1
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Zhao T, Duan P. Photon Upconversion Cooperates with Downshifting in Chiral Systems: Modulation, Amplification, and Applications of Circularly Polarized Luminescence. Angew Chem Int Ed Engl 2024; 63:e202406524. [PMID: 38702292 DOI: 10.1002/anie.202406524] [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: 04/08/2024] [Revised: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 05/06/2024]
Abstract
Circularly polarized luminescence (CPL)-active materials are increasingly recognized for their potential applications such as 3D imaging, data storage, and optoelectronic devices. Typically, CPL materials have required high-energy (HE) photons for excitation to emit low-energy (LE) circularly polarized light, a process known as downshifting CPL (DSCPL). However, the emergence of upconverted CPL (UCCPL), where the absorption of multi LE photons results in the emission of a single HE photon with circular polarization, has recently attracted considerable attention. This minireview highlights the intricate relationship between upconversion and CPL phenomena. During upconversion, the dissymmetry factor (glum) value can be improved in certain systems. Additionally, the integration of both LE and HE photons in upconversion-downshifting-synergistic systems offers avenues for dual-excitation or dual-emission CPL functionalities. More in detail, the emerging UCCPL based on various photon upconversion mechanisms and their synergy with DSCPL are introduced. Additionally, several examples that demonstrate the applications of UCCPL are presented to highlight the future opportunities.
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Affiliation(s)
- Tonghan Zhao
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology (NCNST), No.11, ZhongGuanCun BeiYiTiao, Beijing, 100190, P.R. China
- Present address T. Zhao, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Pengfei Duan
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology (NCNST), No.11, ZhongGuanCun BeiYiTiao, Beijing, 100190, P.R. China
- Present address T. Zhao, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- University of Chinese Academy of Sciences, No.1 Yanqihu East Rd, Huairou District, Beijing, 100049, P. R. China
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2
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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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3
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Zhu C, Liu L, Yang X, Zhou G, Sun Y. The Molecular Design and Electroluminescent Performance of Near-Infrared (NIR) Iridium(III) Complexes Bearing Isoquinoline-, Phthalazine- and Phenazine-Based Ligands. Chemphyschem 2024:e202400232. [PMID: 39031895 DOI: 10.1002/cphc.202400232] [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: 03/02/2024] [Revised: 06/20/2024] [Accepted: 06/20/2024] [Indexed: 07/22/2024]
Abstract
Near-infrared (NIR) light has characteristics of invisibility to human eyes, less background interference, low light scattering, and strong cell penetration. Therefore, NIR luminescent materials have significant applications in imaging, sensing, energy, information storage and display. The development of NIR luminescent materials thus has emerged as a highly dynamic area of research in the realm of contemporary materials. To date, NIR luminescent materials are roughly divided into inorganic materials and organic materials. Compared with inorganic materials, organic NIR luminescent materials have become a hot research topic in recent years due to their rich sources, easy control of structure, simple preparation process, low cost, and good film-forming properties. Among them, iridium(III) [Ir(III)] complexes exhibit excellent properties such as thermal stability, simple synthesis, easy color modulation, short excited state lifetimes, and high brightness, thus becoming one of the ideal luminescent material systems for preparing high-quality organic light-emitting diodes. Therefore, how to obtain Ir(III) complexes with NIR emission and high efficiency through molecular design is a necessary and promising research topic. This work reviews the research progress of representative NIR Ir(III) complexes bearing isoquinoline-, phenazine-, and phthalazine-based ligands reported in recent years and introduces the design strategies and electroluminescent performances of NIR Ir(III) complexes.
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Affiliation(s)
- Chengyun Zhu
- School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry, Engineering Research Center of Energy Storage Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Lina Liu
- School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry, Engineering Research Center of Energy Storage Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Xiaolong Yang
- School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry, Engineering Research Center of Energy Storage Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Guijiang Zhou
- School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry, Engineering Research Center of Energy Storage Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Yuanhui Sun
- School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry, Engineering Research Center of Energy Storage Materials and Devices, Ministry of Education, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
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4
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Kakumachi S, Nakanotani H, Nagasaki Y, Adachi C. Impact of Spontaneous Orientational Polarization on Triplet-Triplet Upconversion-Based Blue Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2024; 16:31392-31398. [PMID: 38843533 DOI: 10.1021/acsami.4c02821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
The spontaneous orientation polarization (SOP) of a permanent dipole moment of the molecule induces a giant surface potential (GSP) in an organic semiconductor film, and GSP is expected to be a crucial parameter for understanding the operational mechanism of organic light-emitting diodes (OLEDs). This study demonstrates that the voltage-dependent migration of a carrier recombination zone induced by a polar electron transporting layer (ETL) having a positive SOP causes a decline in the overall performance of the OLED in triplet-triplet upconversion (TTU) based on OLEDs. Specifically, the TTU efficiency in an OLED with 2,2',2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) as the ETL decreased by 20% due to the reduction of electrically generated triplet exciton density. This decrease resulted in a lower external electroluminescence (EL) quantum efficiency (EQE) of 5.4% at 1 mA cm-2, while the OLED with a nonpolar ETL resulted in an EQE of around 8.1% at 1 mA cm-2. We confirmed a shift in the recombination zone from the current density dependence of the EL spectra in the OLEDs. Our results indicate that the fixed carrier recombination zone near a hole transport layer and an emitting layer (HTL/EML) strongly enhanced the TTU process, while the polar EML/ETL interface induced the migration of the recombination zone depending on voltage, resulting in the decrease of triplet exciton density.
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Affiliation(s)
- Shunta Kakumachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Hajime Nakanotani
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yuto Nagasaki
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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5
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Diaz-Andres A, Tonnelé C, Casanova D. Electronic Couplings for Triplet-Triplet Annihilation Upconversion in Crystal Rubrene. J Chem Theory Comput 2024; 20:4288-4297. [PMID: 38743825 PMCID: PMC11137828 DOI: 10.1021/acs.jctc.4c00185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/06/2024] [Accepted: 05/06/2024] [Indexed: 05/16/2024]
Abstract
Triplet-triplet annihilation photon upconversion (TTA-UC) is a process able to repackage two low-frequency photons into light of higher energy. This transformation is typically orchestrated by the electronic degrees of freedom within organic compounds possessing suitable singlet and triplet energies and electronic couplings. In this work, we propose a computational protocol for the assessment of electronic couplings crucial to TTA-UC in molecular materials and apply it to the study of crystal rubrene. Our methodology integrates sophisticated yet computationally affordable approaches to quantify couplings in singlet and triplet energy transfer, the binding of triplet pairs, and the fusion to the singlet exciton. Of particular significance is the role played by charge-transfer states along the b-axis of rubrene crystal, acting as both partial quenchers of singlet energy transfer and mediators of triplet fusion. Our calculations identify the π-stacking direction as holding notable triplet energy transfer couplings, consistent with the experimentally observed anisotropic exciton diffusion. Finally, we have characterized the impact of thermally induced structural distortions, revealing their key role in the viability of triplet fusion and singlet fission. We posit that our approaches are transferable to a broad spectrum of organic molecular materials, offering a feasible means to quantify electronic couplings.
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Affiliation(s)
- Aitor Diaz-Andres
- Donostia
International Physics Center (DIPC), Donostia 20018, Euskadi, Spain
| | - Claire Tonnelé
- Donostia
International Physics Center (DIPC), Donostia 20018, Euskadi, Spain
- IKERBASQUE,
Basque Foundation for Science, Bilbao 48009, Euskadi, Spain
| | - David Casanova
- Donostia
International Physics Center (DIPC), Donostia 20018, Euskadi, Spain
- IKERBASQUE,
Basque Foundation for Science, Bilbao 48009, Euskadi, Spain
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6
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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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7
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Okamoto T, Izawa S, Hiramoto M, Kobori Y. Efficient Spin Interconversion by Molecular Conformation Dynamics of a Triplet Pair for Photon Up-Conversion in an Amorphous Solid. J Phys Chem Lett 2024; 15:2966-2975. [PMID: 38479407 PMCID: PMC10961844 DOI: 10.1021/acs.jpclett.3c03602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/10/2024] [Accepted: 02/20/2024] [Indexed: 03/22/2024]
Abstract
Solid-state materials with improved light-to-energy conversions in organic photovoltaics and in optoelectronics are expected to be developed by realizing efficient triplet-triplet annihilation (TTA) by manipulating the spin conversion processes to the singlet state. In this study, we elucidate the spin conversion mechanism for delayed fluorescence by TTA from a microscopic view of the molecular conformations. We examine the time evolution of the electron spin polarization of the triplet-pair state (TT state) in an amorphous solid-state system exhibiting highly efficient up-conversion emission by using time-resolved electron paramagnetic resonance. We clarified that the spin-state population of the singlet TT increased through the spin interconversion from triplet and quintet TT states during exciton diffusion with random orientation dynamics between the two triplets for the modulation of the exchange interaction, achieving a high quantum yield of up-conversion emission. This understanding provides us with a guide for the development of efficient light-to-energy conversion devices utilizing TTA.
