1
|
Bai Z, Wang J, Zou P, Jiang R, Yang D, Ma D, Tang BZ, Zhao Z. Creating Efficient Red Thermally Activated Delayed Fluorescence Materials with Cyano-Substituted 11,12-Diphenyldipyrido[3,2-a:2',3'-c]phenazine Acceptors. Chemistry 2024; 30:e202303990. [PMID: 38060300 DOI: 10.1002/chem.202303990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 12/07/2023] [Accepted: 12/07/2023] [Indexed: 12/08/2023]
Abstract
Red luminescent materials are essential components for full color display and white lightening based on organic light-emitting diode (OLED) technology, but the extension of emission color towards red or deep red region generally leads to decreased photoluminescence and electroluminescence efficiencies. Herein, we wish to report two new luminescent molecules (2CNDPBPPr-TPA and 4CNDPBPPr-TPA) consisting of cyano-substituted 11,12-diphenyldipyrido[3,2-a:2',3'-c]phenazine acceptors and triphenylamine donors. As the increase of cyano substituents, the emission wavelength is greatly red-shifted and the reverse intersystem crossing process is promoted, resulting in strong red delayed fluorescence. Meanwhile, due to the formation of intramolecular hydrogen bonds, the molecular structures become rigidified and planarized, which brings about large horizontal dipole ratios. As a result, 2CNDPBPPr-TPA and 4CNDPBPPr-TPA can perform as emitters efficiently in OLEDs, furnishing excellent external quantum efficiencies of 28.8 % at 616 nm and 20.2 % at 648 nm, which are significantly improved in comparison with that of the control molecule without cyano substituents. The findings in this work demonstrate that the introduction of cyano substituents to the acceptors of delayed fluorescence molecules could be a facile and effective approach to explore high-efficiency red or deep red delayed fluorescence materials.
Collapse
Affiliation(s)
- Zhentao Bai
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Jianghui Wang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Peng Zou
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Ruming Jiang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Dezhi Yang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Ben Zhong Tang
- School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| |
Collapse
|
2
|
Seenithurai S, Chai JD. Electronic Properties of Graphene Nano-Parallelograms: A Thermally Assisted Occupation DFT Computational Study. Molecules 2024; 29:349. [PMID: 38257262 PMCID: PMC11154290 DOI: 10.3390/molecules29020349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
In this computational study, we investigate the electronic properties of zigzag graphene nano-parallelograms (GNPs), which are parallelogram-shaped graphene nanoribbons of various widths and lengths, using thermally assisted occupation density functional theory (TAO-DFT). Our calculations revealed a monotonic decrease in the singlet-triplet energy gap as the GNP length increased. The GNPs possessed singlet ground states for all the cases examined. With the increase of GNP length, the vertical ionization potential and fundamental gap decreased monotonically, while the vertical electron affinity increased monotonically. Some of the GNPs studied were found to possess fundamental gaps in the range of 1-3 eV, lying in the ideal region relevant to solar energy applications. Besides, as the GNP length increased, the symmetrized von Neumann entropy increased monotonically, denoting an increase in the degree of the multi-reference character associated with the ground state GNPs. The occupation numbers and real-space representation of active orbitals indicated that there was a transition from the nonradical nature of the shorter GNPs to the increasing polyradical nature of the longer GNPs. In addition, the edge/corner localization of the active orbitals was found for the wider and longer GNPs.
Collapse
Affiliation(s)
- Sonai Seenithurai
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan;
| | - Jeng-Da Chai
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan;
- Center for Theoretical Physics and Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
| |
Collapse
|
3
|
Li X, Tu L, Gao M, Li A, Chen Y, Chi W, Zhang D, Duan L, Xie Y, Tang BZ, Li Z. Highly Efficient Blue Organic Light Emitting Diodes Based on Cyclohexane-Fused Quinoxaline Acceptor. J Phys Chem Lett 2023; 14:6982-6989. [PMID: 37523259 DOI: 10.1021/acs.jpclett.3c01629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Exploring blue organic light emitting diodes (OLED) is an important but challenging issue. Herein, to achieve blue-shifted emission, cyclohexane is fused to quinoxaline to weaken the electron-withdrawing ability and conjugation degree of the acceptor. As a result, blue to cyan fluorescent emitters of Me-DPA-TTPZ, tBu-DPA-TTPZ, and TPA-TTPZ were designed and synthesized with donors of diphenylamine and triphenylamine, which exhibit high photoluminescence quantum yields and good thermal stability. In OLEDs with emitters of TPA-TTPZ, the sensitized and nonsensitized devices demonstrate deep-blue (449 nm) and blue (468 nm) emission with maximum external quantum efficiency and CIE coordinates of 6.1%, (0.15, 0.10) and 5.1%, (0.17, 0.22), respectively, validating their potential as blue emitters in OLEDs.
Collapse
Affiliation(s)
- Xiaoning Li
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Liangjing Tu
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Mingxue Gao
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Aisen Li
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City, Fuzhou 350207, China
| | - Yi Chen
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Weijie Chi
- Department of Chemistry, School of Science, Hainan University, Haikou 570228, China
| | - Dongdong Zhang
- 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
| | - Yujun Xie
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Ben Zhong Tang
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
- School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen 518172, China
| | - Zhen Li
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University Binhai New City, Fuzhou 350207, China
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China
| |
Collapse
|
4
|
Wang X, Wang S, Wang J, Yin S. Reverse Designing the Wavelength-Specific Thermally Activation Delayed Fluorescent Molecules Using a Genetic Algorithm Coupled with Cheap QM Methods. J Phys Chem A 2023. [PMID: 37418642 DOI: 10.1021/acs.jpca.3c01714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2023]
Abstract
Genetic algorithm (GA) optimization coupled with the semiempirical intermediate neglect of differential overlap (INDO)/CIS method is presented to inversely design the red thermally activation delayed fluorescent (TADF) molecules. According to the predefined donor-acceptor (DA) library to build an ADn-type TADF candidate, we utilized the chemical notation language SMILES code to generate a TADF molecule and apply the RDKit program to produce the initial 3D molecular structure. A combined fitness function is proposed to evaluate the performance of the functional-lead TADF molecule. The fitness function includes three key parameters, i.e., the emission wavelength, the energy gap (ΔEST) between the lowest singlet (S1)- and triplet (T1)-excited states, and the oscillator strengths for electron transition from S0 and S1. A cheap QM method, i.e., INDO/CIS, on the basis of an xTB-optimized molecular geometry is applied to quickly calculate the fitness function. Finally, the GA approach is utilized to globally search for the wavelength-specific TADF molecules under our predefined DA library, and the optimum 630 nm red and 660 nm deep red TADF molecules are inversely designed according to the evolution of molecular fitness functions.
Collapse
Affiliation(s)
- Xubin Wang
- School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xian 710119, China
| | - Shiqi Wang
- School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xian 710119, China
| | - Jingwen Wang
- School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xian 710119, China
| | - Shiwei Yin
- School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xian 710119, China
| |
Collapse
|
5
|
Kothavale S, Kim SC, Cheong K, Zeng S, Wang Y, Lee JY. Solution-Processed Pure Red TADF Organic Light-Emitting Diodes With High External Quantum Efficiency and Saturated Red Emission Color. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208602. [PMID: 36653735 DOI: 10.1002/adma.202208602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/29/2022] [Indexed: 06/17/2023]
Abstract
In spite of recent research progress in red thermally activated delayed fluorescence (TADF) emitters, highly efficient solution-processable pure red TADF emitters are rarely reported. Most of the red TADF emitters reported to date are designed using a rigid acceptor unit which renders them insoluble and unsuitable for solution-processed organic light-emitting diodes (OLEDs). To resolve this issue, a novel TADF emitter, 6,7-bis(4-(bis(4-(tert-butyl)phenyl)amino)phenyl)-2,3-bis(4-(tert-butyl)phenyl)quinoxaline-5,8-dicarbonitrile (tBuTPA-CNQx) is designed and synthesized. The highly twisted donor-acceptor architecture and appropriate highest occupied molecular orbital/lowest unoccupied molecular orbital distribution lead to a very small singlet-triplet energy gap of 0.07 eV, high photoluminescence quantum yield of 92%, and short delayed fluorescence lifetime of 52.4 µs. The peripheral t-butyl phenyl decorated quinoxaline acceptor unit and t-butyl protected triphenylamine donor unit are proven to be useful building blocks to improve solubility and minimize the intermolecular interaction. The solution-processed OLED based on tBuTPA-CNQx achieves a high external quantum efficiency (EQE) of 16.7% with a pure red emission peak at 662 nm, which is one of the highest EQE values reported till date in the solution-processed pure red TADF OLEDs. Additionally, vacuum-processable OLED based on tBuTPA-CNQx exhibits a high EQE of 22.2% and negligible efficiency roll-off.
Collapse
Affiliation(s)
- Shantaram Kothavale
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| | - Seung Chan Kim
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| | - Kiun Cheong
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| | - Songkun Zeng
- School of Materials Science & Engineering, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou, 213164, P. R. China
| | - Yafei Wang
- School of Materials Science & Engineering, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou, 213164, P. R. China
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
- SKKU Institute of Energy Science and Technology, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| |
Collapse
|
6
|
Zhao C, Ding Z, Zhang Y, Ni Z, Li S, Gong S, Zou B, Wang K, Yu L. Thermally activated delayed fluorescence with dual-emission and pressure-induced bidirectional shifting: cooperative effects of intramolecular and intermolecular energy transfer. Chem Sci 2023; 14:1089-1096. [PMID: 36756321 PMCID: PMC9891365 DOI: 10.1039/d2sc05792a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022] Open
Abstract
Different from the conventional piezochromic materials with a mono-redshift of single emission, our well-designed molecule demonstrates a sensitive turn-on and color-tunable piezochromic luminescence in response to the hydrostatic pressure. The molecule PXZ-W-SOF possesses dual-emission and pressure-induced bidirectional shifting characteristics. On the basis of in-depth experimental studies, on one hand, it is confirmed that the origin of the dual-emission behavior is the intramolecular charge transfer, namely thermally activated delayed fluorescence (TADF), and the intermolecular excimer; on the other hand, the emission of the excimer exhibits three-step variations with increasing pressure, which is mainly attributed to the molecular structure and its crystal packing state. The remarkable color change of PXZ-W-SOF from sky-blue to green to deep-blue during the whole process of boosting and releasing pressure is a result of intramolecular and intermolecular energy-transfer interactions. The PXZ-W-SOF molecular model is an extremely rare example of highly sensitive fluorescence tuning driven by TADF and excimer conversion under mechanical stimulation, thus providing a novel mechanism for the field of piezochromism. The unique molecular design also offers a new idea for rare deep-blue and ultraviolet TADF materials.
