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Kumar K, Karmakar A, Thakur D, Sharma D, Chen FR, Verma V, Nagar MR, Jou JH, Banik S, Ghosh S. Self-assembled molecular network with waterwheel-like architecture: experimental and theoretical evaluation toward electron transport capabilities for optoelectronic devices. Phys Chem Chem Phys 2024; 26:11922-11932. [PMID: 38572672 DOI: 10.1039/d4cp00390j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
In recent times, self-assembled electron transport materials for optoelectronic devices, both solar cells and organic light-emitting diodes (OLEDs), have been gaining much interest as they help in fabricating high-efficiency devices. However, designing organic small molecular materials with star-shaped self-assembled networks is a challenge. To achieve this sort of target, we chose triazine and benzene-1,3,5-tricarbonyl cores for developing such architecture, and we developed four molecular systems, vizTCpCN, TCmCN, TmCN, and TpCN. Successful isolation of single crystals followed by structural analysis of TmCN revealed interesting molecular arrangements in the solid state resulting in the formation of a waterwheel type architecture with an extended network bearing characteristic voids. Theoretical calculations was carried out to check their electron transportability. The natural transition orbital calculation helped in understanding the locally excited and charge transfer excited states. The low electron reorganization energies of these molecules indicated that these materials may have potential to be used in electron transport layers of optoelectronic devices, particularly in OLEDs. Moreover, the assembled networks have a relatively wide surface area and linked structures, which are advantageous for the conduction of carriers with poor electron recombination inside the ETL, and these may offer a straightforward channel for electron conduction to the emissive layer. Finally, the fabricated electron-only device indicated that the synthesized materials may be used as ETMs in the electron transport layer of optoelectronic devices.
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Affiliation(s)
- Krishan Kumar
- School of Chemical Sciences, IIT Mandi, Himachal Pradesh 175005, India.
| | - Anirban Karmakar
- Centro de Química Estrutural, Instituto Superior Técnico, Avenida Rovisco Pais, Lisboa 1049-001, Portugal
| | - Diksha Thakur
- School of Chemical Sciences, IIT Mandi, Himachal Pradesh 175005, India.
| | - Dipanshu Sharma
- Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Guang-Fu Road, Hsinchu 30013, Taiwan, Republic of China.
| | - Feng-Rong Chen
- Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Guang-Fu Road, Hsinchu 30013, Taiwan, Republic of China.
| | - Varsha Verma
- School of Chemical Sciences, IIT Mandi, Himachal Pradesh 175005, India.
| | - Mangey Ram Nagar
- Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Guang-Fu Road, Hsinchu 30013, Taiwan, Republic of China.
| | - Jwo-Huei Jou
- Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Guang-Fu Road, Hsinchu 30013, Taiwan, Republic of China.
| | - Subrata Banik
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India.
| | - Subrata Ghosh
- School of Chemical Sciences, IIT Mandi, Himachal Pradesh 175005, India.
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Sachnik O, Ie Y, Ando N, Tan X, Blom PWM, Wetzelaer GJAH. Single-Layer Organic Light-Emitting Diode with Trap-Free Host Beats Power Efficiency and Lifetime of Multilayer Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311892. [PMID: 38214416 DOI: 10.1002/adma.202311892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Indexed: 01/13/2024]
Abstract
Organic light-emitting diodes (OLEDs) employing a single active layer potentially offer a number of benefits compared to multilayer devices; reduced number of materials and deposition steps, potential for solution processing, and reduced operating voltage due to the absence of heterojunctions. However, for single-layer OLEDs to achieve efficiencies approaching those of multilayer devices, balanced charge transport is a prerequisite. This requirement excludes many efficient emitters based on thermally activated delayed fluorescence (TADF) that exhibit electron trapping, such as the green-emitting bis(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)methanone (DMAC-BP). By employing a recently developed trap-free large band gap material as a host for DMAC-BP, nearly balanced charge transport is achieved. The single-layer OLED reaches an external quantum efficiency (EQE) of 19.6%, which is comparable to the reported EQEs of 18.9-21% for multilayer devices, but achieves a record power efficiency for DMAC-BP OLEDs of 82 lm W-1, clearly surpassing the reported multilayer power efficiencies of 52.9-59 lm W-1. In addition, the operational stability is greatly improved compared to multilayer devices and the use of conventional host materials in combination with DMAC-BP as an emitter. Next to the obvious reduction in production costs, single-layer OLEDs therefore also offer the advantage of reduced energy consumption and enhanced stability.