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Affiliation(s)
- Tsubasa Okamoto
- Molecular
Photoscience Research Center, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
- Department
of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657−8501, Japan
| | - Seiichiro Izawa
- Laboratory
for Materials and Structures, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
- Precursory
Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Institute
for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Masahiro Hiramoto
- Institute
for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Yasuhiro Kobori
- Molecular
Photoscience Research Center, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
- Department
of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657−8501, Japan
- CREST,
JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012, Japan
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8
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Banappanavar G, Saxena R, Bässler H, Köhler A, Kabra D. Impact of Photoluminescence Imaging Methodology on Transport Parameters in Semiconductors. J Phys Chem Lett 2024; 15:3109-3117. [PMID: 38470078 DOI: 10.1021/acs.jpclett.4c00169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Triplet-triplet annihilation-induced delayed emission provides a pathway for investigating triplets via emission spectroscopy. This bimolecular annihilation depends directly on the transport properties of triplet excitons in disordered organic semiconductors. Photoluminescence (PL) imaging is a direct method for studying exciton and charge-carrier diffusivity. However, most of these studies neglect dispersive transport. Early time scale measurements using this technique can lead to an overestimation of the diffusion coefficient (DT) or diffusion length (Ld). In this study, we investigated the time-dependent triplet DT using PL imaging. We observed an overestimation of Ld in classical delayed PL imaging, often 1 order of magnitude higher than the actual Ld value. We compared various thicknesses of polymeric thin films to study the dispersive nature of triplet excitons. Transient analysis of delayed PL imaging and steady state imaging reveals the importance of considering the time-dependent nature of DT for the triplet excitons in disordered electronic materials.
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Affiliation(s)
- Gangadhar Banappanavar
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Rishabh Saxena
- Soft Matter Optoelectronics and Bavarian Polymer Institute (BPS), University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Heinz Bässler
- Bayreuth Institute of Macromolecular Research (BIMF), University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Anna Köhler
- Soft Matter Optoelectronics and Bavarian Polymer Institute (BPS), University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
- Bayreuth Institute of Macromolecular Research (BIMF), University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany
| | - Dinesh Kabra
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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9
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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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Luo Y, Kong FF, Tian XJ, Yu YJ, Jing SH, Zhang C, Chen G, Zhang Y, Zhang Y, Li XG, Zhang ZY, Dong ZC. Anomalously bright single-molecule upconversion electroluminescence. Nat Commun 2024; 15:1677. [PMID: 38395971 PMCID: PMC10891098 DOI: 10.1038/s41467-024-45450-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 01/23/2024] [Indexed: 02/25/2024] Open
Abstract
Efficient upconversion electroluminescence is highly desirable for a broad range of optoelectronic applications, yet to date, it has been reported only for ensemble systems, while the upconversion electroluminescence efficiency remains very low for single-molecule emitters. Here we report on the observation of anomalously bright single-molecule upconversion electroluminescence, with emission efficiencies improved by more than one order of magnitude over previous studies, and even stronger than normal-bias electroluminescence. Intuitively, the improvement is achieved via engineering the energy-level alignments at the molecule-substrate interface so as to activate an efficient spin-triplet mediated upconversion electroluminescence mechanism that only involves pure carrier injection steps. We further validate the intuitive picture with the construction of delicate electroluminescence diagrams for the excitation of single-molecule electroluminescence, allowing to readily identify the prerequisite conditions for producing efficient upconversion electroluminescence. These findings provide deep insights into the microscopic mechanism of single-molecule upconversion electroluminescence and organic electroluminescence in general.
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Affiliation(s)
- Yang Luo
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Fan-Fang Kong
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Xiao-Jun Tian
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Yun-Jie Yu
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Shi-Hao Jing
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Chao Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Gong Chen
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
| | - Yang Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Yao Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Xiao-Guang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China
| | - Zhen-Yu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Zhen-Chao Dong
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- School of Physics and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China.
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11
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Al-Sharji H, Ilmi R, Khan MS. Recent Progress in Phenoxazine-Based Thermally Activated Delayed Fluorescent Compounds and Their Full-Color Organic Light-Emitting Diodes. Top Curr Chem (Cham) 2024; 382:5. [PMID: 38329582 DOI: 10.1007/s41061-024-00450-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 01/04/2024] [Indexed: 02/09/2024]
Abstract
Third-generation organic light-emitting diodes (OLEDs) based on metal-free thermally activated delayed fluorescent (TADF) materials have sparked tremendous interest in the last decade due to their nearly 100% exciton utilization efficiency, which can address the low-efficiency issue of the first-generation fluorescent emitters and the high-cost issue of the second-generation organometallic phosphorescent emitters. Construction of efficient and stable TADF-OLEDs requires utilizing TADF materials with a narrow singlet-triplet energy gap (ΔEST), high photoluminescence quantum yield (PLQY) and short TADF lifetime. A small ΔEST is necessary for an efficient reverse intersystem crossing (RISC) process, which can be achieved through the effective spatial separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). TADF emitters have been generally designed as intramolecular charge transfer (ICT) molecules with highly twisted donor-acceptor (D-A) molecular architectures. A wide variety of combinations of electron donors and acceptors have been explored. In this review, we shall focus on recent progress in organic TADF molecules incorporating strong electron-donor phenoxazine moiety and their application as emitting layer (EML) in OLEDs.
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Affiliation(s)
- Houda Al-Sharji
- Department of Chemistry, Sultan Qaboos University, P. O. Box 36, Al Khod, 123, Oman
| | - Rashid Ilmi
- Department of Chemistry, Sultan Qaboos University, P. O. Box 36, Al Khod, 123, Oman.
| | - Muhammad S Khan
- Department of Chemistry, Sultan Qaboos University, P. O. Box 36, Al Khod, 123, Oman.
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12
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Tankelevičiūtė E, Samuel IDW, Zysman-Colman E. The Blue Problem: OLED Stability and Degradation Mechanisms. J Phys Chem Lett 2024; 15:1034-1047. [PMID: 38259039 PMCID: PMC10839906 DOI: 10.1021/acs.jpclett.3c03317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 01/11/2024] [Accepted: 01/16/2024] [Indexed: 01/24/2024]
Abstract
OLED technology has revolutionized the display industry and is promising for lighting. Despite its maturity, there remain outstanding device and materials challenges to address. Particularly, achieving stable and highly efficient blue OLEDs is still proving to be difficult; the vast array of degradation mechanisms at play, coupled with the precise balance of device parameters needed for blue high-performance OLEDs, creates a unique set of challenges in the quest for a suitably stable yet high-performance device. Here, we discuss recent progress in the understanding of device degradation pathways and provide an overview of possible strategies to increase device lifetimes without a significant efficiency trade-off. Only careful consideration of all variables that go into OLED development, from the choice of materials to a deep understanding of which degradation mechanisms need to be suppressed for the particular structure, can lead to a meaningful positive change toward commercializable blue devices.
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Affiliation(s)
- Eglė Tankelevičiūtė
- Organic
Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, U.K., KY16 9ST
- Organic
Semiconductor Centre, School of Physics & Astronomy, University of St Andrews, St Andrews, U.K., KY16 9SS
| | - Ifor D. W. Samuel
- Organic
Semiconductor Centre, School of Physics & Astronomy, University of St Andrews, St Andrews, U.K., KY16 9SS
| | - Eli Zysman-Colman
- Organic
Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, U.K., KY16 9ST
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13
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Zhang K, Wang X, Chang Y, Wu Y, Wang S, Wang L. Carbazole-Decorated Organoboron Emitters with Low-Lying HOMO Levels for Solution-Processed Narrowband Blue Hyperfluorescence OLED Devices. Angew Chem Int Ed Engl 2023; 62:e202313084. [PMID: 37775994 DOI: 10.1002/anie.202313084] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/28/2023] [Accepted: 09/29/2023] [Indexed: 10/01/2023]
Abstract
The hyperfluorescence has drawn great attention in achieving efficient narrowband emitting devices based on multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters. However, achieving efficient solution-processed pure blue hyperfluorescence devices is still a challenge, due to the unbalanced charge transport and serious exciton quenching caused by that the holes are easily trapped on the high-lying HOMO (the highest occupied molecular orbital) level of traditional diphenylamine-decorated emitters. Here, we developed two narrowband blue organoboron emitters with low-lying HOMO levels by decorating the MR-TADF core with weakly electron-donating carbazoles, which could suppress the hole trapping effect by reducing the hole traps between host and MR-TADF emitter from deep (0.40 eV) to shallow (0.14/0.20 eV) ones for facilitating hole transport and exciton formation, as well as avoiding exciton quenching. And the large dihedral angle between the carbazole and MR-TADF core makes the carbazole act as a steric hindrance to inhibit molecular aggregation. Accordingly, the optimized solution-processed pure blue hyperfluorescence devices simultaneously realize record external quantum efficiency of 29.2 %, narrowband emission with a full-width at half-maximum of 16.6 nm, and pure blue color with CIE coordinates of (0.139, 0.189), which is the best result for the solution-processed organic light-emitting diodes based on MR-TADF emitters.