Collapse
Affiliation(s)
- Chenyue Zhao
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University Hangzhou 311121 People's Republic of China
| | - Zhipeng Ding
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University Hangzhou 311121 People's Republic of China
| | - Yibin Zhang
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University Hangzhou 311121 People's Republic of China
| | - Zhigang Ni
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University Hangzhou 311121 People's Republic of China
| | - Shijun Li
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University Hangzhou 311121 People's Republic of China
| | - Shaolong Gong
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University Wuhan 430072 People's Republic of China
| | - Bo Zou
- State Key Laboratory of Superhard Materials, Jilin University Qianjin Street 2699 Changchun 130012 People's Republic of China
| | - Kai Wang
- State Key Laboratory of Superhard Materials, Jilin University Qianjin Street 2699 Changchun 130012 People's Republic of China
| | - Ling Yu
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University Hangzhou 311121 People's Republic of China
| |
Collapse
|
7
|
Zhu Y, Qu C, Ye J, Xu Y, Zhang Z, Wang Y. Donor-Acceptor Type of Fused-Ring Thermally Activated Delayed Fluorescence Compounds Constructed through an Oxygen-Containing Six-Membered Ring. ACS APPLIED MATERIALS & INTERFACES 2022; 14:47971-47980. [PMID: 36219720 DOI: 10.1021/acsami.2c12778] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Nowadays, thermally activated delayed fluorescence (TADF) compounds with a fused-ring core skeleton are getting increasing research interest because of their use in high-performance organic light-emitting diodes (OLEDs). In this study, TADF compounds featuring a D-A-type fused-ring core skeleton are developed. The challenging compatibility of a planarized D-A arrangement and the TADF property is achieved through linking the D and A moieties with two oxygen atoms within a six-membered ring. Compared with a single-oxygen analogue possessing a flexible skeleton and a twisted D-A arrangement, these fused-ring compounds with higher skeleton rigidity show higher photoluminescence quantum yields and narrower emission spectra in toluene and in doped thin films. Their electroluminescent devices achieve high external quantum efficiencies (up to 19.4%), suggesting the potential of rarely achieved D-A-type fused-ring TADF systems to serve as high-performance emitters of OLEDs.
Collapse
Affiliation(s)
- Yunlong Zhu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Cheng Qu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Jianjiang Ye
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Yincai Xu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Zuolun Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| |
Collapse
|
8
|
Yang H, Zhang M, Zhao J, Pu C, Lin H, Tao S, Zheng C, Zhang X. Improving Efficiency of Red Thermally Activated Delayed Fluorescence Emitter by Introducing
Quasi‐Degenerate
Orbital Distribution. CHINESE J CHEM 2022. [DOI: 10.1002/cjoc.202100776] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Hao‐Yu Yang
- School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu Sichuan 610054 China
| | - Ming Zhang
- School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu Sichuan 610054 China
- Institute of Functional Nano & Soft Materials (FUNSOM) Soochow University Suzhou Jiangsu 215123 China
| | - Jue‐Wen Zhao
- School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu Sichuan 610054 China
| | - Chun‐Peng Pu
- School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu Sichuan 610054 China
| | - Hui Lin
- School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu Sichuan 610054 China
| | - Si‐Lu Tao
- School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu Sichuan 610054 China
| | - Cai‐Jun Zheng
- School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu Sichuan 610054 China
| | - Xiao‐Hong Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM) Soochow University Suzhou Jiangsu 215123 China
| |
Collapse
|
9
|
Li C, Harrison AK, Liu Y, Zhao Z, Zeng C, Dias FB, Ren Z, Yan S, Bryce MR. Asymmetrical‐Dendronized TADF Emitters for Efficient Non‐doped Solution‐Processed OLEDs by Eliminating Degenerate Excited States and Creating Solely Thermal Equilibrium Routes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202115140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Chensen Li
- State Key Laboratory of Chemical Resource Engineering College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China
- Chemistry Department Durham University South Road Durham DH1 3LE UK
| | | | - Yuchao Liu
- Key Laboratory of Rubber-Plastics Ministry of Education Qingdao University of Science & Technology Qingdao 266042 P.R. China
| | - Zhennan Zhao
- State Key Laboratory of Chemical Resource Engineering College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China
| | - Cheng Zeng
- Key Laboratory of Rubber-Plastics Ministry of Education Qingdao University of Science & Technology Qingdao 266042 P.R. China
| | - Fernando B. Dias
- Physics Department Durham University South Road Durham DH1 3LE UK
| | - Zhongjie Ren
- State Key Laboratory of Chemical Resource Engineering College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China
| | - Shouke Yan
- State Key Laboratory of Chemical Resource Engineering College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China
- Key Laboratory of Rubber-Plastics Ministry of Education Qingdao University of Science & Technology Qingdao 266042 P.R. China
| | - Martin R. Bryce
- Chemistry Department Durham University South Road Durham DH1 3LE UK
| |
Collapse
|
10
|
Bryce MR, Li C, Harrison AK, Liu Y, Zhao Z, Zeng C, Dias FB, Ren Z, Yan S. Asymmetrical-Dendronized TADF Emitters for Efficient Non-doped Solution-Processed OLEDs by Eliminating Degenerate Excited States and Creating Solely Thermal Equilibrium Routes. Angew Chem Int Ed Engl 2021; 61:e202115140. [PMID: 34870886 PMCID: PMC9306820 DOI: 10.1002/anie.202115140] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Indexed: 12/03/2022]
Abstract
The mechanism of thermally activated delayed fluorescence (TADF) in dendrimers is not clear. We report that fully‐conjugated or fully‐nonconjugated structures cause unwanted degenerate excited states due to multiple identical dendrons, which limit their TADF efficiency. We have synthesized asymmetrical “half‐dendronized” and “half‐dendronized‐half‐encapsulated” emitters. By eliminating degenerate excited states, the triplet locally excited state is ≥0.3 eV above the lowest triplet charge‐transfer state, assuring a solely thermal equilibrium route for an effective spin‐flip process. The isolated encapsulating tricarbazole unit can protect the TADF unit, reducing nonradiative decay and enhancing TADF performance. Non‐doped solution‐processed devices reach a high external quantum efficiency (EQEmax) of 24.0 % (65.9 cd A−1, 59.2 lm W−1) with CIE coordinates of (0.24, 0.45) with a low efficiency roll‐off and EQEs of 23.6 % and 21.3 % at 100 and 500 cd m−2.
Collapse
Affiliation(s)
- Martin Robert Bryce
- University of Durham, Department of Chemistry, South Road, DH1 3LE, Durham, UNITED KINGDOM
| | - Chensen Li
- Beijing University of Chemical Technology, State Key Laboratory of Chemical Resource Engineering, CHINA
| | | | - Yuchao Liu
- Qingdao University of Science and Technology, Key Laboratory of Rubber Plastics, CHINA
| | - Zhennan Zhao
- Beijing University of Chemical Technology, State Key Laboratory of Chemical Resource Engineering, CHINA
| | - Cheng Zeng
- Qingdao University, Key laboratory of Rubber Plastics, CHINA
| | | | - Zhongjie Ren
- Beijing University of Chemical Technology, State Key Laboratory of Chemical Resource Engineering, CHINA
| | - Shouke Yan
- Beijing University of Chemical Technology, State Key Laboratory of Chemical Resource Engineering, CHINA
| |
Collapse
|
11
|
Seenithurai S, Chai JD. Electronic Properties of Carbon Nanobelts Predicted by Thermally-Assisted-Occupation DFT. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2224. [PMID: 34578540 PMCID: PMC8465987 DOI: 10.3390/nano11092224] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 11/16/2022]
Abstract
Accurate prediction of properties of large-scale multi-reference (MR) electronic systems remains difficult for traditional computational methods (e.g., the Hartree-Fock theory and Kohn-Sham density functional theory (DFT)). Recently, thermally-assisted-occupation (TAO)-DFT has been demonstrated to offer reliable description of electronic properties of various large-scale MR electronic systems. Consequently, in this work, TAO-DFT is used to unlock the electronic properties associated with C-Belt[n] (i.e., the carbon nanobelts containing n fused 12-membered carbon rings). Our calculations show that for all the system sizes reported (n = 4-24), C-Belt[n] have singlet ground states. In general, the larger the size of C-Belt[n], the more pronounced the MR character of ground-state C-Belt[n], as evident from the symmetrized von Neumann entropy and the occupation numbers of active TAO-orbitals. Furthermore, the active TAO-orbitals are delocalized along the circumference of C-Belt[n], as evident from the visualization of active TAO-orbitals.
Collapse
Affiliation(s)
- Sonai Seenithurai
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan;
| | - Jeng-Da Chai
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan;
- Center for Theoretical Physics and Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
| |
Collapse
|
12
|
Yang Y, Xiao R, Cao X, Chen Z, Lv X, Zhang Y, Gong S, Zou Y, Yang C. Phenoxazine-Dibenzothiophene Sulfoximine Emitters Featuring Both Thermally Activated Delayed Fluorescence and Aggregation Induced Emission. Molecules 2021; 26:5243. [PMID: 34500677 PMCID: PMC8434553 DOI: 10.3390/molecules26175243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 08/17/2021] [Accepted: 08/24/2021] [Indexed: 11/16/2022] Open
Abstract
In this work, we demonstrate dibenzothiophene sulfoximine derivatives as building blocks for constructing emitters featuring both thermally activated delayed fluorescent (TADF) and aggregation-induced emission (AIE) properties, with multiple advantages including high chemical and thermal stability, facile functionalization, as well as tunable electron-accepting ability. A series of phenoxazine-dibenzothiophene sulfoximine structured TADF emitters were successfully synthesized and their photophysical and electroluminescent properties were evaluated. The electroluminescence devices based on these emitters displayed diverse emissions from yellow to orange and reached external quantum efficiencies (EQEs) of 5.8% with 16.7% efficiency roll-off at a high brightness of 1000 cd·m-2.
Collapse
Affiliation(s)
- Yiyu Yang
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China; (Y.Y.); (R.X.); (X.L.); (Y.Z.); (C.Y.)
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Ran Xiao
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China; (Y.Y.); (R.X.); (X.L.); (Y.Z.); (C.Y.)
