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Zhao W, Hu X, Kong F, Tang J, Yan D, Wang J, Liu Y, Sun Y, Sheng R, Chen P. Progress in Research on White Organic Light-Emitting Diodes Based on Ultrathin Emitting Layers. MICROMACHINES 2024; 15:626. [PMID: 38793199 PMCID: PMC11123088 DOI: 10.3390/mi15050626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/26/2024]
Abstract
White organic light-emitting diodes (WOLEDs) hold vast prospects in the fields of next-generation displays and solid-state lighting. Ultrathin emitting layers (UEMLs) have become a research hotspot because of their unique advantage. On the basis of simplifying the device structure and preparation process, they can achieve electroluminescent performance comparable to that of doped devices. In this review, we first discuss the working principles and advantages of WOLEDs based on UEML architecture, which can achieve low cost and more flexibility by simplifying the device structure and preparation process. Subsequently, the successful applications of doping and non-doping technologies in fluorescent, phosphorescent, and hybrid WOLEDs combined with UEMLs are discussed, and the operation mechanisms of these WOLEDs are emphasized briefly. We firmly believe that this article will bring new hope for the development of UEML-based WOLEDs in the future.
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Affiliation(s)
- Wencheng Zhao
- Institute of Physics and Electronic Information, Yantai University, Yantai 264005, China; (W.Z.); (X.H.); (F.K.); (J.T.); (D.Y.); (Y.S.)
| | - Xiaolin Hu
- Institute of Physics and Electronic Information, Yantai University, Yantai 264005, China; (W.Z.); (X.H.); (F.K.); (J.T.); (D.Y.); (Y.S.)
| | - Fankang Kong
- Institute of Physics and Electronic Information, Yantai University, Yantai 264005, China; (W.Z.); (X.H.); (F.K.); (J.T.); (D.Y.); (Y.S.)
| | - Jihua Tang
- Institute of Physics and Electronic Information, Yantai University, Yantai 264005, China; (W.Z.); (X.H.); (F.K.); (J.T.); (D.Y.); (Y.S.)
| | - Duxv Yan
- Institute of Physics and Electronic Information, Yantai University, Yantai 264005, China; (W.Z.); (X.H.); (F.K.); (J.T.); (D.Y.); (Y.S.)
| | - Jintao Wang
- Institute of Information Engineering, Yantai Institute of Technology, Yantai 264005, China;
| | - Yuru Liu
- Institute of Engineering Training Center, Yantai University, Yantai 264005, China;
| | - Yuanping Sun
- Institute of Physics and Electronic Information, Yantai University, Yantai 264005, China; (W.Z.); (X.H.); (F.K.); (J.T.); (D.Y.); (Y.S.)
| | - Ren Sheng
- Institute of Physics and Electronic Information, Yantai University, Yantai 264005, China; (W.Z.); (X.H.); (F.K.); (J.T.); (D.Y.); (Y.S.)
| | - Ping Chen
- Institute of Physics and Electronic Information, Yantai University, Yantai 264005, China; (W.Z.); (X.H.); (F.K.); (J.T.); (D.Y.); (Y.S.)
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2
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Kim KJ, Kim J, Lim JT, Heo J, Park BJ, Nam H, Choi H, Yoon SS, Kim W, Kang S, Kim T. Anthracene derivatives with strong spin-orbit coupling and efficient high-lying reverse intersystem crossing beyond the El-Sayed rule. MATERIALS HORIZONS 2024; 11:1484-1494. [PMID: 38224142 DOI: 10.1039/d3mh01850d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
The attention to materials with hot exciton channel and triplet-triplet fusion (TTF) mediated high-lying reverse intersystem crossing (hRISC) has been raised for their ability to convert non-emissive 'dark' triplets into radiative singlet excitons. This spin conversion process results in high exciton utilization efficiency (EUE) that exceeds the theoretical limits. Notably, it is known that such spin conversion processes from the high-lying excited triplet to the singlet state are facilitated by the orthogonal orbital transition effect governed by the El-Sayed's rule. In this study, an anthracene derivative with indenoquinoline substituent 7,7-dimethyl-9-(10-(4-(naphthalen-1-yl)phenyl)anthracen-9-yl)-7H-indeno[1,2-f]quinoline (2MIQ-NPA) was synthesized and analyzed to investigate whether the hRISC process occurs in these molecules, even when the El-Sayed's rule is not followed. The hRISC channels of the emitter were fully unraveled through DFT calculations and experiments, which were quantitatively subdivided using transient electroluminescence measurements. The results showed that 2MIQ-NPA, which does not follow the El-Sayed's rule and has a relatively strong spin-orbit coupling matrix element of 0.116 cm-1 between the high-lying triplet state of T4 and the lowest singlet state of S1, effectively converted triplet excitons into singlet excitons with an EUE of 64.3%, contributed by a direct hot exciton channel of 19.2% and a TTF-mediated hot exciton channel of 15.1%. Despite the low outcoupling efficiency, the non-doped device with 2MIQ-NPA achieved an excellent device performance with an external quantum efficiency of 7.0%.
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Affiliation(s)
- Ki Ju Kim
- Department of Information Display, Hongik University, Seoul 04066, Republic of Korea.
| | - Jaesung Kim
- Department of Information Display, Hongik University, Seoul 04066, Republic of Korea.
| | - Jong Tae Lim
- Research on Core Technology Convergence of Metamaterials, Hongik University, Seoul 04066, Republic of Korea
| | - Jinyeong Heo
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Bum Jun Park
- Department of Information Display, Hongik University, Seoul 04066, Republic of Korea.
| | - Hyewon Nam
- Department of Information Display, Hongik University, Seoul 04066, Republic of Korea.
| | - Hyeonwoo Choi
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea.
| | - Seung Soo Yoon
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Woojae Kim
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea.
| | - Sunwoo Kang
- Display Research Center, Samsung Display Co., Yongin, 17113, Republic of Korea.
| | - Taekyung Kim
- Department of Information Display, Hongik University, Seoul 04066, Republic of Korea.
- Department of Materials Science and Engineering, Hongik University, Sejong, 30016, Republic of Korea
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3
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Schloemer T, Narayanan P, Zhou Q, Belliveau E, Seitz M, Congreve DN. Nanoengineering Triplet-Triplet Annihilation Upconversion: From Materials to Real-World Applications. ACS NANO 2023; 17:3259-3288. [PMID: 36800310 DOI: 10.1021/acsnano.3c00543] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Using light to control matter has captured the imagination of scientists for generations, as there is an abundance of photons at our disposal. Yet delivering photons beyond the surface to many photoresponsive systems has proven challenging, particularly at scale, due to light attenuation via absorption and scattering losses. Triplet-triplet annihilation upconversion (TTA-UC), a process which allows for low energy photons to be converted to high energy photons, is poised to overcome these challenges by allowing for precise spatial generation of high energy photons due to its nonlinear nature. With a wide range of sensitizer and annihilator motifs available for TTA-UC, many researchers seek to integrate these materials in solution or solid-state applications. In this Review, we discuss nanoengineering deployment strategies and highlight their uses in recent state-of-the-art examples of TTA-UC integrated in both solution and solid-state applications. Considering both implementation tactics and application-specific requirements, we identify critical needs to push TTA-UC-based applications from an academic curiosity to a scalable technology.