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Affiliation(s)
- Kaiyuan Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, 230026, Hefei, P. R. China
| | - Xingdong Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, P. R. China
| | - Yufei Chang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, 230026, Hefei, P. R. China
| | - Yuliang Wu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, 230026, Hefei, P. R. China
| | - Shumeng Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, P. R. China
| | - Lixiang Wang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022, Changchun, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, 230026, Hefei, P. R. China
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14
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Wu Y, Xiao S, Guo K, Qiao X, Yang D, Dai Y, Sun Q, Chen J, Ma D. Understanding the degradation mechanism of TTA-based blue fluorescent OLEDs by exciton dynamics and transient electroluminescence measurements. Phys Chem Chem Phys 2023; 25:29451-29458. [PMID: 37882197 DOI: 10.1039/d3cp03437b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
The lifetime of blue organic light-emitting diodes (OLEDs) has always been a big challenge in practical applications. Blue OLEDs based on triplet-triplet annihilation (TTA) up-conversion materials have potential to achieve long lifetimes due to fusing two triplet excitons to one radiative singlet exciton, but there is a lack of an in-depth understanding of exciton dynamics on degradation mechanisms. In this work, we established a numerical model of exciton dynamics to study the impact factors in the stability of doped blue OLEDs based on TTA up-conversion hosts. By performing transient electroluminescence experiments, the intrinsic parameters related to the TTA up-conversion process of aging devices were determined. By combining the change of excess charge density in the emitting layer (EML) with aging time, it is concluded that the TTA materials are damaged by the excess electrons in the EML during ageing, which is the main degradation mechanism of OLEDs. This work provides a theoretical basis for preparing long-lifetime blue fluorescent OLEDs.
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Affiliation(s)
- Yibing Wu
- 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
- 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.
| | - Kaiwen Guo
- 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
- 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
- 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
- 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
- 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.
| | - Jiangshan Chen
- 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.
| | - Dongge Ma
- 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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15
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Wang C, Wegeberg C, Wenger OS. First-Row d 6 Metal Complex Enables Photon Upconversion and Initiates Blue Light-Dependent Polymerization with Red Light. Angew Chem Int Ed Engl 2023; 62:e202311470. [PMID: 37681516 DOI: 10.1002/anie.202311470] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 09/09/2023]
Abstract
Photosensitizers for sensitized triplet-triplet annihilation upconversion (sTTA-UC) often rely on precious heavy metals, whereas coordination complexes based on abundant first-row transition metals are less common. This is mainly because long-lived triplet excited states are more difficult to obtain for 3d metals, particularly when the d-subshell is only partially filled. Here, we report the first example of sTTA-UC based on a 3d6 metal photosensitizer yielding an upconversion performance competitive with precious metal-based analogues. Using a newly developed Cr0 photosensitizer featuring equally good photophysical properties as an OsII benchmark complex in combination with an acetylene-decorated anthracene annihilator, red-to-blue upconversion is achievable. The upconversion efficiency under optimized conditions is 1.8 %, and the excitation power density threshold to reach the strong annihilation limit is 5.9 W/cm2 . These performance factors, along with high photostability, permit the initiation of acrylamide polymerization by red light, based on radiative energy transfer between delayed annihilator fluorescence and a blue light absorbing photo-initiator. Our study provides the proof-of-concept for photon upconversion with elusive first-row analogues of widely employed precious d6 metal photosensitizers, and for their application in photochemical reactions triggered by excitation wavelengths close to near-infrared.
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Affiliation(s)
- Cui Wang
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
- Current address: Department of Biology and Chemistry, Osnabrück University, Barbarastraße 7, 49076, Osnabrück, Germany
| | - Christina Wegeberg
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
- Current address: Division of Chemical Physics, Department of Chemistry, Lund University Box 124, 22100, Lund, Sweden
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
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16
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Woo JY, Park MH, Jeong SH, Kim YH, Kim B, Lee TW, Han TH. Advances in Solution-Processed OLEDs and their Prospects for Use in Displays. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207454. [PMID: 36300804 DOI: 10.1002/adma.202207454] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/05/2022] [Indexed: 06/16/2023]
Abstract
This review outlines problems and progress in development of solution-processed organic light-emitting diodes (SOLEDs) in industry and academia. Solution processing has several advantages such as low consumption of materials, low-cost processing, and large-area manufacturing. However, use of a solution process entails complications, such as the need for solvent resistivity and solution-processable materials, and yields SOLEDs that have limited luminous efficiency, severe roll-off characteristics, and short lifetime compared to OLEDs fabricated using thermal evaporation. These demerits impede production of practical SOLED displays. This review outlines the industrial demands for commercial SOLEDs and the current status of SOLED development in industries and academia, and presents research guidelines for the development of SOLEDs that have high efficiency, long lifetime, and good processability to achieve commercialization.
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Affiliation(s)
- Joo Yoon Woo
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Min-Ho Park
- Department of Organic Materials and Fiber Engineering, Soongsil University, 369 Sangdo-Ro, Dongjak-Gu, Seoul, 06978, Republic of Korea
| | - Su-Hun Jeong
- Future Technology Research Center, LG Chem, Ltd., 30, Magokjunang 10-ro, Gangseo-gu, Seoul, 07794, Republic of Korea
| | - Young-Hoon Kim
- Department of Energy Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Byungjae Kim
- Future Technology Research Center, LG Chem, Ltd., 30, Magokjunang 10-ro, Gangseo-gu, Seoul, 07794, Republic of Korea
| | - Tae-Woo Lee
- Department of Materials Science and Engineering, School of Chemical and Biological Engineering, Institute of Engineering Research, Research Institute of Advanced Materials, Soft Foundry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Tae-Hee Han
- Division of Materials Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
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17
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Ciobotaru IC, Enculescu M, Polosan S, Enculescu I, Ciobotaru CC. Organic Light-Emitting Diodes with Electrospun Electrodes for Double-Side Emissions. MICROMACHINES 2023; 14:543. [PMID: 36984949 PMCID: PMC10056642 DOI: 10.3390/mi14030543] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Transparent conductive electrodes (TCE) obtained by the electrospinning method and gold covered were used as cathodes in the organic light-emitting diodes (OLEDs) to create double side-emission. The electro-active nanofibers of poly(methyl methacrylate) (PMMA) with diameters in the range of several hundreds of nanometers, were prepared through the electrospinning method. The nanofibers were coated with gold by sputtering deposition, maintaining optimal transparency and conductivity to increase the electroluminescence on both electrodes. Optical, structural, and electrical measurements of the as-prepared transparent electrodes have shown good transparency and higher electrical conductivity. In this study, two types of OLEDs consisting of indium tin oxide (ITO)/ poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT-PSS)/ Ir(III) complex (8-hydroxyquinolinat bis(2-phenylpyridyl) iridium-IrQ(ppy)2 20 wt% embedded in N, N'-Dicarbazolyl-4,4'-biphenyl (CBP) sandwich structure and either gold-covered PMMA electrospun nanoweb (OLED with electrospun cathode) were fabricated together with a similar structure containing thin film gold cathodes (OLED with thin film cathode). The luminance-current-voltage characteristics, the capacitance-voltage, and the electroluminescence properties of these OLEDs were investigated.
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18
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Engmann S, Bittle EG, Gundlach DJ. A Magnetic field sensor based on OLED / organic photodetector stack. ACS APPLIED ELECTRONIC MATERIALS 2023; 5:10.1021/acsaelm.3c00745. [PMID: 37969480 PMCID: PMC10644294 DOI: 10.1021/acsaelm.3c00745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
In this study an all-organic magnetic field sensor based on an organic light emitting diode (OLED) and organic photodetector (OPD) layer stack is presented. This sensor opens possibilities to create printable, flexible magnetic field sensors using commercially viable components, allowing magnetic field sensors to be simply integrated into existing OLED technology. The sensor function is driven by the large magneto-electroluminescence (MEL) of a thermally activated delayed fluorescence (TADF)-emitter based OLED, which in reference devices have shown an MEL of about 60% for magnetic fields on the order of 10 mT. Maximum sensitivity of about 0.15 nA/mT (150 μV/mT or 15 mV/kG with amplification) is achieved at a magnetic field of 3 mT to 4 mT. While the detectivity is limited to ~ 10-3 T·Hz-1/2, we show this can be improved upon on as the magnetic field detection sensitivity of OLEDs measured by an external Si-detector is about an order of magnitude higher. Sensitivity of 2 nA/mT and detectivities better than 10-5 T·Hz -1/2 are demonstrated, and the intrinsic detectivity limit is estimated to be on the order of 10-9 T·Hz -1/2.
