1
|
Qi H, Xie D, Gao Z, Wang S, Peng L, Liu Y, Ying S, Ma D, Yan S. A record-high EQE of 7.65%@3300 cd m -2 achieved in non-doped near-ultraviolet OLEDs based on novel D'-D-A type bipolar fluorophores upon molecular configuration engineering. Chem Sci 2024; 15:11053-11064. [PMID: 39027275 PMCID: PMC11253119 DOI: 10.1039/d4sc02655a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 06/13/2024] [Indexed: 07/20/2024] Open
Abstract
Developing a high-performance near-ultraviolet (NUV) material and its simple non-doped device with a small efficiency roll-off and good color purity is a promising but challenging task. Here, we proposed a novel donor'-donor-acceptor (D'-D-A) type molecular strategy to largely solve the intrinsic contradictions among wide-bandgap NUV emission, fluorescence efficiency, carrier injection and transport. An efficient NUV fluorophore, 3,6-mPPICNC3, exhibiting a hybridized local and charge-transfer state, is achieved through precise molecular configuration engineering, realizing similar hole and electron mobilities at both low and high electric fields. Moreover, the planarized intramolecular charge transfer excited state and steric hindrance effect endow 3,6-mPPICNC3 with a considerable luminous efficiency and good color purity in the aggregation state. Consequently, the non-doped device emitting stable NUV light with Commission Internationale de l'Eclairage (CIE) coordinates of (0.160, 0.032) and a narrow full width at half maximum of 44 nm exhibits a state-of-the-art external quantum efficiency (EQE) of 7.67% and negligible efficiency roll-off over a luminance range from 0 to 3300 cd m-2. This is a record-high efficiency among all the reported non-doped NUV devices. Amazingly, an EQE of 7.85% and CIE coordinates of (0.161, 0.025) are achieved in the doped device. This demonstrates that the D'-D-A-type molecular structure has great potential for developing high-performance organic light-emitting materials and their optoelectronic applications.
Collapse
Affiliation(s)
- Haoyuan Qi
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Danyu Xie
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology Guangzhou 510640 P. R. China
| | - Zexuan Gao
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Shengnan Wang
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Ling Peng
- College of Chemistry and Chemical Engineering, Heze University Heze 274015 P. R. China
| | - Yuchao Liu
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Shian Ying
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Dongge Ma
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology Guangzhou 510640 P. R. China
| | - Shouke Yan
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, 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 P. R. China
| |
Collapse
|
2
|
Lee H, Kim T. Unraveling the Degradation Pathways in Deep Blue Phosphorescent OLEDs Depending on Charge Dynamics: Insights from Numerical Analysis and Magneto-Electroluminescence Characterization. ACS APPLIED MATERIALS & INTERFACES 2024; 16:26468-26477. [PMID: 38739879 DOI: 10.1021/acsami.4c05175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
To analyze the lifetime difference based on the charge dynamics in the emitting layer (EML), we applied two electron transport layers (ETLs) with significantly different electron transporting characteristics to the same EML. Even with the same EML configuration, the device lifetime increased by approximately 4-fold, from 291 h to over 1000 h of LT50 (the time taken for the luminance to decrease to 50% of its initial value of 1000 cd/m2). Although trap/detrap of holes in the dopant molecules was observed through impedance spectroscopy, we found that the most significant difference in lifetime was caused by the quantity of electron current. Surprisingly, depending on the electron transporting layer, the primary bimolecular interaction in the EML (i.e., exciton-exciton, exciton-polaron interaction) dramatically changes even in the same EML configuration, which is theoretically analyzed by the numerical fitting of transient electroluminescence data and experimentally confirmed by magneto-electroluminescence (MEL) measurements. To the best of our knowledge, for the first time, the MEL measurements are demonstrated as a tool that can be utilized to intuitively discern the dominance of bimolecular interaction with respect to the operational stability of phosphorescent organic light-emitting diodes (PhOLEDs).
Collapse
Affiliation(s)
- Hakjun Lee
- Department of Information Display, Hongik University, Seoul 04066, Korea
| | - Taekyung Kim
- Department of Information Display, Hongik University, Seoul 04066, Korea
- Department of Materials Science and Engineering, Hongik University, Sejong 30016, Korea
| |
Collapse
|
3
|
Luo Y, Kong FF, Tian XJ, Yu YJ, Jing SH, Zhang C, Chen G, Zhang Y, Zhang Y, Li XG, Zhang ZY, Dong ZC. Anomalously bright single-molecule upconversion electroluminescence. Nat Commun 2024; 15:1677. [PMID: 38395971 PMCID: PMC10891098 DOI: 10.1038/s41467-024-45450-5] [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: 08/20/2023] [Accepted: 01/23/2024] [Indexed: 02/25/2024] Open
Abstract
Efficient upconversion electroluminescence is highly desirable for a broad range of optoelectronic applications, yet to date, it has been reported only for ensemble systems, while the upconversion electroluminescence efficiency remains very low for single-molecule emitters. Here we report on the observation of anomalously bright single-molecule upconversion electroluminescence, with emission efficiencies improved by more than one order of magnitude over previous studies, and even stronger than normal-bias electroluminescence. Intuitively, the improvement is achieved via engineering the energy-level alignments at the molecule-substrate interface so as to activate an efficient spin-triplet mediated upconversion electroluminescence mechanism that only involves pure carrier injection steps. We further validate the intuitive picture with the construction of delicate electroluminescence diagrams for the excitation of single-molecule electroluminescence, allowing to readily identify the prerequisite conditions for producing efficient upconversion electroluminescence. These findings provide deep insights into the microscopic mechanism of single-molecule upconversion electroluminescence and organic electroluminescence in general.
Collapse
Affiliation(s)
- Yang Luo
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Fan-Fang Kong
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Xiao-Jun Tian
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Yun-Jie Yu
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Shi-Hao Jing
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Chao Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Gong Chen
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
| | - Yang Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Yao Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Xiao-Guang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China
| | - Zhen-Yu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Zhen-Chao Dong
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China.
| |
Collapse
|
4
|
Wei F, Chen J, Zhao X, Wu Y, Wang H, Chen X, Xiong Z. High-Performance Hot-Exciton OLEDs via Fully Harvesting Triplet Excited States from Both the Exciplex Co-Host and the TBRb Emitter. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303192. [PMID: 37587760 PMCID: PMC10582462 DOI: 10.1002/advs.202303192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/12/2023] [Indexed: 08/18/2023]
Abstract
The high-level reverse intersystem crossing (HL-RISC, T2 → S1 ) process from triplet to singlet exciton, namely the "hot exciton" channel, has recently been demonstrated in the traditional fluorescent emitter of TBRb. Although it is a potential pathway to improve the utilization of non-radiative triplet exciton energy, highly efficient fluorescent organic light emitting diodes (FOLEDs) based on this "hot exciton" channel have not been developed. Herein, high-efficiency and low-efficiency roll-off FOLEDs are achieved through doping TBRb molecules into an energy-level matched exciplex co-host. Combining the low-level RISC (LL-RISC, EX3 → EX1 ) process in the exciplex co-host with the HL-RISC process of hot excitons in TBRb to fully harvest the triplet energy, a record-high external quantum efficiency (EQE) of 20.4% is obtained via a proper Dexter energy transfer of triplet excitons, realizing the efficiency breakthrough from fully fluorescent material-based OLEDs with TBRb as an end emitter. Furthermore, the fingerprint Magneto-electroluminescence (MEL) as a sensitive measuring tool is employed to visualize the "hot exciton" channel in TBRb, which also directly verifies the effective energy confinement and the full utilization of hot excitons. Obviously, this work paves a promising way for further fabricating high-efficiency TBRb-based FOLEDs for lighting and flat-panel display applications.
Collapse
Affiliation(s)
- Fuxian Wei
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Jing Chen
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Xi Zhao
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Yuting Wu
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Huiyao Wang
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Xiaoli Chen
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Zuhong Xiong
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| |
Collapse
|
5
|
Jin JM, Chen WC, Tan JH, Li Y, Mu Y, Zhu ZL, Cao C, Ji S, Hu D, Huo Y, Zhang HL, Lee CS. Photo-controllable Luminescence from Radicals Leading to Ratiometric Emission Switching via Dynamic Intermolecular Coupling. Angew Chem Int Ed Engl 2023; 62:e202214281. [PMID: 36314420 DOI: 10.1002/anie.202214281] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/24/2022] [Accepted: 10/28/2022] [Indexed: 11/05/2022]
Abstract
The development of photoinduced luminescent radicals with dynamic emission color is still challenging. Herein we report a novel molecular radical system (TBIQ) that shows photo-controllable luminescence, leading to a wide range of ratiometric color changes via light excitation. The conjugated skeleton of TBIQ is decorated with steric-demanding tertiary butyl groups that enable appropriate intermolecular interaction to make dynamic intermolecular coupling possible for controllable behaviors. We reveal that the helicenic pseudo-planar conformation of TBIQ experiences a planarization process after light excitation, leading to more compactly stacked supermolecules and thus generating radicals via intermolecular charge transfer. The photo-controllable luminescent radical system is employed for a high-level information encryption application. This study may offer unique insight into molecular dynamic motion for optical manufacturing and broaden the scope of smart-responsive materials for advanced applications.
