1
|
Stanitska M, Pokhodylo N, Lytvyn R, Urbonas E, Volyniuk D, Kutsiy S, Ivaniuk K, Kinzhybalo V, Stakhira P, Keruckiene R, Obushak M, Gražulevičius JV. Effects of Electron-Withdrawing Strengths of the Substituents on the Properties of 4-(Carbazolyl- R-benzoyl)-5-CF 3-1 H-1,2,3-triazole Derivatives as Blue Emitters for Doping-Free Electroluminescence Devices. ACS OMEGA 2024; 9:14613-14626. [PMID: 38559965 PMCID: PMC10976381 DOI: 10.1021/acsomega.4c01077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 02/23/2024] [Accepted: 02/27/2024] [Indexed: 04/04/2024]
Abstract
The synthesis of four 4-(carbazolyl-R-benzoyl)-5-CF3-1H-1,2,3-triazoles with extra groups ((3-methyl)-phenyl-, 4-fluorophenyl-, quinolinyl-, or (3-trifluoromethyl)-phenyl-) in the acceptor fragment has been reported. The effects of substituents with different electron-withdrawing strengths on the thermal, electrochemical, photophysical, and electroluminescence properties of the synthesized compounds are discussed. The results of X-ray analyses and density functional theory (DFT) calculations support unusual molecular packing and electronic properties. The compounds are capable of glass formation with glass transition temperatures ranging from 54-84 °C. Ionization potentials of the compounds are in the range of 5.98-6.22 eV and electron affinities range from 3.09 to 3.35 eV. Under ultraviolet excitation, the neat films of the compounds exhibit blue emission with photoluminescence quantum yields ranging from 18 to 27%. The films of selected compounds are used for the preparation of host-free light-emitting layers of organic light-emitting diodes with very simple device structures and an external quantum efficiency of 4.6%.
Collapse
Affiliation(s)
- Mariia Stanitska
- Kaunas
University of Technology, Baršausko st. 59, 51423 Kaunas, Lithuania
- Ivan
Franko National University of Lviv, Kyryla i Mefodiya 6, Lviv 79005, Ukraine
| | - Nazariy Pokhodylo
- Ivan
Franko National University of Lviv, Kyryla i Mefodiya 6, Lviv 79005, Ukraine
| | - Roman Lytvyn
- Ivan
Franko National University of Lviv, Kyryla i Mefodiya 6, Lviv 79005, Ukraine
| | - Ervinas Urbonas
- Kaunas
University of Technology, Baršausko st. 59, 51423 Kaunas, Lithuania
| | - Dmytro Volyniuk
- Kaunas
University of Technology, Baršausko st. 59, 51423 Kaunas, Lithuania
| | - Stepan Kutsiy
- National
University “Lviv Polytechnic”, Stepan Bandera 12, Lviv 79000, Ukraine
| | - Khrystyna Ivaniuk
- National
University “Lviv Polytechnic”, Stepan Bandera 12, Lviv 79000, Ukraine
| | - Vasyl Kinzhybalo
- Institute
of Low Temperature and Structure Research, Okólna 2, Wrocław 50-422, Poland
| | - Pavlo Stakhira
- National
University “Lviv Polytechnic”, Stepan Bandera 12, Lviv 79000, Ukraine
| | - Rasa Keruckiene
- Kaunas
University of Technology, Baršausko st. 59, 51423 Kaunas, Lithuania
| | - Mykola Obushak
- Ivan
Franko National University of Lviv, Kyryla i Mefodiya 6, Lviv 79005, Ukraine
| | | |
Collapse
|
2
|
Pei S, Tang H, Liu H, Gao S, Duan Y, Gao Y, Su Z. Theoretical Study and Design for Thermally Activated Delayed Fluorescence Emitters with Through-Space Charge Transfer from an Acridine Derivative Donor to an O-Bridged Triphenylboron Boroxy Acceptor. Inorg Chem 2024; 63:4557-4565. [PMID: 38395040 DOI: 10.1021/acs.inorgchem.3c03764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
The through-space charge transfer thermally activated delayed fluorescence (TSCT-TADF) properties of a series of molecules were characterized and tested theoretically by density functional theory and time-dependent density functional theory. By analyzing the weak interaction of the molecules at the ground state and calculating the transition contribution ratio of the donor, acceptor, and bridge in the excited state, we verified the through-space charge transfer characteristic of these molecules. We designed new molecules on the basis of the reported molecules (non-TADF molecule 1 and TADF molecule 2) to improve the performance. Smaller singlet-triplet energy gaps and larger spin-orbit coupling were obtained in the designed molecules, which is beneficial to obtain higher intersystem crossing and reverse intersystem crossing rates (kRISC). In addition, we calculated the radiation rate and the singlet-triplet reorganization energy, which is used to characterize the nonradiation rate. The comprehensive evaluation of both radiative and nonradiative processes shows that molecules 4 and 6 have the potential to be highly efficient TSCT-TADF materials.
Collapse
Affiliation(s)
- Shiqi Pei
- School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, P. R. China
- Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun 130022, P. R. China
| | - Hao Tang
- School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, P. R. China
- Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun 130022, P. R. China
| | - Han Liu
- School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, P. R. China
- Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun 130022, P. R. China
| | - Shengxiang Gao
- School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, P. R. China
- Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun 130022, P. R. China
| | - Yingchen Duan
- School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, P. R. China
- Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun 130022, P. R. China
| | - Ying Gao
- Jilin Engineering Normal University, Changchun 130052, P. R. China
| | - Zhongmin Su
- School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, P. R. China
- Jilin Provincial Science and Technology Innovation Center of Optical Materials and Chemistry, Changchun 130022, P. R. China
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
| |
Collapse
|
3
|
Kim H, Lee K, Kim JH, Kim WY. Deep Learning-Based Chemical Similarity for Accelerated Organic Light-Emitting Diode Materials Discovery. J Chem Inf Model 2024; 64:677-689. [PMID: 38270063 DOI: 10.1021/acs.jcim.3c01747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
Thermally activated delayed fluorescence (TADF) material has attracted great attention as a promising metal-free organic light-emitting diode material with a high theoretical efficiency. To accelerate the discovery of novel TADF materials, computer-aided material design strategies have been developed. However, they have clear limitations due to the accessibility of only a few computationally tractable properties. Here, we propose TADF-likeness, a quantitative score to evaluate the TADF potential of molecules based on a data-driven concept of chemical similarity to existing TADF molecules. We used a deep autoencoder to characterize the common features of existing TADF molecules with common chemical descriptors. The score was highly correlated with the four essential electronic properties of TADF molecules and had a high success rate in large-scale virtual screening of millions of molecules to identify promising candidates at almost no cost, validating its feasibility for accelerating TADF discovery. The concept of TADF-likeness can be extended to other fields of materials discovery.
Collapse
Affiliation(s)
- Hyeonsu Kim
- Department of Chemistry, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Kyunghoon Lee
- Department of Chemistry, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Jun Hyeong Kim
- Department of Chemistry, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Woo Youn Kim
- Department of Chemistry, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
- AI Institute, Korea Advanced Institute of Science & Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| |
Collapse
|
4
|
Zhang T, Xiao Y, Wang H, Kong S, Huang R, Ka-Man Au V, Yu T, Huang W. Highly Twisted Thermally Activated Delayed Fluorescence (TADF) Molecules and Their Applications in Organic Light-Emitting Diodes (OLEDs). Angew Chem Int Ed Engl 2023; 62:e202301896. [PMID: 37288654 DOI: 10.1002/anie.202301896] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/09/2023]
Abstract
Thermally activated delayed fluorescence (TADF) materials have attracted great potential in the field of organic light-emitting diodes (OLEDs). Among thousands of TADF materials, highly twisted TADF emitters have become a hotspot in recent years. Compared with traditional TADF materials, highly twisted TADF emitters tend to show multi-channel charge-transfer characters and form rigid molecular structures. This is advantageous for TADF materials, as non-radiative decay processes can be suppressed to facilitate efficient exciton utilization. Accordingly, OLEDs with excellent device performances have also been reported. In this Review, we have summarized recent progress in highly twisted TADF materials and related devices, and give an overview of the molecular design strategies, photophysical studies, and the performances of OLED devices. In addition, the challenges and perspectives of highly twisted TADF molecules and the related OLEDs are also discussed.