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Affiliation(s)
- Sebastian Engmann
- Theiss Research, La Jolla, California 92037, United States
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
| | - Emily G. Bittle
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
| | - David J. Gundlach
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
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19
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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] [Grants] [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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20
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Huang J, Hung H, Hsu K, Chen C, Lee P, Lin H, Lin B, Leung M, Chiu T, Lee J, Friend RH, Wu Y. Numerical Analysis and Optimization of a Hybrid Layer Structure for Triplet–Triplet Fusion Mechanism in Organic Light‐Emitting Diodes. ADVANCED THEORY AND SIMULATIONS 2022. [DOI: 10.1002/adts.202200633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Jun‐Yu Huang
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei 10617 Taiwan
- Cavendish Laboratory University of Cambridge Cambridge CB3 0HE UK
| | - Hsiao‐Chun Hung
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei 10617 Taiwan
| | - Kung‐Chi Hsu
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei 10617 Taiwan
| | - Chia‐Hsun Chen
- Department of Chemistry National Taiwan University Taipei 10617 Taiwan
| | - Pei‐Hsi Lee
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei 10617 Taiwan
| | - Hung‐Yi Lin
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei 10617 Taiwan
| | - Bo‐Yen Lin
- Department of Opto‐Electronic Engineering National Dong Hwa University Shoufeng Hualien 974301 Taiwan
| | - Man‐kit Leung
- Department of Chemistry National Taiwan University Taipei 10617 Taiwan
| | - Tien‐Lung Chiu
- Department of Electrical Engineering Yuan‐Ze University Taoyuan 32003 Taiwan
| | - Jiun‐Haw Lee
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei 10617 Taiwan
| | | | - Yuh‐Renn Wu
- Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei 10617 Taiwan
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21
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Ultra-fast triplet-triplet-annihilation-mediated high-lying reverse intersystem crossing triggered by participation of nπ*-featured excited states. Nat Commun 2022; 13:6892. [DOI: 10.1038/s41467-022-34573-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 10/25/2022] [Indexed: 11/13/2022] Open
Abstract
AbstractThe harvesting of ‘hot’ triplet excitons through high-lying reverse intersystem crossing mechanism has emerged as a hot research issue in the field of organic light-emitting diodes. However, if high-lying reverse intersystem crossing materials lack the capability to convert ‘cold’ T1 excitons into singlet ones, the actual maximum exciton utilization efficiency would generally deviate from 100%. Herein, through comparative studies on two naphthalimide-based compounds CzNI and TPANI, we revealed that the ‘cold’ T1 excitons in high-lying reverse intersystem crossing materials can be utilized effectively through the triplet-triplet annihilation-mediated high-lying reverse intersystem crossing process if they possess certain triplet-triplet upconversion capability. Especially, quite effective triplet-triplet annihilation-mediated high-lying reverse intersystem crossing can be triggered by endowing the high-lying reverse intersystem crossing process with a 3ππ*→1nπ* character. By taking advantage of the permanent orthogonal orbital transition effect of 3ππ*→1nπ*, spin–orbit coupling matrix elements of ca. 10 cm−1 can be acquired, and hence ultra-fast mediated high-lying reverse intersystem crossing process with rate constant over 109 s−1 can be realized.
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22
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Panjwani NA, Behrends J. Framing fusion and fission. NATURE MATERIALS 2022; 21:1221-1222. [PMID: 36284237 DOI: 10.1038/s41563-022-01387-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Affiliation(s)
- Naitik A Panjwani
- Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, Berlin, Germany
| | - Jan Behrends
- Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, Berlin, Germany.
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23
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Ha DG, Wan R, Kim CA, Lin TA, Yang L, Van Voorhis T, Baldo MA, Dincă M. Exchange controlled triplet fusion in metal-organic frameworks. NATURE MATERIALS 2022; 21:1275-1281. [PMID: 36202994 PMCID: PMC9622415 DOI: 10.1038/s41563-022-01368-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 08/16/2022] [Indexed: 05/28/2023]
Abstract
Triplet-fusion-based photon upconversion holds promise for a wide range of applications, from photovoltaics to bioimaging. The efficiency of triplet fusion, however, is fundamentally limited in conventional molecular and polymeric systems by its spin dependence. Here, we show that the inherent tailorability of metal-organic frameworks (MOFs), combined with their highly porous but ordered structure, minimizes intertriplet exchange coupling and engineers effective spin mixing between singlet and quintet triplet-triplet pair states. We demonstrate singlet-quintet coupling in a pyrene-based MOF, NU-1000. An anomalous magnetic field effect is observed from NU-1000 corresponding to an induced resonance between singlet and quintet states that yields an increased fusion rate at room temperature under a relatively low applied magnetic field of 0.14 T. Our results suggest that MOFs offer particular promise for engineering the spin dynamics of multiexcitonic processes and improving their upconversion performance.
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Affiliation(s)
- Dong-Gwang Ha
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ruomeng Wan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Changhae Andrew Kim
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ting-An Lin
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Luming Yang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Troy Van Voorhis
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Marc A Baldo
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Mircea Dincă
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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24
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Franca LG, dos Santos PL, Pander P, Cabral MB, Cristiano R, Cazati T, Monkman AP, Bock H, Eccher J. Delayed Fluorescence by Triplet-Triplet Annihilation from Columnar Liquid Crystal Films. ACS APPLIED ELECTRONIC MATERIALS 2022; 4:3486-3494. [PMID: 35910938 PMCID: PMC9330766 DOI: 10.1021/acsaelm.2c00432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Delayed fluorescence (DF) by triplet-triplet annihilation (TTA) is observed in solutions of a benzoperylene-imidoester mesogen that shows a hexagonal columnar mesophase at room temperature in the neat state. A similar benzoperylene-imide with a slightly smaller HOMO-LUMO gap, that also is hexagonal columnar liquid crystalline at room temperature, does not show DF in solution, and mixtures of the two mesogens show no DF in solution either, because of collisional quenching of the excited triplet states on the imidoester by the imide. In contrast, DF by TTA from the imide but not from the imidoester is observed in condensed films of such mixtures, even though neat films of either single material are not displaying DF. In contrast to the DF from the monomeric imidoester in solution, DF of the imide occurs from dimeric aggregates in the blend films, assisted by the imidoester. Thus, the close contact of intimately stacked molecules of the two different species in the columnar mesophase leads to a unique mesophase-assisted aggregate DF. This constitutes the first observation of DF by TTA from the columnar liquid crystalline state. If the imide is dispersed in films of polybromostyrene, which provides an external heavy-atom effect facilitating triplet formation, DF is also observed. Organic light-emitting diodes (OLEDs) devices incorporating these liquid crystal molecules demonstrated high external quantum efficiency (EQE). On the basis of the literature and to the best of our knowledge, the EQE reported is the highest among nondoped solution-processed OLED devices using a columnar liquid crystal molecule as the emitting layer.