Collapse
Affiliation(s)
- Jia-Ming Jin
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Wen-Cheng Chen
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Ji-Hua Tan
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong SAR, P. R. China
| | - Yang Li
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong SAR, P. R. China
| | - Yingxiao Mu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Ze-Lin Zhu
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong SAR, P. R. China
| | - Chen Cao
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong SAR, P. R. China
| | - Shaomin Ji
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Dehua Hu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Yanping Huo
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Hao-Li Zhang
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.,State Key Laboratory of Applied Organic Chemistry (SKLAOC), Key Laboratory of Special Function Materials and Structure Design (MOE), and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, P. R. China
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong SAR, P. R. China
| |
Collapse
|
6
|
Liao XJ, Pu D, Yuan L, Tong J, Xing S, Tu ZL, Zuo JL, Zheng WH, Zheng YX. Planar Chiral Multiple Resonance Thermally Activated Delayed Fluorescence Materials for Efficient Circularly Polarized Electroluminescence. Angew Chem Int Ed Engl 2023; 62:e202217045. [PMID: 36517419 DOI: 10.1002/anie.202217045] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Chiral boron/nitrogen doped multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters are promising for highly efficient and color-pure circularly polarized organic light-emitting diodes (CP-OLEDs). Herein, we report two pairs of MR-TADF materials (Czp-tBuCzB, Czp-POAB) based on planar chiral paracyclophane with photoluminescence quantum yields of up to 98 %. The enantiomers showed symmetric circularly polarized photoluminescence spectra with dissymmetry factors |gPL | of up to 1.6×10-3 in doped films. Meanwhile, the sky-blue CP-OLEDs with (R/S)-Czp-tBuCzB showed an external quantum efficiency of 32.1 % with the narrowest full-width at half-maximum of 24 nm among the reported CP-OLEDs, while the devices with (R/S)-Czp-POAB displayed the first nearly pure green CP electroluminescence with |gEL | factors at the 10-3 level. These results demonstrate the incorporation of planar chirality into MR-TADF emitter is a reliable strategy for constructing of efficient CP-OLEDs.
Collapse
Affiliation(s)
- Xiang-Ji Liao
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Dongdong Pu
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Li Yuan
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Jingjing Tong
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Shuai Xing
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Zhen-Long Tu
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Jing-Lin Zuo
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.,Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China
| | - Wen-Hua Zheng
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - You-Xuan Zheng
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.,Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China
| |
Collapse
|
7
|
Zhang YL, Yang SY, Feng ZQ, Qu YK, Zhou DY, Zhong C, Liao LS, Jiang ZQ. π-Stacked host materials based on spirofluorene scaffolds for warm white OLEDs achieving 94.7 lm W−1 at 1,000 cd m−2. Sci China Chem 2022. [DOI: 10.1007/s11426-022-1382-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
8
|
Lin C, Han P, Qu F, Xiao S, Li Y, Xie D, Qiao X, Yang D, Dai Y, Sun Q, Qin A, Tang BZ, Ma D. Suppressing singlet-triplet annihilation processes to achieve highly efficient deep-blue AIE-based OLEDs. MATERIALS HORIZONS 2022; 9:2376-2383. [PMID: 35789246 DOI: 10.1039/d2mh00627h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Aggregation-induced emission (AIE) materials are attractive for the fabrication of high efficiency organic light-emitting diodes (OLEDs) by harnessing "hot excitons" from the high-lying triplet exciton states (Tn, n ≥ 2) and high photoluminescence (PL) quantum efficiency in solid films. However, the electroluminescence (EL) efficiency of most AIE-based OLEDs does not meet our expectation due to some unrevealed exciton loss processes. Herein, we further enhance the efficiency of blue AIE-based OLEDs, and find experimentally and theoretically that the serious exciton loss is caused by the quenching of radiative singlet excitons and long-lived triplet excitons [singlet-triplet annihilation (STA)]. In order to suppress the STA process, 1-(2,5-dimethyl-4-(1-pyrenyl)phenyl)pyrene (DMPPP) with triplet-triplet annihilation up-conversion was doped in two AIE emitters to reduce the triplet excitons on the lowest triplet excited state (T1) of AIE molecules. It can be seen that the external quantum efficiency (EQE) of the resulting blue OLEDs was enhanced to 11.8% with CIE coordinates of (0.15, 0.07) and a negligible efficiency roll-off, realizing the efficiency breakthrough of deep-blue AIE-based OLEDs. This work establishes a physical insight in revealing the exciton loss processes and the fabrication of high-performance AIE-based OLEDs.
Collapse
Affiliation(s)
- Chengwei Lin
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Pengbo Han
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Fenlan Qu
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Shu Xiao
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Yuanzhao Li
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Dian Xie
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Xianfeng Qiao
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Dezhi Yang
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Yanfeng Dai
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Qian Sun
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Anjun Qin
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Ben Zhong Tang
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
- Shenzhen Institute of Molecular Aggregate Science and Engineering, School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 2001 Longxiang Boulevard, Longgang District, Shenzhen City, Guangdong 518172, China
| | - Dongge Ma
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| |
Collapse
|
9
|
Zheng P, Cao W, Zhang Y, Li F, Zhang M. Ultrafast Sulfur Mustard Simulant Gas Fluorescent Chemosensors Based on Triazole AIEE Material with High Selectivity and Sensitivity at Room Temperature. ACS Sens 2022; 7:1946-1957. [PMID: 35819023 DOI: 10.1021/acssensors.2c00708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Herein, a novel blue aggregation-induced enhanced emission (AIEE) material 4-N-(naphthalen-l-yl)-3,5-bis(4-N-phenyl-1-naphthylamine)phenyl-4H-1,2,4-triazole (NDTAZ) is developed and used as a fluorescent chemosensor for sulfur mustard (SM) simulant 2-chloroethyl ethyl sulfide (2-CEES) vapor. The NDTAZ chemosensor is designed by introducing an electron-donating N-phenyl-1-naphthylamine group at 3 and 5 position of 4H-1,2,4-triazole (TAZ) to enhance the nucleophilicity of the TAZ group, and a naphthalene ring is connected to 4 position of the TAZ group to construct an AIEE molecule. The NDTAZ films show extraordinary stability and then are further used as reliable and portable fluorescent chemosensors. Upon exposure to 2-CEES vapor, the NDTAZ chemosensor exhibits an instantaneous fluorescence response (not more than 1 s). What should be noted is that this fluorescent chemosensor realizes the visualized detection of fluorescent color change from blue to green at "room temperature", which is rarely reported. The limit of detection is estimated to be 0.55 ppm, which is below the AEGL-1 (0.6 ppm for 1 min) safety ceiling level to SM exposure. Moreover, the NDTAZ chemosensor shows high selectivity toward 2-CEES vapor over closely related substances, including alkylating agents, aryl halide compounds, sulphur-containing compounds, and nerve agent mimics. More impressively, the NDTAZ chemosensor demonstrates good recyclability by water treatment. Also, the sensing mechanism is adequately proved by using multiple experimental methods and theoretical calculation. In addition, the NDTAZ-based facile filter paper-constructed test strips are fabricated for real-time and on-spot detection of leaked 2-CEES gas specifically. Therefore, this fluorescent chemosensor with excellent sensing performance greatly advances the practical detection of SM species at room temperature.
Collapse
Affiliation(s)
- Ping Zheng
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Wenjuan Cao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Yimeng Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Ming Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| |
Collapse
|
10
|
Liu S, Zhang J, Zang C, Zhang L, Xie W, Lee CS. Centimeter-scale hole diffusion and its application in organic light-emitting diodes. SCIENCE ADVANCES 2022; 8:eabm1999. [PMID: 35486728 PMCID: PMC9054018 DOI: 10.1126/sciadv.abm1999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 03/14/2022] [Indexed: 06/14/2023]
Abstract
In conventional organic light-emitting diodes (OLEDs), current balance between electron and hole transport regions is typically achieved by leakage of the major carrier through the devices or by accumulation of the major carrier inside the devices. Both of these are known to reduce performances leading to reduction of efficiency and operation stability due to exciton-polaron annihilation, etc. We found that hole diffusion in a centimeter-scale can be achieved in a PEDOT:PSS layer via composition and interface engineering. This ultralong distance hole diffusion enables substantially enhanced hole diffusion current in the lateral direction perpendicular to the applied electric field in typical organic optoelectronic devices. By introducing this lateral hole diffusion layer (LHDL) at the anode side of OLEDs, reduced carrier accumulation, improved efficiency, and enhanced operation stability are demonstrated. The application of the LHDL provides a third strategy for current balancing with much reduced harmful effects from the previous two approaches.
Collapse
Affiliation(s)
- Shihao Liu
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong SAR 999077, People’s Republic of China
| | - Jiaming Zhang
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
| | - Chunxiu Zang
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
| | - Letian Zhang
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
| | - Wenfa Xie
- State key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People’s Republic of China
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry, City University of Hong Kong, Hong Kong SAR 999077, People’s Republic of China
| |
Collapse
|
11
|
Abstract
Near ultraviolet (NUV) light-emitting materials and devices are significant due to unique applications in anti-counterfeit, manufacturing industries, and hygienic treatments. However, the development of high-efficiency NUV electroluminescent devices encounters great challenges and is far behind their RGB emitter counterparts. Besides the photoluminescence quantum yields (PLQYs) of NUV materials being higher than 40%, charge injection and lopsided carrier transport also determine the device performance, leading to great efforts in optimizing the frontier molecular orbitals to fit the adjacent function layer. In the exploration of NUV materials, organic molecules are one of the primary candidates, given their preparative facility and structural variability. Recently, all-inorganic quantum-dot light-emitting diodes (QLEDs) of Cd-based, ZnSe, graphene and inorganic perovskite emitters and organic-inorganic hybrid lead halide perovskite nanocrystals (NCs) were demonstrated for achieving NUV electroluminescence. Owing to the great efforts devoted to NUV material engineering and device configuration, NUV materials and devices have achieved great advances over the last two decades. In this review, we retrospect the development of NUV materials and devices covering all promising systems, which may inspire the enthusiasm of researchers to explore the huge potential in the NUV region.