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Xiaosong Cao
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China; (Y.Y.); (R.X.); (X.L.); (Y.Z.); (C.Y.)
| | - Zhanxiang Chen
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China; (Z.C.); (S.G.)
| | - Xialei Lv
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China; (Y.Y.); (R.X.); (X.L.); (Y.Z.); (C.Y.)
| | - Youming Zhang
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China; (Y.Y.); (R.X.); (X.L.); (Y.Z.); (C.Y.)
| | - Shaolong Gong
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China; (Z.C.); (S.G.)
| | - Yang Zou
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China; (Y.Y.); (R.X.); (X.L.); (Y.Z.); (C.Y.)
| | - Chuluo Yang
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China; (Y.Y.); (R.X.); (X.L.); (Y.Z.); (C.Y.)
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China; (Z.C.); (S.G.)
| |
Collapse
|
13
|
Balijapalli U, Lee Y, Karunathilaka BSB, Tumen‐Ulzii G, Auffray M, Tsuchiya Y, Nakanotani H, Adachi C. Tetrabenzo[
a
,
c
]phenazine Backbone for Highly Efficient Orange–Red Thermally Activated Delayed Fluorescence with Completely Horizontal Molecular Orientation. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Umamahesh Balijapalli
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Yi‐Ting Lee
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Buddhika S. B. Karunathilaka
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Ganbaatar Tumen‐Ulzii
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Morgan Auffray
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Youichi Tsuchiya
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry Kyushu University 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Hajime Nakanotani
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry Kyushu University 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
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry Kyushu University 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
|
14
|
Balijapalli U, Lee YT, Karunathilaka BSB, Tumen-Ulzii G, Auffray M, Tsuchiya Y, Nakanotani H, Adachi C. Tetrabenzo[a,c]phenazine Backbone for Highly Efficient Orange-Red Thermally Activated Delayed Fluorescence with Completely Horizontal Molecular Orientation. Angew Chem Int Ed Engl 2021; 60:19364-19373. [PMID: 34155775 DOI: 10.1002/anie.202106570] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Indexed: 11/09/2022]
Abstract
Three thermally activated delayed fluorescence (TADF) molecules, namely PQ1, PQ2, and PQ3, are composed of electron-accepting (A) tetrabenzo[a,c]phenazine (TBPZ) and electron-donating (D) phenoxazine (PXZ) units are designed and characterized. The combined effects of planar acceptor manipulation and high steric hindrance between D and A units endow high molecular rigidity that suppresses nonradiative decay of the excitons with improved photoluminescence quantum yields (PLQYs). Particularly, the well-aligned excited states involving a singlet and a triplet charge-transfer excited states and a localized excited triplet state in PQ3 enhances the reverse intersystem crossing rate constant (kRISC ) with a short delay lifetime (τd ). The orange-red OLED based on PQ3 displays a maximum external EL quantum efficiency (EQE) of 27.4 % with a well-suppressed EL efficiency roll-off owing to a completely horizontal orientation of the transition dipole moment in the film state.
Collapse
Affiliation(s)
- Umamahesh Balijapalli
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Yi-Ting Lee
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Buddhika S B Karunathilaka
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Ganbaatar Tumen-Ulzii
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Morgan Auffray
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Youichi Tsuchiya
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Hajime Nakanotani
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry, Kyushu University, 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
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry, Kyushu University, 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
|
15
|
Karthik D, Jung YH, Lee H, Hwang S, Seo BM, Kim JY, Han CW, Kwon JH. Acceptor-Donor-Acceptor-Type Orange-Red Thermally Activated Delayed Fluorescence Materials Realizing External Quantum Efficiency Over 30% with Low Efficiency Roll-Off. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2007724. [PMID: 33792077 DOI: 10.1002/adma.202007724] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/05/2021] [Indexed: 06/12/2023]
Abstract
Two new orange-red thermally activated delayed fluorescence (TADF) materials, PzTDBA and PzDBA, are reported. These materials are designed based on the acceptor-donor-acceptor (A-D-A) configuration, containing rigid boron acceptors and dihydrophenazine donor moieties. These materials exhibit a small ΔEST of 0.05-0.06 eV, photoluminescence quantum yield (PLQY) as high as near unity, and short delayed exciton lifetime (τd ) of less than 2.63 µs in 5 wt% doped film. Further, these materials show a high reverse intersystem crossing rate (krisc ) on the order of 106 s-1 . The TADF devices fabricated with 5 wt% PzTDBA and PzDBA as emitting dopants show maximum EQE of 30.3% and 21.8% with extremely low roll-off of 3.6% and 3.2% at 1000 cd m-2 and electroluminescence (EL) maxima at 576 nm and 595 nm, respectively. The low roll-off character of these materials is analyzed by using a roll-off model and the exciton annihilation quenching rates are found to be suppressed by the fast krisc and short delayed exciton lifetime. These devices show operating device lifetimes (LT50 ) of 159 and 193 h at 1000 cd m-2 for PzTDBA and PzDBA, respectively. The high efficiency and low roll-off of these materials are attributed to the good electronic properties originatng from the A-D-A molecular configuration.
Collapse
Affiliation(s)
- Durai Karthik
- Organic Optoelectronic Device Lab. (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Young Hun Jung
- Organic Optoelectronic Device Lab. (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Hyuna Lee
- Organic Optoelectronic Device Lab. (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Soonjae Hwang
- Organic Optoelectronic Device Lab. (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Bo-Min Seo
- LG Display R & D center, LG Science park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, 07796, Republic of Korea
| | - Jun-Yun Kim
- LG Display R & D center, LG Science park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, 07796, Republic of Korea
| | - Chang Wook Han
- LG Display R & D center, LG Science park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, 07796, Republic of Korea
| | - Jang Hyuk Kwon
- Organic Optoelectronic Device Lab. (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| |
Collapse
|
16
|
Stavrou K, Franca LG, Monkman AP. Photophysics of TADF Guest-Host Systems: Introducing the Idea of Hosting Potential. ACS APPLIED ELECTRONIC MATERIALS 2020; 2:2868-2881. [PMID: 32984822 PMCID: PMC7513578 DOI: 10.1021/acsaelm.0c00514] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/11/2020] [Indexed: 05/29/2023]
Abstract
The thermally activated delayed fluorescence (TADF) donor-acceptor (D-A) molecule, DMAC-TRZ, is used as a TADF emitter "probe" to distinguish the environmental effects of a range of solid-state host materials in guest-host systems. Using the guest's photophysical behavior in solution as a benchmark, a comprehensive study using a variety of typical TADF organic light-emitting diode hosts with different characteristics provides a clearer understanding of guest-host interactions and what affects emitter performance in solid state. We investigate which are the key host characteristics that directly affect charge-transfer (CT) state energy and singlet triplet energy gaps. Using time-resolved photoluminescence measurements, we use the CT state energy distribution obtained from the full width at half-maximum (fwhm) of the emission band and correlate this with other photophysical properties such as the apparent dynamic red shift of CT emission on-set to estimate the disorder-induced heterogeneity of D-A dihedral angles and singlet triplet gaps. Further, the delayed emission stabilization energy value and time-dependent CT band fwhm are shown to be related to a combination of host's rigidity, emitter molecule packing, and the energy difference between guest and host lowest energy triplet states. Concentration dependence studies show that emitter dimerization/aggregation can improve as well as reduce emission efficiency depending on the characteristics of the host. Two similar host materials, mCPCN and mCBPCN, with optimum host characteristics show completely different behaviors, and their hosting potential is extensively explored. We demonstrate that type I and type III TADF emitters behave differently in the same host and that the materials with intrinsic small ΔE ST have the smallest disorder-induced CT energy and reverse intersystem crossing rate dispersion. We also present an optimized method to define the actual triplet energy of a guest-host system, a crucial parameter in understanding the overall mechanism of the TADF efficiency of the system.
Collapse
|
17
|
Liu D, Wei JY, Tian WW, Jiang W, Sun YM, Zhao Z, Tang BZ. Endowing TADF luminophors with AIE properties through adjusting flexible dendrons for highly efficient solution-processed nondoped OLEDs. Chem Sci 2020; 11:7194-7203. [PMID: 33033608 PMCID: PMC7499814 DOI: 10.1039/d0sc02194f] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/15/2020] [Indexed: 12/20/2022] Open
Abstract
The amalgamation of thermally activated delayed fluorescence (TADF) and aggregation-induced emission (AIE) properties, termed AIE-TADF, is a promising strategy to design novel robust luminescent materials. Herein, we transform 2,3,4,5,6-penta(9H-carbazol-9-yl)benzonitrile (5CzBN) from an ACQ molecule into an AIEgen by simply decorating the 5CzBN core with alkyl chain-linked spirobifluorene dendrons. By increasing the number of flexible dendrons, these materials can not only show obvious AIE-TADF characteristics and uniform film morphology, but can also exhibit better resistance to isopropyl alcohol, which are beneficial to fully solution-processed OLEDs. Notably, 5CzBN-PSP shows great device efficiency with an external quantum efficiency (EQE), current efficiency and power efficiency of 20.1%, 58.7 cd A-1 and 46.2 lm W-1, respectively and achieved record-breaking efficiency in solution-processed nondoped OLEDs based on AIE emitters. This work demonstrates a general approach to explore new efficient emitters by the marriage of AIE and TADF which could potentially improve their performance in various areas.