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Affiliation(s)
- Oskar Sachnik
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Yutaka Ie
- Department of Soft Nanomaterials, Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Osaka, Ibaraki, 567-0047, Japan
| | - Naoki Ando
- Department of Soft Nanomaterials, Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Osaka, Ibaraki, 567-0047, Japan
| | - Xiao Tan
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Paul W M Blom
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
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Shen P, Liu H, Zhuang Z, Zeng J, Zhao Z, Tang BZ. Through-Space Conjugated Electron Transport Materials for Improving Efficiency and Lifetime of Organic Light-Emitting Diodes. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200374. [PMID: 35322599 PMCID: PMC9130898 DOI: 10.1002/advs.202200374] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/03/2022] [Indexed: 05/05/2023]
Abstract
Thermally stable electron transport (ET) materials with high electron mobility and high triplet state energy level are highly desired for the fabrication of efficient and stable organic light-emitting diodes (OLEDs). Herein, a new design strategy of constructing through-space conjugated folded configuration is proposed to explore robust ET materials, opposite to the widely used planar configuration. By bonding two quinolines to the 9,10-positions of phenanthrene, two novel folded molecules with high thermal and morphological stabilities and high triplet state energy levels (>2.7 eV) are created. These folded molecules possess excellent ET ability with electron mobilities of three orders of magnitude higher than those of linear and planar counterparts. Theoretical calculation and crystallography analysis demonstrate the through-space conjugated folded configuration has not only reduced reorganization energy but also enlarged charge transfer integral at various dimensions, bringing about efficient multi-dimensional ET, independent of molecular orientation. By adopting the folded molecule as ET layers, OLEDs with no matter delayed fluorescence or phosphorescence emitters can achieve high external quantum efficiencies and long operational lifetimes simultaneously. This work paves a new avenue towards robust ET materials to improve efficiency and stability of OLEDs.
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Affiliation(s)
- Pingchuan Shen
- State Key Laboratory of Luminescent Materials and DevicesGuangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSouth China University of TechnologyGuangzhou510640China
| | - Hao Liu
- State Key Laboratory of Luminescent Materials and DevicesGuangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSouth China University of TechnologyGuangzhou510640China
| | - Zeyan Zhuang
- State Key Laboratory of Luminescent Materials and DevicesGuangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSouth China University of TechnologyGuangzhou510640China
| | - Jiajie Zeng
- State Key Laboratory of Luminescent Materials and DevicesGuangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSouth China University of TechnologyGuangzhou510640China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and DevicesGuangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSouth China University of TechnologyGuangzhou510640China
| | - Ben Zhong Tang
- State Key Laboratory of Luminescent Materials and DevicesGuangdong Provincial Key Laboratory of Luminescence from Molecular AggregatesSouth China University of TechnologyGuangzhou510640China
- Shenzhen Institute of Aggregate Science and TechnologySchool of Science and EngineeringThe Chinese University of Hong KongShenzhenGuangdong518172China
- AIE InstituteGuangzhou Development DistrictHuangpuGuangzhou510530China
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Phenanthroimidazole substituted imidazo[1,2-a]pyridine derivatives for deep-blue electroluminescence with CIEy ∼ 0.08. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113600] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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5