Collapse
Affiliation(s)
- Shuo Chen
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials, Heilongjiang University, 74 Xuefu Road, Harbin 150080, P. R. China.
| | | |
Collapse
|
12
|
Zheng P, Abdurahman A, Zhang Z, Feng Y, Zhang Y, Ai X, Li F, Zhang M. A simple organic multi-analyte fluorescent prober: One molecule realizes the detection to DNT, TATP and Sarin substitute gas. JOURNAL OF HAZARDOUS MATERIALS 2021; 409:124500. [PMID: 33199143 DOI: 10.1016/j.jhazmat.2020.124500] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/03/2020] [Accepted: 11/04/2020] [Indexed: 06/11/2023]
Abstract
The detections of explosives and chemical warfare agents (CWAs) are always important for global security. In this study, a simple donor (D)- acceptor (A) type small organic fluorescent triazole-based molecule (T1) is reported. T1 is composed of a central 4H-1, 2, 4-triazole (TAZ) "core" and three external triphenylamine (TPA) groups. Its spin-coating films can realize the multi-analyte fluorescent prober to detect DNT (2, 4-dinitrotoluene), hydrogen peroxide (H2O2, the substitute for triacetone triperoxide (TATP)) and diethylchlorophosphate (DCP, the substitute for Sarin) vapors. Additionally, the combination of the triple sensing mechanism in the different channels affords three distinct sets of output-signal responses, these three hazardous compounds could be identified rapidly with high sensitivity and selectivity: fluorescence turn-off response to DNT, fluorescence turn-on response to H2O2 and fluorometric-colorimetric dual-channel response to DCP. T1 fluorescent probe is highly advantageous for concurrently monitoring various hazardous target substances and simultaneously possessing the desirable sensitivity and selectivity, excellent reusability. Hereby, this study provides a prototype method to build novel multifunctional fluorescent probes to explosives and CWAs.
Collapse
Affiliation(s)
- Ping Zheng
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
| | - Alim Abdurahman
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
| | - Zhaoxia Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
| | - Yuting Feng
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
| | - Yimeng Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
| | - Xin Ai
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
| | - Ming Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
| |
Collapse
|
13
|
Guo X, Yuan P, Fan J, Qiao X, Yang D, Dai Y, Sun Q, Qin A, Tang BZ, Ma D. Unraveling the Important Role of High-Lying Triplet-Lowest Excited Singlet Transitions in Achieving Highly Efficient Deep-Blue AIE-Based OLEDs. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006953. [PMID: 33565188 DOI: 10.1002/adma.202006953] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/09/2020] [Indexed: 05/27/2023]
Abstract
Aggregation-induced emission (AIE) materials are attractive for achieving highly efficient nondoped organic light-emitting diodes (OLEDs) owing to their strong luminescence in the solid state. However, the electroluminescence efficiency of most AIE-based OLEDs remains low owing to the waste of triplet excitons. Here, using theoretical calculations, photophysical dynamics, and magnetoluminescence measurements, the spin conversion process is demonstrated between the high-lying triplet state (Tn ) and the lowest excited singlet state (S1 ) in AIE materials. Moreover, the relative positions of Tn (n < 4) and S1 are shown to have a significant impact on the spin-conversion efficiency, thus influencing the harvesting of triplet excitons and the device efficiency. Finally, by selecting an upconversion material with an appropriate energy level for further utilizing the triplet excitons, a deep-blue fluorescent OLED with CIE coordinates of (0.15, 0.08), a maximum external quantum efficiency of 10.2%, low efficiency roll-off, and a high brightness of 16817 cd m-2 is developed. This is one of the most efficient deep-blue OLEDs based on AIE materials reported so far. These findings also provide new insights into the design of more efficient AIE molecules and corresponding OLEDs by managing high-lying triplet excitons.
Collapse
Affiliation(s)
- Xiaomin Guo
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Peisen Yuan
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Jianzhong Fan
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Materials and Clean Energy, School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China
| | - Xianfeng Qiao
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Dezhi Yang
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Yanfeng Dai
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Qian Sun
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Anjun Qin
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Ben Zhong Tang
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Dongge Ma
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| |
Collapse
|
14
|
Structural Controls of Tetraphenylbenzene-based AIEgens for Non-doped Deep Blue Organic Light-emitting Diodes. Chem Res Chin Univ 2021. [DOI: 10.1007/s40242-021-0403-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
15
|
Ji L, Shi J, Wei J, Yu T, Huang W. Air-Stable Organic Radicals: New-Generation Materials for Flexible Electronics? ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1908015. [PMID: 32583945 DOI: 10.1002/adma.201908015] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 03/05/2020] [Accepted: 03/08/2020] [Indexed: 05/28/2023]
Abstract
In the last few years, air-stable organic radicals and radical polymers have attracted tremendous attention due to their outstanding performance in flexible electronic devices, including transistors, batteries, light-emitting diodes, thermoelectric and photothermal conversion devices, and among many others. The main issue of radicals from laboratory studies to real-world applications is that the number of known air-stable radicals is very limited, and the radicals that have been used as materials are even less. Here, the known and newly developed air-stable organic radicals are summarized, generalizing the way of observing air-stable radicals. The special electric and photophysical properties of organic radicals and radical polymers are interpreted, which give radicals a wide scope for various of potential applications. Finally, the exciting applications of radicals that have been achieved in flexible electronic devices are summarized. The aim herein is to highlight the recent achievements in radicals in chemistry, materials science, and flexible electronics, and further bridge the gap between these three disciplines.
Collapse
Affiliation(s)
- Lei Ji
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Junqing Shi
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Juan Wei
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Tao Yu
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Wei Huang
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| |
Collapse
|
16
|
Jayabharathi J, Sivaraj S, Thanikachalam V, Seransenguttuvan B. Efficient blue electroluminescence with an external quantum efficiency of 9.20% and CIE y < 0.08 without excimer emission. RSC Adv 2020; 10:25059-25072. [PMID: 35517441 PMCID: PMC9055148 DOI: 10.1039/d0ra03463k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 06/26/2020] [Indexed: 01/13/2023] Open
Abstract
Aromatically substituted phenanthroimidazoles at the C6 and C9 positions enhanced the thermal, photochemical and electroluminescence properties due to extension of conjugation. These new materials exhibit good photophysical properties with high thermal stability, good film-forming property and high luminous efficiency. The electroluminescence performances of C6 and C9 modified phenanthroimidazoles as host emitters were evaluated as well as the dopant in the fabricated devices. Among the non-doped devices, pyrene substituted PPI-Py or PPICN-Py based devices show maximum efficiency: PPI-Py/PPICN-Py: η c (cd A-1) - 9.20/9.98; η p (lm W-1) - 8.50/9.16; η ex (%) - 5.56/5.80. The doped OLEDs, m-MTDATA/TAPC:PPI-Cz (4.81/4.85%), m-MTDATA/TAPC:PPICN-Cz (5.23/5.26%), m-MTDATA/TAPC:PPI-An (5.01/5.04%), m-MTDATA/TAPC:PPICN-An (5.25/5.28%), m-MTDATA/TAPC:PPI-Py (5.61/5.65%) and m-MTDATA/TAPC:PPICN-Py (5.76/5.78%) show improved device efficiencies compared to non-doped devices. Designing C6/C9 modified phenanthrimidazole fluorophores is an efficient strategy for constructing highly efficient OLEDs.
Collapse
Affiliation(s)
| | - Sekar Sivaraj
- Department of Chemistry, Annamalai University Annamalai Nagar Tamilnadu - 608 002 India
| | | | - Balu Seransenguttuvan
- Department of Chemistry, Annamalai University Annamalai Nagar Tamilnadu - 608 002 India
| |
Collapse
|
17
|
Tang X, Pan R, Zhao X, Zhu H, Xiong Z. Achievement of High-Level Reverse Intersystem Crossing in Rubrene-Doped Organic Light-Emitting Diodes. J Phys Chem Lett 2020; 11:2804-2811. [PMID: 32191490 DOI: 10.1021/acs.jpclett.0c00451] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Using the fingerprint magneto-electroluminescence trace, we observe a fascinating high-level reverse intersystem crossing (HL-RISC) in rubrene-doped organic light-emitting diodes (OLEDs). This HL-RISC is achieved from high-lying triplet states (T2,rub) transferred from host triplet states by the Dexter energy transfer to the lowest singlet states (S1,rub) in rubrene. Although HL-RISC decreases with bias current, it increases with lowering temperature. This is contrary to the temperature-dependent RISC from conventional thermally activated delayed fluorescence, because HL-RISC is an exothermic process instead. Moreover, owing to the competition of exciton energy transfer with direct charge trap, HL-RISC changes nonmonotonically with the dopant concentration and increases luminous efficiency to a maximum at 10% of rubrene, which is about ten times greater than that from the pure-rubrene device. Additionally, the HL-RISC process is not observed in bare rubrene-doped films because of the absence of T2,rub. Our findings pave the way for designing highly efficient orange fluorescent OLEDs.
Collapse
Affiliation(s)
- Xiantong Tang
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China
| | - Ruiheng Pan
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Science, Beijing Jiaotong University, Beijing 100044, China
| | - Xi Zhao
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China
| | - Hongqiang Zhu
- Chongqing Key Laboratory of Photo-Electric Functional Materials, Chongqing Normal University, Chongqing 401331, China
| | - Zuhong Xiong
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing 400715, China
| |
Collapse
|
18
|
Wang F, Wang J, Maehrlein SF, Ma Y, Liu F, Zhu XY. Broad-Band Near-Infrared Doublet Emission in a Tetrathiafulvalene-Based Metal-Organic Framework. J Phys Chem Lett 2020; 11:762-766. [PMID: 31935326 DOI: 10.1021/acs.jpclett.9b03383] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The upper limit in LED quantum efficiency from conventional closed-shell molecules is 25% as dictated by singlet and triplet spin statistics. Spin-doublet organic molecules are attractive candidates to exceed this limit, thanks to their 100% theoretical quantum efficiency in radiative recombination. However, examples of stable spin-doublet molecules in the solid state are rare. Here we show broad-band near-infrared emission in the columnar π-π stacked tetrathiafulvalene (TTF) in a metal organic framework (MOF) single crystal. The broad emission is similar to known TTF+• doublet emission and is stabilized in the MOF crystal. This interpretation is supported by the observation of enhanced PL emission following UV oxidation of the MOF crystal to increase the doublet concentration. The findings suggest tetrathiafulvalene-based MOFs as promising materials for near-IR light emission and the MOF structure may be a general strategy to stabilize radical cation species in the solid state.
