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Wu Y, Zhang J, Li D, Du S, Mu X, Liu C, Fang K, Feng T, Wang T, Li W, Ge Z. Optimizing the energy level alignment for achieving record-breaking efficiency in hot exciton deep red OLEDs. MATERIALS HORIZONS 2024; 11:3928-3934. [PMID: 38845573 DOI: 10.1039/d4mh00441h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
To effectively compete with the quenching process in long-wavelength regions like deep red (DR) and near-infrared (NIR), rapid radiative decay is urgently needed to address the challenges posed by the "energy gap law". Herein, we confirmed that it is crucial for hot exciton emitters to attain a narrow energy gap (ΔES1-T2) between the lowest singlet excited (S1) state and second triplet excited (T2) state, while ensuring that T2 slightly exceeds S1 in the energy level. Two proofs-of-concept of hot exciton DR emitters, namely αT-IPD and βT-IPD, were successfully designed and synthesized by coupling electron-acceptors N,N-diphenylnaphthalen-2-amine (αTPA) and N,N-diphenylnaphthalen-1-amine (βTPA) with an electron-withdrawing unit 5-(4-(tert-butyl) phenyl)-5H-pyrazino[2,3-b]indole-2,3-dicarbonitrile (IPD). Both emitters exhibited a narrow ΔES1-T2, with T2 being slightly higher than S1. Additionally, both emitters showed significantly large ΔET2-T1. Moreover, due to their aggregation-induced emission characteristics, J-aggregated packing modes, moderate strength intermolecular CN⋯H-C and C-H⋯π interactions, and unique, comparatively large center-to-center distances among trimers in the crystalline state, both αT-IPD and βT-IPD emitters exhibited remarkable photoluminescence quantum yields of 68.5% and 73.5%, respectively, in non-doped films. Remarkably, the corresponding non-doped DR-OLED based on βT-IPD achieved a maximum external quantum efficiency of 15.5% at an emission peak wavelength of 667 nm, representing the highest reported value for hot exciton DR-OLEDs.
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Affiliation(s)
- Yujie Wu
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, P. R. China
- School of Materials Science and Engineering Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Jiasen Zhang
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, P. R. China
| | - Deli Li
- Institute for Smart Materials & Engineering, University of Jinan, No. 336 Nanxin Zhuang West Road, Jinan 250022, P. R. China
| | - Songyu Du
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, P. R. China
| | - Xilin Mu
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, P. R. China
| | - Chunyu Liu
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, P. R. China
| | - Kaibo Fang
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, P. R. China
- School of Materials Science and Engineering Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Tingting Feng
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, P. R. China
| | - Tao Wang
- School of Materials Science and Engineering Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China
| | - Wei Li
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, P. R. China
| | - Ziyi Ge
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, P. R. China
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Jiao Y, Qiu W, Li M, Su SJ. Modulation of Intermolecular Interactions in Organic Emitters for Highly Efficient Organic Light-Emitting Diodes. Chemistry 2024; 30:e202401635. [PMID: 38794783 DOI: 10.1002/chem.202401635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 05/26/2024]
Abstract
The adverse aggregated-caused quenching (ACQ) problem of most electroluminescent materials existing in highly doped thin films is one of the key factors impeding the commercialization of high-efficiency organic light-emitting diodes (OLEDs) panel. Whereas, by delicately constructing and modulating moderate intermolecular interactions, some aggregates have been demonstrated to present distinct luminescent properties such as tunable emission spectra, improved photoluminescence quantum yields, different emission mechanism and enhanced horizontal transition dipole ratio (Θ) of emitting layer, providing feasible solution for ACQ problem. The luminescence from newly generated emissive state in aggregates is different from the traditional "isolated" molecules in organic electronics and will possess novel properties and applications. Herein, we summarize the different types of intermolecular interactions within emitter aggregates exhibiting distinct luminescent mechanisms, as well as their effects on photoluminescent and electroluminescent properties, offering reliable reference for the advancement of highly efficient OLEDs utilizing aggregated emitters.
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Affiliation(s)
- Yihang Jiao
- State Key Laboratory of Luminescent Materials and Devices and Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, South China University of Technology, Wushan Road 381, Tianhe District, Guangzhou, 510640, Guangdong Province, P. R. China
| | - Weidong Qiu
- State Key Laboratory of Luminescent Materials and Devices and Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, South China University of Technology, Wushan Road 381, Tianhe District, Guangzhou, 510640, Guangdong Province, P. R. China
| | - Mengke Li
- State Key Laboratory of Luminescent Materials and Devices and Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, South China University of Technology, Wushan Road 381, Tianhe District, Guangzhou, 510640, Guangdong Province, P. R. China
| | - Shi-Jian Su
- State Key Laboratory of Luminescent Materials and Devices and Guangdong Basic Research Center of Excellence for Energy & Information Polymer Materials, South China University of Technology, Wushan Road 381, Tianhe District, Guangzhou, 510640, Guangdong Province, P. R. China
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Polesiak E, Makowska-Janusik M, Drapala J, Zagorska M, Banasiewicz M, Kozankiewicz B, Kulszewicz-Bajer I, Pron A. Photophysical and redox properties of new donor-acceptor-donor (DAD) compounds containing benzothiadiazole (A) and dimethyldihydroacridine (D) units: a combined experimental and theoretical study. Phys Chem Chem Phys 2024. [PMID: 39041807 DOI: 10.1039/d4cp02322f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Four donor-acceptor-donor compounds consisting of 9,9-dimethyl-9,10-dihydroacridine donors differently linked to a benzothiadiazole acceptor were designed using DFT calculations and synthesized, namely 4,7-bis(4-(9,9-dimethyl-9,10-dihydroacridine)phenyl)benzo[c][1,2,5]thiadiazole (1), 4,7-bis(2,5-dimethyl-4-(9,9-dimethyl-9,10-dihydroacridine)phenyl)benzo[c][1,2,5]thiadiazole (2), 4,7-bis(3,5-di(9,9-dimethyl-9,10-dihydroacridine)phenyl)benzo[c][1,2,5]thiadiazole (3), and 4-(3,5-di(9,9-dimethyl-9,10-dihydroacridine)phenyl)-7-(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (4). As predicted theoretically, all studied compounds were electrochemically active both in the reduction as well as in the oxidation modes. They underwent one electron quasi-reversible reduction. Oxidation of 1 and 2 involved a two electron process transforming them into dications and carrying out, in parallel, their dimerization. Oxidation of 3 and 4 resulted in their oligomerization (polymerization). The electrochemically determined ionisation potentials (IP) of 1-4 were similar, covering a narrow range of 5.28-5.33 eV and were consistent with DFT calculations. Larger differences were found for experimentally determined electron affinity (EA) values, being significantly lower for 2 (|EA| = 2.59 eV) as compared to 1, 3 and 4 whose |EA| values were higher by 0.15-0.25 eV, again consistent with DFT calculations. DFT calculations predict positive values of ΔE(S1-T1) for all compounds i.e. in the range of 0.18 eV to 0.43 eV for 1, 3 and 4 and a significantly lower value for 2 (0.06 eV), indicating a possible RISC process in this case. DFT calculations of ΔE(S1-T2) lead to negative and very small values for 2-4 implying a possible involvement of higher lying triplets in the generation of singlet excitons. The investigated derivatives exhibited fluorescence in the orange-red spectral range (550-770 nm) and were strongly dependent on the solvent polarity. The highest PLQY value of 37% was measured for 1 in toluene. The PLQY values significantly improved upon deoxygenation of the studied solutions. Solid state samples also exhibited higher PLQY values as compared to those determined for DCM solutions. These findings were rationalized by partial suppression of the vibrationally induced emission quenching in the solid state due to the intermolecular interaction confinement.
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Affiliation(s)
- Emilia Polesiak
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Malgorzata Makowska-Janusik
- Faculty of Science and Technology, Jan Dlugosz University, Al. Armii Krajowej 13/15, 42-200 Częstochowa, Poland
| | - Jakub Drapala
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Malgorzata Zagorska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Marzena Banasiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/44, 02-668, Warsaw, Poland
| | - Boleslaw Kozankiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/44, 02-668, Warsaw, Poland
| | - Irena Kulszewicz-Bajer
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Adam Pron
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
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Qi H, Xie D, Gao Z, Wang S, Peng L, Liu Y, Ying S, Ma D, Yan S. A record-high EQE of 7.65%@3300 cd m -2 achieved in non-doped near-ultraviolet OLEDs based on novel D'-D-A type bipolar fluorophores upon molecular configuration engineering. Chem Sci 2024; 15:11053-11064. [PMID: 39027275 PMCID: PMC11253119 DOI: 10.1039/d4sc02655a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 06/13/2024] [Indexed: 07/20/2024] Open
Abstract
Developing a high-performance near-ultraviolet (NUV) material and its simple non-doped device with a small efficiency roll-off and good color purity is a promising but challenging task. Here, we proposed a novel donor'-donor-acceptor (D'-D-A) type molecular strategy to largely solve the intrinsic contradictions among wide-bandgap NUV emission, fluorescence efficiency, carrier injection and transport. An efficient NUV fluorophore, 3,6-mPPICNC3, exhibiting a hybridized local and charge-transfer state, is achieved through precise molecular configuration engineering, realizing similar hole and electron mobilities at both low and high electric fields. Moreover, the planarized intramolecular charge transfer excited state and steric hindrance effect endow 3,6-mPPICNC3 with a considerable luminous efficiency and good color purity in the aggregation state. Consequently, the non-doped device emitting stable NUV light with Commission Internationale de l'Eclairage (CIE) coordinates of (0.160, 0.032) and a narrow full width at half maximum of 44 nm exhibits a state-of-the-art external quantum efficiency (EQE) of 7.67% and negligible efficiency roll-off over a luminance range from 0 to 3300 cd m-2. This is a record-high efficiency among all the reported non-doped NUV devices. Amazingly, an EQE of 7.85% and CIE coordinates of (0.161, 0.025) are achieved in the doped device. This demonstrates that the D'-D-A-type molecular structure has great potential for developing high-performance organic light-emitting materials and their optoelectronic applications.
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Affiliation(s)
- Haoyuan Qi
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Danyu Xie
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology Guangzhou 510640 P. R. China
| | - Zexuan Gao
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Shengnan Wang
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Ling Peng
- College of Chemistry and Chemical Engineering, Heze University Heze 274015 P. R. China
| | - Yuchao Liu
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Shian Ying
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
| | - Dongge Ma
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology Guangzhou 510640 P. R. China
| | - Shouke Yan
- Key Laboratory of Rubber-Plastics, Ministry of Education, School of Polymer Science and Engineering, Qingdao University of Science and Technology Qingdao 266042 P. R. China
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology Beijing 100029 P. R. China
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Lim J, Kim JM, Lee JY. Deep Learning Prediction of Triplet-Triplet Annihilation Parameters in Blue Fluorescent Organic Light-Emitting Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2312774. [PMID: 38652081 DOI: 10.1002/adma.202312774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 04/16/2024] [Indexed: 04/25/2024]
Abstract
The triplet-triplet annihilation (TTA) ratio and the rate coefficient (kTT) of TTA are key factors in estimating the contribution of triplet excitons to radiative singlet excitons in fluorescent TTA organic light-emitting diodes. In this study, deep learning models are implemented to predict key factors from transient electroluminescence (trEL) data using new numerical equations. A new TTA model is developed that considers both polaron and exciton dynamics, enabling the distinction between prompt and delayed singlet decays with a fundamental understanding of the mechanism. In addition, deep learning models for predicting the kinetic coefficients and TTA ratio are established. After comprehensive optimization inspired by photophysics, determination coefficient values of 0.992 and 0.999 are achieved in the prediction of kTT and TTA ratio, respectively, indicating a nearly perfect prediction. The contribution of each kinetic parameter of polaron and exciton dynamics to the trEL curve is discussed using various deep-learning models.