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Anjali Jha, Sen A, Malla RR. Chemistry of Oxadiazole Analogues: Current Status and Applications. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2021. [DOI: 10.1134/s1068162021030092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Tagare J, Verma N, Tarafder K, Vaidyanathan S. Phenanthroimidazole-based chromophores for organic light-emitting diodes: synthesis, photophysical, and theoretical study. LUMINESCENCE 2020; 35:1338-1349. [PMID: 32510860 DOI: 10.1002/bio.3896] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/18/2020] [Accepted: 06/04/2020] [Indexed: 11/08/2022]
Abstract
Organic light-emitting diodes (OLED) are gaining attention and making a significant contribution to the area of lighting and displays technology. The synthesis of new materials that can act as a host as well as emissive materials is crucial and efforts have been made in this direction in this research. Here, four star-shaped fluorophores, with a donor-acceptor (D-A) structure and with triphenylamine and phenanthroimidazole groups with different substitutions at the N1 position of the imidazole moiety, were designed and synthesized. Synthesized fluorophores showed sufficient thermal stability (10% Td in the range 230-280°C). Ultraviolet-visible (UV-vis) spectra of the fluorophores showed multiple absorption bands (bands in the UV region, due to π-π* transitions of the conjugated aromatic portion) and all fluorophores showed blue emission in dichloromethane solution. Electrochemical analysis indicated that all fluorophores had excellent oxidation and reduction characteristics. Theoretical calculations were also performed to better understand the structural and electronic properties of the synthesized fluorophores. All fluorophores had higher triplet (T1 ) energy (ranging from 2.49-2.52 eV) than the widely used green (Ir(ppy)3 -2.4 eV) and red (Ir (piq)2 acac - 2.2 eV) dopant materials. These results indicated that these fluorophores would be useful as host materials for efficient green and red phosphorescent OLEDs.
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Affiliation(s)
- Jairam Tagare
- Department of Chemistry, National Institute of Technology Rourkela, Rourkela, Odisha, India
| | - Niraj Verma
- Department of Chemistry, National Institute of Technology Rourkela, Rourkela, Odisha, India
| | - Kartick Tarafder
- Department of Physics, National Institute of Technology Karnataka Surathkal, India
| | - Sivakumar Vaidyanathan
- Department of Chemistry, National Institute of Technology Rourkela, Rourkela, Odisha, India
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7
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Gnanasekaran P, Yuan Y, Lee CS, Zhou X, Jen AKY, Chi Y. Realization of Highly Efficient Red Phosphorescence from Bis-Tridentate Iridium(III) Phosphors. Inorg Chem 2019; 58:10944-10954. [PMID: 31365235 DOI: 10.1021/acs.inorgchem.9b01383] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Bis-tridentate Ir(III) metal complexes bring forth interesting photophysical properties, among which the orthogonal arranged, planar tridentate chelates could increase the emission efficiency due to the greater rigidity and, in the meantime, allow strong interligand stacking that could deteriorate the emission efficiency. We bypassed this hurdle by design of five bis-tridentate Ir(III) complexes (1-5), to which both of their monoanionic ancillary and dianionic chromophoric chelate were functionalized derivative of 2-pyrazolyl-6-phenylpyridine, i.e. pzpyphH2 parent chelate. Hence, addition of phenyl substituent to the pyrazolyl fragment of pzpyphH2 gave rise to the precursors of monoanionic chelate (A1H-A3H), on which the additional tert-butyl and/or methoxy groups were introduced at the selected positions for tuning their steric and electronic properties, while precursors of dianionic chelates was judiciously prepared with an isoquniolinyl central unit on pziqphH2 in giving the red-shifted emission (cf. L1H2 and L2H2). Factors affected their photophysical properties were discussed by theoretical methods based on DFT and TD-DFT calculation, confirming that the T1 excited state of all investigated Ir(III) complexes shows a mixed metal-to-ligand charge transfer (MLCT), intraligand charge transfer (ILCT), ligand-to-ligand charge transfer (LLCT), and ligand-centered (LC) transition character. In contrast, the poor quantum yield of 3 is due to the facilitation of the nonradiative decay in comparison to the radiative process. As for potential OLED applications, Ir(III) complex 2 gives superior performance with max. efficiencies of 28.17%, 41.25 cd·A-1 and 37.03 lm·W-1, CIEx,y = 0.63, 0.37 at 50 mA cm-2, and small efficiency roll-off.