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Affiliation(s)
- Tracy Schloemer
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States
| | - Pournima Narayanan
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Qi Zhou
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States
| | - Emma Belliveau
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States
| | - Michael Seitz
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States
| | - Daniel N Congreve
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States
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4
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Yiu TC, Gnanasekaran P, Chen WL, Lin WH, Lin MJ, Wang DY, Lu CW, Chang CH, Chang YJ. Multifaceted Sulfone-Carbazole-Based D-A-D Materials: A Blue Fluorescent Emitter as a Host for Phosphorescent OLEDs and Triplet-Triplet Annihilation Up-Conversion Electroluminescence. ACS APPLIED MATERIALS & INTERFACES 2023; 15:1748-1761. [PMID: 36576167 DOI: 10.1021/acsami.2c21294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Electroluminescence (EL) from the singlet-excited (S1) state is the ideal choice for stable, high-performing deep-blue organic light-emitting diodes (OLEDs) owing to the advantages of an adequately short radiative lifetime, improved device durability, and low cost, which are the most important criteria for their commercialization. Herein, we present the design and synthesis of three donor-acceptor-donor (D-A-D)-configured deep-blue fluorescent materials (denoted as TC-1, TC-2, and TC-3) composed of a thioxanthone or diphenyl sulfonyl acceptor and phenyl carbazolyl donor. These systems exhibit strong deep-blue photoluminescence (422-432 nm) in solutions and redshifted emission (472-486 nm) in thin films. The solid-state photoluminescence quantum yield (PLQY) was estimated to be 78 and 94% for TC-2 and TC-3, respectively. TC-2 and TC-3 possess good molecular packing and large molecular cross-sectional areas, which not only improves the PLQY but enhances the triplet-triplet annihilation up-conversion (TTAUC) efficiency of fluorescent emitters. Furthermore, both compounds were applied as an acceptor for confirming their TTAUC property using bis(2-methyldibenzo[f,h]quinoxaline)(acetylacetonate)iridium(III) (Ir(MDQ)2acac) as the sensitizer. Non-doped OLEDs based on TC-2 and TC-3 exhibit blue EL in the 461-476 nm range. In particular, TC-3 exhibits a maximum external quantum efficiency (EQEmax) of 5.1%, and its EL maximum is 476 nm. In addition, the three emitters were employed as hosts in red OLEDs using bis(1-phenylisoquinoline)(acetylacetonate)iridium(III) (Ir(piq)2acac) as the phosphorescent dopant. The red phosphorescent OLEDs based on TC-1, TC-2, and TC-3 achieve excellent EQEmax values of 21.6, 22.9, and 21.9%, respectively, and peak luminance efficiencies of 12.0, 14.0, and 12.3 cd A-1. These results highlight these fluorophores' versatility and promising prospects in practical OLED applications.
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Affiliation(s)
- Tsz Chung Yiu
- Department of Chemistry, Tunghai University, Taichung 40704, Taiwan
| | | | - Wei-Ling Chen
- Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan
| | - Wei-Han Lin
- Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan
| | - Ming-Jun Lin
- Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan
| | - Di-Yan Wang
- Department of Chemistry, Tunghai University, Taichung 40704, Taiwan
| | - Chin-Wei Lu
- Department of Applied Chemistry, Providence University, Taichung 43301, Taiwan
| | - Chih-Hao Chang
- Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan
| | - Yuan Jay Chang
- Department of Chemistry, Tunghai University, Taichung 40704, Taiwan
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5
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Yang Y, Wei J, Xiang‐YangLiu, Li R, Zhang Z. Novel
Ortho
‐Linkage Donor‐Acceptor Type Host Materials for Efficiently Red Phosphorescence Organic Light‐Emitting Diodes. ChemistrySelect 2022. [DOI: 10.1002/slct.202201647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yong‐Jian Yang
- School of Environment and Chemical Engineering Jiangsu Ocean University, 59 Cangwu Road, Haizhou District Lianyungang 222005 P. R. China
| | - Jia‐Jia Wei
- School of Environment and Chemical Engineering Jiangsu Ocean University, 59 Cangwu Road, Haizhou District Lianyungang 222005 P. R. China
| | - Xiang‐YangLiu
- Wispo Advanced Materials (Suzhou) Co., Ltd. Suzhou Industrial Park (SIP) 200 Xingpu Road, Shengpu Street Suzhou 215126 P.R. China
| | - Runlai Li
- College of Polymer Science & Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Zhen‐Ming Zhang
- School of Environment and Chemical Engineering Jiangsu Ocean University, 59 Cangwu Road, Haizhou District Lianyungang 222005 P. R. China
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6
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Wang L, Fang P, Zhao Z, Huang Y, Liu Z, Bian Z. Rare Earth Complexes with 5d-4f Transition: New Emitters in Organic Light-Emitting Diodes. J Phys Chem Lett 2022; 13:2686-2694. [PMID: 35302781 DOI: 10.1021/acs.jpclett.2c00400] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Organic light-emitting diodes (OLEDs) are considered as next-generation displays and lighting technologies. During the past three decades, various luminescent materials such as fluorescence, phosphorescence, and thermally activated delayed fluorescence materials have been subsequently investigated as emitters. To date, blue OLEDs are still the bottleneck as compared to red and green ones because of the lack of efficient emitters with simultaneous high exciton utilization efficiency and long-term stability. Recently, d-f transition rare earth complexes have been reported as new emitters in OLEDs with potential high efficiency and stability. In this Perspective, we present a brief introduction to OLEDs and an overview of the previous electroluminescence study on d-f transition rare earth complexes. This is followed by our recent developments in cerium(III) complex- and europium(II) complex-based OLEDs. We finally discuss the challenges and opportunities for OLED study based on d-f transition rare earth complexes.
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Affiliation(s)
- Liding Wang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Peiyu Fang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Zifeng Zhao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Yanyi Huang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Zhiwei Liu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Zuqiang Bian
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, College of Engineering, Peking University, Beijing 100871, China
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7
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Loftus LM, Olson EC, Stewart DJ, Phillips AT, Arumugam K, Cooper TM, Haley JE, Grusenmeyer TA. Zn Coordination and the Identity of the Halide Ancillary Ligand Dramatically Influence the Excited-State Dynamics and Bimolecular Reactions of 2,3-Di(pyridin-2-yl)benzo[ g]quinoxaline. Inorg Chem 2021; 60:16570-16583. [PMID: 34662517 DOI: 10.1021/acs.inorgchem.1c02484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The optical properties of coordination complexes with ligands containing nitrogen heterocycles have been extensively studied for decades. One subclass of these materials, metal complexes utilizing substituted pyrazines and quinoxalines as ligands, has been employed in a variety of photochemical applications ranging from photodynamic therapy to organic light-emitting diodes. A vast majority of this work focuses on characterization of the metal-to-ligand charge-transfer states in these metal complexes; however, literature reports rarely investigate the photophysics of the parent pyrazine or quinoxaline ligand or perform control experiments utilizing metal complexes that lack low-lying charge-transfer (CT) states in order to determine how metal-atom coordination influences the photophysical properties of the ligand. With this in mind, we examined the steady-state and time-resolved photophysics of 2,3-di(pyridin-2-yl)benzo[g]quinoxaline (dpb) and explored how the coordination of ZnX2 (X = Cl-, Br-, I-) affects the photophysical properties of dpb. In dpb, we find that the dominant mode of deactivation from the singlet excited state is intersystem crossing (ISC). Coordination of ZnX2 perturbs the relative energies of the ππ* and nπ* excited states of dpb, leading to drastically different rates of ISC as well as radiative and nonradiative decay in the [Zn(dpb)X2] complexes compared to dpb. These differences in the rates change the dominant singlet-excited-state decay pathway from ISC in dpb to a mixture of ISC and fluorescence in [Zn(dpb)Cl2] and [Zn(dpb)Br2] and to nonradiative decay in [Zn(dpb)I2]. Coordination of ZnX2 and the choice of the halide ligand also have profound effects on the rate constants for excited-state bimolecular reactions, including triplet-triplet annihilation and oxygen quenching. These results demonstrate that metal coordination, even in complexes lacking low-lying CT states, and the choice of the ancillary ligand can dramatically alter the photophysical properties of chromophores containing nitrogen heterocycles.