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Affiliation(s)
- Junseop Lim
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, Republic of Korea
| | - Jae-Min Kim
- Department of Advanced Materials Engineering, Chung-Ang University, 4726, Seodong-daero, Daedeok-myeon, Anseong-si, Gyeonggi-do, 17546, Republic of Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, Republic of Korea
- SKKU Institute of Energy Science and Technology, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
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He X, Cheng X, Wu B, Liu J. Nonadiabatic Field with Triangle Window Functions on Quantum Phase Space. J Phys Chem Lett 2024; 15:5452-5466. [PMID: 38747729 PMCID: PMC11129318 DOI: 10.1021/acs.jpclett.4c00793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/29/2024] [Accepted: 05/01/2024] [Indexed: 05/24/2024]
Abstract
Recent progress on the constraint coordinate-momentum phase space (CPS) formulation of finite-state quantum systems has revealed that the triangle window function approach is an isomorphic representation of the exact population-population correlation function of the two-state system. We use the triangle window (TW) function and the CPS mapping kernel element to formulate a novel useful representation of discrete electronic degrees of freedom (DOFs). When it is employed with nonadiabatic field (NaF) dynamics, a new variant of the NaF approach (i.e., NaF-TW) is proposed. The NaF-TW expression of the population of any adiabatic state is always positive semidefinite. Extensive benchmark tests of model systems in both the condensed phase and gas phase demonstrate that the NaF-TW approach is able to faithfully capture the dynamical interplay between electronic and nuclear DOFs in a broad region, including where the states remain coupled all the time, as well as where the bifurcation characteristic of nuclear motion is important.
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Affiliation(s)
- Xin He
- Beijing National Laboratory
for Molecular Sciences, Institute of Theoretical and Computational
Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Xiangsong Cheng
- Beijing National Laboratory
for Molecular Sciences, Institute of Theoretical and Computational
Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Baihua Wu
- Beijing National Laboratory
for Molecular Sciences, Institute of Theoretical and Computational
Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jian Liu
- Beijing National Laboratory
for Molecular Sciences, Institute of Theoretical and Computational
Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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Jayabharathi J, Thanikachalam V. Robust luminogens as cutting-edge tools for efficient light emission in recent decades. Phys Chem Chem Phys 2024; 26:13561-13605. [PMID: 38655772 DOI: 10.1039/d4cp00737a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Blue luminogens play a vital role in white lighting and potential metal-free fluorescent materials and their high-lying excited states contribute to harvesting triplet excitons in devices. However, in TADF-OLEDs (ΔEST < 0.1 eV), although T1 excitons transfer to S1via RISC with 100% IQE, the longer lifetime of blue TADF suffers from efficiency roll-off (RO). In this case, hybridized local and charge transfer (HLCT) materials have attracted significant interest in lighting owing to their 100% hot exciton harvesting and enhanced efficiency. Both academics and industrialists widely use the HLCT strategy to improve the efficiency of fluorescent organic light-emitting diodes (FOLEDs) by harvesting dark triplet excitons through the RISC process. Aggregation-induced emissive materials (AIEgens) possess tight packing in the aggregation state, and twisted AIEgens with HLCT behaviour have a shortened conjugation length, inducing blue emission and making them suitable candidates for OLED applications. TTA-OLEDs are used in commercial BOLEDs because of their moderate efficiency and reasonable operation lifetime. In this review, we discuss the devices based on TTA fluorophores, TADF fluorophores, HLCT fluorophores, AIEgens and HLCT-sensitized fluorophores (HLCT-SF), which break through the statistical limitations.
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Affiliation(s)
- Jayaraman Jayabharathi
- Department of Chemistry, Annamalai University, Annamalainagar, Tamilnadu-608 002, India.
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Yin Y, Zeng S, Xiao C, Fan P, Shin DJ, Kim KJ, Nam H, Ma Q, Ma H, Zhu W, Kim T, Lee JY, Wang Y. Hybridized local and charge transfer dendrimers with near-unity exciton utilization for enabling high-efficiency solution-processed hyperfluorescent OLEDs. MATERIALS HORIZONS 2024; 11:1741-1751. [PMID: 38288665 DOI: 10.1039/d3mh01860a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Achieving both high emission efficiency and exciton utilization efficiency (ηS) in hot exciton materials is still a formidable task. Herein, a proof-of-concept design for improving ηS in hot exciton materials is proposed via elaborate regulation of singlet-triplet energy difference, leading to an additional thermally activated delayed fluorescence (TADF) process. Two novel dendrimers, named D-TTT-H and D-TTT-tBu, were prepared and characterized, in which diphenylamine derivatives were used as a donor moiety and tri(triazolo)triazine (TTT) as an acceptor fragment. Compounds D-TTT-H and D-TTT-tBu showed an intense green color with an emission efficiency of approximately 80% in solution. Impressively, both dendrimers simultaneously exhibited a hot exciton process and TADF characteristic in the solid state, as was demonstrated via theoretical calculation, transient photoluminescence, magneto-electroluminescence and transient electroluminescence measurements, thus achieving almost unity ηS. A solution processable organic light-emitting diode (OLED) employing the dendrimer as a dopant represents the best performance with the highest luminance of 15090 cd m-2 and a maximum external quantum efficiency (EQEmax) of 11.96%. Moreover, using D-TTT-H as a sensitizer, an EQEmax of 30.88%, 24.08% and 14.33% were achieved for green, orange and red solution-processed OLEDs, respectively. This research paves a new avenue to construct a fluorescent molecule with high ηS for efficient and stable OLEDs.
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Affiliation(s)
- Yixiao Yin
- Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering, Changzhou University, Changzhou 213164, China.
| | - Songkun Zeng
- Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering, Changzhou University, Changzhou 213164, China.
| | - Chen Xiao
- Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering, Changzhou University, Changzhou 213164, China.
| | - Peng Fan
- Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering, Changzhou University, Changzhou 213164, China.
| | - Dong Jin Shin
- School of Chemical Engineering, Sungkyunkwan University 2066, Seobu-ro, Jangan-gu, Gyeonggi, Suwon 14169, Korea.
| | - Ki Ju Kim
- Department of Information Display, Hongik University, 04066, Seoul, Korea
| | - Hyewon Nam
- Department of Information Display, Hongik University, 04066, Seoul, Korea
| | - Qian Ma
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China.
| | - Huili Ma
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China.
| | - Weiguo Zhu
- Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering, Changzhou University, Changzhou 213164, China.
| | - Taekyung Kim
- Department of Information Display, Hongik University, 04066, Seoul, Korea
- Department of Materials Science and Engineering, Hongik University, Sejong, 30016, Korea.
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University 2066, Seobu-ro, Jangan-gu, Gyeonggi, Suwon 14169, Korea.
- SKKU Institute of Energy Science and Technology, Sungkyunkwan University 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Korea
| | - Yafei Wang
- Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering, Changzhou University, Changzhou 213164, China.
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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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10
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Diesing S, Zhang L, Zysman-Colman E, Samuel IDW. A figure of merit for efficiency roll-off in TADF-based organic LEDs. Nature 2024; 627:747-753. [PMID: 38538942 PMCID: PMC10972759 DOI: 10.1038/s41586-024-07149-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 02/01/2024] [Indexed: 04/01/2024]
Abstract
Organic light-emitting diodes (OLEDs) are a revolutionary light-emitting display technology that has been successfully commercialized in mobile phones and televisions1,2. The injected charges form both singlet and triplet excitons, and for high efficiency it is important to enable triplets as well as singlets to emit light. At present, materials that harvest triplets by thermally activated delayed fluorescence (TADF) are a very active field of research as an alternative to phosphorescent emitters that usually use heavy metal atoms3,4. Although excellent progress has been made, in most TADF OLEDs there is a severe decrease of efficiency as the drive current is increased, known as efficiency roll-off. So far, much of the literature suggests that efficiency roll-off should be reduced by minimizing the energy difference between singlet and triplet excited states (ΔEST) to maximize the rate of conversion of triplets to singlets by means of reverse intersystem crossing (kRISC)5-20. We analyse the efficiency roll-off in a wide range of TADF OLEDs and find that neither of these parameters fully accounts for the reported efficiency roll-off. By considering the dynamic equilibrium between singlets and triplets in TADF materials, we propose a figure of merit for materials design to reduce efficiency roll-off and discuss its correlation with reported data of TADF OLEDs. Our new figure of merit will guide the design and development of TADF materials that can reduce efficiency roll-off. It will help improve the efficiency of TADF OLEDs at realistic display operating conditions and expand the use of TADF materials to applications that require high brightness, such as lighting, augmented reality and lasing.
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Affiliation(s)
- S Diesing
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, UK
- Organic Semiconductor Centre, EaStCHEM, School of Chemistry, St Andrews, UK
| | - L Zhang
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, UK
- Organic Semiconductor Centre, EaStCHEM, School of Chemistry, St Andrews, UK
| | - E Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM, School of Chemistry, St Andrews, UK.
| | - I D W Samuel
- Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, UK.
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11
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Kumar K, Thakur D. Overview of imidazole-based fluorescent materials with hybridized local and charge transfer and hot-exciton pathway characteristics in excited states. SOFT MATTER 2024; 20:1669-1688. [PMID: 38315555 DOI: 10.1039/d3sm01005h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Herein, we discuss an imidazole-based molecular framework, which can successfully transform triplet excitons present in high triplet levels into singlet states. We explain the working mechanisms of different methods for collecting triplet excitons, including hot excitons or HLCT states. After the development of an hot exciton material by Ma and Yang, many studies have demonstrated that the organic conjugated molecules having imidazole core have possibilities to show high efficiencies via hot exciton pathways. Finally, we provide a detailed investigation of recently published hot exciton luminogens based on imidazole molecular frameworks. This review provides an overview of the molecular structures, frontier molecular orbital information, and glass transition temperature of developed luminogens as well as the efficiency of organic light-emitting diodes (OLED) devices.
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Affiliation(s)
- Krishan Kumar
- School of Chemical Sciences, IIT Mandi, Himachal Pradesh 175005, India.
| | - Diksha Thakur
- School of Chemical Sciences, IIT Mandi, Himachal Pradesh 175005, India.