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Affiliation(s)
- Premkumar Gnanasekaran
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Yi Yuan
- Department of Materials Science and Engineering and Department of Chemistry , City University of Hong Kong , Kowloon , Hong Kong SAR.,Center of Super-Diamond and Advanced Films (COSDAF) , City University of Hong Kong , Kowloon , Hong Kong SAR
| | - Chun-Sing Lee
- Department of Materials Science and Engineering and Department of Chemistry , City University of Hong Kong , Kowloon , Hong Kong SAR.,Center of Super-Diamond and Advanced Films (COSDAF) , City University of Hong Kong , Kowloon , Hong Kong SAR
| | - Xiuwen Zhou
- School of Mathematics and Physics , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - Alex K-Y Jen
- Department of Materials Science and Engineering and Department of Chemistry , City University of Hong Kong , Kowloon , Hong Kong SAR
| | - Yun Chi
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters , National Tsing Hua University , Hsinchu 30013 , Taiwan.,Department of Materials Science and Engineering and Department of Chemistry , City University of Hong Kong , Kowloon , Hong Kong SAR
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8
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Thangaraji V, Rajamalli P, Jayakumar J, Huang MJ, Chen YW, Cheng CH. Quinolinylmethanone-Based Thermally Activated Delayed Fluorescence Emitters and the Application in OLEDs: Effect of Intramolecular H-Bonding. ACS APPLIED MATERIALS & INTERFACES 2019; 11:17128-17133. [PMID: 31038911 DOI: 10.1021/acsami.8b22704] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Three new quinoline TADF emitters, 2QPM-mDC, 2QPM-mDTC, and 4QPM-mDTC, were designed and synthesized and the emitters show Δ EST as low as 0.07 eV and high PL quantum yield (PLQY) up to 98%. An electroluminescence device based on 2QPM-mDTC can reach high EQE over 24%. Compared with the reported TADF devices, the device shows narrow emission bandwidth and high color purity. The excellent device performance is likely ascribed to the molecular design of 2QPM-mDTC containing an intramolecular H-bonding in the molecule.
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Affiliation(s)
- Vasudevan Thangaraji
- Department of Chemistry , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | | | | | - Min-Jie Huang
- Department of Chemistry , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Yu-Wei Chen
- Department of Chemistry , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Chien-Hong Cheng
- Department of Chemistry , National Tsing Hua University , Hsinchu 30013 , Taiwan
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9
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Zhou N, Wang S, Xiao Y, Li X. A Novel trans
-1-(9-Anthryl)-2-phenylethene Derivative Containing a Phenanthroimidazole Unit for Application in Organic Light-Emitting Diodes. Chem Asian J 2017; 13:81-88. [DOI: 10.1002/asia.201701371] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 10/17/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Nonglin Zhou
- School of Chemical Engineering and Technology; Tianjin University; Tianjin 300354 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); Tianjin 300072 China
| | - Shirong Wang
- School of Chemical Engineering and Technology; Tianjin University; Tianjin 300354 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); Tianjin 300072 China
| | - Yin Xiao
- School of Chemical Engineering and Technology; Tianjin University; Tianjin 300354 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); Tianjin 300072 China
| | - Xianggao Li
- School of Chemical Engineering and Technology; Tianjin University; Tianjin 300354 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); Tianjin 300072 China
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10
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Wei C, Zhuang J, Zhang D, Guo W, Yang D, Xie Z, Tang J, Su W, Zeng H, Cui Z. Pyridine-Based Electron-Transport Materials with High Solubility, Excellent Film-Forming Ability, and Wettability for Inkjet-Printed OLEDs. ACS APPLIED MATERIALS & INTERFACES 2017; 9:38716-38727. [PMID: 28994279 DOI: 10.1021/acsami.7b12190] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Film morphology has predominant influence on the performance of multilayered organic light-emitting diodes (OLEDs), whereas there is little reported literature from the angle of the molecular level to investigate the impact on film-forming ability and device performance. In this work, four isomeric cross-linkable electron-transport materials constructed with pyridine, 1,2,4-triazole, and vinylbenzyl ether groups were developed for inkjet-printed OLEDs. Their lowest unoccupied molecular orbital (∼3.20 eV) and highest occupied molecular orbital (∼6.50 eV) levels are similar, which are mainly determined by the 1,2,4-triazole groups. The triplet energies of these compounds can be tuned from 2.51 to 2.82 eV by different coupling modes with the core of pyridine, where the 2,6-pyridine-based compound has the highest value of 2.82 eV. Film formation and solubility of the compounds were investigated. It was found that the 2,6-pyridine-based compound outperformed the 2,4-pyridine, 2,5-pyridine, and 3,5-pyridine-based compounds. The spin-coated blue OLEDs based on the four compounds have achieved over 14.0% external quantum efficiencies (EQEs) at the luminance of 100 cd m-2, and a maximum EQE of 12.1% was obtained for the inkjet-printed device with 2,6-pyridine-based compound.