Collapse
Affiliation(s)
- Tiantian Zhang
- Frontiers Science Center for Flexible Electronics (FSCFE), Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, 127 West Youyi Road, 710072, Xi'an, China
| | - Yuxin Xiao
- Frontiers Science Center for Flexible Electronics (FSCFE), Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, 127 West Youyi Road, 710072, Xi'an, China
| | - Hailan Wang
- Frontiers Science Center for Flexible Electronics (FSCFE), Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, 127 West Youyi Road, 710072, Xi'an, China
| | - Shuting Kong
- Frontiers Science Center for Flexible Electronics (FSCFE), Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, 127 West Youyi Road, 710072, Xi'an, China
| | - Rongjuan Huang
- Frontiers Science Center for Flexible Electronics (FSCFE), Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, 127 West Youyi Road, 710072, Xi'an, China
| | - Vonika Ka-Man Au
- Department of Science and Environmental Studies, The Education University of Hong Kong, 10 Lo Ping Road, Tai Po, New Territories, Hong Kong, China
| | - Tao Yu
- Frontiers Science Center for Flexible Electronics (FSCFE), Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, 127 West Youyi Road, 710072, Xi'an, China
- Key Laboratory of Flexible Electronics of Zhejiang Province, Ningbo Institute of Northwestern Polytechnical University, 218 Qingyi Road, 315103, Ningbo, China
| | - Wei Huang
- Frontiers Science Center for Flexible Electronics (FSCFE), Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, 127 West Youyi Road, 710072, Xi'an, China
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, 211816, Nanjing, China
- State Key Laboratory of Organic Electronics and Information Displays &, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, 210023, Nanjing, China
| |
Collapse
|
5
|
Lu CH, Lin CY, Zeng SX, Chou YP, Chen CH, Liu YH, Lee JH, Wu CC, Wong KT. Engineering the Macrocyclic Donor Structures towards Deep-Blue Thermally Activated Delayed Fluorescence Emitters. ACS APPLIED MATERIALS & INTERFACES 2023; 15:35239-35250. [PMID: 37459567 DOI: 10.1021/acsami.3c05754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Deep-blue thermally activated delayed fluorescence (TADF) molecules present promising potential in organic light-emitting diodes (OLEDs), especially for display applications. Here, an efficient molecular engineering approach to modifying the donor or acceptor features of the D-π-A-configured TADF molecules for deep-blue emission is reported. By introducing oxygen and sulfone as a bridge unit onto the macrocyclic donor, two emitters, c-ON-MeTRZ and c-NS-MeTRZ, are synthesized and characterized, respectively. The reduced donor strength of c-ON-MeTRZ and c-NS-MeTRZ as compared to that of the model molecule c-NN-MeTRZ leads to blue-shifted emissions with high photoluminescence quantum yields (PLQYs) and retains TADF characters, while the new emitter c-NN-MePym with the most blue-shifted emission only exhibits a pure fluorescent nature because of the electron-accepting feature of pyrimidine that is insufficient for inducing the TADF property. In the presence of macrocyclic donors, these new emitters show high horizontal dipole ratios (Θ// = 85-89%), which are beneficial for improving the light out-coupling efficiency. Deep-blue TADF OLEDs incorporating c-ON-MeTRZ as an emitter doped in the mCPCN host achieves a high maximum external quantum efficiency (EQEmax) of 30.2% together with 1931 Commission Internationale de I'Eclairage (CIE) coordinates of (0.14, 0.13), while the counter device employing c-NS-MeTRZ as a dopant gives EQEmax of 15.4% and CIE coordinates of (0.14, 0.09). The EQEmax of c-ON-MeTRZ- and c-NS-MeTRZ-based devices can be significantly improved to 34.4 and 29.3%, respectively, with a polar host DPEPO, which stabilizes the charge transfer (CT) S1 state to give lower ΔEST for improving the reverse intersystem crossing process. The efficient TADF character, high PLQYs, and high anisotropic emission dipole ratios work together to render the superior electroluminescence (EL) efficiencies. Based on the detailed characterizations of physical properties, theoretical analyses, and comprehensive study on the corresponding devices, a clear structure-property-performance relationship has been successfully established to verify the effective molecular design strategy of modulating the macrocyclic donor characters for efficient deep-blue TADF emitters.
Collapse
Affiliation(s)
- Chen-Han Lu
- Department of Electrical Engineering, Graduate Institute of Electronics Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan
| | - Chun-Yen Lin
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Shi-Xian Zeng
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yu-Pin Chou
- Department of Electrical Engineering, Graduate Institute of Electronics Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan
| | - Chia-Hsun Chen
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yi-Hung Liu
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Jiun-Haw Lee
- Department of Electrical Engineering, Graduate Institute of Electronics Engineering and Graduate Institute of Photonics and Optoelectronics, 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
| | - Ken-Tsung Wong
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Institute of Atomic and Molecular Science, Academia Sinica, Taipei 10617, Taiwan
| |
Collapse
|
6
|
Abroshan H, Winget P, Kwak HS, Brown CT, Halls MD. Organic radical emitters: nature of doublet excitons in emissive layers. Phys Chem Chem Phys 2022; 24:16891-16899. [PMID: 35788234 DOI: 10.1039/d2cp00592a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Organic radical emitters have received significant attention as a new route to efficient organic light-emitting diodes (OLEDs). The electronic structure of radical emitters allows bypassing the triplet harvesting issue in current OLED devices. However, the nature of doublet excited states remains elusive due to the complex nature of emissive layers. To date, the computational efforts have treated radical carrying materials as isolated entities in the gas phase. However, OLED materials are applied as thin solid films where intermolecular interactions significantly impact optoelectronic properties of the devices. Here, we combine molecular dynamics simulations and quantum chemical calculations to evaluate the effect of emitter-host interactions on the performance of radical-based emissive layers. Results demonstrate that intermolecular interactions remarkably modulate the electronic properties of the radicals in the thin solid films. The doublet excitons of isolated emitters demonstrate a hybrid character of charge-transfer (CT) and local-excitation (LE), while the emitter-host clusters present a significant CT character. Further, the impact of static and dynamic disorders on the hole-electron recombination is studied. Although the host-emitter interactions simultaneously decrease radiative rates and increase non-radiative rates, the latter rates are 100 times smaller than the former rates, allowing internal quantum efficiency to reach 100% for the doublet-based emission process. The results of this study highlight the significant impact of host-emitter interactions on radiative and non-radiative recombination processes and offer guidelines to tune these interactions for advancing radical-based OLEDs.
Collapse
|
7
|
Li Q, Wu Y, Cao J, Liu Y, Wang Z, Zhu H, Zhang H, Huang F. Pillararene-Induced Intramolecular Through-Space Charge Transfer and Single-Molecule White-Light Emission. Angew Chem Int Ed Engl 2022; 61:e202202381. [PMID: 35234348 DOI: 10.1002/anie.202202381] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Indexed: 12/15/2022]
Abstract
The fabrication of single-molecule white-light emission (SMWLE) materials has become a highly studied topic in recent years and through-space charge transfer (TSCT) is emerging as an important concept in this field. However, the preparation of ideal TSCT-based SMWLE materials is still a big challenge. Herein, we report a bifunctional pillar[5]arene (TPCN-P5-TPA) with a linear donor-spacer-acceptor structure and aggregation-induced emission (AIE) property. The bulky pillar[5]arene between the donor and acceptor induces a twisted conformation and a non-conjugated structure, resulting in intramolecular TSCT. In addition, the AIE feature and pillar[5]arene cavity endow TPCN-P5-TPA with responsiveness to viscosity and polar guests, by which the TSCT emission is triggered. The combination of blue locally-excited state emission and yellow TSCT emission of TPCN-P5-TPA generates SMWLE. Therefore, we provide a new and versatile strategy for the construction of TSCT-based SMWLE materials.