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Affiliation(s)
- Lauren M Loftus
- Materials and Manufacturing Directorate, Functional Materials Division, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433-7750, United States.,General Dynamics Information Technology, 5100 Springfield Pike, Dayton, Ohio 45431, United States
| | - Emma C Olson
- Materials and Manufacturing Directorate, Functional Materials Division, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433-7750, United States.,Southwestern Ohio Council for Higher Education, Dayton, Ohio 45420, United States
| | - David J Stewart
- Materials and Manufacturing Directorate, Functional Materials Division, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433-7750, United States
| | - Alexis T Phillips
- Materials and Manufacturing Directorate, Functional Materials Division, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433-7750, United States.,Southwestern Ohio Council for Higher Education, Dayton, Ohio 45420, United States
| | - Kuppuswamy Arumugam
- Wright State University, Department of Chemistry, 3640 Colonel Glenn Highway, Dayton, Ohio 45435, United States
| | - Thomas M Cooper
- Materials and Manufacturing Directorate, Functional Materials Division, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433-7750, United States
| | - Joy E Haley
- Materials and Manufacturing Directorate, Functional Materials Division, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433-7750, United States
| | - Tod A Grusenmeyer
- Materials and Manufacturing Directorate, Functional Materials Division, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433-7750, United States
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8
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Gao C, Wong WWH, Qin Z, Lo SC, Namdas EB, Dong H, Hu W. Application of Triplet-Triplet Annihilation Upconversion in Organic Optoelectronic Devices: Advances and Perspectives. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2100704. [PMID: 34596295 DOI: 10.1002/adma.202100704] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 08/06/2021] [Indexed: 06/13/2023]
Abstract
Organic semiconductor materials have been widely used in various optoelectronic devices due to their rich optical and/or electrical properties, which are highly related to their excited states. Therefore, how to manage and utilize the excited states in organic semiconductors is essential for the realization of high-performance optoelectronic devices. Triplet-triplet annihilation (TTA) upconversion is a unique process of converting two non-emissive triplet excitons to one singlet exciton with higher energy. Efficient optical-to-electrical devices can be realized by harvesting sub-bandgap photons through TTA-based upconversion. In electrical-to-optical devices, triplets generated after the combination of electrons and holes also can be efficiently utilized via TTA, which resulted in a high internal conversion efficiency of 62.5%. Currently, many interesting explorations and significant advances have been demonstrated in these fields. In this review, a comprehensive summary of these intriguing advances on developing efficient TTA upconversion materials and their application in optoelectronic devices is systematically given along with some discussions. Finally, the key challenges and perspectives of TTA upconversion systems for further improvement for optoelectronic devices and other related research directions are provided. This review hopes to provide valuable guidelines for future related research and advancement in organic optoelectronics.
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Affiliation(s)
- Can Gao
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wallace W H Wong
- ARC Centre of Excellence in Exciton Science, School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Zhengsheng Qin
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shih-Chun Lo
- Centre for Organic Photonics and Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Ebinazar B Namdas
- Centre for Organic Photonics & Electronics, School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Huanli Dong
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Science, Tianjin University, Tianjin, 300072, China
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9
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Exceptionally efficient deep blue anthracene-based luminogens: design, synthesis, photophysical, and electroluminescent mechanisms. Sci Bull (Beijing) 2021; 66:2090-2098. [PMID: 36654267 DOI: 10.1016/j.scib.2021.06.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/05/2021] [Accepted: 06/10/2021] [Indexed: 01/20/2023]
Abstract
Achieving high-efficiency deep blue emitter with CIEy < 0.06 (CIE, Commission Internationale de L'Eclairage) and external quantum efficiency (EQE) >10% has been a long-standing challenge for traditional fluorescent materials in organic light-emitting diodes (OLEDs). Here, we report the rational design and synthesis of two new deep blue luminogens: 4-(10-(4'-(9H-carbazol-9-yl)-2,5-dimethyl-[1,1'-biphenyl]-4-yl)anthracen-9-yl)benzonitrile (2M-ph-pCzAnBzt) and 4-(10-(4-(9H-carbazol-9-yl)-2,5-dimethylphenyl)anthracen-9-yl)benzonitrile (2M-pCzAnBzt). In particular, 2M-ph-pCzAnBzt produces saturated deep blue emissions in a non-doped electroluminescent device with an exceptionally high EQE of 10.44% and CIEx,y (0.151, 0.057). The unprecedented electroluminescent efficiency is attributed to the combined effects of higher-order reversed intersystem crossing and triplet-triplet up-conversion, which are supported by analysis of theoretical calculation, triplet sensitization experiments, as well as nanosecond transient absorption spectroscopy. This research offers a new approach to resolve the shortage of high efficiency deep blue fluorescent emitters.
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10
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Kaiyasuan C, Chasing P, Nalaoh P, Wongkaew P, Sudyoadsuk T, Kongpatpanich K, Promarak V. Twisted Phenanthro[9,10-d]imidazole Derivatives as Non-doped Emitters for Efficient Electroluminescent Devices with Ultra-Deep Blue Emission and High Exciton Utilization Efficiency. Chem Asian J 2021; 16:2328-2337. [PMID: 34184404 DOI: 10.1002/asia.202100559] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/28/2021] [Indexed: 01/26/2023]
Abstract
Herein, two deep-blue emissive molecules (SAF-PI and SAF-DPI) are designed and synthesized using spiro[acridine-9,9'-fluorene] as a donor (D) substituted with 2-(3-methylphenyl)-1-phenyl-phenanthro[9,10-d]imidazole as an acceptor (A), forming twisted D-A and A-D-A structures, respectively. The photophysical studies and density functional theory (DFT) calculations reveal that both molecules exhibit hybridized local excited and charge transfer (HLCT) characteristics with deep blue emission color. They are effectively applied as non-doped emitters in OLEDs. Particularly, SAF-PI-based device achieves the high-definition television (HDTV) standard blue color emission peaked at 428 nm with CIE coordinate of (0.156, 0.053), a narrow full width at half maximum of 55 nm, a maximum external quantum efficiency (EQEmax ) of 4.57% and an exciton utilization efficiency of 65%.
