51
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Wei J, Zhang C, Zhang D, Zhang Y, Liu Z, Li Z, Yu G, Duan L. Indolo[3,2,1‐
jk
]carbazole Embedded Multiple‐Resonance Fluorophors for Narrowband Deep‐blue Electroluminescence with EQE≈34.7 % and CIE
y
≈0.085. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202017328] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Jinbei Wei
- Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Chen Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education Department of Chemistry Tsinghua University Beijing 100084 P. R. China
| | - Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education Department of Chemistry Tsinghua University Beijing 100084 P. R. China
| | - Yuewei Zhang
- 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
| | - Zhiqiang Li
- JiHua Laboratory Foshan 528200 Guangdong Province P. R. China
| | - Gui Yu
- Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Chemical Sciences University of Chinese Academy of Sciences Beijing 100049 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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52
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Wei J, Zhang C, Zhang D, Zhang Y, Liu Z, Li Z, Yu G, Duan L. Indolo[3,2,1‐
jk
]carbazole Embedded Multiple‐Resonance Fluorophors for Narrowband Deep‐blue Electroluminescence with EQE≈34.7 % and CIE
y
≈0.085. Angew Chem Int Ed Engl 2021; 60:12269-12273. [DOI: 10.1002/anie.202017328] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Indexed: 01/08/2023]
Affiliation(s)
- Jinbei Wei
- Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
| | - Chen Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education Department of Chemistry Tsinghua University Beijing 100084 P. R. China
| | - Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education Department of Chemistry Tsinghua University Beijing 100084 P. R. China
| | - Yuewei Zhang
- 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
| | - Zhiqiang Li
- JiHua Laboratory Foshan 528200 Guangdong Province P. R. China
| | - Gui Yu
- Beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
- School of Chemical Sciences University of Chinese Academy of Sciences Beijing 100049 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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53
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Jung YH, Karthik D, Lee H, Maeng JH, Yang KJ, Hwang S, Kwon JH. A New BODIPY Material for Pure Color and Long Lifetime Red Hyperfluorescence Organic Light-Emitting Diode. ACS APPLIED MATERIALS & INTERFACES 2021; 13:17882-17891. [PMID: 33826283 DOI: 10.1021/acsami.1c03175] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A red fluorescent material, 1,3,7,9-tetrakis(4-(tert-butyl)phenyl)-5,5-difluoro-10-(2-methoxyphenyl)-5H-4l4,5l4-dipyrrolo[1,2-c:2',1'-f][1,3,2]diazaborinine (4tBuMB), as an emitting dopant in a thermally activated delayed fluorescence (TADF) sensitized hyperfluorescence organic light-emitting diode (HFOLED) is reported. The 4tBuMB shows a high photoluminescence quantum yield (PLQY) of 99% with an emission maximum at 620 nm and a full width at half-maximum (fwhm) of 31 nm in solution. Further, it shows a deep lowest unoccupied molecular orbital (LUMO) of 3.83 eV. Thus, two TADF materials, 4CzIPN and 4CzTPN, as sensitizing hosts, are selected on the basis of a suitable LUMO level and spectrum overlap with 4tBuMB. The fabricated HFOLED device with 4CzTPN as a sensitizing host and 4tBuMB as an emitting dopant shows a maximum external quantum efficiency (EQE), an emission maximum, an fwhm, and CIE coordinates of 19.4%, 617 nm, 44 nm, and (0.64, 0.36), respectively. The electroluminance performances of the 4CzTPN sensitized device are higher than those of the 4CzIPN-based device, which is attributed to a higher Förster resonance energy transfer (FRET) rate and reduced intersystem crossing/reverse intersystem crossing (ISC/RISC) cycles of the former. Also, the 4CzTPN-based HF device shows a longer device lifetime (LT90) of 954 h than the 4CzIPN-baed device (LT90 of 57 h) at 3000 cd m-2. The higher device stability is due to the higher bond dissociation energies (BDEs) of 4CzTPN and 4tBuMB than that of 4CzIPN.
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Affiliation(s)
- Young Hun Jung
- Organic Optoelectronic Device Laboratory, Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Durai Karthik
- Organic Optoelectronic Device Laboratory, Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Hyuna Lee
- Organic Optoelectronic Device Laboratory, Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Jee Hyun Maeng
- Organic Optoelectronic Device Laboratory, Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Ki Joon Yang
- Organic Optoelectronic Device Laboratory, Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Soonjae Hwang
- Organic Optoelectronic Device Laboratory, Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Jang Hyuk Kwon
- Organic Optoelectronic Device Laboratory, Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
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54
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Su R, Zhao Y, Yang F, Duan L, Lan J, Bin Z, You J. Triazolotriazine-based thermally activated delayed fluorescence materials for highly efficient fluorescent organic light-emitting diodes (TSF-OLEDs). Sci Bull (Beijing) 2021; 66:441-448. [PMID: 36654181 DOI: 10.1016/j.scib.2020.08.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/09/2020] [Accepted: 08/05/2020] [Indexed: 02/06/2023]
Abstract
Thermally activated delayed fluorescence (TADF) sensitized fluorescent organic light-emitting diodes (TSF-OLEDs) have shown great potential for the realization of high efficiency with low efficiency roll-off and good color purity. However, the superior examples of TSF-OLEDs are still limited up to now. Herein, a trade-off strategy is presented for designing efficient TADF materials and achieving high-performance TSF-OLEDs via the construction of a new type of triazolotriazine (TAZTRZ) acceptor. The enhanced electron-withdrawing ability of TAZTRZ acceptor, fused by triazine (TRZ) and triazole (TAZ) together, enables TADF luminogens with small singlet-triplet energy gap (ΔEST) values. Meanwhile, the increased planarity from the TRZ-phenyl linkage (6:6 system) to the TAZ-phenyl linkage (5:6 system) can compensate the decrease of oscillator strength (f) while lowing ΔEST, thus achieving a trade-off between small ΔEST and high f. As a result, the related TSF-OLED achieved an extremely low turn-on voltage of 2.1 V, an outstanding maximum external quantum efficiency (EQEmax) of 23.7% with small efficiency roll-off (EQE1000 of 23.2%; EQE5000 of 20.6%) and an impressively high maximum power efficiency of 82.1 lm W-1, which represents the state-of-the-art performance for yellow TSF-OLEDs.