Collapse
Affiliation(s)
- Qi Li
- State Key Laboratory of Chemical Engineering, Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Yitao Wu
- State Key Laboratory of Chemical Engineering, Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Jiajun Cao
- State Key Laboratory of Chemical Engineering, Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Yang Liu
- State Key Laboratory of Chemical Engineering, Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Zeju Wang
- State Key Laboratory of Chemical Engineering, Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Huangtianzhi Zhu
- State Key Laboratory of Chemical Engineering, Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Haoke Zhang
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, 311215, China.,MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, China.,Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Feihe Huang
- State Key Laboratory of Chemical Engineering, Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China.,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, 311215, China.,Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China
| |
Collapse
|
8
|
Li Q, Wu Y, Cao J, Liu Y, Wang Z, Zhu H, Zhang H, Huang F. Pillararene‐Induced Intramolecular Through‐Space Charge Transfer and Single‐Molecule White‐Light Emission. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Qi Li
- State Key Laboratory of Chemical Engineering Stoddart Institute of Molecular Science Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Yitao Wu
- State Key Laboratory of Chemical Engineering Stoddart Institute of Molecular Science Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Jiajun Cao
- State Key Laboratory of Chemical Engineering Stoddart Institute of Molecular Science Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Yang Liu
- State Key Laboratory of Chemical Engineering Stoddart Institute of Molecular Science Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Zeju Wang
- State Key Laboratory of Chemical Engineering Stoddart Institute of Molecular Science Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Huangtianzhi Zhu
- State Key Laboratory of Chemical Engineering Stoddart Institute of Molecular Science Department of Chemistry Zhejiang University Hangzhou 310027 China
| | - Haoke Zhang
- ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 311215 China
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China
- Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Feihe Huang
- State Key Laboratory of Chemical Engineering Stoddart Institute of Molecular Science Department of Chemistry Zhejiang University Hangzhou 310027 China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 311215 China
- Green Catalysis Center and College of Chemistry Zhengzhou University Zhengzhou 450001 China
| |
Collapse
|
9
|
Wang J, Zhang J, Jiang C, Yao C, Xi X. Effective Design Strategy for Aggregation-Induced Emission and Thermally Activated Delayed Fluorescence Emitters Achieving 18% External Quantum Efficiency Pure-Blue OLEDs with Extremely Low Roll-Off. ACS APPLIED MATERIALS & INTERFACES 2021; 13:57713-57724. [PMID: 34813274 DOI: 10.1021/acsami.1c17449] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
High-color purity organic emitters with a simultaneous combination of aggregation-induced emission (AIE) and thermally activated delayed fluorescence (TADF) characteristics are in great demand due to their excellent comprehensive performances toward efficient organic light-emitting diodes (OLEDs). In this work, two D-π-A-structure emitters, ICz-DPS and ICz-BP, exhibiting AIE and TADF properties were developed, and both the emitters have narrow singlet (S1)-triplet (T1) splitting (ΔEST) and excellent photoluminescence (PL) quantum yields (ΦPL), derived from the distorted configurations and weak intra/intermolecular interactions, suppressing exciton annihilation and concentration quenching. Their doped OLEDs based on ICz-BP provide an excellent electroluminescence external quantum efficiency (ηext) and current efficiency (ηC) of 17.7% and 44.8 cd A-1, respectively, with an ηext roll-off of 2.9%. Their nondoped OLEDs based on ICz-DPS afford high efficiencies of 11.7% and 30.1 cd A-1, with pure-blue emission with Commission Internationale de l'Éclairage (CIE) coordinates of (0.15, 0.08) and a low roll-off of 6.0%. This work also shows a strategy for designing AIE-TADF molecules by rational use of steric hindrance and weak inter/intramolecular interactions to realize high ΦPL values, fast reverse intersystem crossing process, and reduced nonradiative transition process properties, which may open the way toward highly efficient and small-efficiency roll-off devices.
Collapse
Affiliation(s)
- Jinshan Wang
- School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Jianfeng Zhang
- School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Cuifeng Jiang
- School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Chuang Yao
- Chongqing Key Laboratory of Extraordinary Bond Engineering and Advance Materials Technology (EBEAM), Yangtze Normal University, Chongqing 408100, China
| | - Xinguo Xi
- School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| |
Collapse
|
10
|
Kumar K, Kesavan KK, Thakur D, Banik S, Jayakumar J, Cheng CH, Jou JH, Ghosh S. Functional Pyrene-Pyridine-Integrated Hole-Transporting Materials for Solution-Processed OLEDs with Reduced Efficiency Roll-Off. ACS OMEGA 2021; 6:10515-10526. [PMID: 34056206 PMCID: PMC8153793 DOI: 10.1021/acsomega.0c04080] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
A series of new functional pyridine-appended pyrene derivatives, viz., 2,6-diphenyl-4-(pyren-1-yl)pyridine (Py-03), 2,6-bis(4-methoxyphenyl)-4-(pyren-1-yl)pyridine (Py-MeO), 4-(pyren-1-yl)-2,6-di-p-tolylpyridine (Py-Me), and 2,6-bis(4-bromophenyl)-4-(pyren-1-yl)pyridine (Py-Br) were designed, developed, and studied as the hole-transporting materials (HTMs) for organic light-emitting diode (OLED) application. The crystal structures of two molecules revealed to have a large dihedral angle between the pyrene and pyridine units, indicating poor π-electronic communication between them due to ineffective orbital overlap across the pyrene-pyridine systems as the two p-orbitals of pivotal atoms are twisted at 66.80° and 68.75° angles to each other in Py-03 and Py-Me, respectively. The influence of variedly functionalized pyridine units on the electro-optical properties and device performance of the present integrated system for OLED application was investigated. All of the materials have suitable HOMO values (5.6 eV) for hole injection by closely matching the HOMOs of indium tin oxide (ITO) and the light-emitting layer. All of the synthesized molecules have suitable triplet energies, glass transition temperatures, and melting temperatures, which are highly desirable for good HTMs. The pyrene-pyridine-based devices demonstrated stable performance with low-efficiency roll-off. The device with Py-Br as HTM showed a maximum luminance of 17300 cd/m2 with a maximum current efficiency of 22.4 cd/A and an EQE of 9% at 3500 cd/m2 with 7% roll-off from 1000 to 10 000 cd/m2. Also, the devices with Py-Me and Py-03 showed performance roll-up while moving from 1000 to 10 000 cd/m2.
Collapse
Affiliation(s)
- Krishan Kumar
- School
of Basic Sciences, IIT Mandi, Mandi, Himachal Pradesh 175005, India
| | - Kiran Kishore Kesavan
- Department
of Materials Science and Engineering, National
Tsing Hua University, 101, Sec. 2, Guang-Fu Road, Hsinchu 30013, Taiwan, R.O.C.
| | - Diksha Thakur
- School
of Basic Sciences, IIT Mandi, Mandi, Himachal Pradesh 175005, India
| | - Subrata Banik
- Department
of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur 613401, Tamil Nadu, India
| | | | - Chien-Hong Cheng
- Department
of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan, R.O.C.
| | - Jwo-Huei Jou
- Department
of Materials Science and Engineering, National
Tsing Hua University, 101, Sec. 2, Guang-Fu Road, Hsinchu 30013, Taiwan, R.O.C.
| | - Subrata Ghosh
- School
of Basic Sciences, IIT Mandi, Mandi, Himachal Pradesh 175005, India
| |
Collapse
|
11
|
Lee HL, Oh CS, Lee KH, Lee JY, Hong WP. Lifetime-Extending 3-(4-Phenylbenzo[4,5]thieno[3,2- d]pyrimidin-2-yl)benzonitrile Acceptor for Thermally Activated Delayed Fluorescence Emitters. ACS APPLIED MATERIALS & INTERFACES 2021; 13:2908-2918. [PMID: 33404213 DOI: 10.1021/acsami.0c17819] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Highly efficient and long-living green thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) were developed using benzothienopyrimidine-4-benzonitrile acceptor-derived compounds as the TADF emitters. A molecular design merging the benzothienopyrimidine-4-benzonitrile acceptor with either indolocarbazole or diindolocarbazole was employed to prepare two TADF emitters, 5-(2-phenylbenzo[4,5]thieno[3,2-d]pyrimidin-4-yl)-2-(5-phenylindolo[3,2-a]carbazol-12(5H)-yl)benzonitrile and 2-(10,15-diphenyl-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazol-5-yl)-5-(2-phenylbenzo[4,5]thieno[3,2-d]pyrimidin-4-yl)benzonitrile (BTPDIDCz), as the green and greenish-yellow emitters. Among the two emitters, BTPDIDCz with the diindolocarbazole donor combined with the benzothienopyrimidine-4-benzonitrile acceptor demonstrated a high external quantum efficiency of 24.5% and 3 times longer device lifetime than the state-of-the-art green emitter. This work proposed the potential of benzothienopyrimidine-4-benzonitrile as the acceptor for long lifetime in TADF emitters.
Collapse
Affiliation(s)
- Ha Lim Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 440-746, Korea
| | - Chan Seok Oh
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 440-746, Korea
| | - Kyung Hyung Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 440-746, Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 440-746, Korea
| | - Wan Pyo Hong
- School of Advanced Material and Chemical Engineering, Daegu Catholic University, 13-13, Hayang-ro, Hayang-eup, Gyeonsan-si, Gyeongbuk 38430, Korea
| |
Collapse
|
12
|
Zhou T, Qian Y, Wang H, Feng Q, Xie L, Huang W. Recent Advances in Substituent Effects of Blue Thermally Activated Delayed Fluorescence Small Molecules. ACTA CHIMICA SINICA 2021. [DOI: 10.6023/a21010009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
13
|
Yoon J, Kim SK, Kim HJ, Choi S, Jung SW, Lee H, Kim JY, Yoon DW, Han CW, Chae WS, Kwon JH, Cho MJ, Choi DH. Asymmetric Host Molecule Bearing Pyridine Core for Highly Efficient Blue Thermally Activated Delayed Fluorescence OLEDs. Chemistry 2020; 26:16383-16391. [PMID: 32686232 DOI: 10.1002/chem.202002655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/16/2020] [Indexed: 01/12/2023]
Abstract
In this study, two host materials, pCzBzbCz and pCzPybCz, are synthesized to achieve a high efficiency and long lifetime of blue thermally activated delayed fluorescence organic light-emitting diodes (TADF-OLEDs). The molecular design strategy involves the introduction of a pyridine group into the core structure of pCzPybCz as an electron-withdrawing unit, and an electron-donating phenyl group into the structure of pCzBzbCz. These host materials demonstrate good thermal stability and high triplet energy (T1 =3.07 eV for pCzBzbCz and 3.06 eV for pCzPybCz) for the fabrication of blue TADF-OLEDs. In particular, pCzPybCz-based OLED devices demonstrate an external quantum efficiency (EQE) of 22.7 % and an operational lifetime of 24 h (LT90 , time to attain 90 % of initial luminance) at an initial luminance of 1000 cd m-2 . This superior lifetime could be explained by the C-N bond dissociation energy (BDE) in the host molecular structure. Furthermore, a mixed-host system using the electron-deficient 2,4-bis(dibenzo[b,d]furan-2-yl)-6-phenyl-1,3,5-triazine (DDBFT) is proposed to inhibit the formation of the anion state of our host materials. In short, the device operational lifetime is further improved by applying DDBFT. The carbazole-based asymmetric host molecule containing a pyridine core realizes a high-efficiency blue TADF-OLED showing a positive effect on the operating lifetime, and can provide useful strategies for designing new host materials.