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Affiliation(s)
- Chokchai Kaiyasuan
- Department of Materials Science and Engineering School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand
| | - Pongsakorn Chasing
- Department of Materials Science and Engineering School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand
| | - Phattananawee Nalaoh
- Department of Materials Science and Engineering School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand
| | - Praweena Wongkaew
- Department of Materials Science and Engineering School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand
| | - Taweesak Sudyoadsuk
- Department of Materials Science and Engineering School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand
| | - Kanokwan Kongpatpanich
- Department of Materials Science and Engineering School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand
| | - Vinich Promarak
- Department of Materials Science and Engineering School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand.,Research Network of, NANOTEC-VISTEC on Nanotechnology for Energy Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand
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11
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Krotkus S, Matulaitis T, Diesing S, Copley G, Archer E, Keum C, Cordes DB, Slawin AMZ, Gather MC, Zysman-Colman E, Samuel IDW. Fast Delayed Emission in New Pyridazine-Based Compounds. Front Chem 2021; 8:572862. [PMID: 33490031 PMCID: PMC7817954 DOI: 10.3389/fchem.2020.572862] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/13/2020] [Indexed: 11/13/2022] Open
Abstract
Three novel donor-acceptor molecules comprising the underexplored pyridazine (Pydz) acceptor moiety have been synthesized and their structural, electrochemical and photophysical properties thoroughly characterized. Combining Pydz with two phenoxazine donor units linked via a phenyl bridge in a meta configuration (dPXZMePydz) leads to high reverse intersystem crossing rate k RISC = 3.9 · 106 s-1 and fast thermally activated delayed fluorescence (TADF) with <500 ns delayed emission lifetime. Efficient triplet harvesting via the TADF mechanism is demonstrated in OLEDs using dPXZMePydz as the emitter but does not occur for compounds bearing weaker donor units.
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Affiliation(s)
- Simonas Krotkus
- Organic Semiconductor Centre, Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St. Andrews, St Andrews, United Kingdom
| | - Tomas Matulaitis
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St. Andrews, St Andrews, United Kingdom
| | - Stefan Diesing
- Organic Semiconductor Centre, Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St. Andrews, St Andrews, United Kingdom.,Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St. Andrews, St Andrews, United Kingdom
| | - Graeme Copley
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St. Andrews, St Andrews, United Kingdom
| | - Emily Archer
- Organic Semiconductor Centre, Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St. Andrews, St Andrews, United Kingdom
| | - Changmin Keum
- Organic Semiconductor Centre, Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St. Andrews, St Andrews, United Kingdom
| | - David B Cordes
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St. Andrews, St Andrews, United Kingdom
| | - Alexandra M Z Slawin
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St. Andrews, St Andrews, United Kingdom
| | - Malte C Gather
- Organic Semiconductor Centre, Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St. Andrews, St Andrews, United Kingdom
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St. Andrews, St Andrews, United Kingdom
| | - Ifor D W Samuel
- Organic Semiconductor Centre, Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St. Andrews, St Andrews, United Kingdom
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12
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Kukhta NA, Bryce MR. Dual emission in purely organic materials for optoelectronic applications. MATERIALS HORIZONS 2021; 8:33-55. [PMID: 34821289 DOI: 10.1039/d0mh01316a] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Purely organic molecules, which emit light by dual emissive (DE) pathways, have received increased attention in the last decade. These materials are now being utilized in practical optoelectronic, sensing and biomedical applications. In order to further extend the application of the DE emitters, it is crucial to gain a fundamental understanding of the links between the molecular structure and the underlying photophysical processes. This review categorizes the types of DE according to the spin multiplicity and time range of the emission, with emphasis on recent experimental advances. The design rules towards novel DE molecular candidates, the most perspective types of DE and possible future applications are outlined. These exciting developments highlight the opportunities for new materials synthesis and pave the way for accelerated future innovation and developments in this area.
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Affiliation(s)
- Nadzeya A Kukhta
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, UK.
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13
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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.
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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
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14
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Izumi S, Nyga A, de Silva P, Tohnai N, Minakata S, Data P, Takeda Y. Revealing Topological Influence of Phenylenediamine Unit on Physicochemical Properties of Donor-Acceptor-Donor-Acceptor Thermally Activated Delayed Fluorescent Macrocycles. Chem Asian J 2020; 15:4098-4103. [PMID: 33094560 DOI: 10.1002/asia.202001173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/21/2020] [Indexed: 12/14/2022]
Abstract
A new thermally activated delayed fluorescence (TADF)-displaying macrocyclic compound m-1 comprising of two electron-donors (N,N'-diphenyl-m-phenylenediamine) and two electron-acceptors (dibenzo[a,j]phenazine) has been synthesized. The macrocycle developed herein is regarded as a regioisomer of the previously reported TADF macrocycle p-1, which has two N,N'-diphenyl-p-phenylenediamines as the donors. To understand the influence of the topology of the phenylenediamine donors on physicochemical properties of TADF-active macrocycles, herein the molecular structure in the single crystals, photophysical properties, electrochemical behavior, and TADF properties of m-1 have been investigated compared with those of p-1. The substitution of p-phenylene donor with m-phenylene donor led to distinct positive solvatoluminochromism over the full visible-color range, unique oxidative electropolymerization, and slightly lower contribution of TADF, due to the lower CT character in the excited states.
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Affiliation(s)
- Saika Izumi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 5650871, Japan
| | - Aleksandra Nyga
- Faculty of Chemistry, Silesian University of Technology, M. Strzody 9, 44-100, Gliwice, Poland
| | - Piotr de Silva
- Department of Energy Conversion and Storage, Technical University of Denmark, Anker Engelunds Vej 301, 2800 Kgs., Lyngby, Denmark
| | - Norimitsu Tohnai
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 5650871, Japan
| | - Satoshi Minakata
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 5650871, Japan
| | - Przemyslaw Data
- Faculty of Chemistry, Silesian University of Technology, M. Strzody 9, 44-100, Gliwice, Poland.,Centre of Polymer and Carbon Materials, Polish Academy of Science, M. Curie-Sklodowskiej 34, 41-819, Zabrze, Poland
| | - Youhei Takeda
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 5650871, Japan
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15
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Han P, Lin C, Ma D, Qin A, Tang BZ. Violet-Blue Emitters Featuring Aggregation-Enhanced Emission Characteristics for Nondoped OLEDs with CIEy Smaller than 0.046. ACS APPLIED MATERIALS & INTERFACES 2020; 12:46366-46372. [PMID: 32955848 DOI: 10.1021/acsami.0c12722] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
High emission efficiency and finite molecular conjugation in the aggregate state are two desirable features in violet-blue emitters. Aggregation-induced emission luminogens (AIEgens) have emerged as promising luminescent materials that offer these features. Herein, we report the design and synthesis of a group of violet-blue tetraphenylbenzene-based AIEgens with photoluminescence quantum yields over 98% in their film states. When utilizing these AIEgens as nondoped emitting layers, the fabricated organic light-emitting diode exhibits a maximum external quantum efficiency of 4.34% with Commission Internationale de L'Eclairage (CIE) coordinates of (0.159, 0.035), which is amenable to the next-generation ultrahigh-definition television (UHDTV) display standard.