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Affiliation(s)
- Rongchuan Su
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Yuyao Zhao
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Feng Yang
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Lian Duan
- Key Laboratory of Organic Optoelectronics, Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Jingbo Lan
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Zhengyang Bin
- College of Chemistry, Sichuan University, Chengdu 610064, China.
| | - Jingsong You
- College of Chemistry, Sichuan University, Chengdu 610064, China.
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55
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Liu Y, Tong X, Chen X, Wang Y, Ying S, Ren Z, Yan S. Enhanced Upconversion of Triplet Excitons for Conjugated Polymeric Thermally Activated Delayed Fluorescence Emitters by Employing an Intramolecular Sensitization Strategy. ACS APPLIED MATERIALS & INTERFACES 2021; 13:8997-9005. [PMID: 33570400 DOI: 10.1021/acsami.0c22494] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Endowed by a thermally activated delayed fluorescence (TADF) sensitizer with a high constant rate of reverse intersystem crossing, the singlet excitons could be accumulated and then delivered to emitting states through favorable Förster resonance energy transfer, bypassing the inefficient intersystem transition processes of emitters. However, the conventional intermolecular sensitization strategies suffer from inherent aggregation-induced quenching and inevitable phase segregation of TADF sensitizers and emitters. In this context, we proposed a novel intramolecular sensitization strategy by covalently incorporating the TADF sensitizer into conjugated polymeric emitters. After rationally regulating the proportions of sensitizer and emitter units in polymers, the intramolecular sensitized conjugated TADF polymers with anticipated photophysical properties and stable device performance were obtained. A superior kRISC value over 106 s-1 accompanied by a suppressed nonradiative transition of the triplet exciton could be gained; therefore, the photoluminescence quantum yield (PLQY) could reach nearly 90%. In accord with the superior PLQY values enhanced by our intramolecular sensitization strategy, the solution-processed organic light-emitting diodes (OLEDs) can achieve a maximum external quantum efficiency (EQE) value of 17.8% while still maintaining 16.0% at 1000 cd/m2 with extremely low efficiency roll-off. These results convincingly manifest the significance of an intramolecular sensitization strategy for designing high-efficiency polymeric TADF emitters.
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Affiliation(s)
- Yuchao Liu
- Key Laboratory of Rubber-Plastics, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042, P. R. China
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xingwen Tong
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xinrui Chen
- Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China
| | - Yafei Wang
- Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China
| | - Shian Ying
- Key Laboratory of Rubber-Plastics, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042, P. R. China
| | - Zhongjie Ren
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Shouke Yan
- Key Laboratory of Rubber-Plastics, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042, P. R. China
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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56
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Yoon SJ, Kim JH, Chung WJ, Lee JY. Design Approach of Lifetime Extending Thermally Activated Delayed Fluorescence Sensitizers for Highly Efficient Fluorescence Devices. Chemistry 2021; 27:3065-3073. [DOI: 10.1002/chem.202004042] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/27/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Sung Joon Yoon
- School of Chemical Engineering Sungkyunkwan University 2066, Seobu-ro Jangan-gu, Suwon-si Gyeonggi-do 440–746 Republic of Korea
| | - Ji Han Kim
- School of Chemical Engineering Sungkyunkwan University 2066, Seobu-ro Jangan-gu, Suwon-si Gyeonggi-do 440–746 Republic of Korea
| | - Won Jae Chung
- School of Chemical Engineering Sungkyunkwan University 2066, Seobu-ro Jangan-gu, Suwon-si Gyeonggi-do 440–746 Republic of Korea
| | - Jun Yeob Lee
- School of Chemical Engineering Sungkyunkwan University 2066, Seobu-ro Jangan-gu, Suwon-si Gyeonggi-do 440–746 Republic of Korea
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57
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Khammultri P, Kitisriworaphan W, Chasing P, Namuangruk S, Sudyoadsuk T, Promarak V. Efficient white light-emitting polymers from dual thermally activated delayed fluorescence chromophores for non-doped solution processed white electroluminescent devices. Polym Chem 2021. [DOI: 10.1039/d0py01541e] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Conjugated TADF copolymers comprised of two TADF molecules linked with carbazole exhibited stable pure white emission from non-doped OLEDs with CIE coordinates (0.32, 0.35), a maximum luminance efficiency of 9.13 cd A−1, and a maximum EQE of 4.17%.
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Affiliation(s)
- Praetip Khammultri
- Department of Materials Science and Engineering
- School of Molecular Science & Engineering
- Vidyasirimedhi Institute of Science and Technology
- Wangchan
- Thailand
| | - Wipaporn Kitisriworaphan
- School of Chemistry
- Institute of Science
- Suranaree University of Technology
- Nakhon Ratchasima 30000
- Thailand
| | - Pongsakorn Chasing
- Department of Materials Science and Engineering
- School of Molecular Science & Engineering
- Vidyasirimedhi Institute of Science and Technology
- Wangchan
- Thailand
| | - Supawadee Namuangruk
- National Nanotechnology Center (NANOTEC)
- National Science and Technology Development Agency
- Pathum Thani
- Thailand
| | - Taweesak Sudyoadsuk
- Department of Materials Science and Engineering
- School of Molecular Science & Engineering
- Vidyasirimedhi Institute of Science and Technology
- Wangchan
- Thailand
| | - Vinich Promarak
- Department of Materials Science and Engineering
- School of Molecular Science & Engineering
- Vidyasirimedhi Institute of Science and Technology
- Wangchan
- Thailand
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58
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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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59
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Polgar AM, Tonge CM, Christopherson CJ, Paisley NR, Reyes AC, Hudson ZM. Thermally Assisted Fluorescent Polymers: Polycyclic Aromatic Materials for High Color Purity and White-Light Emission. ACS APPLIED MATERIALS & INTERFACES 2020; 12:38602-38613. [PMID: 32846499 DOI: 10.1021/acsami.0c07892] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Thermally activated delayed fluorescence (TADF) sensitization of fluorescence is a promising strategy to improve the color purity and operational lifetime of conventional TADF organic light-emitting diodes (OLEDs). Here, we propose a new design strategy for TADF-sensitized fluorescence based on acrylic polymers with a pendant energy-harvesting host, a TADF sensitizer, and fluorescent emitter monomers. Fluorescent emitters were rationally designed from a series of homologous polycyclic aromatic amines, resulting in efficient and color-pure polymeric fluorophores capable of harvesting both singlet and triplet excitons. Macromolecular analogues of blue, green, and yellow fourth-generation OLED emissive layers were prepared in a facile manner by Cu(0) reversible deactivation radical polymerization, with emission quantum yields up to 0.83 in air and narrow emission bands with full width at half-maximum as low as 57 nm. White-light emission can easily be achieved by enforcing incomplete energy transfer between a deep blue TADF sensitizer and yellow fluorophore to yield a single white-emissive polymer with CIE coordinates (0.33, 0.39) and quantum yield 0.77. Energy transfer to the fluorescent emitters occurs at rates of 1-4 × 108 s-1, significantly faster than deactivation caused by internal conversion or intersystem crossing. Rapid energy transfer facilitates high triplet exciton utilization and efficient sensitized emission, even when TADF emitters with a low quantum yield are used as photosensitizers. Our results indicate that a broad library of untapped polymers exhibiting efficient TADF-sensitized fluorescence should be readily accessible from known TADF materials, including many monomers previously thought unsuitable for use in OLEDs.