Collapse
Affiliation(s)
- Jiwon Yoon
- Department of Chemistry, Research Institute for Natural Sciences, Institution Korea University, 145, Anam-ro, Sungbuk-gu, Seoul, 02841, Republic of Korea
| | - Seong Keun Kim
- Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Hyung Jong Kim
- Department of Chemistry, Research Institute for Natural Sciences, Institution Korea University, 145, Anam-ro, Sungbuk-gu, Seoul, 02841, Republic of Korea
| | - Suna Choi
- Department of Chemistry, Research Institute for Natural Sciences, Institution Korea University, 145, Anam-ro, Sungbuk-gu, Seoul, 02841, Republic of Korea
| | - Sang Won Jung
- Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Hyuna Lee
- Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Jun Yun Kim
- LG Display, Co., Ltd., LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, 07796, Republic of Korea
| | - Dae-Wi Yoon
- LG Display, Co., Ltd., LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, 07796, Republic of Korea
| | - Chang Wook Han
- LG Display, Co., Ltd., LG Science Park, 30, Magokjungang 10-ro, Gangseo-gu, Seoul, 07796, Republic of Korea
| | - Weon-Sik Chae
- Daegu Center, Korea Basic Science Institute, 80 Daehakro, Bukgu, Daegu, 41566, Republic of Korea
| | - Jang Hyuk Kwon
- Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Min Ju Cho
- Department of Chemistry, Research Institute for Natural Sciences, Institution Korea University, 145, Anam-ro, Sungbuk-gu, Seoul, 02841, Republic of Korea
| | - Dong Hoon Choi
- Department of Chemistry, Research Institute for Natural Sciences, Institution Korea University, 145, Anam-ro, Sungbuk-gu, Seoul, 02841, Republic of Korea
| |
Collapse
|
14
|
Su L, Cao F, Cheng C, Tsuboi T, Zhu Y, Deng C, Zheng X, Wang D, Liu Z, Zhang Q. High Fluorescence Rate of Thermally Activated Delayed Fluorescence Emitters for Efficient and Stable Blue OLEDs. ACS APPLIED MATERIALS & INTERFACES 2020; 12:31706-31715. [PMID: 32567302 DOI: 10.1021/acsami.0c07840] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A lack of an efficient and stable blue device is a critical factor restricting the development of organic light-emitting diode (OLED) technology that is currently expected to be overcome by employing thermally activated delayed fluorescence (TADF). Here, we investigate the TADF and electroluminescence (EL) performance of six carbazole/triphenyltriazine derivatives in different hosts. A good linearity between lg(LT50/kF2) and the EL emission wavelength is found, where LT50 is the half-life of the devices and kF is the fluorescence rate of the emitters, suggesting the dominance of the singlet exciton energy and lifetime in device stability. An indolylcarbazole/triphenyltriazine derivative (ICz-TRZ) with the capability to suppress solid-state solvation exhibits blue-shifted emission and an increased kF (1.5 × 108 s-1) in comparison to the control emitters in doped films. ICz-TRZ-based devices achieve a maximum external quantum efficiency (EQE) of 18% and an EQE of 5.5% at a very high luminance of 7 × 104 cd/m2. Ignoring the poor electrochemical stability of ICz-TRZ, the device offers an LT50 approaching 100 h under an initial luminance of 1000 cd/m2 and CIE coordinates of (0.14, 0.19). The findings in this work suggest that computer-aided design of high kF TADF emitters can be an approach to realize efficient and stable blue OLEDs.
Collapse
Affiliation(s)
- Liwu Su
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Fangyi Cao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Yungu (Gu'an) Technology Co. Ltd., Langfang, Hebei 065500, China
| | - Cong Cheng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Taiju Tsuboi
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Yunhui Zhu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Chao Deng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Xinyuan Zheng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Dan Wang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Zhang Liu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Qisheng Zhang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| |
Collapse
|
15
|
Che W, Xie Y, Li Z. Structural Design of Blue‐to‐Red Thermally‐Activated Delayed Fluorescence Molecules by Adjusting the Strength between Donor and Acceptor. ASIAN J ORG CHEM 2020. [DOI: 10.1002/ajoc.202000128] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Weilong Che
- Institute of Molecular Aggregation ScienceTianjin University Tianjin 300072 P. R. China)
| | - Yujun Xie
- Institute of Molecular Aggregation ScienceTianjin University Tianjin 300072 P. R. China)
| | - Zhen Li
- Institute of Molecular Aggregation ScienceTianjin University Tianjin 300072 P. R. China)
- Sauvage Center for Molecular SciencesDepartment of ChemistryWuhan University Wuhan 430072 P. R. China
| |
Collapse
|
16
|
Jung M, Lee KH, Lee JY. Molecular Engineering of Isomeric Benzofurocarbazole Donors for Photophysical Management of Thermally Activated Delayed Fluorescence Emitters. Chemistry 2020; 26:4816-4821. [PMID: 31967700 DOI: 10.1002/chem.201905473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/02/2020] [Indexed: 11/08/2022]
Abstract
Benzofurocarbazole moieties are commonly used donor structures in the design of thermally activated delayed fluorescence (TADF) emitters. However, only 5 H-benzofuro[3,2-c]carbazole (34BFCz) has been reported and, to the best of our knowledge, no other benzofurocarbazole derivatives have been covered in the literature. In the present study, two further benzofurocarbazole moieties, 12 H-benzofuro[3,2-a]carbazole (12BFCz) and 7 H-benzofuro[2,3-b]carbazole (23BFCz), have been synthesized to investigate the effect of the donor structure on the photophysics and device parameters of TADF emitters. Two benzofurocarbazole-derived TADF emitters, 12-(2-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-12 H-benzofuro[3,2-a]carbazole (o12BFCzTrz) and 7-(2-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-7 H-benzofuro[2,3-b]carbazole (o23BFCzTrz), have been compared with 5-(2-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-5 H-benzofuro[3,2-c]carbazole (oBFCzTrz). The benzofurocarbazole donor structure governs the TADF characteristics, such as charge-transfer property and emission color. The 12BFCz donor has proved to be effective in blue-shifting the emission color, and 34BFCz has proven useful for improving the external quantum efficiency (EQE). The 12BFCz-derived o12BFCzTrz showed blue-shifted color coordinates of (0.159, 0.288), compared to (0.178, 0388) for o23BFCzTrz and (0.169, 0.341) for oBFCzTrz. The 34BFCz-derived oBFCzTrz exhibited an EQE of 22.9 %, compared to 19.2 % for o12BFCzTrz and 21.1 % for o23BFCzTrz.