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Affiliation(s)
- Larissa G. Franca
- Department
of Physics, Durham University, South Road, Durham, DH1 3LE, United
Kingdom
- Departamento
de Física, Universidade Federal de
Santa Catarina, 88040900, Florianópolis, Santa Catarina, Brazil
| | - Paloma L. dos Santos
- Department
of Physics, Durham University, South Road, Durham, DH1 3LE, United
Kingdom
| | - Piotr Pander
- Department
of Physics, Durham University, South Road, Durham, DH1 3LE, United
Kingdom
- Faculty
of Chemistry, Silesian University of Technology, Strzody 9, 44-100 Gliwice, Poland
| | - Marília
G. B. Cabral
- Departamento
de Química, Universidade Federal
da Paraíba, CEP 58051-900, João Pessoa, Paraíba, Brazil
- Centre
de Recherche Paul-Pascal, CNRS & Université
de Bordeaux, 33600, Pessac, France
| | - Rodrigo Cristiano
- Departamento
de Química, Universidade Federal
da Paraíba, CEP 58051-900, João Pessoa, Paraíba, Brazil
| | - Thiago Cazati
- Departamento
de Física, Universidade Federal de
Ouro Preto − UFOP, 35400-000, Ouro Preto, Minas
Gerais, Brazil
| | - Andrew P. Monkman
- Department
of Physics, Durham University, South Road, Durham, DH1 3LE, United
Kingdom
| | - Harald Bock
- Centre
de Recherche Paul-Pascal, CNRS & Université
de Bordeaux, 33600, Pessac, France
| | - Juliana Eccher
- Departamento
de Física, Universidade Federal de
Santa Catarina, 88040900, Florianópolis, Santa Catarina, Brazil
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25
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Fu Q, Rui J, Fang J, Ni Y, Fang L, Lu C, Xu Z. Triplet‐triplet Annihilation Up‐conversion Luminescent Assisted Free‐radical Reactions of Polymers Using Visible Light. MACROMOL CHEM PHYS 2022. [DOI: 10.1002/macp.202200038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Qiang Fu
- State Key Laboratory of Materials‐Oriented Chemical Engineering College of Materials Science and Engineering Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing Tech University Nanjing 210009 P.R. China
| | - Jiaqiang Rui
- State Key Laboratory of Materials‐Oriented Chemical Engineering College of Materials Science and Engineering Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing Tech University Nanjing 210009 P.R. China
| | - Jiaojiao Fang
- State Key Laboratory of Materials‐Oriented Chemical Engineering College of Materials Science and Engineering Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing Tech University Nanjing 210009 P.R. China
| | - Yaru Ni
- State Key Laboratory of Materials‐Oriented Chemical Engineering College of Materials Science and Engineering Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing Tech University Nanjing 210009 P.R. China
| | - Liang Fang
- State Key Laboratory of Materials‐Oriented Chemical Engineering College of Materials Science and Engineering Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing Tech University Nanjing 210009 P.R. China
| | - Chunhua Lu
- State Key Laboratory of Materials‐Oriented Chemical Engineering College of Materials Science and Engineering Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing Tech University Nanjing 210009 P.R. China
| | - Zhongzi Xu
- State Key Laboratory of Materials‐Oriented Chemical Engineering College of Materials Science and Engineering Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing Tech University Nanjing 210009 P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing Tech University Nanjing 210009 P.R. China
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26
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Yang L, Chua XW, Yang Z, Ding X, Yu Y, Suwardi A, Zhao M, Ke KL, Ehrler B, Di D. Photon-upconverters for blue organic light-emitting diodes: a low-cost, sky-blue example. NANOSCALE ADVANCES 2022; 4:1318-1323. [PMID: 35342862 PMCID: PMC8886671 DOI: 10.1039/d1na00803j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
In the research ecosystem's quest towards having deployable organic light-emitting diodes with higher-energy emission (e.g., blue light), we advocate focusing on fluorescent emitters, due to their relative stability and colour purity, and developing design strategies to significantly improve their efficiencies. We propose that all triplet-triplet annihilation upconversion (TTA-UC) emitters would make good candidates for triplet fusion-enhanced OLEDs ("FuLEDs"), due to the energetically uphill nature of the photophysical process, and their common requirements. We demonstrate this with the low-cost sky-blue 1,3-diphenylisobenzofuran (DPBF). Having satisfied the criteria for TTA-UC, we show DPBF as a photon upconverter (I th 92 mW cm-2), and henceforth demonstrate it as a bright emitter for FuLEDs. Notably, the devices achieved 6.5% external quantum efficiency (above the ∼5% threshold without triplet contribution), and triplet-exciton-fusion-generated fluorescence contributes up to 44% of the electroluminescence, as shown by transient measurements. Here, triplet fusion translates to a quantum yield (Φ TTA-UC) of 19%, at an electrical excitation of ∼0.01 mW cm-2. The enhancement is meaningful for commercial blue OLED displays. We also found DPBF to have decent hole mobilities of ∼0.08 cm2 V-1 s-1. This additional finding can lead to DPBF being used in other capacities in various printable electronics.
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Affiliation(s)
- Le Yang
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (ASTAR) 2 Fusionopolis Way Singapore 138634 Singapore
- Department of Materials Science and Engineering, National University of Singapore Singapore 117575 Singapore
| | - Xian Wei Chua
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (ASTAR) 2 Fusionopolis Way Singapore 138634 Singapore
- Cavendish Laboratory, University of Cambridge JJ Thomson Avenue Cambridge CB30HE UK
| | - Zhihong Yang
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (ASTAR) 2 Fusionopolis Way Singapore 138634 Singapore
| | - Xiangpeng Ding
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (ASTAR) 2 Fusionopolis Way Singapore 138634 Singapore
| | - Yong Yu
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (ASTAR) 2 Fusionopolis Way Singapore 138634 Singapore
| | - Ady Suwardi
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (ASTAR) 2 Fusionopolis Way Singapore 138634 Singapore
| | - Meng Zhao
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (ASTAR) 2 Fusionopolis Way Singapore 138634 Singapore
| | - Karen Lin Ke
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (ASTAR) 2 Fusionopolis Way Singapore 138634 Singapore
| | - Bruno Ehrler
- Center for Nanophotonics, AMOLF Science Park 104 1098 XG Amsterdam The Netherlands
| | - Dawei Di
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University Hangzhou 310027 China
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27
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Liang Z, Yan X, Cui H, Xie H, Li H, Yan D, Ye C, Wang X, Tao X. Triplet‐Triplet Annihilation Upconversion from Ru(II) Phenanthroline Complexes and 2‐Substituted Anthracene Derivatives. ChemistrySelect 2022. [DOI: 10.1002/slct.202103851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Zuo‐Qin Liang
- Suzhou Key Laboratory of Flexible & Printing Optoelectronic Materials School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou 215009 China
| | - Xu Yan
- Suzhou Key Laboratory of Flexible & Printing Optoelectronic Materials School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou 215009 China
| | - Hao Cui
- Suzhou Key Laboratory of Flexible & Printing Optoelectronic Materials School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou 215009 China
| | - Huan‐Ran Xie
- Suzhou Key Laboratory of Flexible & Printing Optoelectronic Materials School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou 215009 China
| | - Hui Li
- Suzhou Key Laboratory of Flexible & Printing Optoelectronic Materials School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou 215009 China
| | - Dong Yan
- Suzhou Key Laboratory of Flexible & Printing Optoelectronic Materials School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou 215009 China
| | - Chang‐Qing Ye
- Suzhou Key Laboratory of Flexible & Printing Optoelectronic Materials School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou 215009 China
| | - Xiao‐Mei Wang
- Suzhou Key Laboratory of Flexible & Printing Optoelectronic Materials School of Materials Science and Engineering Suzhou University of Science and Technology Suzhou 215009 China
| | - Xu‐Tang Tao
- State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China
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28
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Yakubovich A, Odinokov A, Nikolenko S, Jung Y, Choi H. Computational Discovery of TTF Molecules with Deep Generative Models. Front Chem 2022; 9:800133. [PMID: 35004615 PMCID: PMC8733737 DOI: 10.3389/fchem.2021.800133] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 11/30/2021] [Indexed: 12/02/2022] Open
Abstract
We present a computational workflow based on quantum chemical calculations and generative models based on deep neural networks for the discovery of novel materials. We apply the developed workflow to search for molecules suitable for the fusion of triplet-triplet excitations (triplet-triplet fusion, TTF) in blue OLED devices. By applying generative machine learning models, we have been able to pinpoint the most promising regions of the chemical space for further exploration. Another neural network based on graph convolutions was trained to predict excitation energies; with this network, we estimate the alignment of energy levels and filter molecules before running time-consuming quantum chemical calculations. We present a comprehensive computational evaluation of several generative models, choosing a modification of the Junction Tree VAE (JT-VAE) as the best one in this application. The proposed approach can be useful for computer-aided design of materials with energy level alignment favorable for efficient energy transfer, triplet harvesting, and exciton fusion processes, which are crucial for the development of the next generation OLED materials.
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Affiliation(s)
| | - Alexey Odinokov
- Samsung R&D Institute Russia (SRR), Samsung Electronics, Moscow, Russia
| | - Sergey Nikolenko
- Steklov Institute of Mathematics at Saint Petersburg, Saint Petersburg, Russia.,ISP RAS Research Center for Trusted Artificial Intelligence, Moscow, Russia
| | - Yongsik Jung
- Samsung Advanced Institute of Technology (SAIT), Samsung Electronics, Yeongtong-gu, South Korea
| | - Hyeonho Choi
- Samsung Advanced Institute of Technology (SAIT), Samsung Electronics, Yeongtong-gu, South Korea
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29
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Bossanyi DG, Sasaki Y, Wang S, Chekulaev D, Kimizuka N, Yanai N, Clark J. Spin Statistics for Triplet-Triplet Annihilation Upconversion: Exchange Coupling, Intermolecular Orientation, and Reverse Intersystem Crossing. JACS AU 2021; 1:2188-2201. [PMID: 34977890 PMCID: PMC8715495 DOI: 10.1021/jacsau.1c00322] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Indexed: 06/14/2023]
Abstract
Triplet-triplet annihilation upconversion (TTA-UC) has great potential to significantly improve the light harvesting capabilities of photovoltaic cells and is also sought after for biomedical applications. Many factors combine to influence the overall efficiency of TTA-UC, the most fundamental of which is the spin statistical factor, η, that gives the probability that a bright singlet state is formed from a pair of annihilating triplet states. The value of η is also critical in determining the contribution of TTA to the overall efficiency of organic light-emitting diodes. Using solid rubrene as a model system, we reiterate why experimentally measured magnetic field effects prove that annihilating triplets first form weakly exchange-coupled triplet-pair states. This is contrary to conventional discussions of TTA-UC that implicitly assume strong exchange coupling, and we show that it has profound implications for the spin statistical factor η. For example, variations in intermolecular orientation tune η from to through spin mixing of the triplet-pair wave functions. Because the fate of spin-1 triplet-pair states is particularly crucial in determining η, we investigate it in rubrene using pump-push-probe spectroscopy and find additional evidence for the recently reported high-level reverse intersystem crossing channel. We incorporate all of these factors into an updated model framework with which to understand the spin statistics of TTA-UC and use it to rationalize the differences in reported values of η among different common annihilator systems. We suggest that harnessing high-level reverse intersystem crossing channels in new annihilator molecules may be a highly promising strategy to exceed any spin statistical limit.