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Affiliation(s)
- Pengbo Han
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, SCUT-HKUST Joint Research Institute, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou 510640, China
| | - Chengwei Lin
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, SCUT-HKUST Joint Research Institute, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou 510640, China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, SCUT-HKUST Joint Research Institute, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou 510640, China
| | - Anjun Qin
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, SCUT-HKUST Joint Research Institute, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou 510640, China
| | - Ben Zhong Tang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, SCUT-HKUST Joint Research Institute, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou 510640, China
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, China
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16
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Konidena RK, Thomas KRJ, Dubey DK, Sahoo S, Jou J. Fine‐Tuning the Physicochemical and Electroluminescence Properties of Multiply‐Substituted Bipolar Carbazoles by Functional Group Juggling. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.202000172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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
| | - 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
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17
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Rodella F, Bagnich S, Duda E, Meier T, Kahle J, Athanasopoulos S, Köhler A, Strohriegl P. High Triplet Energy Host Materials for Blue TADF OLEDs-A Tool Box Approach. Front Chem 2020; 8:657. [PMID: 32850669 PMCID: PMC7403631 DOI: 10.3389/fchem.2020.00657] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 06/23/2020] [Indexed: 11/13/2022] Open
Abstract
The synthesis of stable blue TADF emitters and the corresponding matrix materials is one of the biggest challenges in the development of novel OLED materials. We present six bipolar host materials based on triazine as an acceptor and two types of donors, namely, carbazole, and acridine. Using a tool box approach, the chemical structure of the materials is changed in a systematic way. Both the carbazole and acridine donor are connected to the triazine acceptor via a para- or a meta-linked phenyl ring or are linked directly to each other. The photophysics of the materials has been investigated in detail by absorption-, fluorescence-, and phosphorescence spectroscopy in solution. In addition, a number of DFT calculations have been made which result in a deeper understanding of the photophysics. The presence of a phenyl bridge between donor and acceptor cores leads to a considerable decrease of the triplet energy due to extension of the overlap electron and hole orbitals over the triazine-phenyl core of the molecule. This decrease is more pronounced for the para-phenylene than for the meta-phenylene linker. Only direct connection of the donor group to the triazine core provides a high energy of the triplet state of 2.97 eV for the carbazole derivative CTRZ and 3.07 eV for the acridine ATRZ. This is a major requirement for the use of the materials as a host for blue TADF emitters.
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Affiliation(s)
- Francesco Rodella
- Macromolecular Chemistry I, University of Bayreuth, Bayreuth, Germany
| | - Sergey Bagnich
- Soft Matter Optoelectronics, University of Bayreuth, Bayreuth, Germany
| | - Eimantas Duda
- Soft Matter Optoelectronics, University of Bayreuth, Bayreuth, Germany
| | - Tobias Meier
- Soft Matter Optoelectronics, University of Bayreuth, Bayreuth, Germany
| | - Julian Kahle
- Soft Matter Optoelectronics, University of Bayreuth, Bayreuth, Germany
| | | | - Anna Köhler
- Soft Matter Optoelectronics, University of Bayreuth, Bayreuth, Germany
- Bayreuth Institute of Macromolecular Research (BIMF), University of Bayreuth, Bayreuth, Germany
| | - Peter Strohriegl
- Macromolecular Chemistry I, University of Bayreuth, Bayreuth, Germany
- Bayreuth Institute of Macromolecular Research (BIMF), University of Bayreuth, Bayreuth, Germany
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18
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Liu Y, Liu H, Bai Q, Du C, Shang A, Jiang D, Tang X, Lu P. Pyrene[4,5- d]imidazole-Based Derivatives with Hybridized Local and Charge-Transfer State for Highly Efficient Blue and White Organic Light-Emitting Diodes with Low Efficiency Roll-Off. ACS APPLIED MATERIALS & INTERFACES 2020; 12:16715-16725. [PMID: 32180398 DOI: 10.1021/acsami.0c01846] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A family of pyrene[4,5-d]imidazole derivatives, PyPA, PyPPA, PyPPAC, and PyPAC, with different excited states are successfully developed. Among them, PyPPA and PyPPAC possess hybridized local and charge-transfer (HLCT) state, endowing them with pure blue fluorescence as well as high quantum yields. The nondoped organic light-emitting diode (OLED) based on PyPPA displays Commission Internationale de L'Eclairage coordinates of (0.14, 0.13) and achieves a maximum external quantum efficiency (EQE) of 8.47%, which are among the highest value reported to date for nondoped blue HLCT OLEDs. The nondoped OLED based on PyPPAC exhibits a maximum luminance of 50,046 cd m-2 located in the blue region with CIE coordinates of (0.15, 0.21) and an EQE of 6.74% even when the luminance reached over 10,000 cd m-2. In addition, they both reveal ultimate exciton utilizing efficiencies of nearly 100%. The potential of a blue emitter of PyPPA with an HLCT character for application in white OLED (WOLED) is further tested. The efficient two-color hybrid warm WOLED is successfully achieved, which provides the total EQE, power efficiency, and current efficiency of up to 21.19%, 61.46 lm W-1, and 62.13 cd A-1, respectively. The nondoped blue OLEDs and hybrid WOLEDs present good color stabilities with low efficiency roll-offs. Our results prove that taking advantage of the HLCT state, nondoped blue OLEDs as well as hybrid WOLEDs with high performance could be realized, which have a promising prospect for the displays and lightings in the future.
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Affiliation(s)
- Yulong Liu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
- Department of Applied Chemistry, Northeast Agricultural University, Harbin 150030, China
| | - Hui Liu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Qing Bai
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Chunya Du
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Anqi Shang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Dongyan Jiang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Xiangyang Tang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Ping Lu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
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19
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Jayabharathi J, Anudeebhana J, Thanikachalam V, Sivaraj S, Prabhakaran A. Efficient donor-acceptor emitter based nonsymmetrical connection for organic emitting diodes with improving exciton utilization. RSC Adv 2020; 10:4002-4013. [PMID: 35492665 PMCID: PMC9049240 DOI: 10.1039/c9ra10513a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 01/13/2020] [Indexed: 02/06/2023] Open
Abstract
A new strategy developed to construct blue emissive materials having an unsymmetrical connection with identical conjugated phenanthrimidazole groups results in the separation of the frontier orbitals and leads to donor-acceptor (D-A) architecture. The blue device with 2-(naphthalen-1-yl)-1-(4-(1-(naphthalen-1-yl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)-1H-phenanthro[9,10-d]imidazole (p-PPI)/2-(naphthalen-1-yl)-1-(3-(1-(naphthalen-1-yl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)-1H-phenanthro[9,10-d]imidazole (m-PPI) emissive layer (λ EL - 434/420 nm) shows high efficiencies: current efficiency (η c) - 5.83/3.56 cd A-1; power efficiency (η p) - 5.73/3.48 lm W-1; external quantum efficiency (η ex) - 8.98/6.48% at 3.0 V. Their cyano derivatives, p-CNPPI/m-CNPPI (λ EL - 422/406 nm) exhibit maximum efficiencies (η c - 6.28/4.38 cd A-1; η p - 6.14/4.01 lm W-1; η ex - 9.01/6.72%) at 2.9 V compared to the p-PPI/m-PPI devices. The weak charge transfer in the D-A emitters results in deep blue emission. The anisotropic structural characteristics of p-PPI, p-CNPPI, m-PPI and m-CNPPI induced horizontal dipole orientation in films and enhanced EL efficiency. These bipolar materials with suitable triplet energy can be used as hosts in green as well as red phosphorescent organic light emitting devices (PHOLEDs). The green/red device (λ EL - 504/618 nm) with p-CNPPI: Ir(ppy)3/Ir(MDQ)2 (acac) exhibits a maximum L - 8823/38418 cd m-2; η ex - 24.56/17.31%; η c - 84.30/18.09 cd A -1; η p - 86.43/21.43 lm W -1with CIE (0.33, 0.61)/(0.65, 0.34).