Collapse
Affiliation(s)
- Mina Jung
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| | - Kyung Hyung Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| |
Collapse
|
17
|
Feng Q, Tan K, Zheng X, Xie S, Xue K, Bo Y, Zhang H, Lin D, Rao J, Xie X, Xie L, Cao H, Zhang H, Wei Y, Huang W. Simultaneous and Significant Improvements in Efficiency and Stability of Deep‐Blue Organic Light Emitting Diodes through Friedel‐Crafts Arylmethylation of a Fluorophore. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.201900268] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Quanyou Feng
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Kesheng Tan
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Xiaojun Zheng
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Songlin Xie
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Kai Xue
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Yifan Bo
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - He Zhang
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Dongqing Lin
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Junfeng Rao
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Xinmiao Xie
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Linghai Xie
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Hongtao Cao
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Hongmei Zhang
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Ying Wei
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
| | - Wei Huang
- Key Laboratory for Organic Electronics and Information Displays Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing 210023 China
- Shaanxi Institute of Flexible ElectronicsNorthwestern Polytechnical University 127 West Youyi Road Xi'an 710072 China
| |
Collapse
|
18
|
Kothavale S, Lee KH, Lee JY. CN-Modified Imidazopyridine as a New Electron Accepting Unit of Thermally Activated Delayed Fluorescent Emitters. Chemistry 2020; 26:845-852. [PMID: 31654423 DOI: 10.1002/chem.201903877] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Indexed: 11/11/2022]
Abstract
Two efficient thermally activated delayed fluorescent (TADF) emitters were developed by utilizing CN-modified imidazopyridine as an acceptor unit. The CN-modified imidazopyridine acceptor was combined with either an acridine donor or a phenoxazine donor through a phenyl linker to produce two TADF emitters, Ac-CNImPy and PXZ-CNImPy. The acridine-based Ac-CNImPy emitter exhibited sky-blue emission with a CIE coordinate of (0.18, 0.38), whereas the phenoxazine-donor-based PXZ-CNImPy showed greenish-yellow emission with a CIE coordinate of (0.32, 0.58). A high photoluminescence quantum yield of 80 % was observed for the PXZ-CNImPy emitter compared with 40 % for the Ac-CNImPy emitter. Organic light-emitting diodes based on the PXZ-CNImPy emitter demonstrated high external quantum efficiency of 17.0 %. Hence, the CN-modified imidazopyridine unit can be considered as a useful electron acceptor for the future design of highly efficient TADF emitters.
Collapse
Affiliation(s)
- Shantaram Kothavale
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Korea
| | - Kyung Hyung Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Korea
| |
Collapse
|
19
|
Abroshan H, Cho E, Coropceanu V, Brédas J. Suppression of Concentration Quenching in Ortho‐Substituted Thermally Activated Delayed Fluorescence Emitters. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900185] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Hadi Abroshan
- School of Chemistry and Biochemistry Center for Organic Photonics and Electronics Georgia Institute of Technology Atlanta GA 30332‐0400 USA
| | - Eunkyung Cho
- School of Chemistry and Biochemistry Center for Organic Photonics and Electronics Georgia Institute of Technology Atlanta GA 30332‐0400 USA
| | - Veaceslav Coropceanu
- School of Chemistry and Biochemistry Center for Organic Photonics and Electronics Georgia Institute of Technology Atlanta GA 30332‐0400 USA
| | - Jean‐Luc Brédas
- School of Chemistry and Biochemistry Center for Organic Photonics and Electronics Georgia Institute of Technology Atlanta GA 30332‐0400 USA
| |
Collapse
|
20
|
Kothavale S, Lee KH, Lee JY. Molecular Design Strategy of Thermally Activated Delayed Fluorescent Emitters Using CN-Substituted Imidazopyrazine as a New Electron-Accepting Unit. Chem Asian J 2019; 15:122-128. [PMID: 31743615 DOI: 10.1002/asia.201901311] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/16/2019] [Indexed: 11/11/2022]
Abstract
Thermally activated delayed fluorescence (TADF)-based organic light-emitting diodes (OLEDs) have attracted enormous attention recently due to their capability to replace conventional phosphorescent organic light-emitting diodes for practical applications. In this work, a newly designed CN-substituted imidazopyrazine moiety was utilized as an electron-accepting unit in a TADF emitter. Two TADF emitters, 8-(3-cyano-4-(9,9-dimethylacridin-10(9H)-yl)phenyl)-2-phenylimidazo[1,2-a]pyrazine-3-carbonitrile (Ac-CNImPyr) and 8-(3-cyano-4-(10H-phenoxazin-10-yl)phenyl)-2-phenylimidazo[1,2-a]pyrazine-3-carbonitrile (PXZ-CNImPyr), were developed based on the CN-substituted imidazopyrazine acceptor combined with acridine and phenoxazine donor, respectively. A CN-substituted phenyl spacer was introduced between the donor and acceptor for a sufficiently small singlet-triplet energy gap (ΔEST ) and molecular orbital management. Small ΔEST of 0.07 eV was achieved for the phenoxazine donor-based PXZ-CNImPyr emitter. As a result, an organic light-emitting diode based on the PXZ-CNImPyr emitter exhibited a high external quantum efficiency of up to 12.7 %, which surpassed the EQE limit of common fluorescent emitters. Hence, the CN-modified imidazopyrazine unit can be introduced as a new acceptor for further modifications to develop efficient TADF-based OLEDs.
Collapse
Affiliation(s)
- Shantaram Kothavale
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Korea
| | - Kyung Hyung Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Korea
| |
Collapse
|
21
|
Mubarok H, Oh J, Lee H, Jung J, Lee MH. Thermally Activated Delayed Fluorescent Properties of
Ortho
‐Carbazole‐Appended Triazine Compounds. B KOREAN CHEM SOC 2019. [DOI: 10.1002/bkcs.11879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Hanif Mubarok
- Department of ChemistryUniversity of Ulsan Ulsan 44610 Republic of Korea
| | - Jihun Oh
- Department of ChemistryUniversity of Ulsan Ulsan 44610 Republic of Korea
| | - Heechai Lee
- Department of ChemistryUniversity of Ulsan Ulsan 44610 Republic of Korea
| | - Jaehoon Jung
- Department of ChemistryUniversity of Ulsan Ulsan 44610 Republic of Korea
| | - Min Hyung Lee
- Department of ChemistryUniversity of Ulsan Ulsan 44610 Republic of Korea
| |
Collapse
|
22
|
Li G, Lou W, Wang D, Deng C, Zhang Q. Difluoroboron-Enabled Thermally Activated Delayed Fluorescence. ACS APPLIED MATERIALS & INTERFACES 2019; 11:32209-32217. [PMID: 31387348 DOI: 10.1021/acsami.9b08107] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A new series of tetracoordinated boron-enabled thermally activated delayed fluorescence (TADF) materials with a donor-acceptor BF2-type framework were designed and conveniently synthesized. Difluoroboron plays a critical role and acts as a key to coordinate with the latent acceptor of the 2-(4-phenylpyridin-2-yl)phenol (PPyPOH) moiety to realize TADF. TADF materials are air-stable and have a high photoluminescence quantum yield of up to 99%. NOBF2-Cz- and NOBF2-DPCz-doped blue OLEDs demonstrated EQEs of 11.0% with CIE coordinates of (0.14, 0.16) and 15.8% with (0.14, 0.28) and high brightness of 6761 and 19383 cd/m2 could be achieved, respectively. Moreover, the blue OLED doped with NOBF2-DPCz and the green OLED doped with NOBF2-DMAC achieved operational lifetimes at 50% of initial luminance (L0 = 500 cd/m2), LT50, of 54 and 920 h, respectively. This work indicates that these tetracoordinated difluoroboron molecules can act as efficient and stable TADF materials for OLED applications.
Collapse
Affiliation(s)
- Guijie Li
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering , Zhejiang University of Technology , Hangzhou 310014 , P. R. China
| | - Weiwei Lou
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering , Zhejiang University of Technology , Hangzhou 310014 , P. R. China
| | - Dan Wang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , P. R. China
| | - Chao Deng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , P. R. China
| | - Qisheng Zhang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , P. R. China
| |
Collapse
|
23
|
Cheng Z, Li Z, Xu Y, Liang J, Lin C, Wei J, Wang Y. Achieving Efficient Blue Delayed Electrofluorescence by Shielding Acceptors with Carbazole Units. ACS APPLIED MATERIALS & INTERFACES 2019; 11:28096-28105. [PMID: 31290328 DOI: 10.1021/acsami.9b07820] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The design and synthesis of blue thermally activated delayed fluorescence (TADF) emitters that have high electroluminescence efficiency and low efficiency roll-off features remain a great challenge. Herein, we developed a facile and efficient strategy by shielding acceptors with carbazole units for constructing high-performance blue TADF emitters. Benzonitrile (BN), 9,9-diphenylacridan (DPAc), and carbazole (Cz) were adopted as the acceptor, donor, and protector, respectively, to build two TADF emitters named DPAc-DCzBN and DPAc-DtCzBN. The nondoped organic light-emitting diodes (OLEDs) of DPAc-DCzBN as the emitter exhibited a standard sky-blue emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.16, 0.26), high external quantum efficiency (EQE) of 20.0%, and low efficiency roll-off (EQEs of 19.5, 16.1, and 12.6% at 100, 500, and 1000 cd m-2, respectively), which is an outstanding nondoped blue TADF OLED. The doped device of DPAc-DtCzBN displayed a pure blue emission and the corresponding CIE coordinates are (0.16, 0.15). Meanwhile, it also demonstrated high and stabilized EQE values of 23.1, 18.3, and 11.5% at maxima, 100 and 500 cd m-2, respectively, which is a quite high level among the pure blue TADF OLEDs. This study testifies the feasibility of our strategy in constructing high-performance TADF electroluminescent materials.