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Affiliation(s)
- David G. Bossanyi
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
| | - Yoichi Sasaki
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Shuangqing Wang
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
| | - Dimitri Chekulaev
- Department
of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | - Nobuo Kimizuka
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Nobuhiro Yanai
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Jenny Clark
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
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30
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Gao C, Wong WWH, Qin Z, Lo SC, Namdas EB, Dong H, Hu W. Application of Triplet-Triplet Annihilation Upconversion in Organic Optoelectronic Devices: Advances and Perspectives. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2100704. [PMID: 34596295 DOI: 10.1002/adma.202100704] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 08/06/2021] [Indexed: 06/13/2023]
Abstract
Organic semiconductor materials have been widely used in various optoelectronic devices due to their rich optical and/or electrical properties, which are highly related to their excited states. Therefore, how to manage and utilize the excited states in organic semiconductors is essential for the realization of high-performance optoelectronic devices. Triplet-triplet annihilation (TTA) upconversion is a unique process of converting two non-emissive triplet excitons to one singlet exciton with higher energy. Efficient optical-to-electrical devices can be realized by harvesting sub-bandgap photons through TTA-based upconversion. In electrical-to-optical devices, triplets generated after the combination of electrons and holes also can be efficiently utilized via TTA, which resulted in a high internal conversion efficiency of 62.5%. Currently, many interesting explorations and significant advances have been demonstrated in these fields. In this review, a comprehensive summary of these intriguing advances on developing efficient TTA upconversion materials and their application in optoelectronic devices is systematically given along with some discussions. Finally, the key challenges and perspectives of TTA upconversion systems for further improvement for optoelectronic devices and other related research directions are provided. This review hopes to provide valuable guidelines for future related research and advancement in organic optoelectronics.
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Affiliation(s)
- Can Gao
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wallace W H Wong
- ARC Centre of Excellence in Exciton Science, School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Zhengsheng Qin
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shih-Chun Lo
- Centre for Organic Photonics and Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Ebinazar B Namdas
- Centre for Organic Photonics & Electronics, School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Huanli Dong
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Science, Tianjin University, Tianjin, 300072, China
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31
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Hamzehpoor E, Ruchlin C, Tao Y, Ramos-Sanchez JE, Titi HM, Cosa G, Perepichka DF. Room Temperature Phosphorescence vs Triplet-Triplet Annihilation in N-Substituted Acridone Solids. J Phys Chem Lett 2021; 12:6431-6438. [PMID: 34236197 DOI: 10.1021/acs.jpclett.1c01552] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Organic room temperature phosphorescent (ORTP) compounds have recently emerged as a promising class of emissive materials with a multitude of potential applications. However, the number of building blocks that give rise to efficient ORTP materials is still limited, and the rules for engineering phosphorescent properties in organic solids are not well understood. Here, we report ORTP in a series of N-substituted acridone derivatives with electron-donating, electron-withdrawing, and sterically bulky substituents. X-ray crystallography shows that the solid-state packing varies progressively between coparallel and antiparallel π-stacking and separated π-dimers, depending on the size of the substituent. The detailed photophysical studies supported by DFT calculations reveal complex dynamics of singlet and triplet excited states, depending on the electronic effects of substituents and solid-state packing. The programmable molecular packing provides a lever to control the triplet-triplet annihilation that is manifested as delayed fluorescence in acridone derivatives with continuous (both parallel and antiparallel) π-stacking.
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Affiliation(s)
- Ehsan Hamzehpoor
- Department of Chemistry, McGill University 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Cory Ruchlin
- Department of Chemistry, McGill University 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Yuze Tao
- Department of Chemistry, McGill University 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | | | - Hatem M Titi
- Department of Chemistry, McGill University 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Gonzalo Cosa
- Department of Chemistry, McGill University 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Dmitrii F Perepichka
- Department of Chemistry, McGill University 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
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32
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Abstract
Harnessing cost-efficient printable semiconductor materials as near-infrared (NIR) emitters in light-emitting diodes (LEDs) is extremely attractive for sensing and diagnostics, telecommunications, and biomedical sciences. However, the most efficient NIR LEDs suitable for printable electronics rely on emissive materials containing precious transition metal ions (such as platinum), which have triggered concerns about their poor biocompatibility and sustainability. Here, we review and highlight the latest progress in NIR LEDs based on non-toxic and low-cost functional materials suitable for solution-processing deposition. Different approaches to achieve NIR emission from organic and hybrid materials are discussed, with particular focus on fluorescent and exciplex-forming host-guest systems, thermally activated delayed fluorescent molecules, aggregation-induced emission fluorophores, as well as lead-free perovskites. Alternative strategies leveraging photonic microcavity effects and surface plasmon resonances to enhance the emission of such materials in the NIR are also presented. Finally, an outlook for critical challenges and opportunities of non-toxic NIR LEDs is provided.
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Affiliation(s)
- Kunping Guo
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
| | - Marcello Righetto
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
| | - Alessandro Minotto
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
| | - Andrea Zampetti
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
| | - Franco Cacialli
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, London WC1E 6BT, UK
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33
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Wada Y, Wakisaka Y, Kaji H. Efficient Direct Reverse Intersystem Crossing between Charge Transfer-Type Singlet and Triplet States in a Purely Organic Molecule. Chemphyschem 2021; 22:625-632. [PMID: 33586264 DOI: 10.1002/cphc.202001013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/11/2021] [Indexed: 11/07/2022]
Abstract
In the field of organic light-emitting diodes, thermally activated delayed fluorescence (TADF) materials have achieved great performance. The key factor for this performance is the small energy gap (ΔEST ) between the lowest triplet (T1 ) and singlet excited (S1 ) states, which can be realized in a well-separated donor-acceptor system. Such systems are likely to possess similar charge transfer (CT)-type T1 and S1 states. Recent investigations have suggested that the intervention of other type-states, such as locally excited triplet state(s), is necessary for efficient reverse intersystem crossing (RISC). Here, we theoretically and experimentally demonstrate that our blue TADF material exhibits efficient RISC even between singlet CT and triplet CT states without any additional states. The key factor is dynamic flexibility of the torsion angle between the donor and acceptor, which enhances spin-orbit coupling even between the charge transfer-type T1 and S1 states, without sacrificing the small ΔEST . This results in excellent photoluminescence and electroluminescence performances in all the host materials we investigate, with sky-blue to deep-blue emissions. Among the hosts investigated, the deepest blue emission with CIE coordinates of (0.15, 0.16) and the highest EQEMAX of 23.9 % are achieved simultaneously.
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Affiliation(s)
- Yoshimasa Wada
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Yasuaki Wakisaka
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Hironori Kaji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
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34
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The triplet exciton dynamics and diffusion properties of zinc and platinum-octaethylporphyrin nanoaggregates. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2020.113105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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35
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Engmann S, Bittle EG, Richter LJ, Hallani RK, Anthony JE, Gundlach DJ. The role of orientation in the MEL response of OLEDs. JOURNAL OF MATERIALS CHEMISTRY. C 2021; 9:10.1039/d1tc00314c. [PMID: 36967733 PMCID: PMC10037669 DOI: 10.1039/d1tc00314c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Magneto electroluminescence (MEL) is emerging as a powerful tool to study spin dynamics in organic light emitting diodes (OLEDs). The shape of the MEL response is typically used to draw qualitative inference on the dominant process (singlet fission or triplet fusion) in the device. In this study, we develop a quantitative model for MEL and apply it to devices based on Rubrene, and three solution processable anthradithiophene emitters. The four emitters allow us to systematically vary the film structure between highly textured, poly-crystalline to amorphous. We find significant diversity in the MEL, with the textured films giving highly structured responses. We find that the additional structure does not coincide with energy anti-crossings, but intersections in the singlet character between adjacent states. In all cases the MEL can be adequately described by an extended Merrifield model. Via the inclusion of charge injection, we are able to draw additional information on underlying physics in OLED devices.