Collapse
Affiliation(s)
- Dan Liu
- Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research , Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device , School of Chemistry and Chemical Engineering , Southeast University , Nanjing , 211189 , China .
| | - Jing Yi Wei
- Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research , Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device , School of Chemistry and Chemical Engineering , Southeast University , Nanjing , 211189 , China .
| | - Wen Wen Tian
- Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research , Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device , School of Chemistry and Chemical Engineering , Southeast University , Nanjing , 211189 , China .
| | - Wei Jiang
- Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research , Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device , School of Chemistry and Chemical Engineering , Southeast University , Nanjing , 211189 , China .
| | - Yue Ming Sun
- Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research , Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device , School of Chemistry and Chemical Engineering , Southeast University , Nanjing , 211189 , China .
| | - Zheng Zhao
- 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 999077 , China .
| | - Ben Zhong Tang
- 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 999077 , China .
| |
Collapse
|
18
|
Liu Y, Chen Y, Li H, Wang S, Wu X, Tong H, Wang L. High-Performance Solution-Processed Red Thermally Activated Delayed Fluorescence OLEDs Employing Aggregation-Induced Emission-Active Triazatruxene-Based Emitters. ACS APPLIED MATERIALS & INTERFACES 2020; 12:30652-30658. [PMID: 32538076 DOI: 10.1021/acsami.0c07906] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two novel red thermally activated delayed fluorescence (TADF) emitters [triazatruxene (TAT)-dibenzo[a,c]phenazine (DBPZ) and TAT-fluorine-substituted dibenzo[a,c]phenazine (FDBPZ)] were developed by incorporating TAT as the electron donor (D) and DBPZ or FDBPZ as the electron acceptor (A). Both compounds showed aggregation-induced emission behaviors and bright red emission in neat films. Benefited from the rigid and large planar conjugated structure of TAT and DBPZ, TAT-DBPZ and TAT-FDBPZ realized high photoluminescence quantum yields in solid states. Meanwhile, the large steric hindrance between TAT and DBPZ segments produced small singlet-triplet energy splitting (ΔEST), leading to short delayed fluorescence lifetimes and high reverse intersystem crossing (RISC) rate (>106 s-1) for both compounds. The solution-processable doped organic light-emitting diodes (OLEDs) based on TAT-DBPZ achieved a high external quantum efficiency (EQE) of 15.4% with a red emission peak at 604 nm, which was one of the highly efficient solution-processable red TADF OLEDs. TAT-FDBPZ-based doped devices also showed a red emission peak at 611 nm with a maximum EQE of 9.2% and low-efficiency roll-off ratios of 1.0% at 100 cd m-2 and 19% at 1000 cd m-2. Furthermore, their solution-processable nondoped devices displayed EQEs of 5.6 and 2.9% with the red-shifted emission peaks at 626 and 641 nm, respectively. These results indicate the huge potential of utilization of TAT as the donor unit to achieve highly efficient and low-efficiency roll-off solution-processable red TADF OLEDs.
Collapse
Affiliation(s)
- Yang Liu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
| | - Yonghong Chen
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Chinese Academy of Sciences, Beijing 100039, P. R. China
| | - Hua Li
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
| | - Shuai Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
| | - Xiaofu Wu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Hui Tong
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
| | - Lixiang Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
| |
Collapse
|
19
|
TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes. NANOMATERIALS 2020; 10:nano10061236. [PMID: 32630573 PMCID: PMC7353095 DOI: 10.3390/nano10061236] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/12/2020] [Accepted: 06/23/2020] [Indexed: 12/20/2022]
Abstract
At the nanoscale, it has been rather troublesome to properly explore the properties associated with electronic systems exhibiting a radical nature using traditional electronic structure methods. Graphene nanoflakes, which are graphene nanostructures of different shapes and sizes, are typical examples. Recently, TAO-DFT (i.e., thermally-assisted-occupation density functional theory) has been formulated to tackle such challenging problems. As a result, we adopt TAO-DFT to explore the electronic properties associated with diamond-shaped graphene nanoflakes with n = 2–15 benzenoid rings fused together at each side, designated as n-pyrenes (as they could be expanded from pyrene). For all the n values considered, n-pyrenes are ground-state singlets. With increasing the size of n-pyrene, the singlet-triplet energy gap, vertical ionization potential, and fundamental gap monotonically decrease, while the vertical electron affinity and symmetrized von Neumann entropy (which is a quantitative measure of radical nature) monotonically increase. When n increases, there is a smooth transition from the nonradical character of the smaller n-pyrenes to the increasing polyradical nature of the larger n-pyrenes. Furthermore, the latter is shown to be related to the increasing concentration of active orbitals on the zigzag edges of the larger n-pyrenes.
Collapse
|
20
|
Kothavale S, Chung WJ, Lee JY. Rational Molecular Design of Highly Efficient Yellow-Red Thermally Activated Delayed Fluorescent Emitters: A Combined Effect of Auxiliary Fluorine and Rigidified Acceptor Unit. ACS APPLIED MATERIALS & INTERFACES 2020; 12:18730-18738. [PMID: 32216325 DOI: 10.1021/acsami.9b22826] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Molecular design strategies are crucial to develop highly efficient and long-wavelength thermally activated delayed fluorescent (TADF) emitters because the inherent limitation of the energy gap law degrades the efficiency of the red or orange TADF emitters. To resolve the low efficiency issue, we designed and synthesized two TADF emitters, 4,4'-(6-(9,9-dimethylacridin-10(9H)-yl)-7-fluoroquinoxaline-2,3-diyl)dibenzonitrile (FDQCNAc) and 11-(9,9-dimethylacridin-10(9H)-yl)-12-fluorodibenzo[a,c]phenazine-3,6-dicarbonitrile (FBPCNAc), by utilizing fluorine and peripheral cyano-substituted quinoxaline and phenazine acceptors of 4,4'-(6-fluoroquinoxaline-2,3-diyl)dibenzonitrile (FDQCN) and 11-fluorodibenzo[a,c]phenazine-3,6-dicarbonitrile (FBPCN), respectively. A fluorine atom at the ortho position of the acridine donor acts as an auxiliary acceptor to minimize the singlet-triplet energy gap (ΔEST) below 0.1 eV and promotes the reverse intersystem crossing (RISC) process. Organic light-emitting diodes (OLEDs) fabricated with FDQCNAc and FBPCNAc emitters demonstrated high external quantum efficiencies (EQEs) of 27.6 and 23.8% in the yellow-red TADF OLEDs, respectively. In particular, the combination of the F auxiliary acceptor unit and the rigidified FBPCN acceptor unit enabled red-shifted emission by about 58 nm without much sacrifice of the EQE in the red region.
Collapse
Affiliation(s)
- Shantaram Kothavale
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea
| | - Won Jae Chung
- 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
| |
Collapse
|
21
|
Moshkina TN, Nosova EV, Kopotilova AE, Lipunova GN, Valova MS, Sadieva LK, Kopchuk DS, Slepukhin PA, Zaleśny R, Ośmiałowski B, Charushin VN. Synthesis and Photophysical Studies of Novel V‐Shaped 2,3‐Bis{5‐aryl‐2‐thienyl}(dibenzo[ f,h])quinoxalines. ASIAN J ORG CHEM 2020. [DOI: 10.1002/ajoc.202000038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Tatyana N. Moshkina
- Department of Organic and Biomolecular ChemistryUral Federal University 19 Mira Str. Yekaterinburg 620002 Russia
| | - Emiliya V. Nosova
- Department of Organic and Biomolecular ChemistryUral Federal University 19 Mira Str. Yekaterinburg 620002 Russia
- Postovsky Institute of Organic Synthesis Ural Division of the Russian Academy of Sciences 22 S. Kovalevskoy Str. Yekaterinburg 620219 Russia
| | - Alexandra E. Kopotilova
- Department of Organic and Biomolecular ChemistryUral Federal University 19 Mira Str. Yekaterinburg 620002 Russia
| | - Galina N. Lipunova
- Department of Organic and Biomolecular ChemistryUral Federal University 19 Mira Str. Yekaterinburg 620002 Russia
- Postovsky Institute of Organic Synthesis Ural Division of the Russian Academy of Sciences 22 S. Kovalevskoy Str. Yekaterinburg 620219 Russia
| | - Marina S. Valova
- Postovsky Institute of Organic Synthesis Ural Division of the Russian Academy of Sciences 22 S. Kovalevskoy Str. Yekaterinburg 620219 Russia
| | - Leila K. Sadieva
- Department of Organic and Biomolecular ChemistryUral Federal University 19 Mira Str. Yekaterinburg 620002 Russia
- Postovsky Institute of Organic Synthesis Ural Division of the Russian Academy of Sciences 22 S. Kovalevskoy Str. Yekaterinburg 620219 Russia
| | - Dmitry S. Kopchuk
- Department of Organic and Biomolecular ChemistryUral Federal University 19 Mira Str. Yekaterinburg 620002 Russia
- Postovsky Institute of Organic Synthesis Ural Division of the Russian Academy of Sciences 22 S. Kovalevskoy Str. Yekaterinburg 620219 Russia
| | - Pavel A. Slepukhin
- Department of Organic and Biomolecular ChemistryUral Federal University 19 Mira Str. Yekaterinburg 620002 Russia
- Postovsky Institute of Organic Synthesis Ural Division of the Russian Academy of Sciences 22 S. Kovalevskoy Str. Yekaterinburg 620219 Russia
| | - Robert Zaleśny
- Department of Physical and Quantum ChemistryWroclaw University of Science and Technology 27 Wyb. Wyspiańskiego Wrocław PL-50370 Poland
| | - Borys Ośmiałowski
- Department of Organic Chemistry, Faculty of ChemistryNicolaus Copernicus University in Torun 7 Gagarin Street Torun 87-100 Poland
| | - Valery N. Charushin
- Department of Organic and Biomolecular ChemistryUral Federal University 19 Mira Str. Yekaterinburg 620002 Russia
- Postovsky Institute of Organic Synthesis Ural Division of the Russian Academy of Sciences 22 S. Kovalevskoy Str. Yekaterinburg 620219 Russia
| |
Collapse
|
22
|
Zheng K, Ni F, Chen Z, Zhong C, Yang C. Polymorph‐Dependent Thermally Activated Delayed Fluorescence Emitters: Understanding TADF from a Perspective of Aggregation State. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201913210] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kailu Zheng