Collapse
Affiliation(s)
- Zong Cheng
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , P. R. China
| | - Zhiqiang Li
- 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
| | - Jixiong Liang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , P. R. China
| | - Chunhui Lin
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , P. R. China
| | - Jinbei Wei
- 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
|
24
|
Jeon SK, Lee HL, Yook KS, Lee JY. Recent Progress of the Lifetime of Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescent Material. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1803524. [PMID: 30907464 DOI: 10.1002/adma.201803524] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 01/14/2019] [Indexed: 05/22/2023]
Abstract
Recently, the external quantum efficiency and lifetime of organic light-emitting diodes (OLEDs) have been dramatically upgraded due to development of organic materials and device structure. In particular, an intramolecular or intermolecular complex based on thermally activated delayed fluorescent (TADF) materials has greatly contributed to improving OLED device performance. Although high external quantum efficiency has been the main objective of the development of TADF materials as hosts and emitters, recent interest has been directed towards the lifetime of TADF-material-based OLEDs. For the past several years, remarkable advances in the lifetime of phosphorescent and TADF OLEDs have been made using TADF materials as hosts or emitters in the emitting layer. Therefore, since TADF materials are useful as both hosts and emitters for a long lifetime, this work discusses the recent progress made in developing TADF materials for long-lifetime OLEDs.
Collapse
Affiliation(s)
- Sang Kyu Jeon
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 446-740, South Korea
| | - Ha Lim Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 446-740, South Korea
| | - Kyoung Soo Yook
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 446-740, South Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 446-740, South Korea
| |
Collapse
|
25
|
Chen XK, Bakr BW, Auffray M, Tsuchiya Y, Sherrill CD, Adachi C, Bredas JL. Intramolecular Noncovalent Interactions Facilitate Thermally Activated Delayed Fluorescence (TADF). J Phys Chem Lett 2019; 10:3260-3268. [PMID: 31141375 DOI: 10.1021/acs.jpclett.9b01220] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In the conventional molecular design of thermally activated delayed fluorescence (TADF) organic emitters, simultaneously achieving a fast rate of reverse intersystem crossing (RISC) from the triplet to the singlet manifold and a fast rate of radiative decay is a challenging task. A number of recent experimental data, however, point to TADF emitters with intramolecular π-π interactions as a potential pathway to overcome the issue. Here, we report a comprehensive investigation of TADF emitters with intramolecular π···π or lone-pair···π noncovalent interactions. We uncover the impact of those intramolecular noncovalent interactions on the TADF properties. In particular, we find that folded geometries in TADF molecules can trigger lone-pair···π interactions, introduce a n → π* character of the relevant transitions, enhance the singlet-triplet spin-orbit coupling, and ultimately greatly facilitate the RISC process. This work provides a robust foundation for the molecular design of a novel class of highly efficient TADF emitters in which intramolecular noncovalent interactions play a critical function.
Collapse
Affiliation(s)
- Xian-Kai Chen
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Brandon W Bakr
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Morgan Auffray
- Center for Organic Photonics and Electronics Research (OPERA) , Kyushu University , 744 Motooka, Nishi , Fukuoka 819-0395 , Japan
| | - Youichi Tsuchiya
- Center for Organic Photonics and Electronics Research (OPERA) , Kyushu University , 744 Motooka, Nishi , Fukuoka 819-0395 , Japan
| | - C David Sherrill
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA) , Kyushu University , 744 Motooka, Nishi , Fukuoka 819-0395 , Japan
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER) , Kyushu University , 744 Motooka, Nishi-ku , Fukuoka 819-0395 , Japan
| | - Jean-Luc Bredas
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| |
Collapse
|
26
|
Jayakumar J, Wu TL, Huang MJ, Huang PY, Chou TY, Lin HW, Cheng CH. Pyridine-Carbonitrile-Carbazole-Based Delayed Fluorescence Materials with Highly Congested Structures and Excellent OLED Performance. ACS APPLIED MATERIALS & INTERFACES 2019; 11:21042-21048. [PMID: 31088068 DOI: 10.1021/acsami.9b04664] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Three pyridine-carbonitrile-carbazole-based thermally activated delayed fluorescence (TADF) materials with highly sterically congested structures have been synthesized. The donor-acceptor-type TADF emitters (26-, 246-, and 35tCzPPC) consist of a 2,6-diphenylpyridine-3,5-dicarbonitrile core (PPC) as the acceptor and a di( t-butyl)carbazole-substituted phenyl group attached to C4 of the PC core as the donor. The molecules show a unique structure containing two consecutive large twisted angles along the donor and acceptor groups. The structure leads to a nearly complete space separation of the highest occupied molecular orbital and lowest unoccupied molecular orbital, a small Δ EST value, and excellent TADF property. Moreover, the 26- and 246tCzPPC dopants favor a horizontal alignment enhancing the light outcoupling of the device. In contrast, 35tCzPPC favors a perpendicular alignment reducing the light outcoupling efficiency of the device. The 246tCzPPC-based devices show external quantum efficiency as high as 29.6% because of excellent TADF property, very high photoluminescence quantum yield, and high Θ value in the thin films. The device performance is the best among the pyridine-carbonitrile-based TADF emitters.
Collapse
|
27
|
Zhang Y, Li Z, Li C, Wang Y. Suppressing Efficiency Roll-Off of TADF Based OLEDs by Constructing Emitting Layer With Dual Delayed Fluorescence. Front Chem 2019; 7:302. [PMID: 31114787 PMCID: PMC6502957 DOI: 10.3389/fchem.2019.00302] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Accepted: 04/15/2019] [Indexed: 01/30/2023] Open
Abstract
To suppress efficiency roll-off induced by triplet–triplet annihilation (TTA) and singlet–triplet annihilation (STA) in thermally activated delayed fluorescence (TADF) based organic light emitting diodes (OLEDs) is still a challenge. This issue was efficiently addressed by generating dual delayed fluorescence in the emitting layer of OLEDs. A novel TADF compound, PXZ-CMO, featuring a D-A structure was designed and synthesized. By dispersing the emitter into different hosts, devices G1 (MCP host) and G2 (DPEPO host) with identical configurations were carefully fabricated, which showed similar maximum EQE/CE of 12.1%/38.2 cd A−1 and 11.8%/33.1 cd A−1, respectively. Despite severe efficiency roll-off in device G2 with only 6.4% EQE remaining at a luminance of 1,000 cd m−2, a remarkably reduced efficiency roll-off was attained in device G1, retaining EQE as high as 10.4% at the same luminance of 1,000 cd m−2. The excellent device performance with reduced roll-off in device G1 should result from the dual delayed fluorescence in the emitting layer, which possesses great advantages in achieving dynamic and adaptive exciton distribution for radiation acceleration and quench suppression.