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Affiliation(s)
- Alexander M Polgar
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Christopher M Tonge
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Cheyenne J Christopherson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Nathan R Paisley
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Annelie C Reyes
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Zachary M Hudson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
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60
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Yang SY, Tian QS, Yu YJ, Zou SN, Li HC, Khan A, Wu QH, Jiang ZQ, Liao LS. Sky-Blue Thermally Activated Delayed Fluorescence with Intramolecular Spatial Charge Transfer Based on a Dibenzothiophene Sulfone Emitter. J Org Chem 2020; 85:10628-10637. [PMID: 32806105 DOI: 10.1021/acs.joc.0c01200] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intramolecular spatial charge transfer (ISCT) plays a critical role in determining the optical and charge transport properties of thermally activated delayed fluorescence (TADF) materials. Herein, a new donor/acceptor-type TADF compound based on rigid dibenzothiophene sulfone (DBTS) moiety, STF-DBTS, was designed and synthesized. Fluorene unit was used as a rigid linker to position the rigid acceptor and donor subunit in close vicinity with control over their spacing and molecular structure and to achieve high photoluminescence quantum yield (∼53%) and TADF property. For comparison purposes, we constructed the more flexible STF-DPS with a less rotationally constrained diphenylsulphone (DPS) acceptor instead of the rigid DBTS units, and STF-DPS showed no TADF properties and lower PLQY (16.0%). Organic light-emitting diodes (OLEDs) based on STF-DBTS achieve an external quantum efficiency (EQE) of 10.3% at 488 nm, which is a fivefold improvement in EQE with respect to STF-DPS.
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Affiliation(s)
- Sheng-Yi Yang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Qi-Sheng Tian
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - You-Jun Yu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Sheng-Nan Zou
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Hong-Cheng Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Aziz Khan
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Qian-Han Wu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Zuo-Quan Jiang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China
| | - Liang-Sheng Liao
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China.,Institute of Organic Optoelectronics, Jiangsu Industrial Technology Research Institute (JITRI), Wujiang, Suzhou, Jiangsu 215211, China
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61
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Zhang D, Huang T, Duan L. Emerging Self-Emissive Technologies for Flexible Displays. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1902391. [PMID: 31595613 DOI: 10.1002/adma.201902391] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 07/01/2019] [Indexed: 06/10/2023]
Abstract
Featuring a combination of ultrathin and lightweight properties, excellent mechanical flexibility, low power-consumption, and widely tunable saturated emission, flexible displays have opened up a new possibility for optoelectronics. The demands for flexible displays are growing on a continual basis due not only to their successful commercialization but, more importantly, their endless possibilities for wearable integrated systems. Up to now, self-emissive technologies for displays, flexible active-matrix organic light-emitting diodes (flex-AMOLED), flexible quantum dot light-emitting diodes (flex-QLEDs), and flexible perovskite light-emitting diodes (flex-PeLEDs) have been widely reported, but despite the significant progress made in these technologies, enormous obstacles and challenges remain for the vision of truly wearable applications, in particular with flex-QLEDs and flex-PeLEDs. Here, a review of the recent progress of all three self-emissive technologies for flexible displays is conducted, including the emissive active materials, device structures and approaches to manufacturing, the flexible substrates, and conductive electrodes, as well as the encapsulation techniques. The fast-paced improvement made to the efficiency of flexible devices in recent years is also summarized. The review concludes by making suggestions on the future development in this area, and is expected to help researchers in gaining a comprehensive understanding about the newly emerging technologies for flexible displays.