- Renmin Hospital of Wuhan UniversityHubei Key Laboratory on Organic and Polymeric Optoelectronic MaterialsDepartment of ChemistryWuhan University Wuhan 430072 P. R. China
- Shenzhen Key Laboratory of Polymer Science and TechnologyCollege of Materials Science and EngineeringShenzhen University Shenzhen 518060 P. R. China
| | - Fan Ni
- Shenzhen Key Laboratory of Polymer Science and TechnologyCollege of Materials Science and EngineeringShenzhen University Shenzhen 518060 P. R. China
| | - Zhanxiang Chen
- Renmin Hospital of Wuhan UniversityHubei Key Laboratory on Organic and Polymeric Optoelectronic MaterialsDepartment of ChemistryWuhan University Wuhan 430072 P. R. China
| | - Cheng Zhong
- Renmin Hospital of Wuhan UniversityHubei Key Laboratory on Organic and Polymeric Optoelectronic MaterialsDepartment of ChemistryWuhan University Wuhan 430072 P. R. China
| | - Chuluo Yang
- Renmin Hospital of Wuhan UniversityHubei Key Laboratory on Organic and Polymeric Optoelectronic MaterialsDepartment of ChemistryWuhan University Wuhan 430072 P. R. China
- Shenzhen Key Laboratory of Polymer Science and TechnologyCollege of Materials Science and EngineeringShenzhen University Shenzhen 518060 P. R. China
| |
Collapse
|
23
|
Zheng K, Ni F, Chen Z, Zhong C, Yang C. Polymorph‐Dependent Thermally Activated Delayed Fluorescence Emitters: Understanding TADF from a Perspective of Aggregation State. Angew Chem Int Ed Engl 2019; 59:9972-9976. [PMID: 31710142 DOI: 10.1002/anie.201913210] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Indexed: 01/26/2023]
Affiliation(s)
- Kailu Zheng
- Renmin Hospital of Wuhan UniversityHubei Key Laboratory on Organic and Polymeric Optoelectronic MaterialsDepartment of ChemistryWuhan University Wuhan 430072 P. R. China
- Shenzhen Key Laboratory of Polymer Science and TechnologyCollege of Materials Science and EngineeringShenzhen University Shenzhen 518060 P. R. China
| | - Fan Ni
- Shenzhen Key Laboratory of Polymer Science and TechnologyCollege of Materials Science and EngineeringShenzhen University Shenzhen 518060 P. R. China
| | - Zhanxiang Chen
- Renmin Hospital of Wuhan UniversityHubei Key Laboratory on Organic and Polymeric Optoelectronic MaterialsDepartment of ChemistryWuhan University Wuhan 430072 P. R. China
| | - Cheng Zhong
- Renmin Hospital of Wuhan UniversityHubei Key Laboratory on Organic and Polymeric Optoelectronic MaterialsDepartment of ChemistryWuhan University Wuhan 430072 P. R. China
| | - Chuluo Yang
- Renmin Hospital of Wuhan UniversityHubei Key Laboratory on Organic and Polymeric Optoelectronic MaterialsDepartment of ChemistryWuhan University Wuhan 430072 P. R. China
- Shenzhen Key Laboratory of Polymer Science and TechnologyCollege of Materials Science and EngineeringShenzhen University Shenzhen 518060 P. R. China
| |
Collapse
|
24
|
He X, Ren S, Liu H, Zhao S, Liu F, Du C, Min J, Zhang H, Lu P. Efficient Nondoped Pure Blue Organic Light‐Emitting Diodes Based on an Anthracene and 9,9‐Diphenyl‐9,10‐dihydroacridine Derivative. Chem Asian J 2019; 15:163-168. [DOI: 10.1002/asia.201901376] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 10/29/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Xin He
- State Key Laboratory of Supramolecular Structure and MaterialsJilin University Qianjin Avenue Changchun 130012 P. R. China
| | - Shenghong Ren
- State Key Laboratory of Supramolecular Structure and MaterialsJilin University Qianjin Avenue Changchun 130012 P. R. China
| | - Hui Liu
- State Key Laboratory of Supramolecular Structure and MaterialsJilin University Qianjin Avenue Changchun 130012 P. R. China
| | - Shiyuan Zhao
- State Key Laboratory of Metastable Materials Science and TechnologyYanshan University Qinhuangdao 066004 P. R. China
| | - Futong Liu
- State Key Laboratory of Supramolecular Structure and MaterialsJilin University Qianjin Avenue Changchun 130012 P. R. China
| | - Chunya Du
- State Key Laboratory of Supramolecular Structure and MaterialsJilin University Qianjin Avenue Changchun 130012 P. R. China
| | - Jiarui Min
- State Key Laboratory of Metastable Materials Science and TechnologyYanshan University Qinhuangdao 066004 P. R. China
| | - Haiquan Zhang
- State Key Laboratory of Metastable Materials Science and TechnologyYanshan University Qinhuangdao 066004 P. R. China
| | - Ping Lu
- State Key Laboratory of Supramolecular Structure and MaterialsJilin University Qianjin Avenue Changchun 130012 P. R. China
| |
Collapse
|
25
|
Zhou X, Xiang Y, Gong S, Chen Z, Ni F, Xie G, Yang C. Simple construction of deep-red hexaazatrinaphthylene-based thermally activated delayed fluorescence emitters for efficient solution-processed OLEDs with a peak at 692 nm. Chem Commun (Camb) 2019; 55:14190-14193. [PMID: 31701968 DOI: 10.1039/c9cc06804j] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Two solution-processable deep-red thermally activated delayed fluorescence emitters based on a 5,6,11,12,17,18-hexaazatrinaphthylene acceptor core were developed through a simple and catalyst-free nucleophilic substitution reaction. The solution-processed OLEDs using these emitters achieved a peak external quantum efficiency of 4.8% with the emission peak at 692 nm.
Collapse
Affiliation(s)
- Xue Zhou
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China. and Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China.
| | - Yepeng Xiang
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China.
| | - Shaolong Gong
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China.
| | - Zhanxiang Chen
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China.
| | - Fan Ni
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China.
| | - Guohua Xie
- Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China.
| | - Chuluo Yang
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China. and Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China.
| |
Collapse
|
26
|
Zhang YL, Ran Q, Wang Q, Liu Y, Hänisch C, Reineke S, Fan J, Liao LS. High-Efficiency Red Organic Light-Emitting Diodes with External Quantum Efficiency Close to 30% Based on a Novel Thermally Activated Delayed Fluorescence Emitter. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1902368. [PMID: 31490581 DOI: 10.1002/adma.201902368] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 08/20/2019] [Indexed: 06/10/2023]
Abstract
Researchers have spared no effort to design new thermally activated delayed fluorescence (TADF) emitters for high-efficiency organic light-emitting diodes (OLEDs). However, efficient long-wavelength TADF emitters are rarely reported. Herein, a red TADF emitter, TPA-PZCN, is reported, which possesses a high photoluminescence quantum yield (ΦPL ) of 97% and a small singlet-triplet splitting (ΔEST ) of 0.13 eV. Based on the superior properties of TPA-PZCN, red, deep-red, and near-infrared (NIR) OLEDs are fabricated by utilizing different device structure strategies. The red devices obtain a remarkable maximum external quantum efficiency (EQE) of 27.4% and an electroluminescence (EL) peak at 628 nm with Commission Internationale de L'Eclairage (CIE) coordinates of (0.65, 0.35), which represents the best result with a peak wavelength longer than 600 nm among those of the reported red TADF devices. Furthermore, an exciplex-forming cohost strategy is adopted. The devices achieve a record EQE of 28.1% and a deep-red EL peak at 648 nm with the CIE coordinates of (0.66, 0.34). Last, nondoped devices exhibit 5.3% EQE and an NIR EL peak at 680 nm with the CIE coordinates of (0.69, 0.30).
Collapse
Affiliation(s)
- Yuan-Lan Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, 215123, Jiangsu, China
| | - Quan Ran
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, 215123, Jiangsu, China
| | - Qiang Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, 215123, Jiangsu, China
| | - Yuan Liu
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, Hermann-Krone-Bau, Nöthnitzer Str. 61, 01187, Dresden, Germany
| | - Christian Hänisch
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, Hermann-Krone-Bau, Nöthnitzer Str. 61, 01187, Dresden, Germany
| | - Sebastian Reineke
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, Hermann-Krone-Bau, Nöthnitzer Str. 61, 01187, Dresden, Germany
| | - Jian Fan
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, 215123, Jiangsu, China
| | - Liang-Sheng Liao
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, 215123, Jiangsu, China
| |
Collapse
|
27
|
Seenithurai S, Chai JD. Electronic Properties of Linear and Cyclic Boron Nanoribbons from Thermally-Assisted-Occupation Density Functional Theory. Sci Rep 2019; 9:12139. [PMID: 31431672 PMCID: PMC6702209 DOI: 10.1038/s41598-019-48560-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 08/07/2019] [Indexed: 01/08/2023] Open
Abstract
It remains rather difficult for traditional computational methods to reliably predict the properties of nanosystems, especially for those possessing pronounced radical character. Accordingly, in this work, we adopt the recently formulated thermally-assisted-occupation density functional theory (TAO-DFT) to study two-atom-wide linear boron nanoribbons l-BNR[2,n] and two-atom-wide cyclic boron nanoribbons c-BNR[2,n], which exhibit polyradical character when the n value (i.e., the number of boron atoms along the length of l-BNR[2,n] or the circumference of c-BNR[2,n]) is considerably large. We calculate various electronic properties associated with l-BNR[2,n] and c-BNR[2,n], with n ranging from 6 to 100. Our results show that l-BNR[2,n] and c-BNR[2,n] have singlet ground states for all the n values examined. The electronic properties of c-BNR[2,n] exhibit more pronounced oscillatory patterns than those of l-BNR[2,n] when n is small, and converge to the respective properties of l-BNR[2,n] when n is sufficiently large. The larger the n values, the stronger the static correlation effects that originate from the polyradical nature of these ribbons. Besides, the active orbitals are found to be delocalized along the length of l-BNR[2,n] or the circumference of c-BNR[2,n]. The analysis of the size-dependent electronic properties indicates that l-BNR[2,n] and c-BNR[2,n] can be promising for nanoelectronic devices.
Collapse
Affiliation(s)
- Sonai Seenithurai
- Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
| | - Jeng-Da Chai
- Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.