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12
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Kim H, Scholes GD, Min SK. Extension of molecules with an inverted singlet-triplet gap with conjugated branches to alter the oscillator strength. Phys Chem Chem Phys 2024; 26:5508-5516. [PMID: 38282516 DOI: 10.1039/d3cp05580a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
Molecules that violate Hund's rule and possess negative singlet-triplet gaps (ΔEST) have been actively studied for their potential usage in organic light emitting diodes without the need for thermal activation. However, the weak oscillator strength from the symmetry of such molecules has been recognized as their shortcoming for their application in optoelectronic devices. A group of molecules with a common structural motif involving the original molecule with an inverted gap having branches consisting of conjugated molecules of varied structures and extent of conjugation have been predicted to have desirable oscillator strength, but only few detailed and comprehensive studies regarding the form of excited states and the reason behind the improved oscillator strength have been carried out. We show in this work a series of analyses that suggest that the increase of oscillator strength is correlated with the nature of the excited state changing from a localized excitation to a delocalized excitation involving the central molecule and the branches. The resulting oscillator strength thus depends on the energetic matching of the branching molecule and the central molecule, rather than solely the oscillator strength of the central molecule. From the ΔEST inversion point of view, the static correlation with low-lying doubly excited configurations, the key mechanism behind the inversion in the localized excited state, weakens as the excited states delocalize. As a consequence, the dynamic correlation has a more decisive effect in determining the singlet-triplet gap.
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Affiliation(s)
- Hwon Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), South Korea.
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Seung Kyu Min
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), South Korea.
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13
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Li G, Xu K, Zheng J, Fang X, Lou W, Zhan F, Deng C, Yang YF, Zhang Q, She Y. High-Performance Ultraviolet Organic Light-Emitting Diodes Enabled by Double Boron-Oxygen-Embedded Benzo[ m]tetraphene Emitters. J Am Chem Soc 2024; 146:1667-1680. [PMID: 38175122 DOI: 10.1021/jacs.3c12517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Ultraviolet organic light-emitting diodes (UV OLEDs) have attracted increasing attention because of their promising applications in healthcare, industry, and agriculture; however, their development has been hindered by the shortage of robust UV emitters. Herein, we embedded double boron-oxygen units into nonlinear polycyclic aromatic hydrocarbons (BO-PAHs) to regulate their molecular configurations and excited-state properties, enabling novel bent BO-biphenyl (BO-bPh) and helical BO-naphthyl (BO-Nap) emitters with hybridized local and charge-transfer (HLCT) characteristics. They could be facilely synthesized in gram-scale amounts via a highly efficient two-step route. BO-bPh and BO-Nap showed strong UV and violet-blue photoluminescence in toluene with full width at half-maximum values of 25 and 37 nm, along with quantum efficiencies of 98 and 99%, respectively. A BO-bPh-based OLED showed high color purity UV electroluminescence peaking at 394 nm with Commission Internationale de l'Eclairage (CIE) coordinates of (0.166, 0.021). Moreover, the device demonstrated a record-high maximum external quantum efficiency (EQE) of 11.3%, achieved by successful hot exciton utilization. This work demonstrates the promising potential of double BO-PAHs as robust emitters for future UV OLEDs.
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Affiliation(s)
- Guijie Li
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Kewei Xu
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Jianbing Zheng
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Xiaoli Fang
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Weiwei Lou
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Feng Zhan
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, 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
| | - Yun-Fang Yang
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, 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
| | - Yuanbin She
- College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
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14
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Xu Y, Chen B, Su D, Li J, Qi Q, Hu Y, Wang Q, Xia F, Lou X, Zhao Z, Dai J, Dong X, Zhou J. Near-Infrared Conjugated Polymers Containing Thermally Activated Delayed Fluorescence Units Enable Enhanced Photothermal Therapy. ACS APPLIED MATERIALS & INTERFACES 2023; 15:56314-56327. [PMID: 37983087 DOI: 10.1021/acsami.3c13821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
Photothermal therapy (PTT) using near-infrared (NIR) conjugated polymers as photosensitizers has exhibited enormous potential for tumor treatment. However, most NIR conjugated polymers have poor therapeutic efficacy due to their faint absorbance in the NIR region and low photothermal conversion efficiency (PCE). Herein, a valuable strategy for designing NIR polymeric photosensitizer PEKBs with an enhanced PCE accompanied by strong NIR absorbance is proposed by means of inserting TPA-AQ as a thermally activated delayed fluorescence unit into a polymeric backbone. In these PEKBs, PEKB-244 with the appropriate molar content of the TPA-AQ unit displays the strongest NIR absorbance and the highest PCE of 64.5%. Theoretical calculation results demonstrate that the TPA-AQ unit in the polymeric backbone can modulate the intramolecular charge transfer effects and the excited energy decay routes for generating higher heat. The prepared nanoparticles (PEKB-244 NPs) exhibit remarkable photothermal conversion capacities and great biocompatibility in aqueous solutions. Moreover, PEKB-244 NPs also show outstanding photothermal stability, displaying negligible changes in the absorbance within 808 nm irradiation of 1 h (800 mW cm-2). Both in vitro and in vivo experimental results further indicate that PEKB-244 NPs can substantially kill cancer cells under NIR laser irradiation. We anticipate that this novel molecular design strategy can be employed to develop excellent NIR photosensitizers for cancer photothermal therapy.
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Affiliation(s)
- Yating Xu
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Biao Chen
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430034, China
| | - Deliang Su
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Jianqing Li
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou 510640, China
| | - Qiang Qi
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Yuxin Hu
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Quan Wang
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Fan Xia
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Xiaoding Lou
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou 510640, China
| | - Jun Dai
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430034, China
| | - Xiyuan Dong
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430034, China
| | - Jian Zhou
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
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15
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Han P, Lin C, Xia E, Cheng J, Xia Q, Yang D, Qin A, Ma D, Tang BZ. Non-Doped Blue AIEgen-Based OLED with EQE Approaching 10.3 . Angew Chem Int Ed Engl 2023; 62:e202310388. [PMID: 37668100 DOI: 10.1002/anie.202310388] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/22/2023] [Accepted: 09/04/2023] [Indexed: 09/06/2023]
Abstract
Aggregation-induced emission (AIE) luminogens (AIEgens) are attractive for the construction of non-doped blue organic light-emitting diodes (OLEDs) owning to their high emission efficiency in the film state. However, the large internal inversion rate (kIC (Tn) ) between high-lying triplet levels (Tn ) and Tn-1 causes a huge loss of triplet excitons, resulting in dissatisfied device performance of these AIEgens-based non-doped OLEDs. Herein, we designed and synthesized a blue luminogen of DPDPB-AC by fusing an AIEgen of TPB-AC and a DMPPP, which feature hot exciton and triplet-triplet annihilation (TTA) up-conversion process, respectively. DPDPB-AC successfully inherits the AIE feature and excellent horizontal dipole orientation of TPB-AC. Furthermore, it owes smaller kIC (Tn) than TPB-AC. When DPDPB-AC was applied in OLED as non-doped emitting layer, an outstanding external quantum efficiency of 10.3 % and an exceptional brightness of 69311 cd m-2 were achieved. The transient electroluminescent measurements and steady-state dynamic analysis confirm that both TTA and hot exciton processes contribute to such excellent device performance. This work provides a new insight into the design of efficient organic fluorophores by managing high-lying triplet excitons.
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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, Center for Aggregation-Induced Emission, South China University of Technology, Guangzhou, 510640, China
| | - Chengwei Lin
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology, Guangzhou, 510640, China
| | - Erhan Xia
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology, Guangzhou, 510640, China
| | - Jiawei Cheng
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology, Guangzhou, 510640, China
| | - Qing Xia
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology, Guangzhou, 510640, China
| | - Dezhi Yang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology, Guangzhou, 510640, China
| | - Anjun Qin
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology, Guangzhou, 510640, China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology, Guangzhou, 510640, China
| | - Ben Zhong Tang
- Center for Aggregation-Induced Emission, AIE Institute, South China University of Technology, Guangzhou, 510640, China
- School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen (CUHK-Shenzhen), Guangdong, 518172, China
- Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration and Reconstruction, The Hong Kong University of Science & Technology, Kowloon, 999077, Hong Kong, China
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16
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Liu F, Cao G, Feng Z, Cheng Z, Yan Y, Xu Y, Jiang Y, Chang Y, Lv Y, Lu P. Triphenylene-Based Emitters with Hybridized Local and Charge-Transfer Characteristics for Efficient Nondoped Blue OLEDs with a Narrowband Emission and a Small Efficiency Roll-Off. ACS APPLIED MATERIALS & INTERFACES 2023; 15:47307-47316. [PMID: 37750758 DOI: 10.1021/acsami.3c09433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Developing high-efficiency nondoped blue organic light-emitting diodes (OLEDs) with high color purity and low-efficiency roll-off is vital for display and lighting applications. Herein, we developed two asymmetric D-π-A blue emitters, PIAnTP and PyIAnTP, in which triphenylene is first utilized as a functional acceptor. The relatively weak charge transfer (CT) properties, rigid molecular structures, and multiple supramolecular interactions in PIAnTP and PyIAnTP can significantly enhance the fluorescence efficiency and suppress the structural relaxations to obtain a narrowband blue emission. The photophysical experiments and theoretical simulations reveal that they both exhibit a typical hybridized local and charge-transfer (HLCT) excited state and achieve high external quantum efficiency (EQE) via a "hot exciton" channel. As a result, PIAnTP- and PyIAnTP-based nondoped devices realize blue emission at 456 and 464 nm, corresponding to CIE coordinates of (0.16, 0.14) and (0.16, 0.19), narrow full width at half-maximums of 52 and 60 nm, and the high EQEs of 8.36 and 8.69%, respectively. More importantly, the PIAnTP- and PyIAnTP-based nondoped devices show small EQE roll-offs of only 5.9 and 2.4% at 1000 cd m-2, respectively. These results signify an advance in designing a highly efficient blue emitter for nondoped OLEDs.
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Affiliation(s)
- Futong Liu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Gongyi Cao
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Zijun Feng
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Zhuang Cheng
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Yan Yan
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Yangze Xu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Yixuan Jiang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Yulei Chang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Ying Lv
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, P. R. China
| | - Ping Lu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, P. R. China
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Wei F, Chen J, Zhao X, Wu Y, Wang H, Chen X, Xiong Z. High-Performance Hot-Exciton OLEDs via Fully Harvesting Triplet Excited States from Both the Exciplex Co-Host and the TBRb Emitter. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303192. [PMID: 37587760 PMCID: PMC10582462 DOI: 10.1002/advs.202303192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/12/2023] [Indexed: 08/18/2023]
Abstract
The high-level reverse intersystem crossing (HL-RISC, T2 → S1 ) process from triplet to singlet exciton, namely the "hot exciton" channel, has recently been demonstrated in the traditional fluorescent emitter of TBRb. Although it is a potential pathway to improve the utilization of non-radiative triplet exciton energy, highly efficient fluorescent organic light emitting diodes (FOLEDs) based on this "hot exciton" channel have not been developed. Herein, high-efficiency and low-efficiency roll-off FOLEDs are achieved through doping TBRb molecules into an energy-level matched exciplex co-host. Combining the low-level RISC (LL-RISC, EX3 → EX1 ) process in the exciplex co-host with the HL-RISC process of hot excitons in TBRb to fully harvest the triplet energy, a record-high external quantum efficiency (EQE) of 20.4% is obtained via a proper Dexter energy transfer of triplet excitons, realizing the efficiency breakthrough from fully fluorescent material-based OLEDs with TBRb as an end emitter. Furthermore, the fingerprint Magneto-electroluminescence (MEL) as a sensitive measuring tool is employed to visualize the "hot exciton" channel in TBRb, which also directly verifies the effective energy confinement and the full utilization of hot excitons. Obviously, this work paves a promising way for further fabricating high-efficiency TBRb-based FOLEDs for lighting and flat-panel display applications.
