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Lin YD, Lu CW, Su HC. Long-Wavelength Light-Emitting Electrochemical Cells: Materials and Device Engineering. Chemistry 2023; 29:e202202985. [PMID: 36346637 DOI: 10.1002/chem.202202985] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 11/05/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
Abstract
Long-wavelength light-emitting electrochemical cells (LECs) are potential deep-red and near infrared light sources with solution-processable simple device architecture, low-voltage operation, and compatibility with inert metal electrodes. Many scientific efforts have been made to material design and device engineering of the long-wavelength LECs over the past two decades. The materials designed the for long-wavelength LECs cover ionic transition metal complexes, small molecules, conjugated polymers, and perovskites. On the other hand, device engineering techniques, including spectral modification by adjusting microcavity effect, light outcoupling enhancement, energy down-conversion from color conversion layers, and adjusting intermolecular interactions, are also helpful in improving the device performance of long-wavelength LECs. In this review, recent advances in the long-wavelength LECs are reviewed from the viewpoints of materials and device engineering. Finally, discussions on conclusion and outlook indicate possible directions for future developments of the long-wavelength LECs. This review would like to pave the way for the researchers to design materials and device engineering techniques for the long-wavelength LECs in the applications of displays, bio-imaging, telecommunication, and night-vision displays.
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Affiliation(s)
- Yan-Ding Lin
- Department of Applied Chemistry, Providence University, Taichung, 43301, Taiwan
| | - Chin-Wei Lu
- Department of Applied Chemistry, Providence University, Taichung, 43301, Taiwan
| | - Hai-Ching Su
- Institute of Lighting and Energy Photonics, National Yang Ming Chiao Tung University, Tainan, 71150, Taiwan
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Cao HT, Hou PF, Yu WJ, Gao Y, Li B, Feng QY, Zhang H, Wang SS, Su ZM, Xie LH. Enhanced Efficiency of Exciplex Emission from a 9-Phenylfluorene Derivative. ACS APPLIED MATERIALS & INTERFACES 2023; 15:7236-7246. [PMID: 36700822 DOI: 10.1021/acsami.2c22266] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The exciplex-thermally activated delayed fluorescence (exciplex-TADF) system is an excellent candidate for the fabrication of high-efficiency organic light-emitting diodes (OLEDs) because of its more easily achieved small singlet-triplet energy splitting (ΔEST) and doping control. However, exciplex-TADF is still faced with the problems of low external quantum efficiency (ηext) and unclear effect of structure modification in electron acceptors. Herein, we provide a steric hindrance increase strategy to obtain high-efficiency exciplex emissions. Through introducing a 9-phenylfluorene group into N-ethylcarbazole of the dicyano-substituted 9-phenylfluorene, an electron acceptor material with increased steric hindrance is obtained, which helps the exciplex harvest a larger driving force and higher emission efficiencies. Encouragingly, the obtained OLED displays a maximum ηext of 25.8%, which is one of the best efficiency values among reported exciplex-OLEDs, simultaneously possessing excellent current efficiency of 83.6 cd A-1 and power efficiency of 93.7 lm W-1. It is expected that this work will offer a new avenue for designing electron acceptors for highly efficient exciplex emissions.