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Affiliation(s)
- Jayaraman Jayabharathi
- Department of Chemistry, Material Science Lab, Annamalai University Annamalai Nagar Tamilnadu-608 002 India
| | | | - Venugopal Thanikachalam
- Department of Chemistry, Material Science Lab, Annamalai University Annamalai Nagar Tamilnadu-608 002 India
| | - Sekar Sivaraj
- Department of Chemistry, Material Science Lab, Annamalai University Annamalai Nagar Tamilnadu-608 002 India
| | - Annadurai Prabhakaran
- Department of Chemistry, Material Science Lab, Annamalai University Annamalai Nagar Tamilnadu-608 002 India
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20
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Kang S, Moon JH, Kim T, Lee JY. Design of efficient non-doped blue emitters: toward the improvement of charge transport. RSC Adv 2019; 9:27807-27816. [PMID: 35530480 PMCID: PMC9070764 DOI: 10.1039/c9ra04918e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 08/16/2019] [Indexed: 11/25/2022] Open
Abstract
Charge transport and electronic transition properties of a series of newly designed anthracene-based non-doped blue emitters were investigated by density functional theory calculations. For a highly efficient non-doped device, Cz3PhAn-based emitters were designed to suppress the hole and electron reorganization energies required for structural relaxation with respect to the changes of charged states. As a result, the hole hopping rates of triphenylamine (TPA) and phenylbenzimidazole (PBI) substituted Cz3PhAn derivatives (1, 4, and 5-7) were tremendously enhanced as compared to that of Cz3PhAn due to the suppression of the reorganization energy of holes, λ h. Moreover, 1 and 4 emitters showed almost identical hopping rates of holes and electrons, which can possibly lead to a perfect charge balance and high efficiency. The photo-physical properties showed that the emission energy of all 1-10 emitters is in 439-473 nm range. It is expected that our rational design strategy can help develop non-doped blue fluorescent emitters for high efficiency.
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Affiliation(s)
- Sunwoo Kang
- Display Research Center, Samsung Display Co. 1 Giheung-gu Gyunggi South Korea
| | - Jong Hun Moon
- Department of Chemistry, Sungkyunkwan University Suwon 16419 South Korea
| | - Taekyung Kim
- Department of Materials Science and Engineering, Hongik University Sejongsi 30016 South Korea
| | - Jin Yong Lee
- Department of Chemistry, Sungkyunkwan University Suwon 16419 South Korea
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21
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Liu J, Hu T, Li Z, Wei X, Hu X, Gao H, Liu G, Yi Y, Yamada-Takamura Y, Lee CS, Wang P, Wang Y. Intermolecular Interaction-Induced Thermally Activated Delayed Fluorescence Based on a Thiochromone Derivative. J Phys Chem Lett 2019; 10:1888-1893. [PMID: 30939025 DOI: 10.1021/acs.jpclett.9b00512] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Exploration of new extrinsic ways to modulate thermally activated delayed fluorescence (TADF) to achieve high exciton utilization efficiency in organic light-emitting diodes (OLEDs) is highly desirable. A new thiochromone derivative 2,3-bis(4-(9 H-carbazol-9-yl)phenyl)-4 H-thiochromen-4-1,1-dioxide (THI-PhCz) with tunable photophysical properties from crystals to amorphous states is reported. THI-PhCz shows molecular-packing-dependent TADF in different aggregation states based on the differences of intermolecular interactions. Furthermore, it is observed that THI-PhCz doped in amorphous films of different hosts also shows host-dependent TADF with a short delay lifetime (108 ns), which is interpreted as the effect of host-guest intermolecular interaction on the 3CT state except for the effect on the 1CT state in reported references. This work provides a new perspective for generation of TADF by tuning intermolecular interactions in crystals and amorphous films except for molecular design, which is expected to contribute in achieving low-efficiency roll-off OLEDs with effective exciton utilization efficiency.
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Affiliation(s)
- Jianjun Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Taiping Hu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids , Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
| | - Zhiyi Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xiaofang Wei
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xiaoxiao Hu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Honglei Gao
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Guanhao Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Yuanping Yi
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids , Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
| | - Yukiko Yamada-Takamura
- School of Materials Science , Japan Advanced Institute of Science and Technology , Ishikawa 923-1292 , Japan
| | - Chun-Sing Lee
- Center of Super-Diamond and Advanced Films (COSDAF) , City University of Hong Kong , Hong Kong SAR , People's Republic of China
| | - Pengfei Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Ying Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials and CityU-CAS Joint Laboratory of Functional Materials and Devices , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
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22
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Sarma M, Wong KT. Development of Materials for Blue Organic Light Emitting Devices. CHEM REC 2019; 19:1667-1692. [PMID: 30835939 DOI: 10.1002/tcr.201800156] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 01/29/2019] [Indexed: 01/20/2023]
Abstract
The success of organic light emitting diodes (OLED) has been witnessed by the commercialization of this technology for manufacturing the vivid and colorful displays used in our daily life now. The prospective growth of OLED technology on display industry will be optimistic. Over the last three decades, many different approaches on material and device designs have been implemented for improving the efficiency and stability of OLED devices. These efforts install main cornerstones to support the great achievement of OLED technology. However, until now, the performance and stability of blue OLEDs still have some concerns. This troublesome issue should be totally conquered before the large-scale manufactures dominated over other display technologies, particularly liquid crystal-based displays, takes place. Though significant progress has already been made to achieve high performance and long lifetime blue OLEDs, this topic still remains as one of the hot researches in OLEDs. We have been working on this area for about two decades and made some notable contributions. Consequently, in this personal account we have outlined our efforts to obtain better performing blue OLEDs by utilizing a range of emitters based on fluorescence, phosphorescence, delayed fluorescence and exciplex systems. We have also developed some novel host materials for blue OLEDs, which are worth mentioning in this account.
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Affiliation(s)
- Monima Sarma
- Department of Chemistry National Taiwan University, Taipei, 10617, Taiwan.,Department of Chemistry, KL University (KLEF), Vaddeswaram, Andhra Pradesh, 522502, India
| | - Ken-Tsung Wong
- Department of Chemistry National Taiwan University, Taipei, 10617, Taiwan.,Institute of Atomic and Molecular Science Academia Sinica, Taipei, 10617, Taiwan
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23
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Li Z, Li C, Xu Y, Xie N, Jiao X, Wang Y. Nonsymmetrical Connection of Two Identical Building Blocks: Constructing Donor-Acceptor Molecules as Deep Blue Emitting Materials for Efficient Organic Emitting Diodes. J Phys Chem Lett 2019; 10:842-847. [PMID: 30734562 DOI: 10.1021/acs.jpclett.9b00300] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We propose a strategy to construct deep blue emission molecules based on the concept of nonsymmetrical connection of two identical π-conjugated groups. It was demonstrated that the nonsymmetrical connection strategy indeed resulted in the separation of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and the formation of a donor-acceptor (D-A) structure. For D-A molecules constructed by two identical groups, the degree of charge transfer is weaker and deep blue emission is easily achieved. Two D-A molecules (PIpPI and PImPI) were synthesized by employing diphenyl-phenanthroimidazole (PI) as a building block. The nonsymmetric connection of PI groups endows these molecules with a D-A feature that can result in a bipolar transport property. The nondoped organic light-emitting diodes with PIpPI and PImPI as emitter exhibit deep-blue emission and maximum external quantum efficiencies of 8.84% and 6.83%, respectively.
