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Xie Q, Liao C, Liu H, Wang S, Li X. Rational Design of Coumarin-Based Hybridized Local and Charge-Transfer Blue Emitters for Solution-Processed Organic Light-Emitting Diodes. Chemistry 2024; 30:e202401078. [PMID: 38752798 DOI: 10.1002/chem.202401078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Indexed: 05/28/2024]
Abstract
Hybridized local and charge-transfer (HLCT) with the utilization of both singlet and triplet excitons through the "hot excitons" channel have great application potential in highly efficient blue organic light-emitting diodes (OLEDs). The proportion of charge-transfer (CT) and locally excited (LE) components in the relevant singlet and triplet states makes a big difference for the high-lying reverse intersystem crossing process. Herein, three novel donor (D)-acceptor (A) type HLCT materials, 7-([1,1'-biphenyl]-4-yl(9,9-dimethyl-9H-fluoren-2-yl)amino)-3-phenyl-1H-isochromen-1-one (pPh-7P), 7-([1,1'-biphenyl]-4-yl(9,9-dimethyl-9H-fluoren-2-yl)amino)-3-methyl-1H-isochromen-1-one (pPh-7M), and 6-([1,1'-biphenyl]-4-yl(9,9-dimethyl-9H-fluoren-2-yl)amino)-3-methyl-1H-isochromen-1-one (pPh-6M), were rationally designed and synthesized with diphenylamine derivative as donor and oxygen heterocyclic coumarin moiety as acceptors. The proportions of CT and LE components were fine controlled by changing the connection site of diphenylamine derivative at C6/C7-position and the substituent at C3-position of coumarin moiety. The HLCT characteristics of pPh-7P, pPh-7M, and pPh-6M were systematically demonstrated through photophysical properties and density functional theory calculations. The solution-processed doped OLEDs based on pPh-6M exhibited deep-blue electroluminescence with the maximum emission wavelength of 446 nm, maximum luminance of 8755 cd m-2, maximum current efficiency of 5.83 cd A-1, and maximum external quantum efficiency of 6.54 %. The results reveal that pPh-6M with dominant 1LE and 3CT components has better OLED performance.
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Affiliation(s)
- Qi Xie
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
| | - Chuanxin Liao
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
| | - Hongli Liu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
| | - Shirong Wang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
| | - Xianggao Li
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China
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Wang W, Bian J, Chen K, Li C, Long Y, Huang H, Jiang L, Zhao J, Liu S, Chi Z, Xu J, Zhang Y. Achieving Record External Quantum Efficiency of 11.5 % in Solution-Processable Deep-Blue Organic Light-Emitting Diodes Utilizing Hot Exciton Mechanism. Angew Chem Int Ed Engl 2024; 63:e202318782. [PMID: 38354089 DOI: 10.1002/anie.202318782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/16/2024]
Abstract
High performance solution-processable deep-blue emitters with a Commission International de l'Eclairage (CIE) coordinate of CIEy≤0.08 are highly desired in ultrahigh-definition display. Although, deep-blue materials with hybridized local and charge-transfer (HLCT) excited-state feature are promising candidates, their rigidity and planar molecular structures limit their application in solution-processing technique. Herein, four novel deep-blue solution-processable HLCT emitters were first proposed by attaching rigid imide aliphatic rings as functional units onto the HLCT emitting core. The functional units not only improve solubility, enhance thermal properties and morphological stability of the emitting core, but also promote photoluminescence efficiency, balance charge carrier transport, and inhibit aggregation-caused quenching effect due to the weak electron-withdrawing property as well as steric hindrance. The corresponding solution-processable organic light-emitting diodes (OLEDs) substantiate an unprecedented maximum external quantum efficiency (EQEmax) of 11.5 % with an emission peak at 456 nm and excellent colour purity (full width at half maximum=56 nm and CIEy=0.09). These efficiencies represent the state-of-the-art device performance among the solution-processable blue OLEDs based on the "hot exciton" mechanism. This simple strategy opens up a new avenue for designing highly efficient solution-processable deep-blue organic luminescent materials.
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Affiliation(s)
- Wenhui Wang
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Jinkun Bian
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Kaijin Chen
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Chuying Li
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Yubo Long
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Haitao Huang
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Long Jiang
- Instrumental Analysis & Research Center, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Juan Zhao
- PCFM Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Siwei Liu
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Zhenguo Chi
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Jiarui Xu
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
| | - Yi Zhang
- PCFM Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, GBRCE for Functional Molecular Engineering, GD HPPC Lab, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou, 510275, P. R. China
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De R, Maity M, Joseph A, Gupta SP, Nailwal Y, Namboothiry MAG, Pal SK. High Electrical Conductivity and Hole Transport in an Insightfully Engineered Columnar Liquid Crystal for Solution-Processable Nanoelectronics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2308983. [PMID: 38332439 DOI: 10.1002/smll.202308983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/23/2023] [Indexed: 02/10/2024]
Abstract
Discotic liquid crystals (DLCs) are widely acknowledged as a class of organic semiconductors that can harmonize charge carrier mobility and device processability through supramolecular self-assembly. In spite of circumventing such a major challenge in fabricating low-cost charge transport layers, DLC-based hole transport layers (HTLs) have remained elusive in modern organo-electronics. In this work, a minimalistic design strategy is envisioned to effectuate a cyanovinylene-integrated pyrene-based discotic liquid crystal (PY-DLC) with a room-temperature columnar hexagonal mesophase and narrow bandgap for efficient semiconducting behavior. Adequately combined photophysical, electrochemical, and theoretical studies investigate the structure-property relations, logically correlating them with efficient hole transport. With a low reorganization energy of 0.2 eV, PY-DLC exhibits superior charge extraction ability from the contact electrodes at low values of applied voltage, achieving an electrical conductivity of 3.22 × 10-4 S m-1, the highest reported value for any pristine DLC film in a vertical charge transport device. The columnar self-assembly, in conjunction with solution-processable self-healed films, results in commendably elevated values of hole mobility (≈10-3 cm2 V-1s-1). This study provides an unprecedented constructive outlook toward the development of DLC semiconductors as practical HTLs in organic electronics.
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Affiliation(s)
- Ritobrata De
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge city, Sector 81, SAS Nagar, Punjab, 140306, India
| | - Madhusudan Maity
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge city, Sector 81, SAS Nagar, Punjab, 140306, India
| | - Alvin Joseph
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, 695551, India
| | | | - Yogendra Nailwal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge city, Sector 81, SAS Nagar, Punjab, 140306, India
| | - Manoj A G Namboothiry
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala, 695551, India
| | - Santanu Kumar Pal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge city, Sector 81, SAS Nagar, Punjab, 140306, India
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