Collapse
Affiliation(s)
- Feifan Wang
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Jue Wang
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Sebastian F Maehrlein
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Yingzi Ma
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Fang Liu
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - X-Y Zhu
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| |
Collapse
|
19
|
Li H, Wang X, Zhu Y, Li Z. Innovative Organic Electroluminescent Materials with a Doublet Ground State: A Theoretical Investigation. J Phys Chem A 2020; 124:662-673. [PMID: 31910015 DOI: 10.1021/acs.jpca.9b10343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The displaced and distorted harmonic oscillator model, which has been proven to be appropriate in calculating vibronic spectra, is employed to treat the emission spectrum of title molecules in combination with a thermal vibration correlation function. The calculated results indicate that the main peak of the emission spectrum is visibly impacted by the normal modes with lower frequencies and that the shoulder peak is originated from the middle-frequency modes. On the level of time-dependent density functional theory (TDDFT), the calculated fluorescence lifetimes of TTM-3NCz and TTM-3PCz are 22.1 and 26.0 ns, respectively, which happen to coincide with the observed values of TTM-3NCz (17.2 ns) and TTM-3PCz (21.2 ns). The above data indicate that both the calculated radiative decay rates are reasonable at room temperature. Furthermore, we investigate the influence of the Duschinsky effect on the fluorescence quantum efficiency (FQE). When it is considered, the predicted FQE of the TTM-3NCz molecule is only 0.11%, and the observed value (49% in toluene) deviates significantly. If we ignore the Duschinsky effect, the FQE of TTM-3NCz increases dramatically to 41.8%. For the TTM-3PCz molecule (the FQE is 46% in toluene), the calculated FQE is 0.042% with the Duschinsky effect and increases to 45.2% without the Duschinsky effect. This phenomenon might be related to external factors and the nature of the TDDFT only considering a single configuration. In addition, the fluorescent properties of the fluorinated TTM-3NCz molecules are studied predictably. The obtained results show that the perfluorinated TTM-3NCz shows better luminous performance due to larger oscillator strength. Finally, the dimers, which are composed of both single title molecules, are explored theoretically to determine how they impact the fluorescent property; however, the effect can be nearly eliminated because of the small binding energies.
Collapse
Affiliation(s)
- Huixue Li
- School of Chemical Engineering and Technology , Tianshui Normal University , Tianshui , Gansu 741001 , China
| | - Xiaofeng Wang
- School of Chemical Engineering and Technology , Tianshui Normal University , Tianshui , Gansu 741001 , China
| | - Yuancheng Zhu
- School of Chemical Engineering and Technology , Tianshui Normal University , Tianshui , Gansu 741001 , China
| | - Zhifeng Li
- School of Chemical Engineering and Technology , Tianshui Normal University , Tianshui , Gansu 741001 , China
| |
Collapse
|
20
|
Tian Q, Xie S. Spin Injection and Transport in Organic Materials. MICROMACHINES 2019; 10:mi10090596. [PMID: 31510018 PMCID: PMC6780273 DOI: 10.3390/mi10090596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/04/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
This review introduces some important spin phenomena of organic molecules and solids and their devices: Organic spin injection and transport, organic spin valves, organic magnetic field effects, organic excited ferromagnetism, organic spin currents, etc. We summarize the experimental and theoretical progress of organic spintronics in recent years and give prospects.
Collapse
Affiliation(s)
- Qipeng Tian
- School of Physics, Shandong University, Jinan 250100, China.
| | - Shijie Xie
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
| |
Collapse
|
21
|
Xu Y, Liang X, Liang Y, Guo X, Hanif M, Zhou J, Zhou X, Wang C, Yao J, Zhao R, Hu D, Qiao X, Ma D, Ma Y. Efficient Deep-Blue Fluorescent OLEDs with a High Exciton Utilization Efficiency from a Fully Twisted Phenanthroimidazole-Anthracene Emitter. ACS APPLIED MATERIALS & INTERFACES 2019; 11:31139-31146. [PMID: 31368304 DOI: 10.1021/acsami.9b10823] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A novel, efficient, deep-blue fluorescent emitter mPAC, with a meta-connected donor-acceptor structure containing phenanthroimidazole (PPI) as the donor and phenylcarbazole-substituted anthracene (An-CzP) as the acceptor, was designed and synthesized. The meta-linkage provided a highly twisted molecular conformation, which efficiently interrupts the intramolecular π-conjugation, resulting in a deep-blue emission. The optimized nondoped device based on mPAC displayed a deep-blue emission with a narrow full width at half-maximum of 56 nm and Commission Internationale de L'Eclairage coordinates of (0.16, 0.09). The maximum external quantum efficiency (EQEmax) is 6.76%, corresponding to a high exciton utilization efficiency (EUE) of 59.3-88.9%. Experimental results and theoretical analysis indicated that the high EUE is mainly ascribed to the reverse intersystem crossing (RISC) from T2 to S1, a "hot exciton" path in which the large T2-T1 energy gap (1.45 eV) and small T2-S1 energy difference (0.18 eV, T2 > S1) hamper the internal crossing from T2 to T1 and facilitate the RISC process. For the hot exciton path, the T2 state can be feasibly arranged to a high energy level, forming a thermal equilibrium with S1, even slightly higher than the deep-blue S1 to realize an exergonic RISC process, which is usually difficult for the thermally activated delayed fluorescence emitters.
Collapse
Affiliation(s)
- Yuwei Xu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Xiaoming Liang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Yiqian Liang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Xiaomin Guo
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Muddasir Hanif
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Jiadong Zhou
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Xuehong Zhou
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Cong Wang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Jingwen Yao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Ruiyang Zhao
- College of Chemical Engineering , Qingdao University of Science and Technology , Qingdao 266042 , P. R. China
| | - Dehua Hu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Xianfeng Qiao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , P. R. China
| | - Dongge Ma
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , 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 510640 , P. R. China
| |
Collapse
|
22
|
Lu Q, Ma X, Gao T, Xie S, Qu F. Strongly enhanced luminous efficiency of organic light emitting diodes in molecular heterojunctions. Phys Chem Chem Phys 2019; 21:12924-12930. [PMID: 31165113 DOI: 10.1039/c9cp02000d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a comprehensive theory based on the extended Su-Schrieffer-Heeger (SSH) model to study the interconversion from the dark triplet exciton state to a bright singlet one in molecular heterojunctions, containing both intrachain and interchain excitons. By studying the spin mixing and the projection of excitons onto the pure singlet and triplet excitons, unlike usual methods, we found that the internal electroluminescent quantum efficiency, which is largely determined by the singlet fraction, can be widely tuned by the spin-orbit coupling strength, the intensity of hyperfine interaction, electron-phonon coupling and the site energy offset of the two chains constituting the molecular heterojunctions. In addition, the interchain excitons possess a higher fraction of singlet states in comparison with the intrachain excitons. Remarkably, it can reach up to 52% by proper choice of the above-mentioned physical parameters. Our results outline a novel approach to further improve the luminous efficiency of organic light emitting diodes.
Collapse
Affiliation(s)
- Qiuxia Lu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
| | | | | | | | | |
Collapse
|
23
|
Konidena RK, Lee KH, Lee JY, Hong WP. Triggering Thermally Activated Delayed Fluorescence by Managing the Heteroatom in Donor Scaffolds: Intriguing Photophysical and Electroluminescence Properties. Chem Asian J 2019; 14:2251-2258. [PMID: 30969458 DOI: 10.1002/asia.201900388] [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: 03/17/2019] [Revised: 04/09/2019] [Indexed: 02/06/2023]
Abstract
Establishment of the structure-property relationships of thermally activated delayed fluorescence (TADF) materials has become a significant quest for the scientific community. Herein, two new donors, 10H-benzofuro[3,2-b]indole (BFI) and 10H-benzo[4,5]thieno[3,2-b]indole (BTI), have been developed and integrated with a aryltriazine acceptor to design the green TADF emitters benzofuro[3,2-b]indol-10-yl)-5-(4,6-diphenyl-1,3,5-triazin-2-yl)benzonitrile (BFICNTrz) and 2-(10H-benzo[4,5]thieno[3,2-b]indol-10-yl)-5-(4,6-diphenyl-1,3,5-triazin-2-yl)benzonitrile (BTICNTrz), respectively. The physicochemical and electroluminescence properties of the compounds were tuned by exchanging the heteroatom in the donor scaffold. Intriguingly, the electronegativity of the heteroatom and the ionization potential of the donor unit played vital roles in control of the singlet-triplet energy splitting and TADF mechanism of the compounds. Both compounds showed similar singlet excited states that originated from the charge transfer (CT) states (1 CT), whereas the triplet excited states were tuned by the heteroatom in the donor unit. The origin of phosphorescence in the BTICNTrz emitter was CT emission from the triplet state (3 CT), whereas that in the BFICNTrz emitter stemmed from the local triplet excited state (3 LE). Consequently, BTICNTrz showed a small singlet-triplet energy splitting of 0.08 eV, compared with 0.26 eV for BFICNTrz. Thus, BTICNTrz showed efficient delayed fluorescence with a high quantum yield and a short delayed exciton lifetime, whereas BFICNTrz displayed weak delayed fluorescence with a relatively long lifetime. Furthermore, a BTICNTrz-based device exhibited a maximum external quantum efficiency (EQE) of 15.2 % and reduced efficiency roll-off (12 %) compared with its BFICNTrz-based counterpart, which showed a maximum EQE of 6.4 % and severe efficiency roll-off (55 %) at a practical brightness range of 1000 cd m-2 . These results demonstrate that the choice of subunit plays a vital role in the design of efficient TADF emitters.