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Affiliation(s)
- Changting Wei
- Printable Electronics Research Center, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , 398 Ruoshui Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People's Republic of China
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, School of Materials Science and Engineering, Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, People's Republic of China
| | - Jinyong Zhuang
- Printable Electronics Research Center, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , 398 Ruoshui Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People's Republic of China
| | - Dongyu Zhang
- Printable Electronics Research Center, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , 398 Ruoshui Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People's Republic of China
| | - Wenrui Guo
- Printable Electronics Research Center, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , 398 Ruoshui Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People's Republic of China
| | - Dongfang Yang
- Market & Product Planning Department, VOSBU , No. 9 Dize Road, BDA, Beijing 100176, People's Republic of China
| | - Zhongzhi Xie
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren-ai Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People's Republic of China
| | - Jianxin Tang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren-ai Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People's Republic of China
| | - Wenming Su
- Printable Electronics Research Center, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , 398 Ruoshui Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People's Republic of China
| | - Haibo Zeng
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, School of Materials Science and Engineering, Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, People's Republic of China
| | - Zheng Cui
- Printable Electronics Research Center, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , 398 Ruoshui Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, People's Republic of China
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Rajamalli P, Senthilkumar N, Huang PY, Ren-Wu CC, Lin HW, Cheng CH. New Molecular Design Concurrently Providing Superior Pure Blue, Thermally Activated Delayed Fluorescence and Optical Out-Coupling Efficiencies. J Am Chem Soc 2017; 139:10948-10951. [PMID: 28745874 DOI: 10.1021/jacs.7b03848] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Simultaneous enhancement of out-coupling efficiency, internal quantum efficiency, and color purity in thermally activated delayed fluorescence (TADF) emitters is highly desired for the practical application of these materials. We designed and synthesized two isomeric TADF emitters, 2DPyM-mDTC and 3DPyM-pDTC, based on di(pyridinyl)methanone (DPyM) cores as the new electron-accepting units and di(tert-butyl)carbazole (DTC) as the electron-donating units. 3DPyM-pDTC, which is structurally nearly planar with a very small ΔEST, shows higher color purity, horizontal ratio, and quantum yield than 2DPyM-mDTC, which has a more flexible structure. An electroluminescence device based on 3DPyM-pDTC as the dopant emitter can reach an extremely high external quantum efficiency of 31.9% with a pure blue emission. This work also demonstrates a way to design materials with a high portion of horizontal molecular orientation to realize a highly efficient pure-blue device based on TADF emitters.