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Affiliation(s)
- Zhiqiang Li
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
| | - Chenglong Li
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
| | - Yincai Xu
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
| | - Ning Xie
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
| | - Xuechen Jiao
- Department of Materials Science and Engineering , Monash University , Australian Synchrotron, Clayton 3800 , Victoria , Australia
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials , Jilin University , Changchun 130012 , P. R. China
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24
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Joseph V, Thomas KRJ, Sahoo S, Singh M, Dubey DK, Jou JH. Vinyl-Linked Cyanocarbazole-Based Emitters: Effect of Conjugation and Terminal Chromophores on the Photophysical and Electroluminescent Properties. ACS OMEGA 2018; 3:16477-16488. [PMID: 31458283 PMCID: PMC6644140 DOI: 10.1021/acsomega.8b02198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/20/2018] [Indexed: 06/10/2023]
Abstract
A series of carbazole-based dyes functionalized with different auxochromes via vinyl linker have been synthesized and characterized. A progressive shift in the absorption maximum is observed as the conjugation and electron-donating nature of chromophore increases. Dyes containing electron-releasing terminal groups such as triphenylamine and carbazole exhibited positive emission solvatochromism attributable to an induced intramolecular charge transfer from triphenylamine/carbazole donor to cyano acceptor. The superior electroluminescence performance of disubstituted dyes demonstrates the role of an additional cyanocarbazole in achieving balanced charge transport compared to monosubstituted analogues. In addition, the electroluminescence performance of the dyes exhibited trends attributable to the electron richness of the linker/terminal chromophore. Thus, the carbazole-based derivatives displayed better electroluminescence efficiency than the analogous fluorene derivatives. Similarly, 2,7-substituted carbazole derivative exhibited better performance than the 3,6-substituted carbazole derivative. A doped electroluminescent device containing 3 wt % tricarbazole derivative showed blue emission with a high external quantum efficiency of 5.3% at a practical brightness of 1000 cd/m2.
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Affiliation(s)
- Vellaichamy Joseph
- Organic
Materials Laboratory, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - K. R. Justin Thomas
- Organic
Materials Laboratory, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Snehasis Sahoo
- Department
of Materials Science and Engineering, National
Tsing-Hua University, Hsinchu 30013, Taiwan
| | - Meenu Singh
- Department
of Materials Science and Engineering, National
Tsing-Hua University, Hsinchu 30013, Taiwan
| | - Deepak Kumar Dubey
- Department
of Materials Science and Engineering, National
Tsing-Hua University, Hsinchu 30013, Taiwan
| | - Jwo-Huei Jou
- Department
of Materials Science and Engineering, National
Tsing-Hua University, Hsinchu 30013, Taiwan
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25
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Chen CH, Tierce NT, Leung MK, Chiu TL, Lin CF, Bardeen CJ, Lee JH. Efficient Triplet-Triplet Annihilation Upconversion in an Electroluminescence Device with a Fluorescent Sensitizer and a Triplet-Diffusion Singlet-Blocking Layer. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1804850. [PMID: 30368942 DOI: 10.1002/adma.201804850] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/12/2018] [Indexed: 06/08/2023]
Abstract
Solid-state triplet-triplet annihilation upconversion (TTAUC) blue emission in an electroluminescence device (i.e., an organic light-emitting diode (OLED)) is demonstrated. A conventional green fluorophore, tris-(8-hydroxyquinoline)aluminum (Alq3 ), is employed as the sensitizer that generates 75% triplet under electrical pumping for the blue triplet-triplet annihilation emitter, 9,10-bis(2'-naphthyl) anthracene (ADN), with the heterojunction bilayer structure. The operation lifetime is elongated both for ADN blue (4.1x) and Alq3 green (34.8%) emission due to efficient use of excitons and separation of recombination and emission zone. To reduce the singlet quenching (SQ) of blue TTAUC signal by the Alq3 sensitizer with lower bandgap, 1-(2,5-dimethyl-4-(1-pyrenyl)phenyl)pyrene (DMPPP) is inserted between the Alq3 and ADN as a triplet-diffusion-and-singlet-blocking layer. DMPPP exhibits triplet energy close to Alq3 and higher than ADN, as well as higher singlet energy than both Alq3 and ADN. It allows triplet diffusion from Alq3 to ADN, but blocks the SQ of the blue TTAUC signal by Alq3 . 86.1% intrinsic efficiency of TTAUC is demonstrated in this trilayer (Alq3 /DMPPP/ADN) OLED.
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Affiliation(s)
- Chia-Hsun Chen
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan, Republic of China
| | - Nathan T Tierce
- Department of Chemistry, University of California, Riverside, Riverside, CA, 92506, USA
| | - Man-Kit Leung
- Department of Chemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan, Republic of China
| | - Tien-Lung Chiu
- Department of Electrical Engineering, Yuan Ze University, 135 Yuan-Tung Road, Taoyuan, 32003, Taiwan, Republic of China
| | - Chi-Feng Lin
- Department of Electro-Optical Engineering, National United University, 1 Lienda Road, Miaoli, 36003, Taiwan, Republic of China
| | - Christopher J Bardeen
- Department of Chemistry, University of California, Riverside, Riverside, CA, 92506, USA
| | - Jiun-Haw Lee
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan, Republic of China
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26
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Stewart DJ, Shi J, Naranjo TR, Grusenmeyer TA, Artz JM, McCleese CL, O'Donnell RM, Cooper TM, Shensky WM, Haley JE. Manipulating triplet states: tuning energies, absorption, lifetimes, and annihilation rates in anthanthrene derivatives. Phys Chem Chem Phys 2018; 20:28412-28418. [PMID: 30403238 DOI: 10.1039/c8cp06048g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The photophysical properties of anthanthrene, four anthanthrene derivatives containing varying phenyl and p-tBu-phenyl substituents, and two anthanthrones with phenyl and p-tBu-phenyl substituents are examined. In general, as the anthanthrenes and anthanthrones become more substituted, red-shifts are observed in the peak maxima of the ground- and excited-state absorption and fluorescence spectra. The anthanthrones have large (>0.8) intersystem crossing (ISC) quantum yields (ΦT) likely caused by nπ* character in the ground or excited states. A bromo-substituted anthanthrene has a unity ISC yield due to an ISC rate constant of 2.5 × 1010 s-1 caused by heavy-atom induced, spin-orbit coupling. This leads to low fluorescence quantum yields (ΦF) in these three derivatives. The parent anthanthrene and remaining derivatives behave much differently. All have ΦF values from 0.58-0.84 with lower ΦT values as radiative decay outcompetes ISC. The anthanthrones have remarkable excited-state absorption with strong, broad transitions across the visible region with weaker transitions extending to nearly two μm. The anthanthrenes have very similar-shaped, broad transitions in the visible which can be shifted ∼60 nm by controlling the substituents. The triplet lifetimes range from 31-1200 μs and increase as the ISC yields decrease; the bromo-substituted anthanthrene is the shortest, followed by the anthanthrones then the other anthanthrenes. The rate of triplet-triplet annihilation is also affected by the presence of substituents; as the amount of steric bulk is increased, the rate of annihilation decreases.
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Affiliation(s)
- David J Stewart
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Functional Materials Division, Wright-Patterson AFB, Ohio 45433-7750, USA.