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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
| | - Tianyu Huang
- Center for Flexible Electronics Technology, 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, China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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62
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Wang M, Zhang M, Luo Y, Liu Z, Yang C, Lan J, Wu D, You J. Pd(II)-Catalyzed Regioselective Multiple C–H Arylations of 1-Naphthamides with Cyclic Diaryliodonium Salts: One-Step Access to [4]- and [5]Carbohelicenes. Org Lett 2019; 22:135-139. [DOI: 10.1021/acs.orglett.9b04046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Menglei Wang
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Min Zhang
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Yuanyuan Luo
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Zheng Liu
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Chengyong Yang
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Jingbo Lan
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Di Wu
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Jingsong You
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
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Cheng Z, Li Z, Xu Y, Liang J, Lin C, Wei J, Wang Y. Achieving Efficient Blue Delayed Electrofluorescence by Shielding Acceptors with Carbazole Units. ACS APPLIED MATERIALS & INTERFACES 2019; 11:28096-28105. [PMID: 31290328 DOI: 10.1021/acsami.9b07820] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The design and synthesis of blue thermally activated delayed fluorescence (TADF) emitters that have high electroluminescence efficiency and low efficiency roll-off features remain a great challenge. Herein, we developed a facile and efficient strategy by shielding acceptors with carbazole units for constructing high-performance blue TADF emitters. Benzonitrile (BN), 9,9-diphenylacridan (DPAc), and carbazole (Cz) were adopted as the acceptor, donor, and protector, respectively, to build two TADF emitters named DPAc-DCzBN and DPAc-DtCzBN. The nondoped organic light-emitting diodes (OLEDs) of DPAc-DCzBN as the emitter exhibited a standard sky-blue emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.16, 0.26), high external quantum efficiency (EQE) of 20.0%, and low efficiency roll-off (EQEs of 19.5, 16.1, and 12.6% at 100, 500, and 1000 cd m-2, respectively), which is an outstanding nondoped blue TADF OLED. The doped device of DPAc-DtCzBN displayed a pure blue emission and the corresponding CIE coordinates are (0.16, 0.15). Meanwhile, it also demonstrated high and stabilized EQE values of 23.1, 18.3, and 11.5% at maxima, 100 and 500 cd m-2, respectively, which is a quite high level among the pure blue TADF OLEDs. This study testifies the feasibility of our strategy in constructing high-performance TADF electroluminescent materials.
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Affiliation(s)
- Zong Cheng
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , P. R. China
| | - Zhiqiang Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , P. R. China
| | - Yincai Xu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , P. R. China
| | - Jixiong Liang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , P. R. China
| | - Chunhui Lin
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , P. R. China
| | - Jinbei Wei
- 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
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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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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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66
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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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Zhou D, Liu D, Gong X, Ma H, Qian G, Gong S, Xie G, Zhu W, Wang Y. Solution-Processed Highly Efficient Bluish-Green Thermally Activated Delayed Fluorescence Emitter Bearing an Asymmetric Oxadiazole-Difluoroboron Double Acceptor. ACS APPLIED MATERIALS & INTERFACES 2019; 11:24339-24348. [PMID: 31187977 DOI: 10.1021/acsami.9b07511] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Difluoroboron (BF2)-containing dyes have attracted great interest owing to their exceptionally high luminescence efficiency and good electron-withdrawing properties. However, only a few reports on difluoroboron-based thermally activated delayed fluorescence (TADF) have been addressed. In this contribution, a novel BF2-containing TADF molecule of BFOXD, which contains two acceptor fragments of oxadiazole (OXD) and BF2 and one donor unit of 9,9-dimethylacridine, was synthesized and characterized. For comparison, the precursor of OHOXD bearing one acceptor unit was also investigated. Both molecules clearly show TADF characteristics with sky-blue emission in solution and film state. Additionally, OHOXD undergoes excited-state intramolecular proton transfer-coupled intramolecular charge transfer processes. Using 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi) as the host, the organic light-emitting diodes fabricated via a solution process show maximum external quantum efficiency (EQE) of 2.98 and 13.8% for OHOXD- and BFOXD-based devices, respectively. While the bipolar TADF host of 10-(4-((4-(9H-carbazol-9-yl)phenyl)sulfonyl)phenyl)-9,9-dimethyl-9,10-dihydroacridine (CzAcSF) is utilized instead of CzSi, the OHOXD- and BFOXD-based devices exhibit better performances with the maximum EQEs of 12.1 and 20.1%, respectively, which render the most efficient and the bluest emission ever reported for the BF2-based TADF molecules. This research demonstrates that introduction of one more acceptor unit into the TADF molecule could have a positive effect on emission efficiency, which opens a new way to design high-efficiency TADF molecules.
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Affiliation(s)
- Di Zhou
- National Experimental Demonstration Center for Materials Science and Engineering, Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering , Changzhou University , Changzhou 213164 , China
- College of Chemistry , Xiangtan University , Xiangtan 411105 , China
| | - Denghui Liu
- National Experimental Demonstration Center for Materials Science and Engineering, Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering , Changzhou University , Changzhou 213164 , China
| | - Xu Gong
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry , Wuhan University , Wuhan 430072 , China
| | - Huili Ma
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech) , 30 South Puzhu Road , Nanjing 211816 , China
| | - Gaowei Qian
- National Experimental Demonstration Center for Materials Science and Engineering, Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering , Changzhou University , Changzhou 213164 , China
| | - Shaolong Gong
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry , Wuhan University , Wuhan 430072 , China
| | - Guohua Xie
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry , Wuhan University , Wuhan 430072 , China
| | - Weiguo Zhu
- National Experimental Demonstration Center for Materials Science and Engineering, Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering , Changzhou University , Changzhou 213164 , China
| | - Yafei Wang
- National Experimental Demonstration Center for Materials Science and Engineering, Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering , Changzhou University , Changzhou 213164 , China
- Key Laboratory of Advanced Display and System Applications of Ministry of Education , Shanghai University , 149 Yanchang Road , Shanghai 200072 , China
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Kim JH, Lee KH, Lee JY. Design of Thermally Activated Delayed Fluorescent Assistant Dopants to Suppress the Nonradiative Component in Red Fluorescent Organic Light-Emitting Diodes. Chemistry 2019; 25:9060-9070. [PMID: 30985037 DOI: 10.1002/chem.201901135] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Indexed: 11/11/2022]
Abstract
Organic light-emitting diodes are currently under research to achieve high efficiency and long life by using thermally activated delayed fluorescence (TADF) materials. In particular, many studies have focused on ensuring high efficiency in fluorescent devices by introducing TADF materials. Herein, four kinds of orange-colored TADF materials were synthesized and introduced into 5,10,15,20-tetraphenylbisbenz[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene (DBP) red fluorescent devices as assistant dopants. These TADF materials assisted in achieving high efficiency in DBP devices by reducing nonradiative process by Dexter energy transfer and harvesting singlet excitons by a Förster resonance energy transfer process. Among the four TADF materials, 2-(3,5-di-tert-butylphenyl)-6-(9,9-diphenylacridin-10(9H)-yl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (DtBIQAP) showed a higher reverse intersystem crossing rate and a smaller nonradiative rate constant than the other two materials, which can reduce the exciton loss process. As a result, the DtBIQAP-assisted DBP device showed a high maximum external quantum efficiency of 18.2 % and color coordinates of (0.63, 0.37) in red fluorescent organic light-emitting diodes. This study provided a strategy of developing assistant dopants for high external quantum efficiency in TADF-assisted fluorescent devices.