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Affiliation(s)
- Hong-Tao Cao
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Peng-Fei Hou
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Wen-Jing Yu
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Ying Gao
- Institute of Biomass Functional Materials Interdisciplinary Studies, Jilin Engineering Normal University, 3050 Kaixuan Road, Changchun 130052, P.R. China
| | - Bo Li
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Quan-You Feng
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - He Zhang
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Sha-Sha Wang
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
| | - Zhong-Min Su
- College of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun 130024, P.R. China
| | - Ling-Hai Xie
- Center for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.R. China
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Zhang K, Meng X, He L. Cationic Zinc(II) Complexes with Carbazole-Type Counter-Anions: Intracomplex Donor/Acceptor Pairs Affording Exciplexes with Thermally Activated Delayed Fluorescence. Inorg Chem 2023; 62:2135-2145. [PMID: 36691390 DOI: 10.1021/acs.inorgchem.2c03804] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Two cationic zinc(II) complexes with carbazole-type counter-anions, namely, [Zn(tpy)2]2+[CAZ-p-BF3-]2 (Zn-p) and [Zn(tpy)2]2+[CAZ-o-BF3-]2 (Zn-o), have been designed and synthesized, where tpy is 2,2':6',2″-terpyridine, CAZ-p-BF3- is 4-((9H-carbazol-9-yl)phenyl)trifluoroborate, and CAZ-o-BF3- is (2-(9H-carbazol-9-yl)phenyl)trifluoroborate. The complex cation [Zn(tpy)2]2+ (as the acceptor) and the carbazole-type counter-anion CAZ-p-BF3- or CAZ-o-BF3- (as the donor) form an intracomplex donor/acceptor pair. Single-crystal structures reveal that compared to Zn-p, Zn-o exhibits a stronger π-π stacking interaction between the carbazole group (as the donor unit) of the counter-anion and the tpy ligand (as the acceptor unit) of [Zn(tpy)2]2+ because of the different anchoring position of the BF3- anion in the counter-anion. In a doped film, Zn-p and Zn-o afford an isolated exciplex formed between the carbazole group and the tpy ligand within the single complex, which gives green-yellow emission with a thermally activated delayed fluorescence (TADF) feature. In crystalline states, Zn-p and Zn-o afford exciplexes with blue emission centered at 468 nm and green-blue emission centered at 508 nm, respectively. The Zn-p crystalline sample shows a relatively large singlet-triplet energy gap (ΔEST) (0.33 eV) and no TADF, whereas the Zn-o crystalline sample exhibits a small ΔEST (0.06 eV) and distinct TADF, with a reverse intersystem crossing rate at 3.3 × 105 s-1. Zn-p and Zn-o both exhibit intriguing mechanochromic luminescence, with largely red-shifted (by over 70 nm) emission and modulated TADF properties upon mechanically grinding the crystalline samples. The work demonstrates that donor/acceptor pairs affording exciplexes can be formed within cationic metal complexes using counter-anions with donor nature, which opens a new avenue toward photo-active metal complexes with rich photophysical properties.
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Affiliation(s)
- Ke Zhang
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Hubei International Scientific and Technological Cooperation Base of Pesticide and Green Synthesis, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Xianwen Meng
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Hubei International Scientific and Technological Cooperation Base of Pesticide and Green Synthesis, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China
| | - Lei He
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, Hubei International Scientific and Technological Cooperation Base of Pesticide and Green Synthesis, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China.,State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China
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Heteroleptic Ir(III)-based near-infrared organic light-emitting diodes with high radiance capacity. Sci Rep 2023; 13:1369. [PMID: 36697452 PMCID: PMC9877021 DOI: 10.1038/s41598-023-27487-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/03/2023] [Indexed: 01/27/2023] Open
Abstract
Near-infrared organic light-emitting diodes (NIR OLEDs) with heavy metals are regularly reported due to the advantages of their various applications in healthcare services, veil authentication, and night vision displays. For commercial applications, it is necessary to look at radiance capacity (RC) instead of radiance because of power consumption. However, recent papers still reported only simple high radiance performance and do not look at device from the point of view of RC. To overcome this hurdle, we designed Ir(III)-based heteroleptic NIR materials with two types of auxiliary ligand. The proposed emitters achieve a highly oriented horizontal dipole ratio (Ir(mCPDTiq)2tmd, complex 1: 80%, Ir(mCPDTiq)2acac, complex 2: 81%) with a short radiative lifetime (1: 386 ns, 2: 323 ns). The device also shows an extremely low turn-on voltage (Von) of 2.2 V and a high RC of 720 mW/sr/m2/V. The results on the Von and RC of the device is demonstrated an outstanding performance among the Ir(III)-based NIR OLEDs with a similar emission peak.