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Affiliation(s)
- Sebastian Engmann
- Theiss Research, La Jolla, California 92037, United States
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
| | - Emily G Bittle
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
| | - Lee J Richter
- Materials Science and Engineering Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
| | - Rawad K Hallani
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, 40506, United States
- Current address: KAUST Solar Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - John E Anthony
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, 40506, United States
| | - David J Gundlach
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
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Xu Y, Xu P, Hu D, Ma Y. Recent progress in hot exciton materials for organic light-emitting diodes. Chem Soc Rev 2020; 50:1030-1069. [PMID: 33231588 DOI: 10.1039/d0cs00391c] [Citation(s) in RCA: 139] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
According to Kasha's rule, high-lying excited states usually have little effect on fluorescence. However, in some molecular systems, the high-lying excited states partly or even mainly contribute to the photophysical properties, especially in the process of harvesting triplet excitons in organic electroluminescent devices. In the current review, we focus on a type of organic light-emitting diode (OLED) materials called "hot exciton" materials, which can effectively harness the non-radiative triplet excitons via reverse intersystem crossing (RISC) from high-lying triplet states to singlet states (Tn→ Sm; n≥ 2, m≥ 1). Since Ma and Yang proposed the hot exciton mechanism for OLED material design in 2012, there have been many reports aiming at the design and synthesis of novel hot exciton luminogens. Herein, we present a comprehensive review of the recent progress in hot exciton materials. The developments of the hot exciton mechanism are reviewed, the fundamental principles regarding molecular design are discussed, and representative reported hot exciton luminogens are summarized and analyzed, along with their structure-property relationships and OLED applications.
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Affiliation(s)
- Yuwei Xu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China.
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Gu Q, Abdurahman A, Friend RH, Li F. Polymer Light Emitting Diodes with Doublet Emission. J Phys Chem Lett 2020; 11:5638-5642. [PMID: 32573241 DOI: 10.1021/acs.jpclett.0c01399] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Organic light-emitting radicals have developed rapidly due to their unique doublet emission and great potential in display technology. Although some organic light-emitting diodes (OLEDs) exploiting small-molecular radicals as the emitters have been reported, there is no report about the polymer-radical-based OLEDs until now. Herein, a kind of polymer radical, PS-CzTTM, is adopted as the emitter to fabricate solution-processed OLEDs. A maximum external quantum efficiency of 3.0% is achieved for a deep-red device with an emissive layer of PS-CzTTM lightly doped in 2,2',2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1H-benzimidazole) (TPBi). Temperature-dependent time-resolved photoluminescent spectra and transient electroluminescence of radical emitters and devices are first measured. The results demonstrate that the emission channels for both thin films and devices are from the transition of doublet excitons, indicating that the unique doublet emission mechanism of radicals is maintained in PS-CzTTM films and PS-CzTTM-based OLEDs.
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Affiliation(s)
- Qinying Gu
- Department of Physics, Cavendish Laboratory, Cambridge University, Cambridge CB3 0HF, U.K
| | - Alim Abdurahman
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Avenue, 2699 Changchun, P. R. China
| | - Richard H Friend
- Department of Physics, Cavendish Laboratory, Cambridge University, Cambridge CB3 0HF, U.K
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Avenue, 2699 Changchun, P. R. China
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Lim H, Cheon HJ, Lee GS, Kim M, Kim YH, Kim JJ. Enhanced Triplet-Triplet Annihilation of Blue Fluorescent Organic Light-Emitting Diodes by Generating Excitons in Trapped Charge-Free Regions. ACS APPLIED MATERIALS & INTERFACES 2019; 11:48121-48127. [PMID: 31774270 DOI: 10.1021/acsami.9b15303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Three new anthracene-cored molecules, 3,3'-(5-(10-(naphthalen-1-yl)anthracen-9-yl)-1,3-phenylene)dipyridine (AP3Py-Na), 3,3'-(5-(10-(naphthalen-2-yl)anthracen-9-yl)-1,3-phenylene)dipyridine (AP3Py-2Na), and 9,10-bis(3,5-di(pyridin-3-yl)phenyl)anthracene (ADP3Py), were synthesized to be used as an efficiency-enhancement layer (EEL) in blue fluorescent organic light-emitting diodes. Insertion of a very thin EEL (3 nm) between the deep blue emitting layer (EML) and the electron transport layer enhanced the external quantum efficiency (EQE) of the blue device by 44% compared to the device without the EEL, resulting in an EQE of 7.9% and a current efficiency of 9.0 cd A-1 at 1000 cd m-2; the CIE coordinates of the emitting color were (0.13, 0.14). The transient electroluminescence showed that the efficiency enhancement originates from the triplet-triplet annihilation (TTA) process in the EEL, followed by energy transfer to the emitting dye in the EML.
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Affiliation(s)
| | - Hyung Jin Cheon
- School of Materials Science and Engineering , Gyeongsang National University , 501, Jinju-daero , Jinju-si 660-701 , Gyeongsangnam-do , South Korea
| | - Gyeong Seok Lee
- School of Materials Science and Engineering , Gyeongsang National University , 501, Jinju-daero , Jinju-si 660-701 , Gyeongsangnam-do , South Korea
| | - Mikyung Kim
- Samsung Display Company, Limited , 95 Samsung 2-ro , Giheung-gu, Yongin-si 446-711 , Gyeonggi-Do , South Korea
| | - Yun-Hi Kim
- School of Materials Science and Engineering , Gyeongsang National University , 501, Jinju-daero , Jinju-si 660-701 , Gyeongsangnam-do , South Korea
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Kang S, Moon JH, Kim T, Lee JY. Design of efficient non-doped blue emitters: toward the improvement of charge transport. RSC Adv 2019; 9:27807-27816. [PMID: 35530480 PMCID: PMC9070764 DOI: 10.1039/c9ra04918e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 08/16/2019] [Indexed: 11/25/2022] Open
Abstract
Charge transport and electronic transition properties of a series of newly designed anthracene-based non-doped blue emitters were investigated by density functional theory calculations. For a highly efficient non-doped device, Cz3PhAn-based emitters were designed to suppress the hole and electron reorganization energies required for structural relaxation with respect to the changes of charged states. As a result, the hole hopping rates of triphenylamine (TPA) and phenylbenzimidazole (PBI) substituted Cz3PhAn derivatives (1, 4, and 5-7) were tremendously enhanced as compared to that of Cz3PhAn due to the suppression of the reorganization energy of holes, λ h. Moreover, 1 and 4 emitters showed almost identical hopping rates of holes and electrons, which can possibly lead to a perfect charge balance and high efficiency. The photo-physical properties showed that the emission energy of all 1-10 emitters is in 439-473 nm range. It is expected that our rational design strategy can help develop non-doped blue fluorescent emitters for high efficiency.
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Affiliation(s)
- Sunwoo Kang
- Display Research Center, Samsung Display Co. 1 Giheung-gu Gyunggi South Korea
| | - Jong Hun Moon
- Department of Chemistry, Sungkyunkwan University Suwon 16419 South Korea
| | - Taekyung Kim
- Department of Materials Science and Engineering, Hongik University Sejongsi 30016 South Korea
| | - Jin Yong Lee
- Department of Chemistry, Sungkyunkwan University Suwon 16419 South Korea
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Efficient soluble deep blue electroluminescent dianthracenylphenylene emitters with CIE y (y ≤ 0.08) based on triplet-triplet annihilation. Sci Bull (Beijing) 2019; 64:774-781. [PMID: 36659547 DOI: 10.1016/j.scib.2019.04.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/31/2019] [Accepted: 04/18/2019] [Indexed: 01/21/2023]
Abstract
It has been challenging to develop deep blue organic molecular fluorescent emitters with CIE y (y ≤ 0.08) based on triplet-triplet annihilation (TTA). Here, we report facilely available dianthracenylphenylene-based emitters, which have a 3,5-di(4-t-butylphenyl)phenyl moiety at the one end and 4-cyanophenyl or 3-pyridyl at the other end, respectively. Both fluorophores show a high glass transition temperature of over 220 °C with a thermal decomposition temperature of over 430 °C at an initial weight loss of 1%. The preliminary characterizations of the organic light-emitting diodes (OLEDs) that utilized these nondoped emitters provided high EQEs of 4.6%-5.9% with CIE coordinates (0.15, 0.07-0.08). The analysis of the EL transient decay revealed that TTA contributed to the observed performance. The results show that the new emitters are attractive as a potential TTA-based host to afford stable deep blue fluorescent OLEDs.
