwon-Hyeon Kim
- Department of Materials Science and Engineering, RIAM, Seoul National University, Seoul, 151-742, South Korea
| | - Jang-Joo Kim
- Department of Materials Science and Engineering, RIAM, Seoul National University, Seoul, 151-742, South Korea
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Han C, Zhang Z, Ding D, Xu H. Dipole-Dipole Interaction Management for Efficient Blue Thermally Activated Delayed Fluorescence Diodes. Chem 2018. [DOI: 10.1016/j.chempr.2018.06.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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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Yin T, Wu T, Zhong D, Liu J, Liu X, Han Z, Yu H, Qu S. Soft Display Using Photonic Crystals on Dielectric Elastomers. ACS APPLIED MATERIALS & INTERFACES 2018; 10:24758-24766. [PMID: 29968470 DOI: 10.1021/acsami.8b05451] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Soft display has been intensively studied in recent years in the wake of rapid development of a variety of soft materials. The currently existing solutions for translating the traditional hard display into the more convenient soft display mainly include light-emitting diodes, liquid crystals, quantum dots, and phosphors. The desired soft display should take the advantages of facile fabrication processes and cheap raw materials. Besides, the device should be colorful, nontoxic, and not only flexible but also stretchable. However, the foregoing devices may not own all of the desired features. Here, a new type of soft display, which consists of dielectric elastomer and photonic crystals that cover all of the features mentioned above and can achieve the color change dynamically and in situ, is reported. In addition to the above features, the angle-dependent characteristic and the excellent mechanical reliability make it a great candidate for the next generation of soft display. Finally, the vast applications of the present concept in a variety of fields are also prospected.
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Affiliation(s)
- Tenghao Yin
- State Key Laboratory of Fluid Power & Mechatronic System, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics , Zhejiang University , Hangzhou 310027 , China
| | - Tonghao Wu
- State Key Laboratory of Fluid Power & Mechatronic System, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics , Zhejiang University , Hangzhou 310027 , China
| | - Danming Zhong
- State Key Laboratory of Fluid Power & Mechatronic System, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics , Zhejiang University , Hangzhou 310027 , China
| | - Junjie Liu
- State Key Laboratory of Fluid Power & Mechatronic System, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics , Zhejiang University , Hangzhou 310027 , China
| | - Xiangjiang Liu
- College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou 310058 , China
| | - Zilong Han
- State Key Laboratory of Fluid Power & Mechatronic System, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics , Zhejiang University , Hangzhou 310027 , China
| | - Honghui Yu
- Department of Mechanical Engineering , The City College of New York , New York , New York 10031 , United States
| | - Shaoxing Qu
- State Key Laboratory of Fluid Power & Mechatronic System, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics , Zhejiang University , Hangzhou 310027 , China
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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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Zhang D, Song X, Li H, Cai M, Bin Z, Huang T, Duan L. High-Performance Fluorescent Organic Light-Emitting Diodes Utilizing an Asymmetric Anthracene Derivative as an Electron-Transporting Material. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707590. [PMID: 29774610 DOI: 10.1002/adma.201707590] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/18/2018] [Indexed: 06/08/2023]
Abstract
Fluorescent organic light-emitting diodes with thermally activated delayed fluorescent sensitizers (TSF-OLEDs) have aroused wide attention, the power efficiencies of which, however, are limited by the mutual exclusion of high electron-transport mobility and large triplet energy of electron-transporting materials (ETMs). Here, an asymmetric anthracene derivative with electronic properties manipulated by different side groups is developed as an ETM to promote TSF-OLED performances. Multiple intermolecular interactions are observed, leading to a kind of "cable-like packing" in the crystal and favoring the simultaneous realization of high electron-transporting mobility and good exciton-confinement ability, albeit the low triplet energy of the ETM. The optimized TSF-OLEDs exhibit a record-high maximum external quantum efficiency/power efficiency of 24.6%/76.0 lm W-1 , which remain 23.8%/69.0 lm W-1 at a high luminance of even 5000 cd m-2 with an extremely low operation voltage of 3.14 V. This work opens a new paradigm for designing ETMs and also paves the way toward practical application of TSF-OLEDs.
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Affiliation(s)
- Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Xiaozeng Song
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Haoyuan Li
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Minghan Cai
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Zhengyang Bin
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Tianyu Huang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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Zhang D, Song X, Cai M, Duan L. Blocking Energy-Loss Pathways for Ideal Fluorescent Organic Light-Emitting Diodes with Thermally Activated Delayed Fluorescent Sensitizers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1705250. [PMID: 29280207 DOI: 10.1002/adma.201705250] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/08/2017] [Indexed: 06/07/2023]
Abstract
Organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence-sensitized fluorescence (TSF) offer the possibility of attaining an ultimate high efficiency with low roll-off utilizing noble-metal free, easy-to-synthesize, pure organic fluorescent emitters. However, the performances of TSF-OLEDs are still unsatisfactory. Here, TSF-OLEDs with breakthrough efficiencies even at high brightnesses by suppressing the competitive deactivation processes, including direct charge recombination on conventional fluorescent dopants (CFDs) and Dexter energy transfer from the host to the CFDs, are demonstrated. On the one hand, electronically inert terminal-substituents are introduced to protect the electronically active core of the CFDs; on the other hand, delicate device structures are designed to provide multiple energy-funneling paths. As a result, unprecedentedly high maximum external quantum efficiency/power efficiency of 24%/71.4 lm W-1 in a green TSF-OLED are demonstrated, which remain at 22.6%/52.3 lm W-1 even at a high luminance of 5000 cd m-2 . The work unlocks the potential of TSF-OLEDs, paving the way toward practical applications.
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Affiliation(s)
- Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Xiaozeng Song
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Minghan Cai
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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