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Affiliation(s)
- P Rajamalli
- Departments of †Chemistry and ‡Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - N Senthilkumar
- Departments of †Chemistry and ‡Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - P-Y Huang
- Departments of †Chemistry and ‡Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - C-C Ren-Wu
- Departments of †Chemistry and ‡Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - H-W Lin
- Departments of †Chemistry and ‡Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - C-H Cheng
- Departments of †Chemistry and ‡Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
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12
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A comprehensive study of the optoelectronic properties of donor-acceptor based derivatives of 1,3,4-oxadiazole. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.04.088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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Synthesis and properties of polymeric host materials constructed by silane-carbazole backbone and electron-affinitive cyanohexyl substituent for blue phosphorescence dopant. Chem Res Chin Univ 2017. [DOI: 10.1007/s40242-017-6477-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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14
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15
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Novel Design of Iridium Phosphors with Pyridinylphosphinate Ligands for High-Efficiency Blue Organic Light-emitting Diodes. Sci Rep 2016; 6:38478. [PMID: 27929124 PMCID: PMC5144070 DOI: 10.1038/srep38478] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/09/2016] [Indexed: 12/02/2022] Open
Abstract
Due to the high quantum efficiency and wide scope of emission colors, iridium (Ir) (III) complexes have been widely applied as guest materials for OLEDs (organic light-emitting diodes). Contrary to well-developed Ir(III)-based red and green phosphorescent complexes, the efficient blue emitters are rare reported. Like the development of the LED, the absence of efficient and stable blue materials hinders the widely practical application of the OLEDs. Inspired by this, we designed two novel ancillary ligands of phenyl(pyridin-2-yl)phosphinate (ppp) and dipyridinylphosphinate (dpp) for efficient blue phosphorescent iridium complexes (dfppy)2Ir(ppp) and (dfppy)2Ir(dpp) (dfppy = 2-(2,4-difluorophenyl)pyridine) with good electron transport property. The devices using the new iridium phosphors display excellent electroluminescence (EL) performances with a peak current efficiency of 58.78 cd/A, a maximum external quantum efficiency of 28.3%, a peak power efficiency of 52.74 lm/W and negligible efficiency roll-off ratios. The results demonstrated that iridium complexes with pyridinylphosphinate ligands are potential blue phosphorescent materials for OLEDs.
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16
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Sawama Y, Masuda M, Nakatani R, Yokoyama H, Monguchi Y, Dohi T, Kita Y, Sajiki H. Site-Selective Iron(III) Chloride-Catalyzed Arylation of 4-Aryl-4-methoxy-2,5-cyclohexadienones for the Synthesis of Polyarylated Phenols. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201600577] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Yoshinari Sawama
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Masahiro Masuda
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Ryosuke Nakatani
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Hiroki Yokoyama
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Yasunari Monguchi
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
| | - Toshifumi Dohi
- College of Pharmaceutical Sciences; Ritsumeikan University; 1-1-1 Nojihigashi Kusatsu Shiga 525-8577 Japan
| | - Yasuyuki Kita
- College of Pharmaceutical Sciences; Ritsumeikan University; 1-1-1 Nojihigashi Kusatsu Shiga 525-8577 Japan
| | - Hironao Sajiki
- Gifu Pharmaceutical University; 1-25-4 Daigaku-nishi Gifu 501-1196 Japan
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17
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Rajamalli P, Senthilkumar N, Gandeepan P, Ren-Wu CC, Lin HW, Cheng CH. A Method for Reducing the Singlet-Triplet Energy Gaps of TADF Materials for Improving the Blue OLED Efficiency. ACS APPLIED MATERIALS & INTERFACES 2016; 8:27026-27034. [PMID: 27648600 DOI: 10.1021/acsami.6b10678] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have successfully synthesized a series of blue thermally activated delayed fluorescence emitters, BPy-pC, BPy-pTC, BPy-p2C, and BPy-p3C, bearing a 4-benzoylpyridine core as the electron-accepting unit and carbazolyl, tert-butylcarbazolyl, dicarbazolyl, and tercarbazolyl groups as the electron-donating units, respectively. The density functional theory calculation shows that all of the compounds have their lowest unoccupied molecular orbitals on the benzoylpyridine moiety. However, the highest occupied molecular orbital (HOMO) of BPy-p3C is widely dispersed to the whole tercarbazolyl group, while the HOMOs of BPy-pC and BPy-pTC are mainly on the carbazolyl and extended to the phenyl ring. As a result, ΔEST is reduced from 0.29 eV for BPy-pC to 0.05 eV for BPy-p3C, and the organic light-emitting diodes using these materials as dopants emit blue light and their maximum external quantum efficiencies (EQEs) increase from 4.2% to 23.9% for BPy-pC and BPy-p3C, respectively. The EQE of the BPy-p3C-based device increases 2 times more than that of the BPy-pTC-based device without a significant change in the color coordinates.