- Center for Theoretical Physics and Center for Quantum Science and Engineering, National Taiwan University, Taipei, 10617, Taiwan.
| |
Collapse
|
28
|
Chen JX, Tao WW, Xiao YF, Wang K, Zhang M, Fan XC, Chen WC, Yu J, Li S, Geng FX, Zhang XH, Lee CS. Efficient Orange-Red Thermally Activated Delayed Fluorescence Emitters Feasible for Both Thermal Evaporation and Solution Process. ACS APPLIED MATERIALS & INTERFACES 2019; 11:29086-29093. [PMID: 31329407 DOI: 10.1021/acsami.9b08729] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Development of red thermally activated delayed fluorescence (TADF) emitters has been lagging behind when compared with those of blue and green fluorophores, especially for solution-processable ones. In this work, two novel orange-red TADF emitters 3,6-di(10H-phenoxazin-10-yl)dibenzo[a,c]phenazine (DBPZ-DPXZ) and 10,10'-(11,12-bis(3,5-di-tert-butylphenyl)dibenzo[a,c]phenazine-3,6-diyl)bis(10H-phenoxazine) (tDBBPZ-DPXZ) are developed. A high-performance orange-red TADF emitter, DBPZ-DPXZ, is first prepared by connecting a rigid acceptor and two rigid donor segments. While this design strategy endows DBPZ-DPXZ with an excellent TADF performance leading to a vacuum-processed organic light-emitting diode (OLED) with a high external quantum efficiency (EQE) of 17.8%, the rigid segments limit its solubility and applications in solution-processed devices. Based on this prototype, tDBBPZ-DPXZ is designed with the addition of 3,5-di-tert-butylphenyl groups to boost its solubility with barely an influence on the photophysical properties. In particular, tDBBPZ-DPXZ maintains nearly an identical photoluminescence quantum yield of 83% and singlet-triplet energy splitting of 0.03 eV with EQE of 17.0% in a vacuum-processed orange-red OLED. Furthermore, it can be applied on the orange-red solution-processed OLED realizing an EQE as high as 10.1%, representing one of the state-of-the-art results of the reported orange-red solution-processed TADF-OLEDs. This work provides an effective strategy to address the conflicting requirements between high efficiency and good solubility and develop efficient soluble orange-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 & Devices , Soochow University , Suzhou , Jiangsu 215123 , P.R. China
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry , City University of Hong Kong , Kowloon , Hong Kong SAR 999077 , P.R. China
- College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , P.R. China
| | - Wen-Wen Tao
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P.R. China
| | - Ya-Fang Xiao
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry , City University of Hong Kong , Kowloon , Hong Kong SAR 999077 , P.R. China
| | - Kai Wang
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P.R. China
| | - Ming Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P.R. China
| | - Xiao-Chun Fan
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P.R. China
| | - Wen-Cheng Chen
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry , City University of Hong Kong , Kowloon , Hong Kong SAR 999077 , P.R. China
| | - Jia Yu
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P.R. China
| | - Shengliang Li
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry , City University of Hong Kong , Kowloon , Hong Kong SAR 999077 , P.R. China
| | - Feng-Xia Geng
- College of Chemistry, Chemical Engineering and Materials Science , Soochow University , Suzhou 215123 , P.R. China
| | - Xiao-Hong Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , P.R. China
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Chemistry , City University of Hong Kong , Kowloon , Hong Kong SAR 999077 , P.R. China
| |
Collapse
|
29
|
Zeng W, Zhou T, Ning W, Zhong C, He J, Gong S, Xie G, Yang C. Realizing 22.5% External Quantum Efficiency for Solution-Processed Thermally Activated Delayed-Fluorescence OLEDs with Red Emission at 622 nm via a Synergistic Strategy of Molecular Engineering and Host Selection. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1901404. [PMID: 31222835 DOI: 10.1002/adma.201901404] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 05/29/2019] [Indexed: 06/09/2023]
Abstract
Developing high-efficiency solution-processable thermally activated delayed-fluorescence (TADF) emitters, especially in longer wavelength regions, is a formidable challenge. Three red TADF emitters, namely NAI_R1, NAI_R2, and NAI_R3, are developed by phenyl encapsulation and tert-butyl substitution on a prototypical 1,8-naphthalimide-acridine hybrid. This design strategy not only grants these molecules high solubility, excellent thermal stability, and good film-forming ability, but also pulls down their charge-transfer (CT) energy levels excited states. Furthermore, dispersing these emitters into two different host materials of mCP and mCPCN finely tailors their CT-state energy levels. More importantly, a synergistic combination of molecular engineering and host selection can effectively manipulate the competition between the radiative and nonradiative decay rates of the CT singlet states of these emitters and the reverse intersystem crossing from their triplet to singlet states. Consequently, the optimal combination of NAI_R3 emitter and mCP host successfully results in a state-of-the-art external quantum efficiency (EQE) of 22.5% for solution-processed red TADF organic light-emitting diodes (OLEDs) with an emission peak above 620 nm. This finding demonstrates that a synergistic strategy of molecular engineering and host selection with TADF emitters could provide a new pathway for developing efficient solution-processable TADF systems.
Collapse
Affiliation(s)
- Weixuan Zeng
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Tao Zhou
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China
| | - Weimin Ning
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China
| | - Cheng Zhong
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China
| | - Jiawei He
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China
| | - Shaolong Gong
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China
| | - Guohua Xie
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China
| | - Chuluo Yang
- Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan, 430072, P. R. China
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| |
Collapse
|
30
|
Huang T, Liu D, Jiang J, Jiang W. Quinoxaline and Pyrido[x,y-b]pyrazine-Based Emitters: Tuning Normal Fluorescence to Thermally Activated Delayed Fluorescence and Emitting Color over the Entire Visible-Light Range. Chemistry 2019; 25:10926-10937. [PMID: 31210382 DOI: 10.1002/chem.201902116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Indexed: 02/02/2023]
Abstract
Quinoxaline (Q), pyrido[2,3-b]pyrazine (PP) and pyrido[3,4-b]pyrazine (iPP) are used as electron acceptors (A) to design a series of D-π-A-type light-emitting materials with different donor (D) groups. By adjusting the molecular torsion angles through changing D from carbazole (Cz) to 10-dimethylacridine (DMAC) or 10H-phenoxazine (PXZ) for a fixed A, the luminescence is tuned from normal fluorescence to thermally activated delayed fluorescence (TADF). By gradually enhancing the intramolecular charge-transfer extent through combining different D and A, the emission color is continuously and regularly tuned from pure blue to orange-red. Organic light-emitting diodes (OLEDs) containing these compounds as doped emitters exhibit bright electroluminescence with emission colors covering the entire visible-light range. An external quantum efficiency (ηext ) of 1.2 % with excellent color coordinates of (0.16, 0.07) is obtained for the pure-blue OLED of Q-Cz. High ηext values of 12.9 (35.9) to 16.7 % (51.9 cd A-1 ) are realized in the green, yellow, and orange-red TADF OLEDs. All PP- and iPP-based TADF emitters exhibit superior efficiency stabilities to that of analogues of Q. This provides a practical strategy to tune the emission color of Q, PP, and iPP derivatives with the same molecular skeletons over the entire visible-light range.
Collapse
Affiliation(s)
- Tingting Huang
- State Key Laboratory of Fine Chemicals, College of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, 116024, P.R. China
| | - Di Liu
- State Key Laboratory of Fine Chemicals, College of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, 116024, P.R. China
| | - Jingyang Jiang
- State Key Laboratory of Fine Chemicals, College of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, 116024, P.R. China
| | - Wenfeng Jiang
- State Key Laboratory of Fine Chemicals, College of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian, 116024, P.R. China
| |
Collapse
|
31
|
Wu Z, Liu Y, Yu L, Zhao C, Yang D, Qiao X, Chen J, Yang C, Kleemann H, Leo K, Ma D. Strategic-tuning of radiative excitons for efficient and stable fluorescent white organic light-emitting diodes. Nat Commun 2019; 10:2380. [PMID: 31147542 PMCID: PMC6542840 DOI: 10.1038/s41467-019-10104-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 04/15/2019] [Indexed: 11/10/2022] Open
Abstract
The emerging thermally activated delayed fluorescence materials have great potential for efficiencies in organic light-emitting diodes by optimizing molecular structures of the emitter system. However, it is still challenging in the device structural design to achieve high efficiency and stable device operation in white organic light-emitting diodes. Here we propose a universal design strategy for thermally activated delayed fluorescence emitter-based fluorescent white organic light-emitting diodes, establishing an advanced system of “orange thermally activated delayed fluorescence emitter sensitized by blue thermally activated delayed fluorescence host” combined with an effective exciton-confined emissive layer. Compared to reference single-layer and double-layer emissive devices, the external quantum efficiency improves by 31 and 45%, respectively, and device operational stability also shows nearly fivefold increase. Additionally, a detailed optical simulation for the present structure is made, indicating the validity of the design strategy in the fluorescent white organic light-emitting diodes. Demonstrating white organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters with high performance and operational stability remains a challenge. Here, the authors show efficient and stable white OLEDs based on a double-dopant TADF system.
Collapse
Affiliation(s)
- Zhongbin Wu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, People's Republic of China.,Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, Nöthnitzer Str. 61, Dresden, 01187, Germany
| | - Yuan Liu
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, Nöthnitzer Str. 61, Dresden, 01187, Germany
| | - Ling Yu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China
| | - Chenyang Zhao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, People's Republic of China
| | - Dezhi Yang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, People's Republic of 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, People's Republic of China
| | - Jiangshan Chen
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, People's Republic of China
| | - Chuluo Yang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, People's Republic of China
| | - Hans Kleemann
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, Nöthnitzer Str. 61, Dresden, 01187, Germany
| | - Karl Leo
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP), Technische Universität Dresden, Nöthnitzer Str. 61, Dresden, 01187, Germany.
| | - Dongge Ma
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, People's Republic of China.
| |
Collapse
|
32
|
Liang X, Tu ZL, Zheng YX. Thermally Activated Delayed Fluorescence Materials: Towards Realization of High Efficiency through Strategic Small Molecular Design. Chemistry 2019; 25:5623-5642. [PMID: 30648301 DOI: 10.1002/chem.201805952] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Indexed: 12/22/2022]
Abstract
Thermally activated delayed fluorescence (TADF) is one of the most intriguing and promising discoveries towards realization of highly-efficient organic light emitting diodes (OLED) utilizing small molecules as emitters. It has the capability of manifesting all excitons generated during the electroluminescent processes, consequently achieving 100 % of internal quantum efficiency. Since the report of the first efficient OLED based on a TADF small molecule in 2012 by Adachi et al., the quest for optimal TADF materials for OLED application has never stopped. Various TADF molecules bearing different design concepts and strategies have been designed and produced, with the aim to boost the overall performances of corresponding OLEDs. In this minireview, the general principles of TADF molecular design based on three basic categories of TADF species: twisted intramolecular charge transfer (TICT), through-space charge transfer (TSCT) and multi-resonance induced TADF (MR-TADF) are discussed in detail. Several key aspects with respect to each category, as well as some effective methods to enhance the efficiency of TADF materials and corresponding OLEDs from the molecular engineering perspectives, are summarized and discussed to exhibit a general landscape of TADF molecular design to a wide variety of scientific researchers within this particular disciplinary area.