Collapse
Affiliation(s)
- Rajendra Kumar Konidena
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Korea
| | - Kyung Hyung Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Korea
| | - Wan Pyo Hong
- LG Chem, Ltd, LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, 07796, Republic of Korea
| |
Collapse
|
24
|
Liu J, Hu T, Li Z, Wei X, Hu X, Gao H, Liu G, Yi Y, Yamada-Takamura Y, Lee CS, Wang P, Wang Y. Intermolecular Interaction-Induced Thermally Activated Delayed Fluorescence Based on a Thiochromone Derivative. J Phys Chem Lett 2019; 10:1888-1893. [PMID: 30939025 DOI: 10.1021/acs.jpclett.9b00512] [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
Exploration of new extrinsic ways to modulate thermally activated delayed fluorescence (TADF) to achieve high exciton utilization efficiency in organic light-emitting diodes (OLEDs) is highly desirable. A new thiochromone derivative 2,3-bis(4-(9 H-carbazol-9-yl)phenyl)-4 H-thiochromen-4-1,1-dioxide (THI-PhCz) with tunable photophysical properties from crystals to amorphous states is reported. THI-PhCz shows molecular-packing-dependent TADF in different aggregation states based on the differences of intermolecular interactions. Furthermore, it is observed that THI-PhCz doped in amorphous films of different hosts also shows host-dependent TADF with a short delay lifetime (108 ns), which is interpreted as the effect of host-guest intermolecular interaction on the 3CT state except for the effect on the 1CT state in reported references. This work provides a new perspective for generation of TADF by tuning intermolecular interactions in crystals and amorphous films except for molecular design, which is expected to contribute in achieving low-efficiency roll-off OLEDs with effective exciton utilization efficiency.
Collapse
Affiliation(s)
- Jianjun Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Taiping Hu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids , Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
| | - Zhiyi Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xiaofang Wei
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xiaoxiao Hu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Honglei Gao
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Guanhao Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Yuanping Yi
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids , Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
| | - Yukiko Yamada-Takamura
- School of Materials Science , Japan Advanced Institute of Science and Technology , Ishikawa 923-1292 , Japan
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF) , City University of Hong Kong , Hong Kong SAR , People's Republic of China
| | - Pengfei Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Ying Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| |
Collapse
|
25
|
Li Z, Li C, Xu Y, Xie N, Jiao X, Wang Y. Nonsymmetrical Connection of Two Identical Building Blocks: Constructing Donor-Acceptor Molecules as Deep Blue Emitting Materials for Efficient Organic Emitting Diodes. J Phys Chem Lett 2019; 10:842-847. [PMID: 30734562 DOI: 10.1021/acs.jpclett.9b00300] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We propose a strategy to construct deep blue emission molecules based on the concept of nonsymmetrical connection of two identical π-conjugated groups. It was demonstrated that the nonsymmetrical connection strategy indeed resulted in the separation of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and the formation of a donor-acceptor (D-A) structure. For D-A molecules constructed by two identical groups, the degree of charge transfer is weaker and deep blue emission is easily achieved. Two D-A molecules (PIpPI and PImPI) were synthesized by employing diphenyl-phenanthroimidazole (PI) as a building block. The nonsymmetric connection of PI groups endows these molecules with a D-A feature that can result in a bipolar transport property. The nondoped organic light-emitting diodes with PIpPI and PImPI as emitter exhibit deep-blue emission and maximum external quantum efficiencies of 8.84% and 6.83%, respectively.
Collapse
Affiliation(s)
- Zhiqiang Li
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
| | - Chenglong Li
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
| | - Yincai Xu
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
| | - Ning Xie
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
| | - Xuechen Jiao
- Department of Materials Science and Engineering , Monash University , Australian Synchrotron, Clayton 3800 , Victoria , Australia
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
| |
Collapse
|
26
|
Jayabharathi J, Thanikachalam V, Ramya R, Panimozhi S. Strategic tuning of excited-state properties of electroluminescent materials with enhanced hot exciton mixing. RSC Adv 2019; 9:33693-33709. [PMID: 35528924 PMCID: PMC9073535 DOI: 10.1039/c9ra07509g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 10/14/2019] [Indexed: 12/30/2022] Open
Abstract
Deep blue emitters with excellent stability, high quantum yield and multifunctionality are the major issues for full-color displays. In line with this, new multifunctional, thermally stable blue emitters viz., N-(4-(10-(1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1H-phenanthro[9,10-d]imidazol-2-yl)anthracen-9-yl)phenyl)-N-phenylbenzenamine (DPIAPPB) and 2-(10-(9H-carbazol-9-yl)anthracen-9-yl)-1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1H-phenanthro[9,10-d]imidazole (CADPPI) with hybridized local charge transfer state (HLCT) and hot exciton properties have been synthesized. These molecules show high photoluminescence quantum yield (Φs/f): (DPIAPPB – 0.82/0.70 and CADPPI – 0.91/0.83). The CADPPI based device (EL – 467 nm) shows high efficiencies [ηc – 9.85 cd A−1; ηp – 10.84 lm W−1; ηex – 4.78% at 2.8 V; CIE (0.15, 0.10)] compared to the DPIAPPB device (EL − 472 nm) [ηc – 6.56 cd A−1; ηp – 6.16 lm W−1; ηex – 4.15% at 2.8 V with CIE (0.15, 0.12)]. The green device with CADPPI:Ir(ppy)3 exhibits a maximum L – 59 012 cd m−2; ηex – 16.8%; ηc – 37.3 cd A−1; ηp – 39.8 lm W−1 with CIE (0.30, 0.60) and the red device with CADPPI:Ir(MDQ)2(acac) shows a maximum L – 43 456 cd m−2; ηex – 21.9%; ηc – 36.0 cd A−1; ηp – 39.6 lm W−1 with CIE (0.64, 0.35). The CADPPI:Ir(ppy)3 device exhibits L – 90 12 cd m−2; ηex – 18.8%; ηc − 27.3 cd A−1; ηp – 29.8 lm W−1; CIE (0.30, 0.60).![]()
Collapse
|
27
|
Bian M, Chen Z, Qu B, Xiao L. Highly Efficient Organic Blue Electroluminescent Materials and Devices with Mesoscopic Structures. CHEM REC 2018; 19:1562-1570. [DOI: 10.1002/tcr.201800140] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 09/28/2018] [Indexed: 01/18/2023]
Affiliation(s)
- Mengying Bian
- State Key Laboratory for Mesoscopic Physics and Department of PhysicsPeking University Beijing 100871 P. R. China
| | - Zhijian Chen
- State Key Laboratory for Mesoscopic Physics and Department of PhysicsPeking University Beijing 100871 P. R. China
| | - Bo Qu
- State Key Laboratory for Mesoscopic Physics and Department of PhysicsPeking University Beijing 100871 P. R. China
| | - Lixin Xiao
- State Key Laboratory for Mesoscopic Physics and Department of PhysicsPeking University Beijing 100871 P. R. China
| |
Collapse
|
28
|
Chen XK, Kim D, Brédas JL. Thermally Activated Delayed Fluorescence (TADF) Path toward Efficient Electroluminescence in Purely Organic Materials: Molecular Level Insight. Acc Chem Res 2018; 51:2215-2224. [PMID: 30141908 DOI: 10.1021/acs.accounts.8b00174] [Citation(s) in RCA: 215] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Since the seminal work of Tang and Vanslyke in 1987 on small-molecule emitters and that of Friend and co-workers in 1990 on conjugated-polymer emitters, organic light-emitting diodes (OLEDs) have attracted much attention from academia as well as industry, as the OLED market is estimated to reach the $30 billion mark by the end of 2018. In these first-generation organic emitters, on the basis of simple spin statistics, electrical excitation resulted in the formation of ∼25% singlet excitons and ∼75% triplet excitons. Radiative decay of the singlet excitons to the singlet ground state leads to a prompt fluorescence emission, while the triplet excitons only lead to weak phosphorescence due to the very small spin-orbit couplings present in purely organic molecules. The consequence is a ca. 75% energy loss, which triggered wide-ranging efforts to try and harvest as many of the triplet excitons as possible. In 1998, Thompson, Forrest, and their co-workers reported second-generation OLED emitters based on coordination complexes with heavy transition metals (e.g., iridium or platinum). Here, the triplet excitons stimulate efficient and fast phosphorescence due to the strong spin-orbit couplings enabled by the heavy-metal atoms. Internal quantum efficiencies (IQE) up to 100% have been reported, which means that for every electron injected into the device, a photon is emitted. While these second-generation emitters are those mainly exploited in current OLED applications, there is strong impetus from both cost and environmental standpoints to find new ways of exploiting purely organic emitters, which in addition can offer greater flexibility to fine-tune the electronic and optical properties by exploiting the synthetic organic chemistry toolbox. In 2012, Adachi and co-workers introduced a promising strategy, based on thermally activated delayed fluorescence (TADF), to harvest the triplet excitons in purely organic molecular materials. These materials now represent the third generation of OLED emitters. Impressive photophysical properties and device performances have been reported, with internal quantum efficiencies also reaching nearly 100%. Our objectives in this Account are threefold: (i) to lay out a comprehensive description, at the molecular level, of the fundamental photophysical processes behind TADF emitters; (ii) to discuss some of the challenges facing the design of TADF emitters, such as the need to balance the efficiency of thermal activation of triplet excitons into the singlet manifold with the efficiency of radiative transition to the ground state; and (iii) to highlight briefly some of the recent molecular-design strategies that pave the way to new classes of TADF materials.