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Affiliation(s)
- Pachaiyappan Rajamalli
- Department of Chemistry and ‡Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Natarajan Senthilkumar
- Department of Chemistry and ‡Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Parthasarathy Gandeepan
- Department of Chemistry and ‡Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Chen-Cheng Ren-Wu
- Department of Chemistry and ‡Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Hao-Wu Lin
- Department of Chemistry and ‡Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Chien-Hong Cheng
- Department of Chemistry and ‡Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
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18
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Bai Q, Liu H, Yao L, Shan T, Li J, Gao Y, Zhang Z, Liu Y, Lu P, Yang B, Ma Y. Adjusting Nitrogen Atom Orientations of Pyridine Ring in Tetraphenylsilane-Based Hosts for Highly Efficient Blue Phosphorescent Organic Light-Emitting Devices. ACS APPLIED MATERIALS & INTERFACES 2016; 8:24793-24802. [PMID: 27579808 DOI: 10.1021/acsami.6b09488] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Four wide bandgap host materials, namely, 9-(4-diphenyl(4-(pyridin-3-yl)phenyl)silyl-phenyl)-9H-carbazole (CSmP), 9-(4-diphenyl(4-(pyridin-2-yl)phenyl)silylphenyl)-9H-carbazole (CSoP), 9-(4-diphenyl(4-(pyridin-3-yl)phenyl)silylphenyl)-9H-3,9'-bicarbazole (DCSmP), and 9-(4-(diphenyl(4-(pyridin-2-yl)phenyl)silyl)phenyl)-9H-3,9'-bicarbazole (DCSoP), have developed by incorporation of pyridine with varied N atom orientation and carbazole/dimer carbazole units into the tetraphenylsilane skeleton for blue phosphorescent light-emitting diodes. These host materials all possess wide bandgap (3.54-3.64 eV) and high triplet energies (2.77-2.95 eV). As revealed by the absorption and emission spectra, theoretical calculations, and CV measurements, the N atom orientation exerts a strong influence on the LUMO energy level and electron-transportation behaviors without deterioring the photophysical properties. Among them, DCSmP with 3-pyridyl substituent manifests the best electron-transporting capability. The FIrpic-doped blue phosphorescent device using DCSmP as host material exhibits excellent electroluminescence performance with a maximum current efficiency of 40.1 cd A(-1) and a maximum external quantum efficiency of 20.0%. The current efficiency and external quantum efficiency are improved 3-fold, higher than those fabricated from DCSpP with 4-pyridyl as substituent, demonstrating an effective strategy for large improvement in device performance by a subtle change in molecular structure.
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Affiliation(s)
- Qing Bai
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - He Liu
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - Liang Yao
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - Tong Shan
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - Jinyu Li
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - Yu Gao
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - Zhe Zhang
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - Yulong Liu
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - Ping Lu
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - Bing Yang
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University , No. 2699, Qianjin Street, Changchun, Jilin 130012, P. R. China
| | - Yuguang Ma
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou, Guangdong 510640, China
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19
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Tian G, Wei X, Xiang N, Huang J, Cao J, Wang Z, Zhang J, Su J. Small organic molecules based on oxazole/thiazole with excellent performances in green and red phosphorescent organic light-emitting diodes. RSC Adv 2016. [DOI: 10.1039/c6ra07976h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Four small organic host materials based on oxazole/thiazole have been synthesized and fully characterized. The best performance of compound 2d was a maximum current efficiency of 50.7 cd A−1 for green device and a maximum current efficiency of 18.7 cd A−1 for red device.
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Affiliation(s)
- Guojian Tian
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals
- East China University of Science and Technology
- Shanghai 200237
- PR China
| | - Xiang Wei
- Key Laboratory of Advanced Display and System Applications
- Ministry of Education
- Shanghai University
- Shanghai 200072
- PR China
| | - Ning Xiang
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals
- East China University of Science and Technology
- Shanghai 200237
- PR China
| | - Jinhai Huang
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals
- East China University of Science and Technology
- Shanghai 200237
- PR China
| | - Jin Cao
- Key Laboratory of Advanced Display and System Applications
- Ministry of Education
- Shanghai University
- Shanghai 200072
- PR China
| | - Zixing Wang
- Key Laboratory of Advanced Display and System Applications
- Ministry of Education
- Shanghai University
- Shanghai 200072
- PR China
| | - Jianhua Zhang
- Key Laboratory of Advanced Display and System Applications
- Ministry of Education
- Shanghai University
- Shanghai 200072
- PR China
| | - Jianhua Su
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals
- East China University of Science and Technology
- Shanghai 200237
- PR China
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20
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Tamargo RJI, Poudel TN, Lee YR. Mild base-promoted benzannulation for the construction of polyfunctionalized m-terphenyl derivatives and their application as potent UV-filters. RSC Adv 2016. [DOI: 10.1039/c6ra15193k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
An efficient and facile transition-metal-free benzannulation was developed for the construction of polyfunctionalized m-terphenyl derivatives.