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Dai J, Yao L, Wang C, Wang Y, Liu F, Yan X, Sun P, Zhang H, Wang Y, Zhou J, Lu G. Molecular Conformation Engineering To Achieve Longer and Brighter Deep Red/Near-Infrared Emission in Crystalline State. J Phys Chem Lett 2022; 13:4754-4761. [PMID: 35612820 DOI: 10.1021/acs.jpclett.2c01226] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A series of molecules 1-5 containing the same fluorophore and different alkyl chains are synthesized to reveal the significant effect of molecular conformations on the emission properties. In crystalline state, molecules 1-3 exhibit strong orange emissions with maxima (λem) of about 600 nm and quantum yields (ΦF) of around 60%, while molecules 4 and 5 display much longer emissions to the deep red/near-infrared (NIR) region as well as even higher efficiencies (λem = 693 nm, ΦF = 73% for 4; λem = 654 nm, ΦF = 93% for 5). The largely red-shifted emissions of 4 and 5 as well as the significantly improved ΦF are very unusual. Furthermore, the ΦF of 4 and 5 represent the highest values among organic solids with similar deep red/NIR emission wavelengths. On the basis of the experimental measurements and theoretical calculations, the new molecular design of conformation engineering, the impressive emission properties, and the potential NIR fluorescence sensing and lasing applications are comprehensively investigated.
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Affiliation(s)
- Jianan Dai
- State Key Laboratory of Integrated Optoelectronics, Key Laboratory of Advanced Gas Sensors of Jilin Province, College of Electronic Science & Engineering, Jilin University, Changchun 130012, China
| | - Lianfei Yao
- Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, China
| | - Chenguang Wang
- State Key Laboratory of Integrated Optoelectronics, Key Laboratory of Advanced Gas Sensors of Jilin Province, College of Electronic Science & Engineering, Jilin University, Changchun 130012, China
| | - Yinghui Wang
- Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, China
| | - Fangmeng Liu
- State Key Laboratory of Integrated Optoelectronics, Key Laboratory of Advanced Gas Sensors of Jilin Province, College of Electronic Science & Engineering, Jilin University, Changchun 130012, China
| | - Xu Yan
- State Key Laboratory of Integrated Optoelectronics, Key Laboratory of Advanced Gas Sensors of Jilin Province, College of Electronic Science & Engineering, Jilin University, Changchun 130012, China
| | - Peng Sun
- State Key Laboratory of Integrated Optoelectronics, Key Laboratory of Advanced Gas Sensors of Jilin Province, College of Electronic Science & Engineering, Jilin University, Changchun 130012, China
| | - Hongyu Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Ji Zhou
- State Key Laboratory of Integrated Optoelectronics, Key Laboratory of Advanced Gas Sensors of Jilin Province, College of Electronic Science & Engineering, Jilin University, Changchun 130012, China
- State Kay Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Geyu Lu
- State Key Laboratory of Integrated Optoelectronics, Key Laboratory of Advanced Gas Sensors of Jilin Province, College of Electronic Science & Engineering, Jilin University, Changchun 130012, China
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Zhang Y, Wu C, Zhu M, Miao J. High Performance Near-Infrared Emitters with Methylated Triphenylamine and Thiadiazolo[3,4-g]quinoxaline-Based Fluorophores. Molecules 2021; 26:6386. [PMID: 34770795 PMCID: PMC8588353 DOI: 10.3390/molecules26216386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022] Open
Abstract
Three near-infrared emitters (2TPA-QBT, 2MeTPA-BT and TPA-QBT-MeTPA) were rationally designed and synthesized. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations showed that the introduction of mono- or di-methyl groups between the donors and acceptor could result in the spatial configuration changing greatly for 2MeTPA-QBT and TPA-QBT-MeTPA compared to their parent compound 2TPA-QBT. The emission of TPA-QBT-MeTPA had a more obvious hybridized local and charge transfer feature (HLCT) based on the influence of the steric hindrance of the methyl substituent. Attributed to their different spatial configurations and luminescence mechanisms, different emission wavelengths with photoluminescent quantum yields of 26%, 38% and 34% in toluene, as well as 24%, 27% and 31% in 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) doped film, were observed for 2TPA-QBT, 2MeTPA-QBT and TPA-QBT-MeTPA, respectively. The constructed organic light-emitting devices (OLEDs) displayed electroluminescence with emission peaks at 728, 693 and 710 nm, with maximum external quantum efficiencies of 1.58%, 1.33% and 3.02% for the 2TPA-QBT, 2MeTPA-QBT and TPA-QBT-MeTPA-doped OLEDs, respectively. This work illustrated the effect of spatial configuration changes on the luminescence properties of donor-acceptor-type organic emitters.
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Affiliation(s)
| | | | | | - Jingsheng Miao
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China; (Y.Z.); (C.W.); (M.Z.)
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