Collapse
Affiliation(s)
- Xian-Kai Chen
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Dongwook Kim
- Department of Chemistry, Kyonggi University, 154-42 Gwanggyosan-Ro, Yeongtong-Gu, Suwon 16227, Korea
| | - Jean-Luc Brédas
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| |
Collapse
|
29
|
Chen J, Wang K, Zheng C, Zhang M, Shi Y, Tao S, Lin H, Liu W, Tao W, Ou X, Zhang X. Red Organic Light-Emitting Diode with External Quantum Efficiency beyond 20% Based on a Novel Thermally Activated Delayed Fluorescence Emitter. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1800436. [PMID: 30250791 PMCID: PMC6145404 DOI: 10.1002/advs.201800436] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/17/2018] [Indexed: 04/14/2023]
Abstract
A novel thermally activated delayed fluorescence (TADF) emitter 12,15-di(10H-phenoxazin-10-yl)dibenzo[a,c]dipyrido[3,2-h:2',3'-j]phenazine (DPXZ-BPPZ) is developed for a highly efficient red organic light-emitting diode (OLED). With rigid and planar constituent groups and evident steric hindrance between electron-donor (D) and electron-acceptor (A) segments, DPXZ-BPPZ realizes extremely high rigidity to suppress the internal conversion process. Meanwhile, the highly twisted structure between D and A segments will also lead to an extremely small singlet-triplet energy split to DPXZ-BPPZ. Therefore, DPXZ-BPPZ successfully realizes an efficient fluorescent radiation transition and reverse intersystem crossing process, and possesses an extremely high photoluminescence quantum efficiency of 97.1 ± 1.1% under oxygen-free conditions. The OLED based on DPXZ-BPPZ shows red emission with a peak at 612 nm and a Commission Internationale de L'Eclairage (CIE) coordinate of (0.60, 0.40), and it achieves high maximum forward-viewing efficiencies of 20.1 ± 0.2% (external quantum efficiency), 30.2 ± 0.6 cd A-1 (current efficiency), and 30.9 ± 1.3 lm W-1 (power efficiency). The prepared OLED has the best performance among the reported red TADF OLEDs. These results prove that DPXZ-BPPZ is an ideal candidate for red TADF emitters, and the designing approach is valuable for highly efficient red TADF emitters.
Collapse
Affiliation(s)
- Jia‐Xiong Chen
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow UniversitySuzhouJiangsu215123P. R. China
| | - Kai Wang
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow UniversitySuzhouJiangsu215123P. R. China
| | - Cai‐Jun Zheng
- School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of China (UESTC)ChengduSichuan610054P. R. China
| | - Ming Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow UniversitySuzhouJiangsu215123P. R. China
- School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of China (UESTC)ChengduSichuan610054P. R. China
| | - Yi‐Zhong Shi
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow UniversitySuzhouJiangsu215123P. R. China
| | - Si‐Lu Tao
- School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of China (UESTC)ChengduSichuan610054P. R. China
| | - Hui Lin
- School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of China (UESTC)ChengduSichuan610054P. R. China
| | - Wei Liu
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow UniversitySuzhouJiangsu215123P. R. China
| | - Wen‐Wen Tao
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow UniversitySuzhouJiangsu215123P. R. China
| | - Xue‐Mei Ou
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow UniversitySuzhouJiangsu215123P. R. China
| | - Xiao‐Hong Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon‐Based Functional Materials & DevicesSoochow UniversitySuzhouJiangsu215123P. R. China
| |
Collapse
|
30
|
Gan S, Hu S, Li XL, Zeng J, Zhang D, Huang T, Luo W, Zhao Z, Duan L, Su SJ, Tang BZ. Heavy Atom Effect of Bromine Significantly Enhances Exciton Utilization of Delayed Fluorescence Luminogens. ACS APPLIED MATERIALS & INTERFACES 2018; 10:17327-17334. [PMID: 29722959 DOI: 10.1021/acsami.8b05389] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Raising triplet exciton utilization of pure organic luminescent materials is of significant importance for efficiency advancement of organic light-emitting diodes (OLEDs). Herein, by introducing bromine atom(s) onto a typical molecule (bis(carbazol-9-yl)-4,5-dicyanobenzene) with thermally activated delayed fluorescence, we demonstrate that the heavy atom effect of bromine can increase spin-orbit coupling and promote the reverse intersystem crossing, which endow the molecules with more distinct delayed fluorescence. In consequence, the triplet exciton utilization is improved greatly with the increase of bromine atoms, affording apparently advanced external quantum efficiencies of OLEDs. Utilizing the enhancement effect of bromine atoms on delayed fluorescence should be a simple and promising design concept for efficient organic luminogens with high exciton utilization.
Collapse
Affiliation(s)
- Shifeng Gan
- State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Shimin Hu
- State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Xiang-Long Li
- State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Jiajie Zeng
- State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Dongdong Zhang
- 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
| | - Wenwen Luo
- State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular, Engineering of Ministry of Education, Department of Chemistry , Tsinghua University , Beijing 100084 , China
| | - Shi-Jian Su
- State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
| | - Ben Zhong Tang
- State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , China
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction , The Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong , China
| |
Collapse
|
31
|
Peng S, Zhao Y, Fu C, Pu X, Zhou L, Huang Y, Lu Z. Acquiring High-Performance Deep-Blue OLED Emitters through an Unexpected Blueshift Color-Tuning Effect Induced by Electron-Donating -OMe Substituents. Chemistry 2018; 24:8056-8060. [PMID: 29655182 DOI: 10.1002/chem.201800974] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/05/2018] [Indexed: 11/11/2022]
Abstract
A series of blue-emissive 7-(diphenylamino)-4-phenoxycoumarin derivatives bearing -CF3 , -OMe, or -N(Me)2 substituents on the phenoxy subunit were synthesized. Although both the -CF3 and -N(Me)2 modifications were found to trigger redshifted fluorescence, the -OMe substitution was demonstrated to exert an unexpected blueshift color-tuning effect toward the deep-blue region. The reason is that the moderate electron-donating -OMe group can endow coumarins with unaltered HOMO but elevated LUMO energy levels. Moreover, the -OMe substitution was found to be beneficial to the thermal stability of these coumarins. Therefore, the trimethoxy-substituted objective compound can act as a high-performance deep-blue organic light-emitting diode (OLED) emitter, and OLED based on it emits deep-blue light with CIE coordinates of (0.148, 0.084), maximum luminance of 7800 cd m-2 , and maximum external quantum efficiency of 5.1 %. These results not only shed light on the molecular design strategy for high-performance deep-blue OLED emitters through color-tuning, but also show the perspective of coumarin derivatives as deep-blue OLED emitters.
Collapse
Affiliation(s)
- Song Peng
- Key Laboratory of Green Chemistry and Technology (Ministry of, Education), College of Chemistry, Sichuan University, Chengdu, 610064, P.R. China
| | - Yihuan Zhao
- Key Laboratory of Green Chemistry and Technology (Ministry of, Education), College of Chemistry, Sichuan University, Chengdu, 610064, P.R. China
| | - Caixia Fu
- Key Laboratory of Green Chemistry and Technology (Ministry of, Education), College of Chemistry, Sichuan University, Chengdu, 610064, P.R. China
| | - Xuemei Pu
- Key Laboratory of Green Chemistry and Technology (Ministry of, Education), College of Chemistry, Sichuan University, Chengdu, 610064, P.R. China
| | - Liang Zhou
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P.R. China
| | - Yan Huang
- Key Laboratory of Green Chemistry and Technology (Ministry of, Education), College of Chemistry, Sichuan University, Chengdu, 610064, P.R. China
| | - Zhiyun Lu
- Key Laboratory of Green Chemistry and Technology (Ministry of, Education), College of Chemistry, Sichuan University, Chengdu, 610064, P.R. China
| |
Collapse
|
32
|
Ye R, Cui Q, Yao C, Liu R, Li L. Tunable fluorescence behaviors of a supramolecular system based on a fluorene derivative and cucurbit[8]uril and its application for ATP sensing. Phys Chem Chem Phys 2018; 19:31306-31315. [PMID: 29148551 DOI: 10.1039/c7cp06434a] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this work, we developed a supramolecular fluorescent system based on host-guest interactions between a fluorene derivative carrying two bispyridinium units (FPy) and cucurbit[8]uril (CB[8]). In aqueous solution, the system showed outstanding tunable emission properties. After being encapsulated into the rigid hydrophobic cavity of the CB[8] host, the fluorescence emission of fluorene had an obvious red-shift with enhanced quantum yield. Interestingly, the emission behavior of the FPy/CB[8] complex showed a two-step self-assembly process when the molar ratio of FPy to CB[8] changed from 1 : 1 to 1 : 2. Besides, the influence of several factors on the emission properties of the FPy/CB[8] complex was also investigated, like pH value, salt concentration, and temperature. Finally, the fluorescent FPy/CB[8] complexes displayed a good performance for detection of adenosine-5'-triphosphate (ATP), which can cause aggregation-induced quenching of the complexes via electrostatic attraction.