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Affiliation(s)
| | - Tej Narayan Poudel
- School of Chemical Engineering
- Yeungnam University
- Gyeongsan 712-749
- Republic of Korea
| | - Yong Rok Lee
- School of Chemical Engineering
- Yeungnam University
- Gyeongsan 712-749
- Republic of Korea
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21
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Bagdžiūnas G, Grybauskaitė G, Kostiv N, Ivaniuk K, Volyniuk D, Lazauskas A. Green and red phosphorescent organic light-emitting diodes with ambipolar hosts based on phenothiazine and carbazole moieties: photoelectrical properties, morphology and efficiency. RSC Adv 2016. [DOI: 10.1039/c6ra12692h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The two low-molar mass compounds based on phenothiazine and carbazole moieties were synthesized and investigated as the ambipolar hosts for the green and red phosphorescent organic light emitting diodes.
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Affiliation(s)
- Gintautas Bagdžiūnas
- Department of Polymer Chemistry and Technology
- Kaunas University of Technology
- Kaunas
- Lithuania
| | - Gintarė Grybauskaitė
- Department of Polymer Chemistry and Technology
- Kaunas University of Technology
- Kaunas
- Lithuania
| | - Nataliya Kostiv
- Department of Polymer Chemistry and Technology
- Kaunas University of Technology
- Kaunas
- Lithuania
- Lviv Polytechnic National University
| | | | - Dmytro Volyniuk
- Department of Polymer Chemistry and Technology
- Kaunas University of Technology
- Kaunas
- Lithuania
| | - Algirdas Lazauskas
- Institute of Materials Science of Kaunas University of Technology
- LT-51423 Kaunas
- Lithuania
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22
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Yook KS, Lee JY. Bipolar Host Materials for Organic Light-Emitting Diodes. CHEM REC 2015; 16:159-72. [DOI: 10.1002/tcr.201500221] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Indexed: 01/19/2023]
Affiliation(s)
- Kyoung Soo Yook
- School of Chemical Engineering Sungkyunkwan University; 2066, Seobu-ro Jangan-gu Suwon Gyeonggi 440-746 Republic of Korea
- School of Mechanical Engineering Sungkyunkwan University; 2066, Seobu-ro Jangan-gu Suwon Gyeonggi 440-746 Republic of Korea
| | - Jun Yeob Lee
- School of Chemical Engineering Sungkyunkwan University; 2066, Seobu-ro Jangan-gu Suwon Gyeonggi 440-746 Republic of Korea
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23
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Zhang X, Yang T, Wei Q, Chen Y, Guo X, Xie L, Lai W, Fan Q, Qian Y, Huang W. Arylfluorene based universal hosts for solution-processed RGB and white phosphorescent organic light-emitting devices. RSC Adv 2015. [DOI: 10.1039/c5ra19231e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A series of easily synthesized arylfluorenes (AFs)/carbazole universal host materials have been demonstrated for efficient solution-processable phosphorescent OLEDs.
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24
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Kumar S, Patil S. High Tg fluoranthene-based electron transport materials for organic light-emitting diodes. NEW J CHEM 2015. [DOI: 10.1039/c5nj00750j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluoranthene-based thermally stable electron transport materials for organic light-emitting diodes were synthesized and their performance in devices was investigated.
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Affiliation(s)
- Shiv Kumar
- Solid State and Structural Chemistry Unit
- Indian Institute of Science
- Bangalore
- India
| | - Satish Patil
- Solid State and Structural Chemistry Unit
- Indian Institute of Science
- Bangalore
- India
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