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41
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Design of electron blocking layer with electron stabilizing unit for improved efficiency and lifetime in blue fluorescent organic light-emitting diodes. J IND ENG CHEM 2019. [DOI: 10.1016/j.jiec.2019.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Dey A, Kabra D. Kinetics of Triplet Exciton Energy-Transfer Processes in Triplet Sensitizer-Doped Fluorescent Polymers. J Phys Chem A 2019; 123:4858-4862. [DOI: 10.1021/acs.jpca.9b02984] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amrita Dey
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Dinesh Kabra
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Xu Y, Liang X, Zhou X, Yuan P, Zhou J, Wang C, Li B, Hu D, Qiao X, Jiang X, Liu L, Su SJ, Ma D, Ma Y. Highly Efficient Blue Fluorescent OLEDs Based on Upper Level Triplet-Singlet Intersystem Crossing. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1807388. [PMID: 30714207 DOI: 10.1002/adma.201807388] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/21/2019] [Indexed: 06/09/2023]
Abstract
Purely organic electroluminescent materials, such as thermally activated delayed fluorescent (TADF) and triplet-triplet annihilation (TTA) materials, basically harness triplet excitons from the lowest triplet excited state (T1 ) to realize high efficiency. Here, a fluorescent material that can convert triplet excitons into singlet excitons from the high-lying excited state (T2 ), referred to here as a "hot exciton" path, is reported. The energy levels of this compound are determined from the sensitization and nanosecond transient absorption spectroscopy measurements, i.e., small splitting energy between S1 and T2 and rather large T2 -T1 energy gap, which are expected to impede the internal conversion (IC) from T2 to T1 and facilitate the reverse intersystem crossing from the high-lying triplet state (hRISC). Through sensitizing the T2 state with ketones, the existence of the hRISC process with an ns-scale delayed lifetime is confirmed. Benefiting from this fast triplet-singlet conversion, the nondoped device based on this "hot exciton" material reaches a maximum external quantum efficiency exceeding 10%, with a small efficiency roll-off and CIE coordinates of (0.15, 0.13). These results reveal that the "hot exciton" path is a promising way to exploit high efficient, stable fluorescent emitters, especially for the pure-blue and deep-blue fluorescent organic light-emitting devices.
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Affiliation(s)
- Yuwei Xu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Xiaoming Liang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Xuehong Zhou
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Peisen Yuan
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China
| | - Jiadong Zhou
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Cong Wang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Binbin Li
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Dehua Hu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Xianfeng Qiao
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Xiaofang Jiang
- Institute of Modern Optical Technologies, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou, 510006, China
| | - Linlin Liu
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Shi-Jian Su
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Dongge Ma
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Yuguang Ma
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, China
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44
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The contribution of triplet excitons to the total singlet production yield in a sky-blue emitting co-polymer film. Polym Bull (Berl) 2019. [DOI: 10.1007/s00289-019-02729-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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45
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Xie Y, Gong Y, Han M, Zhang F, Peng Q, Xie G, Li Z. Tetraphenylcyclopentadiene-Based Hyperbranched Polymers: Convenient Syntheses from One Pot “A4 + B2” Polymerization and High External Quantum Yields up to 9.74% in OLED Devices. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02051] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Yujun Xie
- Department of Chemistry, Wuhan University, Wuhan 430072, China
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Yanbin Gong
- Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Mengmeng Han
- Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Fengyuan Zhang
- Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Qian Peng
- Key Laboratory of Organic Solids, Beijing National Laboratory for Molecular Science (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Guohua Xie
- Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Zhen Li
- Department of Chemistry, Wuhan University, Wuhan 430072, China
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
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46
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Fu C, Luo S, Li Z, Ai X, Pang Z, Li C, Chen K, Zhou L, Li F, Huang Y, Lu Z. Highly efficient deep-blue OLEDs based on hybridized local and charge-transfer emitters bearing pyrene as the structural unit. Chem Commun (Camb) 2019; 55:6317-6320. [DOI: 10.1039/c9cc02355k] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Pyrene is a quite promising structural unit for HLCT emitters, and deep-blue OLEDs showing quite high brightness over 10 000 cd m−2 and EQEmax over 10.5% have been achieved.
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47
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Dey A, Kabra D. Role of Bimolecular Exciton Kinetics in Controlling the Efficiency of Organic Light-Emitting Diodes. ACS APPLIED MATERIALS & INTERFACES 2018; 10:38287-38293. [PMID: 30298717 DOI: 10.1021/acsami.8b10559] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Here, we have carried out a spectroscopic investigation on the operational organic light-emitting diodes (OLEDs) to determine the role of emission layer thickness on the optoelectronic performance of OLEDs based on a poly(9,9-dioctylfluorene- alt-benzothiadiazole) (F8BT) copolymer system. Our study shows that delayed fluorescence (DF) via triplet-triplet annihilation (TTA) contributes significantly to boost the OLED efficiency through its fractional contribution. Interestingly, we note that DF contribution varies as a function of the emissive layer thickness. From the time-resolved electroluminescence (TREL) and triplet absorption (under electrical excitation) studies, we have seen that the emissive layer thickness controls triplet exciton generation and decay processes. From TREL, we have also shown that singlet-triplet annihilation (STA) is the dominant fluorescence quenching mechanism in bulk of the emissive layer, whereas thinner devices have significant exciton quenching at the interface of the injection layer/F8BT. The strength of STA differs in thin versus thick samples, which has been correlated with the spectral & spatial overlap integral of singlet and triplet states. Hence, STA strength and triplet population density are critical parameters for an explanation of high efficiency in unusually thick F8BT OLEDs.
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Affiliation(s)
- Amrita Dey
- Department of Physics , Indian Institute of Technology Bombay , Powai, Mumbai 400076 , India
| | - Dinesh Kabra
- Department of Physics , Indian Institute of Technology Bombay , Powai, Mumbai 400076 , India
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48
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Zhang D, Song X, Li H, Cai M, Bin Z, Huang T, Duan L. High-Performance Fluorescent Organic Light-Emitting Diodes Utilizing an Asymmetric Anthracene Derivative as an Electron-Transporting Material. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707590. [PMID: 29774610 DOI: 10.1002/adma.201707590] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/18/2018] [Indexed: 06/08/2023]
Abstract
Fluorescent organic light-emitting diodes with thermally activated delayed fluorescent sensitizers (TSF-OLEDs) have aroused wide attention, the power efficiencies of which, however, are limited by the mutual exclusion of high electron-transport mobility and large triplet energy of electron-transporting materials (ETMs). Here, an asymmetric anthracene derivative with electronic properties manipulated by different side groups is developed as an ETM to promote TSF-OLED performances. Multiple intermolecular interactions are observed, leading to a kind of "cable-like packing" in the crystal and favoring the simultaneous realization of high electron-transporting mobility and good exciton-confinement ability, albeit the low triplet energy of the ETM. The optimized TSF-OLEDs exhibit a record-high maximum external quantum efficiency/power efficiency of 24.6%/76.0 lm W-1 , which remain 23.8%/69.0 lm W-1 at a high luminance of even 5000 cd m-2 with an extremely low operation voltage of 3.14 V. This work opens a new paradigm for designing ETMs and also paves the way toward practical application of TSF-OLEDs.
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Affiliation(s)
- Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Xiaozeng Song
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Haoyuan Li
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Minghan Cai
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Zhengyang Bin
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Tianyu Huang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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49
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Emergence of White Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8020299] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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50
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Jayabharathi J, Ramya R, Thanikachalam V, Nethaji P. Tailoring the molecular design of twisted dihydrobenzodioxin phenanthroimidazole derivatives for non-doped blue organic light-emitting devices. RSC Adv 2018; 8:29031-29043. [PMID: 35548015 PMCID: PMC9084391 DOI: 10.1039/c8ra05004j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 07/30/2018] [Indexed: 11/21/2022] Open
Abstract
Three fused polycyclic aryl fragments, namely, naphthyl, methoxynaphthyl, and pyrenyl have been used to construct blue-emissive phenanthroimidazole-functionalized target molecules, i.e., 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-2-(naphthalen-1-yl)-1H-phenanthro[9,10-d]imidazole (1), 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-2-(1-methoxynaphthalen-4-yl)-1H-phenanthro[9,10-d]imidazole (2), and 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-2-(pyren-10-yl)-1H-phenanthro[9,10-d]imidazole (3). The up-conversion of triplets to singlets via a triplet–triplet annihilation (TTA) process is dominant in these compounds due to 2ET1 > ES1. The pyrenyl dihydrobenzodioxin phenanthroimidazole (3)-based nondoped OLED exhibits blue emission (450 nm) with CIE (0.15, 0.14), a luminance of 53 890 cd m−2, power efficiency of 5.86 lm W−1, external quantum efficiency of 5.30%, and current efficiency of 6.90 cd A−1. The efficient device performance of pyrenyl dihydrobenzodioxin phenanthroimidazole is due to the TTA contribution to the electroluminescent process. Efficient blue emitters, 1-(2,3-dihydrobenzodioxinyl)-2-naphthylphenanthroimidazole, 1-(2,3-dihydrobenzodioxinyl)-2-methoxynaphthylphenanthroimidazole and 1-(2,3-dihydrobenzodioxinyl)-2-pyrenylphenanthroimidazole have been reported.![]()
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