Collapse
Affiliation(s)
- Rongqin Ye
- State Key Lab for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
| | | | | | | | | |
Collapse
|
33
|
Liu Y, Hao Z, Jiang H, Liu Y, Wang Y, Tan H, Xie G. High-efficiency blue OLEDs based on dendritic dinuclear iridium (III) complexes grafted with fluorene core and blue fluorescence chromospheres. Tetrahedron 2018. [DOI: 10.1016/j.tet.2017.12.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
34
|
Cabero Zabalaga M, Wei J, Yang H, Fan BB, Sun Y, Zhao W. Unraveling the Characteristic Shape for Magnetic Field Effects in Polymer-Fullerene Solar Cells. ACS OMEGA 2017; 2:7777-7783. [PMID: 31457335 PMCID: PMC6645333 DOI: 10.1021/acsomega.7b01470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 10/31/2017] [Indexed: 06/10/2023]
Abstract
Spin-dependent effects in organic solar cells (OSCs) are responsible for tuning the electric current when an external magnetic field is applied. Here, we report the magnetic field effect (MFE) on wide-bandgap (WBG) solar cells based on the polymers PBDT(O)-T1 and PBDT(Se)-T1 blended with PC70BM. Furthermore, we propose an experimental method based on the electrical transport (i-V) measurements to unveil the negative magneto conductance (MC) at small bias. The observed curves in a double-logarithmic scale display a particular S-like shape, independent of the OSC power conversion efficiency (PCE) or MC amplitudes. Additionally, from the slope of the S-like shape curve, it is possible to identify the fullerene concentrations that would result in the minimum MC and the maximum PCE. Our work opens up a door to find more patterns to describe MFE and PCE in polymer-fullerene solar cells, without the application of external magnetic or luminous sources.
Collapse
Affiliation(s)
- Marco
Antonio Cabero Zabalaga
- Fert Beijing Institute, BDBC, School of Electronic and Information
Engineering, and Heeger Beijing
Research and Development Center, School of Chemistry and Environment, Beihang University, Beijing 100191, China
| | - Jiaqi Wei
- Fert Beijing Institute, BDBC, School of Electronic and Information
Engineering, and Heeger Beijing
Research and Development Center, School of Chemistry and Environment, Beihang University, Beijing 100191, China
| | - Huaiwen Yang
- Fert Beijing Institute, BDBC, School of Electronic and Information
Engineering, and Heeger Beijing
Research and Development Center, School of Chemistry and Environment, Beihang University, Beijing 100191, China
| | - Bing Bing Fan
- Fert Beijing Institute, BDBC, School of Electronic and Information
Engineering, and Heeger Beijing
Research and Development Center, School of Chemistry and Environment, Beihang University, Beijing 100191, China
| | - Yanming Sun
- Fert Beijing Institute, BDBC, School of Electronic and Information
Engineering, and Heeger Beijing
Research and Development Center, School of Chemistry and Environment, Beihang University, Beijing 100191, China
| | - Weisheng Zhao
- Fert Beijing Institute, BDBC, School of Electronic and Information
Engineering, and Heeger Beijing
Research and Development Center, School of Chemistry and Environment, Beihang University, Beijing 100191, China
| |
Collapse
|
35
|
Wang T, Wu Z, Sun W, Jin S, Zhang X, Zhou C, Jiang J, Luo Y, Zhang G. Macroscopic Wires from Fluorophore-Quencher Dyads with Long-Lived Blue Emission. J Phys Chem A 2017; 121:7183-7190. [DOI: 10.1021/acs.jpca.7b08268] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Shengye Jin
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | | | - Chuanyao Zhou
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | | | | | | |
Collapse
|
36
|
Xu L, Hu R, Tang BZ. Room Temperature Multicomponent Polymerizations of Alkynes, Sulfonyl Azides, and Iminophosphorane toward Heteroatom-Rich Multifunctional Poly(phosphorus amidine)s. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01096] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Liguo Xu
- State
Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Rongrong Hu
- State
Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Ben Zhong Tang
- State
Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration and Reconstruction, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong
| |
Collapse
|
37
|
Chen WC, Yuan Y, Xiong Y, Rogach AL, Tong QX, Lee CS. Aromatically C6- and C9-Substituted Phenanthro[9,10-d]imidazole Blue Fluorophores: Structure-Property Relationship and Electroluminescent Application. ACS APPLIED MATERIALS & INTERFACES 2017; 9:26268-26278. [PMID: 28692277 DOI: 10.1021/acsami.7b06547] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this study, a series of aromatically substituted phenanthro[9,10-d]imidazole (PI) fluorophores at C6 and C9 (no. 6 and 9 carbon atoms) have been synthesized and systematically characterized by theoretical, thermal, photophysical, electrochemical, and electroluminescent (EL) studies. C6 and C9 modifications have positive influences on the thermal properties of the new materials. Theoretical calculations suggest that the C6 and the C9 positions of PI are electronically different. Theoretical and experimental evidences of intramolecular charge transfer (ICT) between two identical moieties attaching to the C6 and the C9 positions are observed. Photophysical properties of the fluorophores are greatly influenced by size and conjugation extent of the substituents as well as linking steric hindrance. It is found that the C6 and C9 positions afford moderate conjugated extension compared to the C2 modification. Moreover, ICT characteristics of the new fluorophores increase as the size of the substituted aromatic group, and are partially influenced by steric hindrance, with the anthracene and the pyrene derivatives having the strongest ICT excited properties. EL performances of the fluorophores were evaluated as host emitters or dopants in organic light-emitting devices (OLEDs). Most of the devices showed significantly improved efficiencies compared to the OLED using the nonmodified emitter. Among all the devices, a 5 wt % TPI-Py doped device exhibited excellent performances with an external quantum efficiency >5% at 1000 cd/m2 and a deep-blue color index of (0.155, 0.065), which are comparable to the most advanced deep-blue devices. Our study can give useful information for designing C6/C9-modificated PI fluorophores and provide an efficient approach for constructing high-performance deep-blue OLEDs.
Collapse
Affiliation(s)
- Wen-Cheng Chen
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, Guangdong P.R. China
| | - Yi Yuan
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University , 243 University Road, Shantou, Guangdong 515063, P.R. China
| | | | | | - Qing-Xiao Tong
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University , 243 University Road, Shantou, Guangdong 515063, P.R. China
| | - Chun-Sing Lee
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, Guangdong P.R. China
| |
Collapse
|
38
|
Deng J, Jia W, Chen Y, Liu D, Hu Y, Xiong Z. Guest concentration, bias current, and temperature-dependent sign inversion of magneto-electroluminescence in thermally activated delayed fluorescence devices. Sci Rep 2017; 7:44396. [PMID: 28295056 PMCID: PMC5353579 DOI: 10.1038/srep44396] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/07/2017] [Indexed: 11/18/2022] Open
Abstract
Non-emissive triplet excited states in devices that undergo thermally activated delayed fluorescence (TADF) can be up-converted to singlet excited states via reverse intersystem crossing (RISC), which leads to an enhanced electroluminescence efficiency. Exciton-based fluorescence devices always exhibit a positive magneto-electroluminescence (MEL) because intersystem crossing (ISC) can be suppressed effectively by an external magnetic field. Conversely, TADF devices should exhibit a negative MEL because RISC is suppressed by the external magnetic field. Intriguingly, we observed a positive MEL in TADF devices. Moreover, the sign of the MEL was either positive or negative, and depended on experimental conditions, including doping concentration, current density and temperature. The MEL observed from our TADF devices demonstrated that ISC in the host material and RISC in the guest material coexisted. These competing processes were affected by the experimental conditions, which led to the sign change of the MEL. This work gives important insight into the energy transfer processes and the evolution of excited states in TADF devices.
Collapse
Affiliation(s)
- Junquan Deng
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing, 400715, P. R. China
| | - Weiyao Jia
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing, 400715, P. R. China
| | - Yingbing Chen
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing, 400715, P. R. China
| | - Dongyu Liu
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing, 400715, P. R. China
| | - Yeqian Hu
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing, 400715, P. R. China
| | - Zuhong Xiong
- School of Physical Science and Technology, MOE Key Laboratory on Luminescence and Real-Time Analysis, Southwest University, Chongqing, 400715, P. R. China
| |
Collapse
|
39
|
Samanta PK, Kim D, Coropceanu V, Brédas JL. Up-Conversion Intersystem Crossing Rates in Organic Emitters for Thermally Activated Delayed Fluorescence: Impact of the Nature of Singlet vs Triplet Excited States. J Am Chem Soc 2017; 139:4042-4051. [DOI: 10.1021/jacs.6b12124] [Citation(s) in RCA: 474] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Pralok K. Samanta
- Laboratory
for Computational and Theoretical Chemistry of Advanced Materials,
Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Dongwook Kim
- Laboratory
for Computational and Theoretical Chemistry of Advanced Materials,
Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
- Department
of Chemistry, Kyonggi University, 154-42 Gwanggyosan-Ro, Yeongtong-Gu, Suwon 440-760, Korea
| | - Veaceslav Coropceanu
- School
of Chemistry and Biochemistry, Center for Organic Photonics and Electronics
(COPE), Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Jean-Luc Brédas
- Laboratory
for Computational and Theoretical Chemistry of Advanced Materials,
Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| |
Collapse
|
40
|
Chen WC, Yuan Y, Ni SF, Tong QX, Wong FL, Lee CS. Achieving efficient violet-blue electroluminescence with CIE y <0.06 and EQE >6% from naphthyl-linked phenanthroimidazole-carbazole hybrid fluorophores. Chem Sci 2017; 8:3599-3608. [PMID: 30155205 PMCID: PMC6094158 DOI: 10.1039/c6sc05619a] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/18/2017] [Indexed: 12/22/2022] Open
Abstract
Naphthyl-linked donor–π–acceptor fluorophores were utilized to achieve high performance and good color purity violet-blue emission in organic light-emitting devices (OLEDs).