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27
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Oh CS, Pereira DDS, Han SH, Park HJ, Higginbotham HF, Monkman AP, Lee JY. Dihedral Angle Control of Blue Thermally Activated Delayed Fluorescent Emitters through Donor Substitution Position for Efficient Reverse Intersystem Crossing. ACS APPLIED MATERIALS & INTERFACES 2018; 10:35420-35429. [PMID: 30238749 DOI: 10.1021/acsami.8b10595] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This study shows a molecular design strategy for controlling the dihedral angle of two carbazole donors linked to a 2,4-diphenyl-1,3,5-triazine acceptor by a phenyl unit. Using this approach, six thermally activated delayed fluorescence emitters were synthesized with donors placed in various positions around a central phenyl core, and the photophysical relationship between the donor position and its dihedral angle was investigated. We demonstrate that this angle can affect both the strength of the charge transfer state and the conjugation across the entire molecule, effectively changing the singlet-triplet energy gap of the system. We conclude that materials containing two substituted -ortho donors or one -ortho and an adjacent -meta have the smallest energy gaps and the shortest delayed fluorescence lifetimes. On the other hand, emitters with no -ortho substituted donors have larger energy gaps and slow-to-negligible delayed fluorescence. When applying these materials to organic light-emitting diodes, these blue-emitting devices have a range of electrical properties, the best producing efficiencies as high as 21.8% together with high resistance to roll-off that correlate with the reverse intersystem crossing rates obtained.
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Affiliation(s)
- Chan Seok Oh
- 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
| | - Hee-Jun Park
- School of Chemical Engineering , Sungkyunkwan University , 2066, Seobu-ro , Jangan-gu, Suwon , Gyeonggi 440-746 , Korea
| | | | - Andrew P Monkman
- Department of Physics , Durham University , South Road , Durham DH1 3LE , U.K
| | - Jun Yeob Lee
- School of Chemical Engineering , Sungkyunkwan University , 2066, Seobu-ro , Jangan-gu, Suwon , Gyeonggi 440-746 , Korea
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28
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Song W, Chen Y, Xu Q, Mu H, Cao J, Huang J, Su J. [1,2,4]Triazolo[1,5- a]pyridine-Based Host Materials for Green Phosphorescent and Delayed-Fluorescence OLEDs with Low Efficiency Roll-Off. ACS APPLIED MATERIALS & INTERFACES 2018; 10:24689-24698. [PMID: 29974742 DOI: 10.1021/acsami.8b07462] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Herein, a series of universal bipolar host materials, 9,9'-([1,2,4]triazolo[1,5- a]pyridine-2,6-diylbis(4,1-phenylene))bis(9 H-carbazole) (TP26Cz1), 3-(2-(4-(9 H-carbazol-9-yl)phenyl)-[1,2,4]triazolo[1,5- a] pyridine-6-yl)-9-phenyl-9 H-carbazole (TP26Cz2), 9,9'-([1,2,4]triazolo[1,5- a]pyridine-2,7-diylbis(4,1-phenylene))bis(9 H-carbazole) (TP27Cz1), and 3-(2-(4-(9 H-carbazol-9-yl)phenyl)-[1,2,4]triazolo[1,5- a]pyridin-7-yl)-9-phenyl-9 H-carbazole (TP27Cz2), using [1,2,4]triazolo[1,5- a]pyridine (TP) as electron-transporting moiety and carbazole as hole-transporting moiety, were designed and synthesized. All four compounds possess remarkable carrier-transporting properties and excellent thermal stability with high glass-transition temperature ( Tg) in the range of 136-144 °C. The hole- and electron-transporting abilities could be regulated by adjusting the linkage mode between the carbazole and TP units, and balanced charge-transporting properties were realized in TP26Cz2 and TP27Cz2. The phosphorescent and thermally activated delayed-fluorescence (TADF) organic light-emitting diodes (OLEDs) based on these host materials exhibit superior performance with high efficiency and low roll-off. For example, TP26Cz2-hosted phosphorescent OLED (PhOLED) exhibits the maximum external quantum efficiency (ηext) of 25.6%, and at the high luminance of 5000 cd m-2, the ηext still remained at 25.2%. TP27Cz1-hosted TADF device exhibits the maximum ηext of 15.5% and only dropped to 15.4% at the luminance of 1000 cd m-2. Moreover, the influence of linking mode of carbazole unit and TP units in these hosts on their photophysical and carrier-transporting properties as well as the electroluminescence (EL) performance of devices was discussed.
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Affiliation(s)
| | | | | | | | - Jingjing Cao
- State Key Laboratory of Applied Organic Chemistry (SKLAOC), College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , P. R. China
| | - Jinhai Huang
- Shanghai Taoe Chemical Technology Co., Ltd , Shanghai 200030 , P. R. China
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29
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Liu Y, Wang Y, Li C, Ren Z, Ma D, Yan S. Efficient Thermally Activated Delayed Fluorescence Conjugated Polymeric Emitters with Tunable Nature of Excited States Regulated via Carbazole Derivatives for Solution-Processed OLEDs. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00565] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Yuchao Liu
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yukun Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry Chinese Academy of Sciences, Beijing 130022, China
- University of Chinese Academy of Sciences, Beijing 10039, China
| | - 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
| | - Dongge Ma
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Shouke Yan
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
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30
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Zhang D, Song X, Li H, Cai M, Bin Z, Huang T, Duan L. High-Performance Fluorescent Organic Light-Emitting Diodes Utilizing an Asymmetric Anthracene Derivative as an Electron-Transporting Material. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707590. [PMID: 29774610 DOI: 10.1002/adma.201707590] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/18/2018] [Indexed: 06/08/2023]
Abstract
Fluorescent organic light-emitting diodes with thermally activated delayed fluorescent sensitizers (TSF-OLEDs) have aroused wide attention, the power efficiencies of which, however, are limited by the mutual exclusion of high electron-transport mobility and large triplet energy of electron-transporting materials (ETMs). Here, an asymmetric anthracene derivative with electronic properties manipulated by different side groups is developed as an ETM to promote TSF-OLED performances. Multiple intermolecular interactions are observed, leading to a kind of "cable-like packing" in the crystal and favoring the simultaneous realization of high electron-transporting mobility and good exciton-confinement ability, albeit the low triplet energy of the ETM. The optimized TSF-OLEDs exhibit a record-high maximum external quantum efficiency/power efficiency of 24.6%/76.0 lm W-1 , which remain 23.8%/69.0 lm W-1 at a high luminance of even 5000 cd m-2 with an extremely low operation voltage of 3.14 V. This work opens a new paradigm for designing ETMs and also paves the way toward practical application of TSF-OLEDs.
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Affiliation(s)
- Dongdong 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
| | - Haoyuan Li
- 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
| | - Zhengyang Bin
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Tianyu Huang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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31
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Thurakkal S, Soman A, Unni KN, Joseph J, Ramaiah D. Simple solution processable carbazole-oxadiazole hybrids for un-doped deep-blue OLEDs. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2018.03.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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32
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Tierce NT, Chen CH, Chiu TL, Lin CF, Bardeen CJ, Lee JH. Exciton dynamics in heterojunction thin-film devices based on exciplex-sensitized triplet–triplet annihilation. Phys Chem Chem Phys 2018; 20:27449-27455. [DOI: 10.1039/c8cp05261a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A triplet-diffusion-singlet-blocking layer and fluorescent dopant enhance blue emission due to triplet–triplet annihilation in an organic light emitting diode structure.
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Affiliation(s)
- Nathan T. Tierce
- Department of Chemistry, University of California, Riverside
- Riverside
- USA
| | - Chia-Hsun Chen
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering
- National Taiwan University
- Taiwan
- Republic of China
| | - Tien-Lung Chiu
- Department of Electrical Engineering
- Yuan Ze University
- Taiwan
- Republic of China
| | - Chi-Feng Lin
- Department of Electro-Optical Engineering
- National United University
- Taiwan
- Republic of China
| | | | - Jiun-Haw Lee
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering
- National Taiwan University
- Taiwan
- Republic of China
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