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Affiliation(s)
- Fuxian Wei
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Jing Chen
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Xi Zhao
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Yuting Wu
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Huiyao Wang
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Xiaoli Chen
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
| | - Zuhong Xiong
- Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and TechnologySouthwest UniversityChongqing400715P. R. China
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18
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Wang B, Wang H, Hu Y, Waterhouse GIN, Lu S. Carbon Dot Based Multicolor Electroluminescent LEDs with Nearly 100% Exciton Utilization Efficiency. NANO LETTERS 2023; 23:8794-8800. [PMID: 37487142 DOI: 10.1021/acs.nanolett.3c02271] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Carbon dots (CDs) are promising nanomaterials for next-generation lighting and displays due to their tunable bandgap, high photoluminescence quantum yield (PLQY), and high stability. However, the exciton utilization efficiency (EUE) of CD-based films can only reach 25%, fundamentally limiting their application in electroluminescent light-emitting diodes (LEDs). Improving the EUE is therefore of great significance. Herein, we developed composite films containing CDs and poly(9-vinylcarbazole) (PVK). The films were then used to construct a series of high-performance electroluminescent LEDs with tunable emission colors covering the blue to green regions as the concentration of CDs in the films increased, delivering a maximum external quantum efficiency and current efficiency of 2.62% and 5.11 cd/A, respectively. Theoretical calculations and experiments established that the excellent performance at low film PLQY was due to a hot exciton effect in the CDs, achieving nearly 100% EUE. This work provides new design strategies toward high-performance CD-based electroluminescent LEDs.
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Affiliation(s)
- Boyang Wang
- Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou 450000, People's Republic of China
| | - Hongwei Wang
- Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou 450000, People's Republic of China
| | - Yongsheng Hu
- School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450000, People's Republic of China
| | | | - Siyu Lu
- Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou 450000, People's Republic of China
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19
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Du S, Luo M, Li D, Lyu L, Li W, Zhao M, Wang Z, Zhang J, Liu D, Li Y, Su SJ, Ge Z. Hot-Exciton Mechanism and AIE Effect Boost the Performance of Deep-Red Emitters in Non-Doped OLEDs. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2303304. [PMID: 37354127 DOI: 10.1002/adma.202303304] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/29/2023] [Indexed: 06/26/2023]
Abstract
Luminescent materials possessing a "hot-exciton" mechanism and aggregation-induced emission (AIE) qualities are well-suited for use as emitting materials in nondoped organic light-emitting diodes (OLEDs), particularly in deep-red regions where their ground state and singlet excited state surfaces are in proximity, leading to the formation of multiple nonradiative channels. However, designing molecules that artificially combine the hot-exciton mechanism and AIE attributes remains a formidable task. In this study, a versatile strategy is presented to achieve hot-exciton fluorescence with AIE property by increasing the first singlet excited (S1 ) state through modulation of the conjugation length of the newly created acceptor unit, matching the energy level of high-lying triplet (Tn ) states, and enhancing exciton utilization efficiency by employing suitable donor moieties. This approach reduces the aggregation-caused quenching (ACQ) in the aggregate state, resulting in the proof-of-concept emitter DT-IPD, which produces an unprecedented external quantum efficiency (EQE) of 12.2% and Commission Internationale de I'Eclairage (CIE) coordinates of (0.69, 0.30) in a deep-red non-doped OLED at 685 nm, representing the highest performance among all deep-red OLEDs based on materials with hot-exciton mechanisms. This work provides novel insights into the design of more efficient hot-exciton emitters with AIE properties.
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Affiliation(s)
- Songyu Du
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Ming Luo
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Deli Li
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Wushan Road 381, Tianhe District, Guangzhou, Guangdong Province, 510640, P. R. China
| | - Lingling Lyu
- Institute of New Energy Technology, Ningbo Dayang Technology Co., Ltd, Zhongguan Road 1219, Ningbo, 315000, P. R. China
| | - Wei Li
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Mengyu Zhao
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Zhichuan Wang
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Jiasen Zhang
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Denghui Liu
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Wushan Road 381, Tianhe District, Guangzhou, Guangdong Province, 510640, P. R. China
| | - Yong Li
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Shi-Jian Su
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Wushan Road 381, Tianhe District, Guangzhou, Guangdong Province, 510640, P. R. China
| | - Ziyi Ge
- Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
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20
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Danyliv I, Ivaniuk K, Danyliv Y, Helzhynskyy I, Andruleviciene V, Volyniuk D, Stakhira P, Baryshnikov GV, Grazulevicius JV. Derivatives of 2-Pyridone Exhibiting Hot-Exciton TADF for Sky-Blue and White OLEDs. ACS APPLIED ELECTRONIC MATERIALS 2023; 5:4174-4186. [PMID: 37637972 PMCID: PMC10449007 DOI: 10.1021/acsaelm.3c00443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 07/04/2023] [Indexed: 08/29/2023]
Abstract
Development of emissive materials for utilization in organic light-emitting diodes (OLEDs) remains a highly relevant research field. One of the most important aspects in the development of efficient emitters for OLEDs is the efficiency of triplet-to-singlet exciton conversion. There are many concepts proposed for the transformation of triplet excitons to singlet excitons, among which thermally activated delayed fluorescence (TADF) is the most efficient and widespread. One of the variations of the TADF concept is the hot exciton approach according to which the process of exciton relaxation into the lowest energy electronic state (internal conversion as usual) is slower than intersystem crossing between high-lying singlets and triplets. In this paper, we present the donor-acceptor materials based on 2-pyridone acceptor coupled to the different donor moieties through the phenyl linker demonstrating good performance as components of sky-blue, green-yellow, and white OLEDs. Despite relatively low photoluminescence quantum yields, the compound containing 9,9-dimethyl-9,10-dihydroacridine donor demonstrated very good efficiency in sky-blue OLED with the single emissive layer, which showed an external quantum efficiency (EQE) of 3.7%. It also forms a green-yellow-emitting exciplex with 4,4',4″-tris[phenyl(m-tolyl)amino]triphenylamine. The corresponding OLED showed an EQE of 6.9%. The white OLED combining both exciplex and single emitter layers demonstrated an EQE of 9.8% together with excellent current and power efficiencies of 16.1 cd A-1 and 6.9 lm W-1, respectively. Quantum-chemical calculations together with the analysis of photoluminescence decay curves confirm the ability of all of the studied compounds to exhibit TADF through the hot exciton pathway, but the limiting factor reducing the efficiency of OLEDs is the low photoluminescence quantum yields caused mainly by nonradiative intersystem crossing dominating over the radiative fluorescence pathway.
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Affiliation(s)
- Iryna Danyliv
- Lviv
Polytechnic National University, Stepan Bandera 12, 79013 Lviv, Ukraine
| | - Khrystyna Ivaniuk
- Lviv
Polytechnic National University, Stepan Bandera 12, 79013 Lviv, Ukraine
| | - Yan Danyliv
- Lviv
Polytechnic National University, Stepan Bandera 12, 79013 Lviv, Ukraine
| | - Igor Helzhynskyy
- Lviv
Polytechnic National University, Stepan Bandera 12, 79013 Lviv, Ukraine
| | - Viktorija Andruleviciene
- Department
of Polymer Chemistry and Technology, Kaunas
University of Technology, K. Barsauskas str. 59, Kaunas 51423, Lithuania
| | - Dmytro Volyniuk
- Department
of Polymer Chemistry and Technology, Kaunas
University of Technology, K. Barsauskas str. 59, Kaunas 51423, Lithuania
| | - Pavlo Stakhira
- Lviv
Polytechnic National University, Stepan Bandera 12, 79013 Lviv, Ukraine
| | - Glib V. Baryshnikov
- Laboratory
of Organic Electronics, Department of Science and Technology, Linköping University, SE-60174 Norrköping, Sweden
- Department
of Chemistry and Nanomaterials Science, Bohdan Khmelnytsky National University, 18031 Cherkasy, Ukraine
| | - Juozas V. Grazulevicius
- Department
of Polymer Chemistry and Technology, Kaunas
University of Technology, K. Barsauskas str. 59, Kaunas 51423, Lithuania
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21
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Park SW, Kim D, Rhee YM. Overcoming the Limitation of Spin Statistics in Organic Light Emitting Diodes (OLEDs): Hot Exciton Mechanism and Its Characterization. Int J Mol Sci 2023; 24:12362. [PMID: 37569740 PMCID: PMC10418923 DOI: 10.3390/ijms241512362] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
Triplet harvesting processes are essential for enhancing efficiencies of fluorescent organic light-emitting diodes. Besides more conventional thermally activated delayed fluorescence and triplet-triplet annihilation, the hot exciton mechanism has been recently noticed because it helps reduce the efficiency roll-off and improve device stability. Hot exciton materials enable the conversion of triplet excitons to singlet ones via reverse inter-system crossing from high-lying triplet states and thereby the depopulation of long-lived triplet excitons that are prone to chemical and/or efficiency degradation. Although their anti-Kasha characteristics have not been clearly explained, numerous molecules with behaviors assigned to the hot exciton mechanism have been reported. Indeed, the related developments appear to have just passed the stage of infancy now, and there will likely be more roles that computational elucidations can play. With this perspective in mind, we review some selected experimental studies on the mechanism and the related designs and then on computational studies. On the computational side, we examine what has been found and what is still missing with regard to properly understanding this interesting mechanism. We further discuss potential future points of computational interests toward aiming for eventually presenting in silico design guides.