Collapse
Affiliation(s)
- Xiao Liang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Zhen-Long Tu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - You-Xuan Zheng
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China
| |
Collapse
|
33
|
Zhang K, Cai L, Fan J, Zhang Y, Lin L, Wang CK. Effect of intermolecular interaction on excited-state properties of thermally activated delayed fluorescence molecules in solid phase: A QM/MM study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 209:248-255. [PMID: 30414573 DOI: 10.1016/j.saa.2018.10.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/20/2018] [Accepted: 10/28/2018] [Indexed: 06/09/2023]
Abstract
Recently, thermally activated delayed fluorescence (TADF) molecules have attracted great attention since nearly 100% exciton usage efficiency was obtained in TADF molecules. Most TADF molecules used in organic light-emitting diodes are in aggregation state, so it is necessary to make out the intermolecular interaction on their photophysical properties. In this work, the excited-state properties of the molecule AI-Cz in solid phase are theoretically studied by the combined quantum mechanics and molecular mechanics (QM/MM) method. Our results show that geometry changes between the ground state (S0) and the first singlet excited state (S1) are limited due to the intermolecular π-π and CH-π interactions. The energy gap between S1 and the first triplet excited state is broadened and the transition properties of excited states are changed. Moreover, the Huang-Rhys factors and the reorganization energy between S0 and S1 are decreased in solid phase, because the vibration modes and rotations are hindered by intermolecular interaction. The non-radiative rate has a large decrease in solid phase which improves the light-emitting performance of the molecule. Our calculation provides a reasonable explanation for experimental measurements and highlights the effect of intermolecular interaction on excited-states properties of TADF molecules.
Collapse
Affiliation(s)
- Kai Zhang
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, 250014 Jinan, China
| | - Lei Cai
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, 250014 Jinan, China
| | - Jianzhong Fan
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, 250014 Jinan, China
| | - Yuchen Zhang
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, 250014 Jinan, China
| | - Lili Lin
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, 250014 Jinan, China.
| | - Chuan-Kui Wang
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, School of Physics and Electronics, Shandong Normal University, 250014 Jinan, China.
| |
Collapse
|
34
|
Konidena RK, Lee JY. Molecular Design Tactics for Highly Efficient Thermally Activated Delayed Fluorescence Emitters for Organic Light Emitting Diodes. CHEM REC 2018; 19:1499-1517. [DOI: 10.1002/tcr.201800136] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/10/2018] [Indexed: 01/15/2023]
Affiliation(s)
- Rajendra Kumar Konidena
- School of Chemical EngineeringSungkyunkwan University 2066 Seobu-ro, Jangan-gu, Suwon Gyeonggi Korea
| | - Jun Yeob Lee
- School of Chemical EngineeringSungkyunkwan University 2066 Seobu-ro, Jangan-gu, Suwon Gyeonggi Korea
| |
Collapse
|
35
|
More YW, Padghan SD, Bhosale RS, Pawar RP, Puyad AL, Bhosale SV, Bhosale SV. Proton Triggered Colorimetric and Fluorescence Response of a Novel Quinoxaline Compromising a Donor-Acceptor System. SENSORS (BASEL, SWITZERLAND) 2018; 18:E3433. [PMID: 30322092 PMCID: PMC6210483 DOI: 10.3390/s18103433] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/24/2018] [Accepted: 10/08/2018] [Indexed: 02/04/2023]
Abstract
Quinoxaline-based novel acid-responsive probe Q1 was designed on the basis of a conjugated donor-acceptor (D-A) subunit. Q1 shows colorimetric and fluorometric changes through protonation and deprotonation in dichloromethane. With the addition of the trifluoroacetic acid (TFA), UV-vis absorption spectral changes in peak intensity of Q1 was observed. Moreover, the appearance of a new peaks at 284 nm 434 nm in absorption spectra with the addition of TFA indicating protonation of quinoxaline nitrogen and form Q1.H⁺ and Q1.2H⁺. The emission spectra display appearance of new emission peak at 515 nm. The optical property variations were supported by time resolved fluorescence studies. The energy band gap was calculated by employing cyclic voltammetry and density functional calculations. Upon addition of triethylamine (TEA) the fluorescence emission spectral changes of Q1 are found to be reversible. Q1 shows color changes from blue to green in basic and acidic medium, respectively. The paper strip test was developed for making Q1 a colorimetric and fluorometric indicator.
Collapse
Affiliation(s)
- Yogesh W More
- Polymers and Functional Material Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.
| | - Sachin D Padghan
- Polymers and Functional Material Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.
| | - Rajesh S Bhosale
- Polymers and Functional Material Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.
- Department of Chemistry, Indrashil University, Kadi, Mehsana 382740, India.
| | - Rajendra P Pawar
- Department of Chemistry, Deogiri College, Aurangabad 431005, India.
| | - Avinash L Puyad
- School of Chemical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 436106, India.
| | - Sidhanath V Bhosale
- Polymers and Functional Material Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.
| | | |
Collapse
|
36
|
Phenanthro[9′,10′:4,5]imidazo[2,1-a]isoquinoline derivatives containing phenoxazine moiety: Synthesis and photophysical properties. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2018.04.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
37
|
Delocalization of frontier orbitals induced red emission for heptazine based thermally activated delayed fluorescence molecule: First-principles study. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
38
|
Yu L, Wu Z, Xie G, Zeng W, Ma D, Yang C. Molecular design to regulate the photophysical properties of multifunctional TADF emitters towards high-performance TADF-based OLEDs with EQEs up to 22.4% and small efficiency roll-offs. Chem Sci 2018; 9:1385-1391. [PMID: 29675187 PMCID: PMC5885939 DOI: 10.1039/c7sc04669c] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 12/12/2017] [Indexed: 12/23/2022] Open
Abstract
Simultaneously achieving high efficiency and low efficiency roll-off remains a big challenge for OLEDs based on thermally activated delayed fluorescence (TADF) emitters. To address this issue, we elaborately designed and synthesized a series of new emitters with both TADF and aggregation-induced emission (AIE) properties by introducing 9,9-dimethyl-9,10-dihydroacridine (DMAC) or 10H-phenoxazine (PXZ) as donor units into a quinoxaline framework. By tuning the electron-donating capability of the donor as well as the amount of donor unit, the photophysical properties of the TADF-AIE emitters can be systematically regulated, with emissions ranging from green to red. We demonstrated efficient doped OLEDs with a maximum EQE of 22.4%, a maximum current efficiency (CEmax) of 80.3 cd A-1 and a maximum power efficiency (PEmax) of 64.1 lm W-1 for the green device, and an EQEmax of 14.1%, a CEmax of 36.1 cd A-1 and a PEmax of 28.1 lm W-1 for the orange device. Remarkably, these orange devices rendered small roll-offs of 1.4% and 21.3% respectively at a luminance of 100 and 1000 cd m-2. Attributed to the unique TADF and AIE features, the non-doped devices perform outstandingly with an EQEmax of 12.0%, a CEmax of 41.2 cd A-1 and a PEmax of 45.4 lm W-1.
Collapse
Affiliation(s)
- Ling Yu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials , Hubei Key Lab on Organic and Polymeric Optoelectronic Materials , Department of Chemistry , Wuhan University , Wuhan , 430072 , People's Republic of China .
| | - Zhongbin Wu
- State Key Laboratory of Polymer Physics and Chemistry , Changchun Institute of Applied Chemistry , University of Chinese Academy of Sciences , Changchun 130022 , People's Republic of China .
| | - Guohua Xie
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials , Hubei Key Lab on Organic and Polymeric Optoelectronic Materials , Department of Chemistry , Wuhan University , Wuhan , 430072 , People's Republic of China .
| | - Weixuan Zeng
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials , Hubei Key Lab on Organic and Polymeric Optoelectronic Materials , Department of Chemistry , Wuhan University , Wuhan , 430072 , People's Republic of China .
| | - Dongge Ma
- State Key Laboratory of Polymer Physics and Chemistry , Changchun Institute of Applied Chemistry , University of Chinese Academy of Sciences , Changchun 130022 , People's Republic of China .
- Institute of Polymer Optoelectronic Materials and Devices , State Key Laboratory of Luminescent Materials and Devices , South China University of Technology , Guangzhou 510640 , People's Republic of China
| | - Chuluo Yang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials , Hubei Key Lab on Organic and Polymeric Optoelectronic Materials , Department of Chemistry , Wuhan University , Wuhan , 430072 , People's Republic of China .
| |
Collapse
|
39
|
Zeng W, Lai HY, Lee WK, Jiao M, Shiu YJ, Zhong C, Gong S, Zhou T, Xie G, Sarma M, Wong KT, Wu CC, Yang C. Achieving Nearly 30% External Quantum Efficiency for Orange-Red Organic Light Emitting Diodes by Employing Thermally Activated Delayed Fluorescence Emitters Composed of 1,8-Naphthalimide-Acridine Hybrids. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1704961. [PMID: 29218854 DOI: 10.1002/adma.201704961] [Citation(s) in RCA: 224] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/14/2017] [Indexed: 05/18/2023]
Abstract
The combination of rigid acridine donor and 1,8-naphthalimide acceptor has afforded two orange-red emitters of NAI-DMAC and NAI-DPAC with high rigidity in molecular structure and strongly pretwisted charge transfer state. Endowed with high photoluminescence quantum yields (ΦPL ), distinct thermally activated delayed fluorescence (TADF) characteristics, and preferentially horizontal emitting dipole orientations, these emitters afford record-high orange-red TADF organic light-emitting diodes (OLEDs) with external quantum efficiencies of up to 21-29.2%, significantly surpassing all previously reported orange-to-red TADF OLEDs. Notably, the influence of microcavity effect is verified to support the record-high efficiency. This finding relaxes the usually stringent material requirements for effective TADF emitters by comprising smaller radiative transition rates and less than ideal ΦPL s.
Collapse
Affiliation(s)
- Weixuan Zeng
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Hsin-Yu Lai
- Department of Electrical Engineering, Graduate Institute of Electronics Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10617, Taiwan
| | - Wei-Kai Lee
- Department of Electrical Engineering, Graduate Institute of Electronics Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10617, Taiwan
| | - Min Jiao
- Department of Electrical Engineering, Graduate Institute of Electronics Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10617, Taiwan
| | - Yi-Jiun Shiu
- Department of Electrical Engineering, Graduate Institute of Electronics Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10617, Taiwan
| | - Cheng Zhong
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Shaolong Gong
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Tao Zhou
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Guohua Xie
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Monima Sarma
- Department of Chemistry, Institute of Atomic and Molecular Science Academia Sinica, National Taiwan University, Taipei, 10617, Taiwan
| | - Ken-Tsung Wong
- Department of Chemistry, Institute of Atomic and Molecular Science Academia Sinica, National Taiwan University, Taipei, 10617, Taiwan
| | - Chung-Chih Wu
- Department of Electrical Engineering, Graduate Institute of Electronics Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10617, Taiwan
| | - Chuluo Yang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| |
Collapse
|
40
|
Yu L, Wu Z, Xie G, Zhong C, Zhu Z, Ma D, Yang C. An efficient exciton harvest route for high-performance OLEDs based on aggregation-induced delayed fluorescence. Chem Commun (Camb) 2018; 54:1379-1382. [DOI: 10.1039/c7cc09925h] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two new fluoro-substituted quinoxaline derivatives featuring both AIE and TADF characteristics are designed and synthesized. Based on the emitters, the doped OLEDs have realized a maximum EQE close to 25% and the non-doped device presents an orange emission with the EQE over 10%.