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Affiliation(s)
- Ji Han Kim
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 440-746, Korea
| | - Kyung Hyung Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 440-746, Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 440-746, Korea
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Song X, Zhang D, Li H, Cai M, Huang T, Duan L. Exciplex System with Increased Donor-Acceptor Distance as the Sensitizing Host for Conventional Fluorescent OLEDs with High Efficiency and Extremely Low Roll-Off. ACS APPLIED MATERIALS & INTERFACES 2019; 11:22595-22602. [PMID: 31198026 DOI: 10.1021/acsami.9b05963] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Exciplex systems with efficient thermally activated delayed fluorescence as the sensitizing hosts for fluorescent organic light-emitting diodes (OLEDs) have been flourished recently, while the device performances are still lagging behind. Here, a donor molecule sterically encapsulated with tert-butyl units is designed and synthesized to increase the donor-acceptor separation in an exciplex system, leading to reduced singlet-triplet energy gap (Δ ESTs) and improved reverse intersystem crossing (RISC) efficiency. OLEDs utilizing exciplexes with increased donor-acceptor distance ( rDA) as the hosts for conventional fluorescent dopants exhibit a maximum external quantum efficiency (EQEmax) as high as 16.5%, benefiting from the enhanced RISC process and suppressed exciton loss by the Dexter interaction. Furthermore, extremely low efficiency roll-off is obtained with EQEs of 16.2% at 5000 cd/m2 and 15.2% at 10 000 cd/m2. The results here represent the state-of-the-art performances for devices based on exciplexes as the hosts for conventional fluorescent dopants, manifesting the superiority of exciplexes with increased rDA as the sensitizing hosts for fluorescent dopants.
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Affiliation(s)
| | | | - Haoyuan Li
- School of Chemistry and Biochemistry, Center for Organic Photonics and Electronics (COPE) , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
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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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Zhang B, Xie Z. Recent Applications of Interfacial Exciplex as Ideal Host of Power-Efficient OLEDs. Front Chem 2019; 7:306. [PMID: 31134183 PMCID: PMC6514091 DOI: 10.3389/fchem.2019.00306] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/16/2019] [Indexed: 12/22/2022] Open
Abstract
Currently, exploring the applications of intermolecular donor-acceptor exciplex couple as host of OLEDs with phosphorescence, thermally activated delayed fluorescence (TADF) or fluorescence emitter as dopant is a hot topic. Compared to other host strategies, interfacial exciplex has the advantage in various aspects, such as barrier-free charge injection, unimpeded charge transport, and the energy-saving direct exciton formation process at the “Well”-like heterojunction interface region. Most importantly, due to a very fast and efficient reverse intersystem-crossing (RISC) process, such a host is capable of regulating singlet/triplet exciton populations in itself as well as in the dopant emitters both under photoluminescent (PL) and electroluminescent (EL) driving conditions. In this mini-review, we briefly summarize and comment on recent applications of this ideal host in OLEDs (including both thermal-evaporation OLEDs and solution-processed OLEDs) with diverse emitters, e.g., fluorescence, phosphorescence, delayed fluorescence, or others. Special attention is given to illustrate the peculiar achievement of high overall EL performance with superiorities of low driving voltages, slow roll-off rate, high power efficiencies and satisfied device lifetime using this host strategy, which is then concluded by personal perspectives on the relevant next-step in this field.
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Affiliation(s)
- Baohua Zhang
- Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou, China
| | - Zhiyuan Xie
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China
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72
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Zhang D, Duan L. Polycyclic Aromatic Hydrocarbon Derivatives toward Ideal Electron-Transporting Materials for Organic Light-Emitting Diodes. J Phys Chem Lett 2019; 10:2528-2537. [PMID: 31038961 DOI: 10.1021/acs.jpclett.9b00526] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
One seemingly fundamental issue for electron-transporting materials (ETMs) in organic light-emitting diodes (OLEDs) is the mutual exclusion of a high electron-transporting mobility ( μe) and a large molecular triplet energy for good exciton confinement. Very recently, a trade-off was realized by adopting polycyclic aromatic hydrocarbon (PAH) derivatives as bipolar ETMs. Though the intrinsic low triplet energy of PAH moieties, good exciton confinement abilities are realized by manipulating the peripheral groups, integrating large μe values and long-term stabilities simultaneously. The resulting state-of-the-art OLED performances manifest the bright future of such ETMs. This Perspective summarizes the theoretical and experimental work relating to the relationship between the molecular structure of PAH-type ETMs and their electronic properties, focusing on charge transfer and exciton confinement abilities; the Perspective concludes by providing a vision of future developments in this field.
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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
- Center for Flexible Electronics Technology , 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 , China
- Center for Flexible Electronics Technology , Tsinghua University , Beijing 100084 , P.R. China
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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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74
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Li X, Shi YZ, Wang K, Zhang M, Zheng CJ, Sun DM, Dai GL, Fan XC, Wang DQ, Liu W, Li YQ, Yu J, Ou XM, Adachi C, Zhang XH. Thermally Activated Delayed Fluorescence Carbonyl Derivatives for Organic Light-Emitting Diodes with Extremely Narrow Full Width at Half-Maximum. ACS APPLIED MATERIALS & INTERFACES 2019; 11:13472-13480. [PMID: 30892014 DOI: 10.1021/acsami.8b19635] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two novel thermally activated delayed fluorescence (TADF) emitters, 3-phenylquinolino[3,2,1- de]acridine-5,9-dione (3-PhQAD) and 7-phenylquinolino[3,2,1- de]acridine-5,9-dione (7-PhQAD), were designed and synthesized based on a rigid quinolino[3,2,1- de]acridine-5,9-dione (QAD) framework. With the effective superimposed resonance effect from electron-deficient carbonyls and electron-rich nitrogen atom, both emitters realize significant TADF characteristics with small Δ ESTs of 0.18 and 0.19 eV, respectively. And, molecular relaxations were dramatically suppressed for both emitters because of their conjugated structure. In the devices, 3-PhQAD realizes superior performance with a maximum external quantum efficiency (EQE) of 19.1% and a narrow full width at half-maximum (FWHM) of 44 nm, whereas a maximum EQE of 18.7% and an extremely narrow FWHM of 34 nm are realized for 7-PhQAD. These superior results reveal that apart from nitrogen and boron-aromatic systems, QAD framework can also act as a TADF matrix with effective resonance effect, and QAD derivatives are ideal candidates to develop TADF emitters with narrow FWHMs for practical applications.