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Affiliation(s)
- Soo Wan Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Dongwook Kim
- Department of Chemistry, Kyonggi University, Suwon 16227, Republic of Korea
| | - Young Min Rhee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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22
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Wang W, Chen K, Wu H, Long Y, Zhao J, Jiang L, Liu S, Chi Z, Xu J, Zhang Y. Benzoxazole-Based Hybridized Local and Charge-Transfer Deep-Blue Emitters for Solution-Processable Organic Light-Emitting Diodes and the In fluences of Hexahydrophthalimido. ACS APPLIED MATERIALS & INTERFACES 2023; 15:13415-13426. [PMID: 36867671 DOI: 10.1021/acsami.2c23254] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Hybridized local and charge-transfer (HLCT) emitters have attracted extensive attention, but the insolubility and severe self-aggregation tendency restrict their applications in solution-processable organic light-emitting diodes (OLEDs), particularly deep-blue OLEDs. Herein, two novel benzoxazole-based solution-processable HLCT emitters (BPCP and BPCPCHY) are designed and synthesized, in which benzoxazole acts as an acceptor, carbazole acts as a donor, and hexahydrophthalimido (HP, with a large intramolecular torsion angle and spatial distortion characteristics) acts as a bulky modified end-group with weak electron-withdrawing effects. Both BPCP and BPCPCHY exhibit HLCT characteristics and emit near ultraviolet in toluene at 404 and 399 nm. Compared to the BPCP, the BPCPCHY solid shows much better thermal stability (Tg, 187 vs 110 °C), higher oscillator strengths of the S1-to-S0 transition (0.5346 vs 0.4809), and faster kr (1.1 × 108 vs 7.5 × 107 s-1) and thus a much higher ΦPL in the neat film. The introduction of HP groups greatly suppresses the intra-/intermolecular charge-transfer effect and self-aggregation trends, and the BPCPCHY neat films placed in air for 3 months can still maintain an excellent amorphous morphology. The solution-processable deep-blue OLEDs utilizing BPCP and BPCPCHY achieved a CIEy of 0.06 with maximum external quantum efficiency (EQEmax) values of 7.19 and 8.53%, respectively, which are among the best results of the solution-processable deep-blue OLEDs based on the "hot exciton" mechanism. All of the above results indicate that benzoxazole is an excellent acceptor for constructing deep-blue HLCT materials, and the strategy of introducing HP as a modified end-group into an HLCT emitter provides a new perspective to develop solution-processable efficient deep-blue OLEDs with high morphological stability.
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Affiliation(s)
- Wenhui Wang
- PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Kaijin Chen
- PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Huiyan Wu
- PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
- Guangdong Testing Institute of Product Quality Supervision, Guangzhou 510670, China
| | - Yubo Long
- PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Juan Zhao
- School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Long Jiang
- Instrumental Analysis & Research Center, Sun Yat-sen University, Guangzhou 510275, China
| | - Siwei Liu
- PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhenguo Chi
- PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Jiarui Xu
- PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Yi Zhang
- PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
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23
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Xu L, Liu H, Peng X, Shen P, Zhong Tang B, Zhao Z. Efficient Circularly Polarized Electroluminescence from Achiral Luminescent Materials**. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/ange.202300492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Affiliation(s)
- Letian Xu
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Hao Liu
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Xiaoluo Peng
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Pingchuan Shen
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Ben Zhong Tang
- School of Science and Engineering Shenzhen Institute of Aggregate Science and Technology The Chinese University of Hong Kong Shenzhen Guangdong 518172 China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
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24
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Wang Z, Yan Z, Chen Q, Song X, Liang J, Ye K, Zhang Z, Bi H, Wang Y. Toward Narrowband and Efficient Blue Fluophosphors by Locking the Stretching Vibration of Indolocarbazole Skeletons. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 36890783 DOI: 10.1021/acsami.2c23278] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Developing efficient and color-saturated deep-blue emitting molecules with small Commission Internationale de L'Eclairage (CIE) y values is challenging and has great potential for wide-color gamut displays. Herein, we introduce an intramolecular locking strategy to restrain molecular stretching vibrations of the emission spectral broadening. By cyclizing rigid fluorenes and connecting electron-donating groups to the indolo[3,2,1-jk]-indolo[1',2',3':1,7]indolo[2,3-b]carbazole (DIDCz) framework, the in-plane swing of peripheral bonds and stretching vibrations of the indolocarbazole skeleton are restricted due to an increased steric hindrance from cyclized groups and diphenylamine auxochromophores. As a result, reorganization energies at the high-frequency region (1300-1800 cm-1) are reduced, realizing pure blue emission with a small full-width-at-half-maximum (FWHM) of 30 nm by suppressing shoulder peaks of polycyclic aromatic hydrocarbon (PAH) frameworks. The fabricated bottom-emitting organic light-emitting diode (OLED) exhibits an efficient external quantum efficiency (EQE) of 7.34% and deep-blue coordinates of (0.140, 0.105) at a high brightness of 1000 cd/m2. The FWHM of the electroluminescent spectrum is only 32 nm, which is one of the narrowest electroluminescent emissions among the reported intramolecular charge transfer fluophosphors. Our current findings provide a new molecular design strategy to conceive efficient and narrowband emitters with small reorganization energies.
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Affiliation(s)
| | - Zhiping Yan
- Ji Hua Laboratory, Foshan 528200, P. R. China
| | - Qishen Chen
- Ji Hua Laboratory, Foshan 528200, P. R. China
| | - Xiaoxian Song
- Ji Hua Laboratory, Foshan 528200, P. R. China
- Jihua Hengye Electronic Materials Co. Ltd., Foshan, Guangdong Province 528200, P. R. China
| | - Jie Liang
- Ji Hua Laboratory, Foshan 528200, P. R. China
| | - Kaiqi Ye
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Zuolun Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Hai Bi
- Ji Hua Laboratory, Foshan 528200, P. R. China
- Jihua Hengye Electronic Materials Co. Ltd., Foshan, Guangdong Province 528200, P. R. China
| | - Yue Wang
- Ji Hua Laboratory, Foshan 528200, P. R. China
- Jihua Hengye Electronic Materials Co. Ltd., Foshan, Guangdong Province 528200, P. R. China
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25
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Zhang Y, Gao C, Wang P, Liu Y, Liu Z, Xie W, Xu H, Dang Y, Liu D, Ren Z, Yan S, Wang Z, Hu W, Dong H. High Electron Mobility Hot-Exciton Induced Delayed Fluorescent Organic Semiconductors. Angew Chem Int Ed Engl 2023; 62:e202217653. [PMID: 36631427 DOI: 10.1002/anie.202217653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023]
Abstract
The development of high mobility emissive organic semiconductors is of great significance for the fabrication of miniaturized optoelectronic devices, such as organic light emitting transistors. However, great challenge exists in designing key materials, especially those who integrates triplet exciton utilization ability. Herein, dinaphthylanthracene diimides (DNADIs), with 2,6-extended anthracene donor, and 3'- or 4'-substituted naphthalene monoimide acceptors were designed and synthesized. By introducing acceptor-donor-acceptor structure, both materials show high electron mobility. Moreover, by fine-tuning of substitution sites, good integration with high solid state photoluminescence quantum yield of 26 %, high electron mobility of 0.02 cm2 V-1 s-1 , and the feature of hot-exciton induced delayed fluorescence were obtained in 4'-DNADI. This work opens a new avenue for developing high electron mobility emissive organic semiconductors with efficient utilization of triplet excitons.
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Affiliation(s)
- Y Zhang
- National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,Department of Chemistry, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - C Gao
- National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - P Wang
- National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,Department of Chemistry, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Y Liu
- Department Key Laboratory of Rubber-Plastics, Ministry of Education/ Shandong Provincial Key Laboratory of Rubber-plastics, Qingdao University of Science & Technology, Qingdao, 266042, China
| | - Z Liu
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - W Xie
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - H Xu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Sciences, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China
| | - Y Dang
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Sciences, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China
| | - D Liu
- National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Z Ren
- State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - S Yan
- Department Key Laboratory of Rubber-Plastics, Ministry of Education/ Shandong Provincial Key Laboratory of Rubber-plastics, Qingdao University of Science & Technology, Qingdao, 266042, China.,State Key Laboratory of Chemical Resource Engineering, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Z Wang
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - W Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Sciences, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China.,Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, 350207, China
| | - H Dong
- National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,Department of Chemistry, University of Chinese Academy of Sciences, Beijing, 100049, China
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26
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Xu L, Liu H, Peng X, Shen P, Tang BZ, Zhao Z. Efficient Circularly Polarized Electroluminescence from Achiral Luminescent Materials. Angew Chem Int Ed Engl 2023; 62:e202300492. [PMID: 36825493 DOI: 10.1002/anie.202300492] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/20/2023] [Accepted: 02/24/2023] [Indexed: 02/25/2023]
Abstract
Circularly polarized electroluminescence (CP-EL) is generally produced in organic light-emitting diodes (OLEDs) based on special CP luminescent (CPL) materials, while common achiral luminescent materials are rarely considered to be capable of direct producing CP-EL. Herein, near ultraviolet CPL materials with high photoluminescence quantum yields and good CPL dissymmetry factors are developed, which can induce blue to red CPL for various achiral luminescent materials. Strong near ultraviolet CP-EL with the best external quantum efficiencies (ηext s) of 9.0 % and small efficiency roll-offs are achieved by using them as emitters for CP-OLEDs. By adopting them as hosts or sensitizers, commercially available yellow-orange achiral phosphorescence, thermally activated delayed fluorescence (TADF) and multi-resonance (MR) TADF materials can generate intense CP-EL, with high dissymmetry factors and outstanding ηext s (30.8 %), demonstrating a simple and universal avenue towards efficient CP-EL.
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Affiliation(s)
- Letian Xu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Hao Liu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Xiaoluo Peng
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Pingchuan Shen
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Ben Zhong Tang
- School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
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27
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Nandi RP, Kalluvettukuzhy NK, Pagidi S, Thilagar P. Molecular Persistent Room-Temperature Phosphorescence from Tetraarylaminoboranes. Inorg Chem 2023; 62:1122-1134. [PMID: 36630685 DOI: 10.1021/acs.inorgchem.2c03386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Herein, we report the synthesis, molecular structure, and optical features of tetrarylaminoboranes 1 (Mes2B-N(Ph)(C10H7)) and 2 (Mes2B-N(Ph)(C14H9)). In the solution state, 1 shows aggregation-induced emission enhancement and color switching, while 2 displays emission color switching and aggregation-caused quenching. At 77 K, frozen solutions of 1 show delayed fluorescence (DF) and phosphorescence, whereas 2 display only DF. Pristine solids of 1 and 2 showed delayed fluorescence under ambient conditions; however, crystals of both compounds show no phosphorescence under similar conditions. Polymethyl methacrylate thin films of 1 (1 wt % doping concentration) exhibit persistent room-temperature phosphorescence (pRTP) lasting for ∼0.5 s. In contrast, 2 does not show phosphorescence under similar conditions. Systematic photophysical studies and theoretical (DFT and TD-DFT) calculations are performed on these molecules to rationalize their intriguing optical characteristics.