In this work, we revealed a new approach for the development of efficient violet-blue emitting materials featuring a hybrid local and charge transfer (HLCT) excited state through the incorporation of naphthyl group(s) as a weak n-type π spacer in a donor–π–acceptor (D–π–A) system. The resulting materials (TPINCz and TPIBNCz) show improved intramolecular charge transfer properties and highly efficient violet-blue fluorescence. It is demonstrated that the pattern of the π spacers has significant influence on the photophysical properties. The incorporation of a naphthyl/binaphthyl spacer between the donor and acceptor moieties can alleviate the common dilemma that enhancing device performance by increasing the charge transfer excited properties often leads to red-shifted emissions. A device using TPINCz as an emissive dopant shows a violet-blue emission with CIE coordinates of (0.153, 0.059) and a record high EQE of 6.56 ± 0.11% at a brightness of 1000 cd m–2. To the best of our knowledge, this performance is the highest among the reported devices with CIEy ≤0.08. Our study provides a new pathway for the design of high-performance violet-blue emitters with a D–π–A architecture in organic electroluminescence applications.
Collapse
Affiliation(s)
- Wen-Cheng Chen
- Center of Super-Diamond and Advanced Films (COSDAF) , Department of Chemistry , City University of Hong Kong , Hong Kong SAR , PR China .
| | - Yi Yuan
- Center of Super-Diamond and Advanced Films (COSDAF) , Department of Chemistry , City University of Hong Kong , Hong Kong SAR , PR China . .,Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province , Shantou University , 243 University Road , Shantou , Guangdong 515063 , PR China .
| | - Shao-Fei Ni
- Department of Chemistry , Southern University of Science and Technology , Shenzhen , 518055 , PR China
| | - Qing-Xiao Tong
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province , Shantou University , 243 University Road , Shantou , Guangdong 515063 , PR China .
| | - Fu-Lung Wong
- Center of Super-Diamond and Advanced Films (COSDAF) , Department of Chemistry , City University of Hong Kong , Hong Kong SAR , PR China .
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF) , Department of Chemistry , City University of Hong Kong , Hong Kong SAR , PR China .
| |
Collapse
|
41
|
Zhang D, Zhao C, Zhang Y, Song X, Wei P, Cai M, Duan L. Highly Efficient Full-Color Thermally Activated Delayed Fluorescent Organic Light-Emitting Diodes: Extremely Low Efficiency Roll-Off Utilizing a Host with Small Singlet-Triplet Splitting. ACS APPLIED MATERIALS & INTERFACES 2017; 9:4769-4777. [PMID: 28094502 DOI: 10.1021/acsami.6b15272] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Numerous efforts have been devoted to boost the efficiency of thermally activated delayed fluorescence (TADF) devices; however, strategies to suppress the device efficiency roll-off are still in urgent need. Here, a general and effective approach to suppress the efficiency roll-off of TADF devices is proposed, that is, utilizing TADF materials as the hosts for TADF emitters. Bearing small singlet-triplet splitting (ΔEST) with donor and acceptor units, TADF materials as the hosts possess the potential to achieve matched frontier energy levels with the adjacent transporting layers, facilitating balanced charge injection as well as bipolar charge transport mobilities beneficial to the balanced charges transportation. Furthermore, an enhanced Förster energy transfer from the host to the dopant can be anticipated, helpful to reduce the exciton concentration. Based on the principles, a new TADF material based on indeno[2,1-b]carbazole/1,3,5-triazin derivation is synthesized and used as the universal host for the full-color TADF devices. Remarkable low efficiency roll-off was achieved with above 90% of the maximum external quantum efficiencies (EQEmax's) maintained even at a brightness of 2000 cd/m2, along with EQEmax's of 23.2, 21.0, and 19.2% for orange, green, and sky-blue TADF devices, respectively. Through computational simulation, we identified the suppressed exciton annihilation rates compared with devices adopting conventional hosts. The state-of-the-art low efficiency roll-off of those TADF devices manifests the great potential of such host design strategy, paving an efficient strategy toward their practical application.
Collapse
Affiliation(s)
- Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Chongguang Zhao
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Yunge 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
| | - Pengcheng Wei
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Minghan Cai
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| |
Collapse
|
42
|
Cui LS, Nomura H, Geng Y, Kim JU, Nakanotani H, Adachi C. Controlling Singlet-Triplet Energy Splitting for Deep-Blue Thermally Activated Delayed Fluorescence Emitters. Angew Chem Int Ed Engl 2016; 56:1571-1575. [PMID: 28035781 DOI: 10.1002/anie.201609459] [Citation(s) in RCA: 191] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/28/2016] [Indexed: 11/08/2022]
Abstract
The development of efficient metal-free organic emitters with thermally activated delayed fluorescence (TADF) properties for deep-blue emission is still challenging. A new family of deep-blue TADF emitters based on a donor-acceptor architecture has been developed. The electronic interaction between donor and acceptor plays a key role in the TADF mechanism. Deep-blue OLEDs fabricated with these TADF emitters achieved high external quantum efficiencies over 19.2 % with CIE coordinates of (0.148, 0.098).
Collapse
Affiliation(s)
- Lin-Song Cui
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Hiroko Nomura
- Kyulux Inc., Suite 227, Fukuoka Industry-Academia Symphonicity (FiaS), Bldg.2, 4-1 Kyudai-Shinmachi, Nishi-ku, Fukuoka, 819-0388, Japan
| | - Yan Geng
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Jong Uk Kim
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Hajime Nakanotani
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Chihaya Adachi
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.,Japan Science and Technology Agency, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.,International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| |
Collapse
|
43
|
Cui LS, Nomura H, Geng Y, Kim JU, Nakanotani H, Adachi C. Controlling Singlet-Triplet Energy Splitting for Deep-Blue Thermally Activated Delayed Fluorescence Emitters. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201609459] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Lin-Song Cui
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Hiroko Nomura
- Kyulux Inc.; Suite 227, Fukuoka Industry-Academia Symphonicity (FiaS), Bldg.2; 4-1 Kyudai-Shinmachi, Nishi-ku Fukuoka 819-0388 Japan
| | - Yan Geng
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Jong Uk Kim
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Hajime Nakanotani
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Chihaya Adachi
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
- Japan Science and Technology Agency, ERATO; Adachi Molecular Exciton Engineering Project; 744 Motooka, Nishi Fukuoka 819-0395 Japan
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| |
Collapse
|
44
|
Obolda A, Ai X, Zhang M, Li F. Up to 100% Formation Ratio of Doublet Exciton in Deep-Red Organic Light-Emitting Diodes Based on Neutral π-Radical. ACS APPLIED MATERIALS & INTERFACES 2016; 8:35472-35478. [PMID: 27933759 DOI: 10.1021/acsami.6b12338] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In a neutral π-radical-based organic light-emitting diode (OLED), although the emission comes from the doublet excitons and their transition to the ground state is spin-allowed, the upper limit of internal quantum efficiency (IQE) is not clear, 50% or 100%? In this work, the deep-red OLEDs based on a neutral π-radical were fabricated. Up to 100% doublet exciton formation ratio was obtained through rational designing device structure and host-guest doping system. This indicates the IQE of neutral π-radical-based OLEDs will reach 100% if the nonradiative pathways of radicals can be suppressed. The maximum external quantum efficiency of the optimized device is as high as 4.3%, which is among the highest values of deep-red/near-infrared OLEDs with nonphosphorescent materials as emitters. Our results also indicate that using partially reduced radical mixture as emitter may be a way to solve aggregation-caused quenching in radical-based OLEDs.
Collapse
Affiliation(s)
- Ablikim Obolda
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Qianjin Avenue 2699, Changchun 130012, P.R. China
| | - Xin Ai
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Qianjin Avenue 2699, Changchun 130012, P.R. China
| | - Ming Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Qianjin Avenue 2699, Changchun 130012, P.R. China
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Qianjin Avenue 2699, Changchun 130012, P.R. China
| |
Collapse
|
45
|
Ban X, Lin B, Jiang W, Sun Y. Constructing a Novel Dendron for a Self-Host Blue Emitter with Thermally Activated Delayed Fluorescence: Solution-Processed Nondoped Organic Light-Emitting Diodes with Bipolar Charge Transfer and Stable Color Purity. Chem Asian J 2016; 12:216-223. [DOI: 10.1002/asia.201601384] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 11/10/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Xinxin Ban
- School of Chemical Engineering; Huaihai Institute of Technology; Cang Wu Road 59 China) Lianyungang 222005
| | - Baoping Lin
- School of Chemistry and Chemical Engineering; Southeast University; Si Pai Lou 2 China) Nanjing 211189
| | - Wei Jiang
- School of Chemistry and Chemical Engineering; Southeast University; Si Pai Lou 2 China) Nanjing 211189
| | - Yueming Sun
- School of Chemistry and Chemical Engineering; Southeast University; Si Pai Lou 2 China) Nanjing 211189
| |
Collapse
|
46
|
Evolution of emission manners of organic light-emitting diodes: From emission of singlet exciton to emission of doublet exciton. CHINESE CHEM LETT 2016. [DOI: 10.1016/j.cclet.2016.06.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
47
|
Shuai Z, Peng Q. Organic light-emitting diodes: theoretical understanding of highly efficient materials and development of computational methodology. Natl Sci Rev 2016. [DOI: 10.1093/nsr/nww024] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Theoretical understanding of organic light-emitting diodes started from the quest to the nature of the primary excitation in organic molecular and polymeric materials. We found the electron correlation strength, bond-length alternation as well as the conjugation extent have strong influences on the orderings of the lowest lying excited states through the first application of density matrix renormalization group theory to quantum chemistry. The electro-injected free carriers (with spin 1/2) can form both singlet and triplet bound states. We found that the singlet exciton formation ratio can exceed the conventional 25% spin statistics limit. We proposed a vibration correlation function formalism to evaluate the excited-state decay rates, which is shown to not only give reasonable estimations for the quantum efficiency but also a quantitative account for the aggregation-induced emission (AIE). It is suggested to unravel the AIE mechanism through resonance Raman spectroscopy.
Collapse
Affiliation(s)
- Zhigang Shuai
- MOE Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
- CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Qian Peng
- CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| |
Collapse
|