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Affiliation(s)
- Xing Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Yi-Zhong Shi
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Kai Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Ming Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China (UESTC) , Chengdu , Sichuan 610054 , P. R. China
| | - Cai-Jun Zheng
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China (UESTC) , Chengdu , Sichuan 610054 , P. R. China
| | - Dian-Ming Sun
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Gao-Le Dai
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Xiao-Chun Fan
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - De-Qi Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
- School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China (UESTC) , Chengdu , Sichuan 610054 , P. R. China
| | - Wei Liu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Yan-Qing Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Jia Yu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Xue-Mei Ou
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
| | - Chihaya Adachi
- Japan Science and Technology Agency (JST), ERATO, Adachi Molecular Exciton Engineering Project , 744 Motooka , Nishi, Fukuoka 819-0395 , Japan
| | - Xiao-Hong Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P. R. China
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75
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Zhang DD, Suzuki K, Song XZ, Wada Y, Kubo S, Duan L, Kaji H. Thermally Activated Delayed Fluorescent Materials Combining Intra- and Intermolecular Charge Transfers. ACS APPLIED MATERIALS & INTERFACES 2019; 11:7192-7198. [PMID: 30672273 DOI: 10.1021/acsami.8b19428] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A novel thermally activated delayed fluorescent (TADF) compound, 9-(3-((4,6-diphenyl-1,3,5-triazin-2-yl)oxy)phenyl)-3,6-diphenyl-9 H-carbazole (PhCz- o-Trz), with a donor-σ-acceptor (D-σ-A) motif is developed. A flexible small space σ-junction is adopted to partly suppress the intramolecular charge transfer (intra-CT) while inversely enhancing the intermolecular charge transfer (inter-CT) between D/A moieties, realizing the coexistence of both intra-CT and inter-CT in an amorphous aggregate. The coexistence of dual CTs increases the complexity of the singlet and triplet state mixing, enhancing the triplet-to-singlet spin-flip transition and thereby the TADF emission. Additionally, PhCz- o-Trz is evaluated not only as an emitter but also as a sensitizing host for fluorescent and phosphorescent dopants, all exhibiting high efficiencies with alleviated efficiency roll-offs. These results shed light on the development of new TADF materials with dual CTs and may further deepen our understanding about TADF mechanisms.
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Affiliation(s)
- Dong-Dong Zhang
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 6611-0011 , Japan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry , Tsinghua University , Beijing 10086 , P. R. China
| | - Katsuaki Suzuki
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 6611-0011 , Japan
| | - Xiao-Zeng Song
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry , Tsinghua University , Beijing 10086 , P. R. China
| | - Yoshimasa Wada
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 6611-0011 , Japan
| | - Shosei Kubo
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 6611-0011 , Japan
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry , Tsinghua University , Beijing 10086 , P. R. China
| | - Hironori Kaji
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 6611-0011 , Japan
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76
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Xie Y, Gong Y, Han M, Zhang F, Peng Q, Xie G, Li Z. Tetraphenylcyclopentadiene-Based Hyperbranched Polymers: Convenient Syntheses from One Pot “A4 + B2” Polymerization and High External Quantum Yields up to 9.74% in OLED Devices. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02051] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Yujun Xie
- Department of Chemistry, Wuhan University, Wuhan 430072, China
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Yanbin Gong
- Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Mengmeng Han
- Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Fengyuan Zhang
- Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Qian Peng
- Key Laboratory of Organic Solids, Beijing National Laboratory for Molecular Science (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Guohua Xie
- Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Zhen Li
- Department of Chemistry, Wuhan University, Wuhan 430072, China
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
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77
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Cai M, Zhang D, Xu J, Hong X, Zhao C, Song X, Qiu Y, Kaji H, Duan L. Unveiling the Role of Langevin and Trap-Assisted Recombination in Long Lifespan OLEDs Employing Thermally Activated Delayed Fluorophores. ACS APPLIED MATERIALS & INTERFACES 2019; 11:1096-1108. [PMID: 30525372 DOI: 10.1021/acsami.8b16784] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Recent research studies on noble-metal-free thermally activated delayed fluorescent (TADF) materials have boosted the efficiencies of organic light-emitting diodes (OLEDs) to unity. However, the short lifespan still hinders their further practical application. Carrier recombination pathways have been reported to have a significant influence on the efficiencies of TADF devices, though their effects on device lifetimes remain rarely studied. Here, we have designed and synthesized five pyrimidine or pyrazine/carbazole isomers as hosts for TADF OLEDs to explore the inherent role of Langevin recombination (LR) and trap-assisted recombination (TAR) in device lifetimes. It is revealed that for LR dominant devices, lifetimes would increase by reducing the host triplet energy levels, whereas for TAR dominant devices, lifetimes are insensitive to the host triplet excitons as recombination mainly takes place on dopants. Still, LR dominant devices are favored as they offer more room for optimization. We further apply this concept in designing a stable LR dominant blue TADF device, achieving a long LT50 (lifespan up to 50% of the initial luminance) of 269 h and high external quantum efficiency of 17.9% at 1000 cd m-2 simultaneously.