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Affiliation(s)
- Rajendra Prasad Nandi
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Neena K Kalluvettukuzhy
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sudhakar Pagidi
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Pakkirisamy Thilagar
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
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28
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Lian M, Ye Z, Mu Y, Hu D, Liu Y, Zhang H, Ji S, Huo Y. Progress on Blue-Emitting Hot Exciton Materials. CHINESE J ORG CHEM 2023. [DOI: 10.6023/cjoc202207042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
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29
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Yang J, Zheng W, Hu D, Zhu F, Ma Y, Yan D. An Efficient Blue-Emission Crystalline Thin-Film OLED Sensitized by "Hot Exciton" Fluorescent Dopant. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2203997. [PMID: 36394078 PMCID: PMC9839864 DOI: 10.1002/advs.202203997] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 09/30/2022] [Indexed: 05/29/2023]
Abstract
Crystalline thin-film organic light-emitting diodes (C-OLEDs) can achieve a large light emission and a low Joule-heat loss under low driving voltage due to the high carrier mobility of the crystalline thin films. However, it is urgent for the C-OLEDs to improve their external quantum efficiency (EQE). Here, a novel strategy is proposed using a doped "hot exciton" material to sensitize a high PLQY blue emitter in C-OLEDs. Benefiting from the capability of the "hot exciton" material harnessing triplet/singlet excitons, the C-OLED exhibits an efficiency breakthrough with a maximum EQE of 6.2%, a much enhanced blue photon output with pure blue emission Commission International de L'Eclairage (CIE) (0.14, 0.15), a low turn-on/operation voltage of 2.6 V(@1 cd m-2 )/3.8 V (@1000 cd m-2 ), and a maximum power efficiency (PE) of 9.4 lm W-1 . This work unlocks the potential of C-OLEDs for achieving high photon output with high EQE.
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Affiliation(s)
- Jingjie Yang
- State Key Laboratory of Polymer Physics and ChemistryChangchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China
- School of Applied Chemistry and EngineeringUniversity of Science and Technology of ChinaHefei230026China
| | - Wantao Zheng
- State Key Laboratory of Polymer Physics and ChemistryChangchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China
- School of Applied Chemistry and EngineeringUniversity of Science and Technology of ChinaHefei230026China
| | - Dehua Hu
- State Key Laboratory of Luminescent Materials and DevicesSouth China University of TechnologyGuangzhou510640China
| | - Feng Zhu
- State Key Laboratory of Polymer Physics and ChemistryChangchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China
- School of Applied Chemistry and EngineeringUniversity of Science and Technology of ChinaHefei230026China
| | - Yuguang Ma
- State Key Laboratory of Luminescent Materials and DevicesSouth China University of TechnologyGuangzhou510640China
| | - Donghang Yan
- State Key Laboratory of Polymer Physics and ChemistryChangchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China
- School of Applied Chemistry and EngineeringUniversity of Science and Technology of ChinaHefei230026China
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30
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Yang J, Hu D, Zhu F, Ma Y, Yan D. High-efficiency blue-emission crystalline organic light-emitting diodes sensitized by "hot exciton" fluorescent nanoaggregates. SCIENCE ADVANCES 2022; 8:eadd1757. [PMID: 36516245 PMCID: PMC9750145 DOI: 10.1126/sciadv.add1757] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 11/18/2022] [Indexed: 05/31/2023]
Abstract
Sensitizing fluorescent materials is an effective way to maximally use excitons and obtain high-efficiency blue organic light-emitting diodes (OLEDs). However, it is a persistent challenge for present amorphous thin-film OLEDs to improve photon emission under low driving voltage, severely impeding the development of OLED technology. Here, we propose a novel OLED architecture consisting of a crystalline host matrix (CHM) and embedded "hot exciton" nanoaggregates (HENAs), which effectively sensitize blue dopant (D) emission. Owing to the advantages of the crystalline thin-film route, the device exhibits largely enhanced blue photon output [Commission International de L'Eclairage coordinates of (0.15, 0.17)], with a low turn-on/operation voltage of 2.5 V (at 1 cd/m2)/3.3 V (at 1000 cd/m2), an extremely low Joule heat loss ratio (7.8% at 1000 cd/m2), and a maximum external quantum efficiency (EQE) up to 9.14%. These areal photon output features have outperformed the present amorphous thin-film blue OLEDs with high EQE, demonstrating that the CHM-HENA-D OLED is promising for future OLEDs.
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Affiliation(s)
- Jingjie Yang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Dehua Hu
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Feng Zhu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Yuguang Ma
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Donghang Yan
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China
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Ju Kim K, Kim T. Study on charge dynamics and recombination process via transient electroluminescence analysis in blue fluorescence organic light-emitting diodes. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Han P, Xia E, Qin A, Tang BZ. Adjustable and smart AIEgens for nondoped blue and deep blue organic light-emitting diodes. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Zhu Y, Qu C, Ye J, Xu Y, Zhang Z, Wang Y. Donor-Acceptor Type of Fused-Ring Thermally Activated Delayed Fluorescence Compounds Constructed through an Oxygen-Containing Six-Membered Ring. ACS APPLIED MATERIALS & INTERFACES 2022; 14:47971-47980. [PMID: 36219720 DOI: 10.1021/acsami.2c12778] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Nowadays, thermally activated delayed fluorescence (TADF) compounds with a fused-ring core skeleton are getting increasing research interest because of their use in high-performance organic light-emitting diodes (OLEDs). In this study, TADF compounds featuring a D-A-type fused-ring core skeleton are developed. The challenging compatibility of a planarized D-A arrangement and the TADF property is achieved through linking the D and A moieties with two oxygen atoms within a six-membered ring. Compared with a single-oxygen analogue possessing a flexible skeleton and a twisted D-A arrangement, these fused-ring compounds with higher skeleton rigidity show higher photoluminescence quantum yields and narrower emission spectra in toluene and in doped thin films. Their electroluminescent devices achieve high external quantum efficiencies (up to 19.4%), suggesting the potential of rarely achieved D-A-type fused-ring TADF systems to serve as high-performance emitters of OLEDs.
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Affiliation(s)
- Yunlong Zhu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Cheng Qu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Jianjiang Ye
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Yincai Xu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Zuolun Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 P. R. China
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Liu C, Liao J, Zheng Y, Chen Y, Liu H, Shi X. Random forest algorithm-enhanced dual-emission molecularly imprinted fluorescence sensing method for rapid detection of pretilachlor in fish and water samples. JOURNAL OF HAZARDOUS MATERIALS 2022; 439:129591. [PMID: 35853336 DOI: 10.1016/j.jhazmat.2022.129591] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/25/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
A sensitive and efficient fluorescence sensor based on dual-emission molecularly imprinted polymers (Dual-em-MIPs) was successfully developed using the random forest (RF) machine-learning algorithm for the rapid detection of pretilachlor. SiO2 coatings on red-emitting CdSe/ZnS quantum dots (r-SiO2@QDs) as intermediate light-emitting components are non-selective for pretilachlor, whereas molecularly imprinted layers coated with blue-emitting nitrogen-doped graphene quantum dots (N-GQDS) are selective. Fluorescence images of the Dual-em-MIPs were acquired. The red (R), green (G), and blue (B) color values of the image were analyzed using an RF algorithm, and the classifier was trained using 103 fluorescent images for automatic analyses. Under optimized conditions, an excellent linear relationship between the sensor and pretilachlor was obtained in the range of 0.001-5.0 mg/L (R2, 0.9958). Additionally, the satisfactory recoveries of Dual-em-MIPs ranged between 92.2 % and 107.6 % for the real samples, with a relative standard deviation (RSD) under 6.5 %. The satisfactory recoveries of the RF model based on the fluorescence sensor were 84.2-108.2 % with the RSD under 6.4 %. Overall, the proposed fluorescence sensor based on Dual-em-MIPs and machine learning methods was successfully used to determine pretilachlor in the environment and in aquatic products.
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Affiliation(s)
- Chenxi Liu
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Jingxin Liao
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Yong Zheng
- School of Mathematics, South China University of Technology, Guangzhou, China
| | - Ying Chen
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China; Department of Food Science and Technology, National University of Singapore, Science Drive 2, 117542, Singapore
| | - Hongsheng Liu
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China.
| | - Xizhi Shi
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo 315211, PR China.
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Guo X, Li G, Lou J, Chen K, Huang R, Yang D, Zhang H, Wang Z, Tang BZ. New-Fashioned Universal and Functional Host-Material from a Near-Ultraviolet Organic Emitter for High-Efficiency Organic Light-Emitting Diodes with Low Efficiency Roll-Offs. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2204029. [PMID: 36084169 DOI: 10.1002/smll.202204029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/10/2022] [Indexed: 06/15/2023]
Abstract
In this work, a near-ultraviolet (NUV) emitter, 2MCz-CNMCz, with hot-exciton property is designed based on a "long-short axis" strategy, which exhibits good thermal stability, bipolar carrier transport ability, and high T1 energy level. Its nondoped NUV organic light-emitting diode (OLED) achieves a record maximum external quantum efficiency (ηext ) of 7.76%, with a peak at 404 nm and CIE coordinates of (0.158, 0.039). The corresponding high exciton utilization efficiency (ηr ) in the electroluminescence process reveals its potential as a functional sensitizing host. As expected, the TBPe-based blue fluorescent OLED with 2MCz-CNMCz as the host material shows better efficiency and lower efficiency roll-off than that with traditional host material mCP. Meanwhile, the Ir complexes-based green/yellow/red phosphorescent OLEDs with 2MCz-CNMCz host are also fabricated, reaching high ηext values of 26.1%, 30.4%, and 20.4%, respectively, and displaying negligible efficiency roll-offs at 1000 cd m-2 , which are among the best OLED performances based on the same emitters. To the authors' best knowledge, this is the first report on the design of high-quality universal and functional host material, and may bring new inspiration to the preparation of high-efficiency, low roll-off, full-color OLEDs.
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Affiliation(s)
- Xuecheng Guo
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, China
| | - Ganggang Li
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, China
| | - Jingli Lou
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, China
| | - Kongqi Chen
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, China
| | - Ruishan Huang
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, China
| | - Dezhi Yang
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, China
| | - Han Zhang
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, China
| | - Zhiming Wang
- AIE Institute, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, South China University of Technology (SCUT), Guangzhou, 510640, China
| | - Ben Zhong Tang
- Shenzhen Institute of Aggregate Science and Technology, School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Shenzhen, 518172, China
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Lin C, Han P, Qu F, Xiao S, Li Y, Xie D, Qiao X, Yang D, Dai Y, Sun Q, Qin A, Tang BZ, Ma D. Suppressing singlet-triplet annihilation processes to achieve highly efficient deep-blue AIE-based OLEDs. MATERIALS HORIZONS 2022; 9:2376-2383. [PMID: 35789246 DOI: 10.1039/d2mh00627h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Aggregation-induced emission (AIE) materials are attractive for the fabrication of high efficiency organic light-emitting diodes (OLEDs) by harnessing "hot excitons" from the high-lying triplet exciton states (Tn, n ≥ 2) and high photoluminescence (PL) quantum efficiency in solid films. However, the electroluminescence (EL) efficiency of most AIE-based OLEDs does not meet our expectation due to some unrevealed exciton loss processes. Herein, we further enhance the efficiency of blue AIE-based OLEDs, and find experimentally and theoretically that the serious exciton loss is caused by the quenching of radiative singlet excitons and long-lived triplet excitons [singlet-triplet annihilation (STA)]. In order to suppress the STA process, 1-(2,5-dimethyl-4-(1-pyrenyl)phenyl)pyrene (DMPPP) with triplet-triplet annihilation up-conversion was doped in two AIE emitters to reduce the triplet excitons on the lowest triplet excited state (T1) of AIE molecules. It can be seen that the external quantum efficiency (EQE) of the resulting blue OLEDs was enhanced to 11.8% with CIE coordinates of (0.15, 0.07) and a negligible efficiency roll-off, realizing the efficiency breakthrough of deep-blue AIE-based OLEDs. This work establishes a physical insight in revealing the exciton loss processes and the fabrication of high-performance AIE-based OLEDs.