Collapse
Affiliation(s)
- Yuewei Zhang
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, China
| | - Zhiqiang Li
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, China
| | - Chenglong Li
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, China.,State Key Laboratory on Integrated Optoelectronics, Key Laboratory of Advanced Gas Sensors, College of Electronic Science and Engineering, Jilin University, Changchun, China
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, China
| |
Collapse
|
28
|
Li C, Ren Z, Sun X, Li H, Yan S. Deep-Blue Thermally Activated Delayed Fluorescence Polymers for Nondoped Solution-Processed Organic Light-Emitting Diodes. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00083] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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
| | - Zhongjie Ren
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiaoli Sun
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Huihui Li
- 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/Shandong Provincial Key Laboratory of Rubber-plastics, Qingdao University of Science & Technology, Qingdao 266042, China
| |
Collapse
|
29
|
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
|
30
|
Cai M, Zhang D, Xu J, Hong X, Zhao C, Song X, Qiu Y, Kaji H, Duan L. Unveiling the Role of Langevin and Trap-Assisted Recombination in Long Lifespan OLEDs Employing Thermally Activated Delayed Fluorophores. ACS APPLIED MATERIALS & INTERFACES 2019; 11:1096-1108. [PMID: 30525372 DOI: 10.1021/acsami.8b16784] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Recent research studies on noble-metal-free thermally activated delayed fluorescent (TADF) materials have boosted the efficiencies of organic light-emitting diodes (OLEDs) to unity. However, the short lifespan still hinders their further practical application. Carrier recombination pathways have been reported to have a significant influence on the efficiencies of TADF devices, though their effects on device lifetimes remain rarely studied. Here, we have designed and synthesized five pyrimidine or pyrazine/carbazole isomers as hosts for TADF OLEDs to explore the inherent role of Langevin recombination (LR) and trap-assisted recombination (TAR) in device lifetimes. It is revealed that for LR dominant devices, lifetimes would increase by reducing the host triplet energy levels, whereas for TAR dominant devices, lifetimes are insensitive to the host triplet excitons as recombination mainly takes place on dopants. Still, LR dominant devices are favored as they offer more room for optimization. We further apply this concept in designing a stable LR dominant blue TADF device, achieving a long LT50 (lifespan up to 50% of the initial luminance) of 269 h and high external quantum efficiency of 17.9% at 1000 cd m-2 simultaneously.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Hironori Kaji
- Institute for Chemical Research , Kyoto University , Uji , Kyoto 6611-0011 , Japan
| | | |
Collapse
|
31
|
Kim M, Yoon S, Han SH, Ansari R, Kieffer J, Lee JY, Kim J. Molecular Design Approach Managing Molecular Orbital Superposition for High Efficiency without Color Shift in Thermally Activated Delayed Fluorescent Organic Light‐Emitting Diodes. Chemistry 2019; 25:1829-1834. [DOI: 10.1002/chem.201805616] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Mounggon Kim
- Department of Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109 USA
| | - Seong‐Jun Yoon
- Department of Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109 USA
| | - Si Hyun Han
- School of Chemical Engineering Sungkyunkwan University 2066, Seobu-ro, Jangan-gu Suwon Gyeonggi 440-746 Korea
| | - Ramin Ansari
- Department of Chemical Engineering University of Michigan Ann Arbor Michigan 48109 USA
| | - John Kieffer
- Department of Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109 USA
| | - Jun Yeob Lee
- School of Chemical Engineering Sungkyunkwan University 2066, Seobu-ro, Jangan-gu Suwon Gyeonggi 440-746 Korea
| | - Jinsang Kim
- Department of Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109 USA
| |
Collapse
|
32
|
Cai M, Zhang D, Duan L. High Performance Thermally Activated Delayed Fluorescence Sensitized Organic Light‐Emitting Diodes. CHEM REC 2018; 19:1611-1623. [DOI: 10.1002/tcr.201800148] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/23/2018] [Indexed: 01/22/2023]
Affiliation(s)
- Minghan Cai
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of EducationDepartment of ChemistryTsinghua University Beijing 100084 China
| | - Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of EducationDepartment of ChemistryTsinghua University Beijing 100084 China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of EducationDepartment of ChemistryTsinghua University Beijing 100084 China
- Center for Flexible Electronics TechnologyTsinghua University Beijing 100084 China
| |
Collapse
|
33
|
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
|
34
|
Konidena RK, Thomas KRJ, Pathak A, Dubey DK, Sahoo S, Jou JH. Tuning the Photophysical and Electroluminescence Properties in Asymmetrically Tetrasubstituted Bipolar Carbazoles by Functional Group Disposition. ACS APPLIED MATERIALS & INTERFACES 2018; 10:24013-24027. [PMID: 29931980 DOI: 10.1021/acsami.8b04566] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Carbazoles decorated with both donor and acceptor fragments offer a classical way to optimize bipolar functional properties. In this work, a series of carbazoles featuring triphenylamine donors and cyano acceptors are synthesized and their structure-property relationship is studied. The effects of connectivity and the chromophore number density on photophysical and electroluminescence properties are investigated. The position of the triphenylamine donor on the 3,6-dicyanocarbazole nucleus significantly affected the photophysical and electroluminescence properties. The dye possessing triphenylamine on C2 and C7 displayed a red shift in absorption when compared with the structural analogue with triphenylamine tethered to C1 and C8. The emission wavelength of the dyes are tunable from blue to green, by altering the position of triphenylamine and cyano substituents. All of the dyes exhibited positive solvatochromism in emission, attributable to the photoinduced intramolecular charge transfer from the triphenylamine donor to the cyano acceptor. However, the extent of charge transfer and hybridization of local and charge-transfer-excited states is highly dependent on the position of triphenylamine and cyano groups on the carbazole nucleus. Dyes containing cyano substituents at C2 and C7 showed a prolonged excited state lifetime, broad emission, and large Stokes shifts, indicating the presence of a higher charge transfer component in the excited state. The dyes displayed exceptional thermal stability with the onset decomposition temperature (10% weight loss) > 350 °C. Electrochemical measurements revealed low oxidation potential for dyes containing triphenylamine at C3 and/or C6. Addition of a cyano acceptor on carbazole led to the stabilization of lowest unoccupied molecular orbital. Furthermore, the materials were tested as emitting dopants in solution-processable multilayer organic light emitting diodes and found to display deep-blue/sky-blue electroluminescence with external quantum efficiency as high as 6.5% for a deep-blue emitter (CIE y ∼ 0.06).
Collapse
Affiliation(s)
- Rajendra Kumar Konidena
- Organic Materials Laboratory, Department of Chemistry , Indian Institute of Technology Roorkee , Roorkee 247 667 , India
| | - K R Justin Thomas
- Organic Materials Laboratory, Department of Chemistry , Indian Institute of Technology Roorkee , Roorkee 247 667 , India
| | - Ambika Pathak
- Organic Materials Laboratory, Department of Chemistry , Indian Institute of Technology Roorkee , Roorkee 247 667 , India
| | - Deepak Kumar Dubey
- Department of Material Science and Engineering , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Snehasis Sahoo
- Department of Material Science and Engineering , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Jwo-Huei Jou
- Department of Material Science and Engineering , National Tsing Hua University , Hsinchu 30013 , Taiwan
| |
Collapse
|
35
|
Lifetime enhancement of blue thermally activated delayed fluorescent devices by separated carrier channels using dibenzofuran-triazine type hosts. J IND ENG CHEM 2018. [DOI: 10.1016/j.jiec.2018.01.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
36
|
Seo JA, Im Y, Han SH, Lee CW, Lee JY. Unconventional Molecular Design Approach of High-Efficiency Deep Blue Thermally Activated Delayed Fluorescent Emitters Using Indolocarbazole as an Acceptor. ACS APPLIED MATERIALS & INTERFACES 2017; 9:37864-37872. [PMID: 28980471 DOI: 10.1021/acsami.7b09351] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Unconventional blue thermally activated delayed fluorescent emitters having electron-donating type indolocarbazole as an acceptor were developed by attaching carbazolylcarbazole or acridine donors to the indolocarbazole acceptor. Three compounds were derived from the indolocarbazole acceptor. The indolocarbazole-acridine combined products showed efficient delayed fluorescent behavior and a high quantum efficiency of 19.5% with a color coordinate of (0.15, 0.16) when they were evaluated as thermally activated delayed fluorescent emitters in deep blue fluorescent devices. This is the first demonstration of the use of electron-donating carbazole-derived moieties as efficient acceptor units of blue thermally activated delayed fluorescent emitters.
Collapse
Affiliation(s)
- Jeong-A Seo
- School of Chemical Engineering, Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea
| | - Yirang Im
- School of Chemical Engineering, Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea
| | - Si Hyun Han
- School of Chemical Engineering, Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea
| | - Chil Won Lee
- Department of Chemistry, Dankook University , Cheonan, Chungcheongnam-do 31116, Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University , 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi 440-746, Korea
| |
Collapse
|
37
|
Geng Y, Cui LS, Kim JU, Nakanotani H, Adachi C. Molecular Design for Blue Thermal Activated Delayed Fluorescence Materials: Substitution Position Effect. CHEM LETT 2017. [DOI: 10.1246/cl.170587] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Yan Geng
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395
| | - Lin-Song Cui
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395
| | - Jong Uk Kim
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395
| | - Hajime Nakanotani
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395
- Japan Science and Technology Agency, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi-ku, Fukuoka 819-0395
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395
- Japan Science and Technology Agency, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi-ku, Fukuoka 819-0395
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395
| |
Collapse
|
38
|
Lee YH, Park S, Oh J, Shin JW, Jung J, Yoo S, Lee MH. Rigidity-Induced Delayed Fluorescence by Ortho Donor-Appended Triarylboron Compounds: Record-High Efficiency in Pure Blue Fluorescent Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2017; 9:24035-24042. [PMID: 28653832 DOI: 10.1021/acsami.7b05615] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A synthetic approach to highly efficient thermally activated delayed fluorescence (TADF) is proposed that uses ortho donor (D)-acceptor (A) compounds (PXZoB, DPAoB, and CzoB), wherein the acceptor is based on triarylboron and the donor is phenoxazine (PXZ), diphenylamine (DPA), or carbazole (Cz). Combined with the ortho D-A connectivity, the bulky nature of the triarylboron endows the D-A dyads with inherent steric "locking" for a highly twisted arrangement, leading to a small energy difference between singlet and triplet excited states (ΔEST) and thus exhibiting very efficient TADF with microsecond-range lifetimes. In sharp contrast, the corresponding para D-A derivatives, DPApB and CzpB, only display short-lived, normal fluorescence. Organic light-emitting diodes (OLEDs) incorporating the proposed ortho D-A compounds as emitters display orange, greenish-blue, and pure blue emission and exhibit high external quantum efficiency (ηEQE). In particular, the pure blue OLEDs based on the proposed ortho D-A emitters with a carbazole donor (CzoB) show a record-high ηEQE of 22.6% with CIE color coordinates of (0.139, 0.150), well illustrating the validity of the proposed approach. Upon optical optimization, the ηEQE is further improved to 24.1%.