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Affiliation(s)
| | | | | | | | | | | | | | - Hironori Kaji
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 6611-0011 , Japan
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78
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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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79
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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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80
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Ban X, Chen F, Zhao Y, Zhu A, Tong Z, Jiang W, Sun Y. Strategy for the Realization of Highly Efficient Solution-Processed All-Fluorescence White OLEDs-Encapsulated Thermally Activated Delayed Fluorescent Yellow Emitters. ACS APPLIED MATERIALS & INTERFACES 2018; 10:37335-37344. [PMID: 30303007 DOI: 10.1021/acsami.8b13101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Fabrication of highly efficient all thermally activated delayed fluorescence (TADF) white organic light-emitting diodes (WOLEDs) through solution-process still remains a big challenge. Here, two encapsulated TADF molecules with a small singlet-triplet energy gap (Δ EST) and high photoluminescence quantum yield (PLQY) were designed and synthesized as yellow emitters for solution-processed WOLEDs. The high current, power, and external quantum efficiencies of 41.6 cd A-1, 30.4 lm W-1, and 17.3% were achieved for the solution-processed all-fluorescence WOLEDs with a single-emission layer. In contrast, even with the same Δ EST and PLQY, the corresponding unencapsulated parent emitters will account for nearly 50% loss of the potential device efficiency. This is for the first time that the small molecular TADF blue host and TADF yellow guest are used to construct solution-processed all-fluorescence WOLEDs, which exhibit high efficiency comparable with most of the vacuum-deposited all-fluorescence white devices. These results not only demonstrate the great potential of TADF emitters in achieving highly efficient solution-processed WOLEDs, but also testify the key role of molecular encapsulation in reducing polar-exciton quenching and enhancing electroluminescence performance.
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Affiliation(s)
- Xinxin Ban
- Jiangsu Key Laboratory of Function Control Technology for Advanced Materials, School of Chemical Engineering , Huaihai Institute of Technology , Lianyungang , Jiangsu 222005 , China
| | - Feng Chen
- Jiangsu Key Laboratory of Function Control Technology for Advanced Materials, School of Chemical Engineering , Huaihai Institute of Technology , Lianyungang , Jiangsu 222005 , China
| | - Yaqing Zhao
- Jiangsu Key Laboratory of Function Control Technology for Advanced Materials, School of Chemical Engineering , Huaihai Institute of Technology , Lianyungang , Jiangsu 222005 , China
| | - Aiyun Zhu
- Jiangsu Key Laboratory of Function Control Technology for Advanced Materials, School of Chemical Engineering , Huaihai Institute of Technology , Lianyungang , Jiangsu 222005 , China
| | - Zhiwei Tong
- Jiangsu Key Laboratory of Function Control Technology for Advanced Materials, School of Chemical Engineering , Huaihai Institute of Technology , Lianyungang , Jiangsu 222005 , China
| | - Wei Jiang
- School of Chemistry and Chemical Engineering , Southeast University , Nanjing , Jiangsu 211189 , China
| | - Yueming Sun
- School of Chemistry and Chemical Engineering , Southeast University , Nanjing , Jiangsu 211189 , China
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81
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Chen L, Zhang S, Li H, Chen R, Jin L, Yuan K, Li H, Lu P, Yang B, Huang W. Breaking the Efficiency Limit of Fluorescent OLEDs by Hybridized Local and Charge-Transfer Host Materials. J Phys Chem Lett 2018; 9:5240-5245. [PMID: 30141940 DOI: 10.1021/acs.jpclett.8b02138] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hybridized local and charge-transfer (HLCT) states with "hot exciton" properties are effective in harvesting high-lying triplet excitons for electroluminescence in organic light-emitting diodes (OLEDs). Here, we propose a technique based on the HLCT mechanism at the high-lying excited states to develop HLCT-sensitized fluorescent (HLCT-SF) OLEDs using HLCT host molecules and metal-free fluorescent dopants for highly efficient OLEDs. A maximum external quantum efficiency (EQE) up to 6.3% and an exciton utilizing efficiency (EUE) of 64% were achieved, apparently exceeding the upper limits of the EQE (5%) and EUE (25%) in conventional fluorescent OLEDs. The HLCT-SF process via long-range Förster resonance energy transfer from the singlet excited states of the HLCT host to that of the fluorescent guest is efficient in harvesting "hot triplet excitons" by efficient high-lying reverse intersystem crossing, and the newly proposed HLCT-SF OLEDs represent an important advance in realizing high-performance OLEDs.
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Affiliation(s)
- Lingfeng Chen
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing University of Posts & Telecommunications , 9 Wenyuan Road , Nanjing 210023 , China
| | - Shitong Zhang
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Hui Li
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing University of Posts & Telecommunications , 9 Wenyuan Road , Nanjing 210023 , China
| | - Runfeng Chen
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing University of Posts & Telecommunications , 9 Wenyuan Road , Nanjing 210023 , China
| | - Lu Jin
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing University of Posts & Telecommunications , 9 Wenyuan Road , Nanjing 210023 , China
| | - Kai Yuan
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing University of Posts & Telecommunications , 9 Wenyuan Road , Nanjing 210023 , China
| | - Huanhuan Li
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing University of Posts & Telecommunications , 9 Wenyuan Road , Nanjing 210023 , China
| | - Ping Lu
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Bing Yang
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Wei Huang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, National Synergistic Innovation Center for Advanced Materials , Nanjing Tech University , 30 South Puzhu Road , Nanjing 211816 , People's Republic of China
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82
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Kuo H, Zhu Z, Lee C, Chen Y, Liu S, Chou P, Jen AK, Chi Y. Bis-Tridentate Iridium(III) Phosphors with Very High Photostability and Fabrication of Blue-Emitting OLEDs. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1800846. [PMID: 30250813 PMCID: PMC6145234 DOI: 10.1002/advs.201800846] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/09/2018] [Indexed: 05/08/2023]
Abstract
Sky-blue and blue-emitting, carbazolyl functionalized, bis-tridentate Ir(III) phosphors Cz-1-Cz-3 with bright emission and short radiative lifetime are successfully synthesized in a one-pot manner. They exhibit very high photostability against UV-vis irradiation in degassed toluene, versus both green and true-blue-emitting reference compounds, i.e., fac-[Ir(ppy)3] and mer-[Ir(pmp)3]. Organic light-emitting diodes (OLEDs) based on Cz-2 exhibit maximum external quantum efficiency (EQE) of 21.6%, EQE of 15.1% at 100 cd m-2, and with CIE x,y coordinates of (0.17, 0.25). This study provides a conceptual solution to the exceedingly stable and efficient blue phosphor. It is promising that long lifespan blue OLED based on these emitters can be attained with further engineering of devices suitable for commercial application.