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Affiliation(s)
- Chengwei Lin
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Pengbo Han
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Fenlan Qu
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Shu Xiao
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Yuanzhao Li
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Dian Xie
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Xianfeng Qiao
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Dezhi Yang
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Yanfeng Dai
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Qian Sun
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Anjun Qin
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
| | - Ben Zhong Tang
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
- Shenzhen Institute of Molecular Aggregate Science and Engineering, School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 2001 Longxiang Boulevard, Longgang District, Shenzhen City, Guangdong 518172, China
| | - Dongge Ma
- Center for Aggregation-Induced Emission, Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
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Lei M, Zheng J, Yang Y, Yan L, Liu X, Xu B. Carbon Dots-Based Delayed Fluorescent Materials: Mechanism, Structural Regulation and Application. iScience 2022; 25:104884. [PMID: 36039289 PMCID: PMC9418853 DOI: 10.1016/j.isci.2022.104884] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Delayed fluorescent (DF) materials have high internal quantum efficiency because of the triplet excitons involved in the radiation transition, and the spin-forbidden transition can effectively improve their luminescent lifetime. Compared with traditional afterglow materials including metal-containing inorganic coordination compounds and organic compounds, the DF materials based on carbon dots (CDs) have drawn extensive attention because of their advantages of low toxicity, environmental friendliness, stable luminescence, easy preparation and low cost. Most CDs-based DF materials can be realized by embedding CDs in matrix with covalent bonds, hydrogen bonds or/and other supramolecular interactions. Recently, matrix-free self-protective CDs-based DF materials are emerging. This review systematically summarizes the DF mechanism and structural regulation strategies of CDs-based DF materials, and the applications of CDs-based DF materials in anti-counterfeiting, information encryption, temperature sensing and other fields are introduced. Finally, the existing problems and future potentials of CDs-based DF materials are proposed and prospected.
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Affiliation(s)
- Mingxiu Lei
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Jingxia Zheng
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Yongzhen Yang
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
- Corresponding author
| | - Lingpeng Yan
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
- Corresponding author
| | - Xuguang Liu
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Bingshe Xu
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
- Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Taiyuan 030032, China
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38
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Wang Y, Guo Z, Gao Y, Tian Y, Deng Y, Ma X, Yang W. Tuning Hybridized Local and Charge-Transfer Mixing for Efficient Hot-Exciton Emission with Improved Color Purity. J Phys Chem Lett 2022; 13:6664-6673. [PMID: 35839081 DOI: 10.1021/acs.jpclett.2c01917] [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: 06/15/2023]
Abstract
Delayed fluorescence (DF) emitters with high color purity are of high interest for applications in high-resolution displays. However, the charge transfer required by high emitting efficiency usually conflicts with the expected color purity. In this work, we investigated the S1/S0 conformational relaxation, spin-orbital coupling (SOC), and vibronic coupling of hot-exciton emitters while hybrid local and charge transfer (HLCT) state tuning was achieved by a structural meta-effect. The meta-linkage leads to suppressed S1/S0 conformational relaxation and weakened vibronic coupling, while the unsacrificed emitting efficiency is largely ensured by multiple rISC channels (Tn → Sm) with thermally accessible triplet-singlet energy gap (ΔEST) and effective SOC. We demonstrated that the unique excited-state mechanism provides opportunities to improve the emitting color purity of hot-exciton emitters without sacrificing emitting efficiency by HLCT state tuning with simple chemical structural modification, for which hot-exciton emitters might play a more important role for high-resolution organic light-emitting diode displays.
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Affiliation(s)
- Yaxin Wang
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P.R. China
| | - Zilong Guo
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P.R. China
| | - Yixuan Gao
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P.R. China
| | - Yiran Tian
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P.R. China
| | - Yingyi Deng
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P.R. China
| | - Xiaonan Ma
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P.R. China
| | - Wensheng Yang
- Institute of Molecular Plus, Tianjin University, Tianjin 300072, P.R. China
- Engineering Research Center for Nanomaterials, Henan University, Kaifeng 475004, P.R. China
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Wang J, Jiang X, Liang T, Pan Y, Yang B. Theoretical study on the mechanism of hot excitons combined with aggregation-induced emission in efficient red fluorescent molecules. Phys Chem Chem Phys 2022; 24:17632-17640. [PMID: 35833615 DOI: 10.1039/d2cp02552c] [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
Fluorescent emitters with the hot exciton mechanism combined with aggregation induced emission (AIE) character show prospective applications in organic light emitting diodes (OLEDs). However, theoretical studies on amorphous states are limited. In this work, a theoretical study is performed on the photophysical properties of the reported compound 4-(7-(10-ethyl-10H-phenothiazin-3-yl)benzo[c][1,2,5]thiadiazol-4-yl)-N,N-diphenylaniline (PBTPA), which possesses a hot exciton mechanism and AIE. The aggregation states of this molecule in a film are given by molecular dynamics (MD) simulations, and then the photophysical properties are studied by using the QM/MM method with the consideration of the solid-state effect (SSE). The results explain the hot exciton and AIE mechanism of the molecule. First, there is a hot exciton channel between the S1 and T2 state of the PBTPA. Second, the conformational changes of PBTPA between the ground state and the excited state are restricted in the aggregate state. Last, in the low frequency region, the rotation motion is suppressed, and then the reorganization energy and Huang-Rhys (HR) factor in the aggregate state are much smaller. Therefore, the molecules show strong fluorescence efficiency in the aggregated state.
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Affiliation(s)
- Jiao Wang
- School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China.
| | - Xinnan Jiang
- School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China.
| | - Tingdong Liang
- School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China.
| | - Yuyu Pan
- School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China.
| | - Bing Yang
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, 130012, P. R. China
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Li G, Wen J, Zhan F, Lou W, Yang YF, Hu Y, She Y. Fused 6/5/6 Metallocycle-Based Tetradentate Pt(II) Emitters for Efficient Green Phosphorescent OLEDs. Inorg Chem 2022; 61:11218-11231. [PMID: 35834800 DOI: 10.1021/acs.inorgchem.2c01202] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pt(II) complexes are promising phosphorescent materials for organic light-emitting diode (OLED) applications in the fields of display, lighting, healthcare, aerospace, and so on. A series of novel biphenyl (bp)-based tetradentate 6/5/6 Pt(II) emitters using oxygen or carbon as a linking atom was designed and developed. The intermolecular interactions in crystal packing, electrochemical, and photophysical properties of the bp-based Pt(II) emitters and also their excited-state properties were systematically studied, which could be effectively regulated by ligand modification through linking group control; however, their emission spectra nearly showed no change. All the bp-based Pt(II) emitters exhibited vibronically featured emission spectra with dominant peaks at 502-505 nm and photoluminescent quantum yields of 24-34% in dichloromethane solution. Green OLED using Pt(bp-12) as an emitter achieved a maximum brightness (Lmax) of 16,644 cd/m2.
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Affiliation(s)
- Guijie Li
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Jianfeng Wen
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Feng Zhan
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 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, Zhejiang 310014, P. R. China
| | - Yun-Fang Yang
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Ying Hu
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Yuanbin She
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
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Nandi RP, Ghosh S, Venkatasubbaiah K, Kumbhar D, Thilagar P. Tribophosphorescence from a Simple Boronic Ester. CHEMPHOTOCHEM 2022. [DOI: 10.1002/cptc.202200026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - Pakkirisamy Thilagar
- IISc: Indian Institute of Science Inorganic and Physical Chemistry Indian Institute of Science Bangalore 560012 Bangalore INDIA
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42
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Li G, Li B, Zhang H, Guo X, Lin C, Chen K, Wang Z, Ma D, Tang BZ. Efficient Ultraviolet Organic Light-Emitting Diodes with a CIEy of 0.04 and Negligible-Efficiency Roll-Off. ACS APPLIED MATERIALS & INTERFACES 2022; 14:10627-10636. [PMID: 35171553 DOI: 10.1021/acsami.1c24285] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Organic light-emitting diodes (OLEDs) with ultraviolet (UV) emission (λEL ≤ 400 nm) have attracted special attention in commercial and civil fields owing to their special functions. Nevertheless, the lack of high-quality ultraviolet emitters restricts the practical application of UV OLEDs. Herein, a novel organic molecule with desirable UV emission, 2Na-CzCN, is developed for UV OLEDs. Theoretical investigation indicates that it is equipped with hybridized local and charge-transfer (HLCT) characteristics, which is in favor of the high-lying reverse intersystem crossing (RISC) process, thus remarkably boosting the exciton utilization in electroluminescence (EL). Significantly, the nondoped device derived from the 2Na-CzCN emitter exhibits an EL emission peak of 398 nm with a maximum external quantum efficiency (EQE) of 5.92%, which represents the record-high result among nondoped UV OLEDs. The doped UV OLED of 2Na-CzCN radiates robust UV emission at a peak of 392 nm with a maximum EQE of 6.15%. Coupled with the narrow full width at half-maximum (FWHM) of the EL spectra, desirable color purities with Commission Internationale de l'Eclairage (CIE) coordinates of (0.15, 0.06) and (0.16, 0.04) for nondoped and doped OLEDs are presented, respectively. Additionally, the potential of 2Na-CzCN adopted as the host material is demonstrated with phosphorescent OLEDs (PhOLEDs), and all of the devices show good EL performances with low-efficiency roll-offs. An orange PhOLED with 2Na-CzCN acquires a maximum current and external quantum efficiency of 84.9 cd A-1 and 25.3%, respectively. These findings may pave an avenue for the development of high-performance UV emitters.
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Affiliation(s)
- Ganggang Li
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, AIE Institute, Guangzhou International Campus, South China University of Technology, Guangzhou 510640, China
| | - Baoxi Li
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, AIE Institute, Guangzhou International Campus, South China University of Technology, Guangzhou 510640, China
| | - Han Zhang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, AIE Institute, Guangzhou International Campus, South China University of Technology, Guangzhou 510640, China
| | - Xuecheng Guo
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, AIE Institute, Guangzhou International Campus, South China University of Technology, Guangzhou 510640, China
| | - Chengwei Lin
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, AIE Institute, Guangzhou International Campus, South China University of Technology, Guangzhou 510640, China
| | - Kongqi Chen
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, AIE Institute, Guangzhou International Campus, South China University of Technology, Guangzhou 510640, China
| | - Zhiming Wang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, AIE Institute, Guangzhou International Campus, South China University of Technology, Guangzhou 510640, China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, AIE Institute, Guangzhou International Campus, South China University of Technology, Guangzhou 510640, China
| | - Ben Zhong Tang
- Shenzhen Institute of Aggregate Science and Technology, School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Shenzhen 518172, China
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43
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Chen J, Liu H, Guo J, Wang J, Qiu N, Xiao S, Chi J, Yang D, Ma D, Zhao Z, Tang BZ. Robust Luminescent Molecules with High-Level Reverse Intersystem Crossing for Efficient Near Ultraviolet Organic Light-Emitting Diodes. Angew Chem Int Ed Engl 2022; 61:e202116810. [PMID: 34981618 DOI: 10.1002/anie.202116810] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Indexed: 12/21/2022]
Abstract
Organic light-emitting diodes (OLEDs) radiating near ultraviolet (NUV) light are of high importance but rarely reported due to the lack of robust organic short-wavelength emitters. Here, we report a short π-conjugated molecule (POPCN-2CP) with high thermal and morphological stabilities and strong NUV photoluminescence. Its neat film exhibits an electroluminescence (EL) peak at 404 nm with a maximum external quantum efficiency (ηext,max ) of 7.5 % and small efficiency roll-off. The doped films of POPCN-2CP in both non-polar and polar hosts at a wide doping concentration range (10-80 wt%) achieve high-purity NUV light (388-404 nm) and excellent ηext,max s of up to 8.2 %. The high-level reverse intersystem crossing improves exciton utilization and accounts for the superb ηext,max s. POPCN-2CP can also serve as an efficient host for blue fluorescence, thermally activated delayed fluorescence and phosphorescence emitters, providing excellent EL performance via Förster energy transfer.