Collapse
Affiliation(s)
- Ling Yu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University
- Wuhan
- People's Republic of China
| | - Zhongbin Wu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences
- Changchun 130022
- People's Republic of China
| | - Guohua Xie
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University
- Wuhan
- People's Republic of China
| | - Cheng Zhong
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University
- Wuhan
- People's Republic of China
| | - Zece Zhu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University
- Wuhan
- People's Republic of China
| | - Dongge Ma
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences
- Changchun 130022
- People's Republic of China
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology
- Guangzhou 510640
| | - Chuluo Yang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University
- Wuhan
- People's Republic of China
| |
Collapse
|
41
|
Zhang Z, Zheng Y, Sun Z, Dai Z, Tang Z, Ma J, Ma C. Direct Olefination of Fluorinated Quinoxalines via
Cross- Dehydrogenative Coupling Reactions: A New Near-Infrared Probe for Mitochondria. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201700237] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Zeyuan Zhang
- School of Chemistry and Chemical Engineering; Shandong University; Jinan 250100 People's Republic of China
| | - Yiwen Zheng
- School of Chemistry and Chemical Engineering; Shandong University; Jinan 250100 People's Republic of China
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences; Chinese Academy of Sciences; Beijing 100190 People's Republic of China
| | - Zuobang Sun
- School of Chemistry and Chemical Engineering; Shandong University; Jinan 250100 People's Republic of China
| | - Zhen Dai
- School of Chemistry and Chemical Engineering; Shandong University; Jinan 250100 People's Republic of China
| | - Ziqiang Tang
- School of Chemistry and Chemical Engineering; Shandong University; Jinan 250100 People's Republic of China
| | - Jiangshan Ma
- School of Chemistry and Chemical Engineering; Shandong University; Jinan 250100 People's Republic of China
| | - Chen Ma
- School of Chemistry and Chemical Engineering; Shandong University; Jinan 250100 People's Republic of China
- State Key Laboratory of Natural and Biomimetic Drugs; Peking University; Beijing 100191 People's Republic of China
| |
Collapse
|
42
|
Ganesan P, Ranganathan R, Chi Y, Liu XK, Lee CS, Liu SH, Lee GH, Lin TC, Chen YT, Chou PT. Functional Pyrimidine-Based Thermally Activated Delay Fluorescence Emitters: Photophysics, Mechanochromism, and Fabrication of Organic Light-Emitting Diodes. Chemistry 2017; 23:2858-2866. [PMID: 28028848 DOI: 10.1002/chem.201604883] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Indexed: 11/11/2022]
Abstract
A new series of molecules, T1-T4, possessing thermally activated delayed fluorescence (TADF) have been strategically designed and synthesized. Molecules T1-T4 contain the dimethyl acridine as the electron donor, which is linked to either symmetrical or unsymmetrical diphenyl pyrimidine as an acceptor. In comparison to the ubiquitous triazine acceptor, the selection of pyrimidine as an acceptor has advantages of facile functionalization and less stabilized unoccupied π orbitals, so that the energy gap toward the blue region can be accessed. Together with acridine donors, the resulting donor-acceptor functional materials reveal remarkable TADF properties. In the solid state, molecules T1-T4 all exhibit intriguing mechanochromism. The crystal structures, together with spectroscopy and dynamics acquired upon application of stressing, lead us to propose two types of structural arrangement that give distinct emission properties, one with and the other without TADF. Upon fabricating organic light-emitting diodes, the T1-T4 films prepared from sublimation all exhibit dominant TADF behavior; this accounts for their high performance: an electroluminescent emission at λ=490 nm, with an external quantum efficiency of 14.2 %, can be attained when T2 is used as an emitter.
Collapse
Affiliation(s)
- Paramaguru Ganesan
- Department of Chemistry, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Revathi Ranganathan
- Department of Chemistry, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Yun Chi
- Department of Chemistry, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Xiao-Ke Liu
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, S.A.R. China
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong, S.A.R. China
| | - Shih-Hung Liu
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Gene-Hsiang Lee
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Tzu-Chieh Lin
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Yi-Ting Chen
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
| |
Collapse
|
43
|
Yang Z, Mao Z, Xie Z, Zhang Y, Liu S, Zhao J, Xu J, Chi Z, Aldred MP. Recent advances in organic thermally activated delayed fluorescence materials. Chem Soc Rev 2017; 46:915-1016. [DOI: 10.1039/c6cs00368k] [Citation(s) in RCA: 1413] [Impact Index Per Article: 201.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Thermally activated delayed fluorescence: harvesting dark triplet excitons to generate bright emissive singlet excitons.
Collapse
Affiliation(s)
- Zhiyong Yang
- PCFM Lab
- GD HPPC Lab
- Guangdong Engineering Technology Research Center for High-performance Organic and Polymer Photoelectric Functional Films
- State Key Laboratory of Optoelectronic Material and Technologies
- School of Chemistry
| | - Zhu Mao
- PCFM Lab
- GD HPPC Lab
- Guangdong Engineering Technology Research Center for High-performance Organic and Polymer Photoelectric Functional Films
- State Key Laboratory of Optoelectronic Material and Technologies
- School of Chemistry
| | - Zongliang Xie
- PCFM Lab
- GD HPPC Lab
- Guangdong Engineering Technology Research Center for High-performance Organic and Polymer Photoelectric Functional Films
- State Key Laboratory of Optoelectronic Material and Technologies
- School of Chemistry
| | - Yi Zhang
- PCFM Lab
- GD HPPC Lab
- Guangdong Engineering Technology Research Center for High-performance Organic and Polymer Photoelectric Functional Films
- State Key Laboratory of Optoelectronic Material and Technologies
- School of Chemistry
| | - Siwei Liu
- PCFM Lab
- GD HPPC Lab
- Guangdong Engineering Technology Research Center for High-performance Organic and Polymer Photoelectric Functional Films
- State Key Laboratory of Optoelectronic Material and Technologies
- School of Chemistry
| | - Juan Zhao
- PCFM Lab
- GD HPPC Lab
- Guangdong Engineering Technology Research Center for High-performance Organic and Polymer Photoelectric Functional Films
- State Key Laboratory of Optoelectronic Material and Technologies
- School of Chemistry
| | - Jiarui Xu
- PCFM Lab
- GD HPPC Lab
- Guangdong Engineering Technology Research Center for High-performance Organic and Polymer Photoelectric Functional Films
- State Key Laboratory of Optoelectronic Material and Technologies
- School of Chemistry
| | - Zhenguo Chi
- PCFM Lab
- GD HPPC Lab
- Guangdong Engineering Technology Research Center for High-performance Organic and Polymer Photoelectric Functional Films
- State Key Laboratory of Optoelectronic Material and Technologies
- School of Chemistry
| | | |
Collapse
|
44
|
Enoki T, Matsuo K, Ohshita J, Ooyama Y. Synthesis and optical and electrochemical properties of julolidine-structured pyrido[3,4-b]indole dye. Phys Chem Chem Phys 2017; 19:3565-3574. [DOI: 10.1039/c6cp08573c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The julolidine-structured pyrido[3,4-b]indole dye ET-1 possesses the ability to act as a calorimetric and fluorescent sensor for Brønsted and Lewis acids.
Collapse
Affiliation(s)
- Toshiaki Enoki
- Department of Applied Chemistry
- Graduate School of Engineering
- Hiroshima University
- Higashi-Hiroshima 739-8527
- Japan
| | - Keishi Matsuo
- Department of Applied Chemistry
- Graduate School of Engineering
- Hiroshima University
- Higashi-Hiroshima 739-8527
- Japan
| | - Joji Ohshita
- Department of Applied Chemistry
- Graduate School of Engineering
- Hiroshima University
- Higashi-Hiroshima 739-8527
- Japan
| | - Yousuke Ooyama
- Department of Applied Chemistry
- Graduate School of Engineering
- Hiroshima University
- Higashi-Hiroshima 739-8527
- Japan
| |
Collapse
|
45
|
Wu Z, Wang Q, Yu L, Chen J, Qiao X, Ahamad T, Alshehri SM, Yang C, Ma D. Managing Excitons and Charges for High-Performance Fluorescent White Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2016; 8:28780-28788. [PMID: 27706937 DOI: 10.1021/acsami.6b10087] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The simultaneous realization of high efficiency, stable spectra, high color rendering index (CRI), and low-efficiency roll-off in a fluorescent white organic light-emitting diode (WOLED) still remains a big challenge. Here, we demonstrate high-performance conventional fluorescent-dopant-based WOLEDs by strategic management of singlet and triplet excitons within an efficient emissive zone. This design consists of two separated red/green sub-EMLs with ultralow doping concentration and a sandwiched sub-EML doped with red and green fluorescent dyes at a relatively high concentration, which can harness all electrogenerated excitons and reduce the energy loss to the utmost extent. Accordingly, the resulting WOLED realizes an external quantum efficiency (EQE) of 18.2% with a maximum power efficiency of 44.6 lm W-1. At the practical luminance of 1000 cd m-2 for the lighting source, the EQE still remains as high as 16.2% with a CRI of 82 and stable color spectra. A comprehensive understanding of the device working mechanism is performed to guide design of efficient and stable fluorescent WOLEDs.
Collapse
Affiliation(s)
- Zhongbin Wu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Changchun 130022, P. R. China
| | - Qi Wang
- Department of Electrical Engineering and Computer Science, University of Michigan , Ann Arbor, Michigan 48109, United States
| | - Ling Yu
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University , Wuhan 430072, P. R. China
| | - Jiangshan Chen
- 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
| | - Tansir Ahamad
- Department of Chemistry, King Saud University , Riyadh 11451, Kingdom of Saudi Arabia
| | - Saad M Alshehri
- Department of Chemistry, King Saud University , Riyadh 11451, Kingdom of Saudi Arabia
- Department of Chemistry, College of Science & General Studies, Alfaisal University , Riyadh 11451, Kingdom of Saudi Arabia
| | - Chuluo Yang
- Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University , Wuhan 430072, P. R. China
| | - Dongge Ma
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Changchun 130022, P. R. China
- 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
- Department of Chemistry, King Saud University , Riyadh 11451, Kingdom of Saudi Arabia
| |
Collapse
|