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Affiliation(s)
- Hsin‐Hung Kuo
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of MattersNational Tsing Hua UniversityHsinchu30013Taiwan
| | - Ze‐lin Zhu
- Center of Super‐Diamond and Advanced Films (COSDAF) and Department of ChemistryCity University of Hong KongHong Kong SAR
| | - Chun‐Sing Lee
- Center of Super‐Diamond and Advanced Films (COSDAF) and Department of ChemistryCity University of Hong KongHong Kong SAR
| | - Yi‐Kuang Chen
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of MattersNational Tsing Hua UniversityHsinchu30013Taiwan
| | - Shih‐Hung Liu
- Department of ChemistryNational Taiwan UniversityTaipei10617Taiwan
| | - Pi‐Tai Chou
- Department of ChemistryNational Taiwan UniversityTaipei10617Taiwan
| | - Alex K.‐Y. Jen
- Department of Materials Science and Engineering and Department of ChemistryCity University of Hong KongHong Kong SAR
| | - Yun Chi
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of MattersNational Tsing Hua UniversityHsinchu30013Taiwan
- Department of Materials Science and Engineering and Department of ChemistryCity University of Hong KongHong Kong SAR
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83
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Noto N, Tanaka Y, Koike T, Akita M. Strongly Reducing (Diarylamino)anthracene Catalyst for Metal-Free Visible-Light Photocatalytic Fluoroalkylation. ACS Catal 2018. [DOI: 10.1021/acscatal.8b02885] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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84
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Wu D, Chen L, Ma S, Luo H, Cao J, Chen R, Duan Z, Mathey F. Synthesis of 1,3-Azaphospholes with Pyrrolo[1,2- a]quinoline Skeleton and Their Optical Applications. Org Lett 2018; 20:4103-4106. [PMID: 29931983 DOI: 10.1021/acs.orglett.8b01663] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A facile synthesis of 1,3-azaphospholes with a pyrrolo[1,2- a]quinoline skeleton has been described. These new annulated 1,3-azaphospholes exhibit good photoelectric performance and can be used as the emitting dopant in organic light-emitting diodes (OLEDs) and dye for bioimaging.
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Affiliation(s)
- Di Wu
- College of Chemistry and Molecular Engineering, International Phosphorus Laboratory, International Joint Research Laboratory for Functional Organophosphorus Materials of Henan Province , Zhengzhou University , Zhengzhou 450001 , P. R. China
| | - Lingfeng Chen
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials , Nanjing University of Posts & Telecommunications , Nanjing 210023 , P. R. China
| | - Shuangliang Ma
- College of Chemistry and Molecular Engineering, International Phosphorus Laboratory, International Joint Research Laboratory for Functional Organophosphorus Materials of Henan Province , Zhengzhou University , Zhengzhou 450001 , P. R. China
| | - Huiying Luo
- Department of Anatomy, College of Basic Medicine , Zhengzhou University , Zhengzhou 450001 , P. R. China.,Guangzhou University of Chinese Medicine , Guangzhou 510000 , P. R. China
| | - Jing Cao
- Department of Anatomy, College of Basic Medicine , Zhengzhou University , Zhengzhou 450001 , P. R. China
| | - Runfeng Chen
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials , Nanjing University of Posts & Telecommunications , Nanjing 210023 , P. R. China
| | - Zheng Duan
- College of Chemistry and Molecular Engineering, International Phosphorus Laboratory, International Joint Research Laboratory for Functional Organophosphorus Materials of Henan Province , Zhengzhou University , Zhengzhou 450001 , P. R. China
| | - Francois Mathey
- College of Chemistry and Molecular Engineering, International Phosphorus Laboratory, International Joint Research Laboratory for Functional Organophosphorus Materials of Henan Province , Zhengzhou University , Zhengzhou 450001 , P. R. China
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85
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Sarma M, Wong KT. Exciplex: An Intermolecular Charge-Transfer Approach for TADF. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19279-19304. [PMID: 29613766 DOI: 10.1021/acsami.7b18318] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Organic materials that display thermally activated delayed fluorescence (TADF) are a striking class of functional materials that have witnessed a booming progress in recent years. In addition to pure TADF emitters achieved by the subtle manipulations of intramolecular charge transfer processes with sophisticated molecular structures, a new class of efficient TADF-based OLEDs with emitting layer formed by blending electron donor and acceptor molecules that involve intermolecular charge transfer have also been fabricated. In contrast to pure TADF materials, the exciplex-based systems can realize small Δ EST (0-0.05 eV) much more easily since the electron and hole are positioned on two different molecules, thereby giving small exchange energy. Consequently, exciplex-based OLEDs have the prospective to maximize the TADF contribution and achieve theoretical 100% internal quantum efficiency. Therefore, the challenging issue of achieving small Δ EST in organic systems could be solved. In this article, we summarize and discuss the latest and most significant developments regarding these rapidly evolving functional materials, wherein the majority of the reported exciplex forming systems are categorized into two subgroups, viz. (a) exciplex as TADF emitters and (b) those as hosts for fluorescent, phosphorescent and TADF dopants according to their structural features and applications. The working mechanisms of the direct electroluminescence from the donor/acceptor interface and the exciplex-forming systems as cohost for the realization of high efficiency OLEDs are reviewed and discussed. This article delivers a summary of the current progresses and achievements of exciplex-based researches and points out the future challenges to trigger more research endeavors to this growing field.
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Affiliation(s)
- Monima Sarma
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - Ken-Tsung Wong
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
- Institute of Atomic and Molecular Science , Academia Sinica , Taipei 10617 , Taiwan
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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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