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Affiliation(s)
- Jinke Chen
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Hao Liu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Jingjing Guo
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Jianghui Wang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Nuoling Qiu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Shu Xiao
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Jiajin Chi
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Dezhi Yang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Ben Zhong Tang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
- Shenzhen Institute of Aggregate Science and Technology, School of Science and Engineering, The Chinese University of Hong Kong Shenzhen, Guangdong, 518172, China
- AIE Institute, Guangzhou Development District, Huangpu, Guangzhou, 510530, China
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44
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Serevičius T, Skaisgiris R, Dodonova J, Fiodorova I, Genevičius K, Tumkevičius S, Kazlauskas K, Juršėnas S. Temporal Dynamics of Solid-State Thermally Activated Delayed Fluorescence: Disorder or Ultraslow Solvation? J Phys Chem Lett 2022; 13:1839-1844. [PMID: 35174704 PMCID: PMC8883520 DOI: 10.1021/acs.jpclett.1c03810] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Time-resolved emission spectra of thermally activated delayed fluorescence (TADF) compounds in solid hosts demonstrate significant temporal shifts. To explain the shifts, two possible mechanisms were suggested, namely, slow solid-state solvation and conformational disorder. Here we employ solid hosts with controllable polarity for analysis of the temporal dynamics of TADF. We show that temporal fluorescence shifts are independent of the dielectric constant of the solid film; however, these shifts evidently depend on the structural parameters of both the host and the TADF dopant. A ≤50% smaller emission peak shift was observed in more rigid polymer host polystyrene than in poly(methyl methacrylate). The obtained results imply that both the host and the dopant should be as rigid as possible to minimize fluorescence instability.
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Affiliation(s)
- Tomas Serevičius
- Institute
of Photonics and Nanotechnology, Vilnius
University, Saulėtekio 3, LT-10257 Vilnius, Lithuania
| | - Rokas Skaisgiris
- Institute
of Photonics and Nanotechnology, Vilnius
University, Saulėtekio 3, LT-10257 Vilnius, Lithuania
| | - Jelena Dodonova
- Institute
of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania
| | - Irina Fiodorova
- Institute
of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania
| | - Kristijonas Genevičius
- Institute
of Chemical Physics, Vilnius University, Saulėtekio 3, LT-10257 Vilnius, Lithuania
| | - Sigitas Tumkevičius
- Institute
of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania
| | - Karolis Kazlauskas
- Institute
of Photonics and Nanotechnology, Vilnius
University, Saulėtekio 3, LT-10257 Vilnius, Lithuania
| | - Saulius Juršėnas
- Institute
of Photonics and Nanotechnology, Vilnius
University, Saulėtekio 3, LT-10257 Vilnius, Lithuania
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45
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Noda T, Sasabe H, Owada T, Sugiyama R, Arai A, Kumada K, Tsuneyama H, Saito Y, Kido J. Constructing Soluble Anthracene‐Based Blue Emitters Free of Electrically Inert Alkyl Chains for Efficient Evaporation‐ and Solution‐Based OLEDs. Chempluschem 2022; 87:e202100517. [DOI: 10.1002/cplu.202100517] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/26/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Taito Noda
- Yamagata Daigaku Department of Organic Materials Science JAPAN
| | - Hisahiro Sasabe
- Yamagata University: Yamagata Daigaku Organic Materials Science 4-3-16 Jonan 992-8510 Yonezawa JAPAN
| | | | - Ryo Sugiyama
- Yamagata Daigaku Organic Materials Science JAPAN
| | - Ayato Arai
- Yamagata Daigaku Organic Materials Science JAPAN
| | - Kengo Kumada
- Yamagata Daigaku Organic Materials Science JAPAN
| | | | - Yu Saito
- Yamagata Daigaku Organic Materials Science JAPAN
| | - Junji Kido
- Yamagata Daigaku Department of Organic Materials Science JAPAN
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46
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Chen J, Liu H, Guo J, Wang J, Qiu N, Xiao S, Chi J, Yang D, Ma D, Zhao Z, Tang BZ. Robust Luminescent Molecules with High‐Level Reverse Intersystem Crossing for Efficient Near Ultraviolet Organic Light‐Emitting Diodes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202116810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jinke Chen
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Hao Liu
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Jingjing Guo
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Jianghui Wang
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Nuoling Qiu
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Shu Xiao
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Jiajin Chi
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Dezhi Yang
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
| | - Ben Zhong Tang
- State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of Technology Guangzhou 510640 China
- Shenzhen Institute of Aggregate Science and Technology School of Science and Engineering The Chinese University of Hong Kong Shenzhen Guangdong 518172 China
- AIE Institute, Guangzhou Development District, Huangpu Guangzhou 510530 China
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47
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Bai X, Wu SX, Duan YC, Pan QQ, Gao FW, Kan YH, Su ZM. Turning conventional non-TADF units into high-lying reverse intersystem crossing TADF emitters: different symmetric D–A–D-type modified donor units. NEW J CHEM 2022. [DOI: 10.1039/d2nj02484e] [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
DFT and TD-DFT calculations were performed to turn conventional non-TADF units into high-lying reverse intersystem crossing D–A–D-type TADF emitters.
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Affiliation(s)
- Xue Bai
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Shui-xing Wu
- Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province, School of Chemistry & Chemical Engineering, Hainan Normal University, Haikou 571158, China
| | - Ying-chen Duan
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Qing-qing Pan
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
| | - Feng-wei Gao
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
- Chongqing Research Institute, Changchun University of Science and Technology, No. 618 Liangjiang Avenue, Longxing Town, Yubei District, Chongqing City 401135, China
| | - Yu-he Kan
- Jiangsu Province Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai’an 223300, China
| | - Zhong-min Su
- School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, 7989 Weixing Road, Changchun 130012, China
- State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130021, China
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48
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Wang X, Li Y, Wu Y, Qin K, Xu D, Wang D, Ma H, Ning S, Wu Z. A 2-phenylfuro[2,3- b]quinoxaline-triphenylamine-based emitter: photophysical properties and application in TADF-sensitized fluorescence OLEDs. NEW J CHEM 2022. [DOI: 10.1039/d2nj03508a] [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
We have demonstrated that the T1-state energy of a fluorescence dopant (FD) is close to that of the thermally activated delayed fluorescence (TADF)-type exciplex co-host, and the energy loss caused by the T1 states of the FD could be suppressed in TADF-sensitized fluorescence (TSF) OLEDs.
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Affiliation(s)
- XinYe Wang
- School of Chemistry, Xi’an JiaoTong University, Xi’an 710049, P. R. China
| | - YiXiang Li
- School of Chemistry, Xi’an JiaoTong University, Xi’an 710049, P. R. China
| | - Yuan Wu
- School of Electronic Information and Artificial Intelligence, Shaanxi University of Science and Technology Xi’an, Shaanxi, 710021, P. R. China
| | - Ke Qin
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing 211816, P. R. China
| | - DeFei Xu
- School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, P. R. China
| | - DongDong Wang
- School of Chemistry, Xi’an JiaoTong University, Xi’an 710049, P. R. China
| | - HuiLi Ma
- Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing 211816, P. R. China
| | - ShuYa Ning
- School of Electronic Information and Artificial Intelligence, Shaanxi University of Science and Technology Xi’an, Shaanxi, 710021, P. R. China
| | - ZhaoXin Wu
- Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, P. R. China
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49
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Nemati Bideh B, Shahroosvand H. New Molecularly Engineered Binuclear Ruthenium (II) Complexes for Highly Efficient Near-Infrared Light-Emitting Electrochemical Cell (NIR-LEC). Dalton Trans 2022; 51:3652-3660. [DOI: 10.1039/d1dt03212g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abstract: From practical point of view, the stability, response time and efficiency of near-infrared light-emitting electrochemical cell (NIR-LEC) are key factors. By using the high potential of chemical modification potential...
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50
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Lim H, Woo SJ, Ha YH, Kim YH, Kim JJ. Breaking the Efficiency Limit of Deep-Blue Fluorescent OLEDs Based on Anthracene Derivatives. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2100161. [PMID: 34687094 DOI: 10.1002/adma.202100161] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 08/31/2021] [Indexed: 06/13/2023]
Abstract
Triplet harvesting is important for the realization of high-efficiency fluorescent organic light-emitting diodes (OLEDs). Triplet-triplet annihilation (TTA) is one triplet-harvesting strategy. However, for blue-emitting anthracene derivatives, the theoretical maximum radiative singlet-exciton ratio generated from the TTA process is known to be 15% in addition to the initially generated singlets of 25%, which is insufficient for high-efficiency fluorescent devices. In this study, nearly 25% of the radiative singlet-exciton ratio is realized by TTA using an anthracene derivative, breaking the theoretical limit. As a result, efficient deep-blue TTA fluorescent devices are developed, exhibiting external quantum efficiencies of 10.2% and 8.6% with Commission Internationale de l'Eclairage color coordinates of (0.134, 0.131) and (0.137, 0.076), respectively. The theoretical model provided herein explains the experimental results considering both the TTA and reverse intersystem crossing to a singlet state from higher triplet states formed by the TTA, clearly demonstrating that the radiative singlet ratio generated from TTA can reach 37.5% (total radiative singlet-exciton ratio: 62.5%), well above 15% (total 40%), despite the molecule having S1 , T2 < 2T1 < Q1 energy levels, which will lead to the development of high-efficiency fluorescent OLEDs with external quantum efficiencies exceeding 28% if the outcoupling efficiency is 45%.
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Affiliation(s)
- Hyoungcheol Lim
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Seung-Je Woo
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea
- Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul, 08826, South Korea
| | - Yeon Hee Ha
- Department of Chemistry and RIGET, Gyeongsang National University, Jinju, 52828, South Korea
| | - Yun-Hi Kim
- Department of Chemistry and RIGET, Gyeongsang National University, Jinju, 52828, South Korea
| | - Jang-Joo Kim
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, South Korea
- Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul, 08826, South Korea
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