Collapse
Affiliation(s)
- Young Hoon Lee
- Department of Chemistry and Energy Harvest Storage Research Center, University of Ulsan , Ulsan 44610, Republic of Korea
| | - Sunghee Park
- School of Electrical Engineering, Korea Advanced Institute of Science & Technology , Daejeon 34141, Republic of Korea
| | - Jihun Oh
- Department of Chemistry and Energy Harvest Storage Research Center, University of Ulsan , Ulsan 44610, Republic of Korea
| | - Jong Won Shin
- Korea Institute of Science and Technology Information , Daegu 41515, Republic of Korea
| | - Jaehoon Jung
- Department of Chemistry and Energy Harvest Storage Research Center, University of Ulsan , Ulsan 44610, Republic of Korea
| | - Seunghyup Yoo
- School of Electrical Engineering, Korea Advanced Institute of Science & Technology , Daejeon 34141, Republic of Korea
| | - Min Hyung Lee
- Department of Chemistry and Energy Harvest Storage Research Center, University of Ulsan , Ulsan 44610, Republic of Korea
| |
Collapse
|
39
|
Wang C, Zhang J, Tang J, Zou G. A Sequential Suzuki Coupling Approach to Unsymmetrical Aryl s
-Triazines from Cyanuric Chloride. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201700260] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Chen Wang
- School of Chemistry & Molecular Engineering; East China University of Science & Technology; 130 Meilong Rd Shanghai People's Republic of China
| | - Jiehui Zhang
- School of Chemistry & Molecular Engineering; East China University of Science & Technology; 130 Meilong Rd Shanghai People's Republic of China
| | - Jie Tang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development &; Shanghai Key Laboratory of Green Chemistry and Chemical Processes, SCME; East China Normal University; 3663 North Zhongshan Rd. Shanghai People's Republic of China
| | - Gang Zou
- School of Chemistry & Molecular Engineering; East China University of Science & Technology; 130 Meilong Rd Shanghai People's Republic of China
| |
Collapse
|
40
|
Wang S, Cheng Z, Song X, Yan X, Ye K, Liu Y, Yang G, Wang Y. Highly Efficient Long-Wavelength Thermally Activated Delayed Fluorescence OLEDs Based on Dicyanopyrazino Phenanthrene Derivatives. ACS APPLIED MATERIALS & INTERFACES 2017; 9:9892-9901. [PMID: 28247753 DOI: 10.1021/acsami.6b14796] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Highly efficient long-wavelength thermally activated delayed fluorescence (TADF) materials are developed using 2,3-dicyanopyrazino phenanthrene (DCPP) as the electron acceptor (A), and carbazole (Cz), diphenylamine (DPA), or 9,9-dimethyl-9,10-dihydroacridine (DMAC) as the electron donor (D). Because of the large, rigid π-conjugated structure and strong electron-withdrawing capability of DCPP, TADF molecules with emitting colors ranging from yellow to deep-red are realized with different electron-donating groups and π-conjugation length. The connecting modes between donor and acceptor, that is, with or without the phenyl ring as π-bridge, are also investigated to study the π-bridge effect on the thermal, photophysical, electrochemical, and electroluminescent properties. Yellow, orange, red, and deep-red organic light-emitting diodes (OLEDs) based on DCPP derivatives exhibit high efficiencies of 47.6 cd A-1 (14.8%), 34.5 cd A-1 (16.9%), 12.8 cd A-1 (10.1%), and 13.2 cd A-1 (15.1%), with Commission Internationale de L'Eclairage (CIE) coordinates of (0.44, 0.54), (0.53, 0.46), (0.60, 0.40), and (0.64, 0.36), respectively, which are among the best values for long-wavelength TADF OLEDs.
Collapse
Affiliation(s)
- Shipan Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China
| | - Zong Cheng
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China
| | - Xiaoxian Song
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China
| | - Xianju Yan
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China
| | - Kaiqi Ye
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China
| | - Yu Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China
| | - Guochun Yang
- Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University , Changchun 130024, People's Republic of China
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China
| |
Collapse
|
41
|
Zhang D, Zhao C, Zhang Y, Song X, Wei P, Cai M, Duan L. Highly Efficient Full-Color Thermally Activated Delayed Fluorescent Organic Light-Emitting Diodes: Extremely Low Efficiency Roll-Off Utilizing a Host with Small Singlet-Triplet Splitting. ACS APPLIED MATERIALS & INTERFACES 2017; 9:4769-4777. [PMID: 28094502 DOI: 10.1021/acsami.6b15272] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Numerous efforts have been devoted to boost the efficiency of thermally activated delayed fluorescence (TADF) devices; however, strategies to suppress the device efficiency roll-off are still in urgent need. Here, a general and effective approach to suppress the efficiency roll-off of TADF devices is proposed, that is, utilizing TADF materials as the hosts for TADF emitters. Bearing small singlet-triplet splitting (ΔEST) with donor and acceptor units, TADF materials as the hosts possess the potential to achieve matched frontier energy levels with the adjacent transporting layers, facilitating balanced charge injection as well as bipolar charge transport mobilities beneficial to the balanced charges transportation. Furthermore, an enhanced Förster energy transfer from the host to the dopant can be anticipated, helpful to reduce the exciton concentration. Based on the principles, a new TADF material based on indeno[2,1-b]carbazole/1,3,5-triazin derivation is synthesized and used as the universal host for the full-color TADF devices. Remarkable low efficiency roll-off was achieved with above 90% of the maximum external quantum efficiencies (EQEmax's) maintained even at a brightness of 2000 cd/m2, along with EQEmax's of 23.2, 21.0, and 19.2% for orange, green, and sky-blue TADF devices, respectively. Through computational simulation, we identified the suppressed exciton annihilation rates compared with devices adopting conventional hosts. The state-of-the-art low efficiency roll-off of those TADF devices manifests the great potential of such host design strategy, paving an efficient strategy toward their practical application.
Collapse
Affiliation(s)
- Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Chongguang Zhao
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Yunge Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Xiaozeng Song
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Pengcheng Wei
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Minghan Cai
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University , Beijing 100084, China
| |
Collapse
|
42
|
Cui LS, Nomura H, Geng Y, Kim JU, Nakanotani H, Adachi C. Controlling Singlet-Triplet Energy Splitting for Deep-Blue Thermally Activated Delayed Fluorescence Emitters. Angew Chem Int Ed Engl 2016; 56:1571-1575. [PMID: 28035781 DOI: 10.1002/anie.201609459] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/28/2016] [Indexed: 11/08/2022]
Abstract
The development of efficient metal-free organic emitters with thermally activated delayed fluorescence (TADF) properties for deep-blue emission is still challenging. A new family of deep-blue TADF emitters based on a donor-acceptor architecture has been developed. The electronic interaction between donor and acceptor plays a key role in the TADF mechanism. Deep-blue OLEDs fabricated with these TADF emitters achieved high external quantum efficiencies over 19.2 % with CIE coordinates of (0.148, 0.098).
Collapse
Affiliation(s)
- Lin-Song Cui
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Hiroko Nomura
- Kyulux Inc., Suite 227, Fukuoka Industry-Academia Symphonicity (FiaS), Bldg.2, 4-1 Kyudai-Shinmachi, Nishi-ku, Fukuoka, 819-0388, Japan
| | - Yan Geng
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Jong Uk Kim
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Hajime Nakanotani
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Chihaya Adachi
- Department of Applied Chemistry, Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.,Japan Science and Technology Agency, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.,International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan
| |
Collapse
|
43
|
Cui LS, Nomura H, Geng Y, Kim JU, Nakanotani H, Adachi C. Controlling Singlet-Triplet Energy Splitting for Deep-Blue Thermally Activated Delayed Fluorescence Emitters. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201609459] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Lin-Song Cui
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Hiroko Nomura
- Kyulux Inc.; Suite 227, Fukuoka Industry-Academia Symphonicity (FiaS), Bldg.2; 4-1 Kyudai-Shinmachi, Nishi-ku Fukuoka 819-0388 Japan
| | - Yan Geng
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Jong Uk Kim
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Hajime Nakanotani
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| | - Chihaya Adachi
- Department of Applied Chemistry; Center for Organic Photonics and Electronics Research (OPERA); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
- Japan Science and Technology Agency, ERATO; Adachi Molecular Exciton Engineering Project; 744 Motooka, Nishi Fukuoka 819-0395 Japan
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER); Kyushu University; 744 Motooka, Nishi Fukuoka 819-0395 Japan
| |
Collapse
|