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Dong X, Xie X, Shen S, Qin Y, Pang Z, Lv X, Wang Y. Highly Efficient, Low-Roll-Off, Red, "Hot Exciton" Organic Light-Emitting Diodes Promoted by the Heavy-Atom Effect of Selenium. J Phys Chem Lett 2024; 15:9239-9246. [PMID: 39226390 DOI: 10.1021/acs.jpclett.4c02166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
It is important to attain red hot exciton materials applicable in highly efficient organic light-emitting diodes with low-efficiency roll-off, but their development is restricted by the energy gap law. Herein, the sulfur atom was replaced by a heavier selenium atom based on benzothiadiazole to obtain a new benzoselenadiazole acceptor with a heavy atom effect and stronger electron-withdrawing ability. Two novel red hot exciton materials named BSe-DtBuTPA and BSe-2PhCz-d24 were designed and synthesized based on the benzoselenadiazole unit. Benefiting from the heavy-atom effect of selenium and the small ΔES1T2, both emitters exhibited ultrafast high-lying reverse intersystem crossing rate constants (7.00 × 107 and 1.17 × 107 s-1). The devices based on BSe-DtBuTPA and BSe-2PhCz-d24 demonstrated maximum external quantum efficiencies of 4.81 and 7.15% with emission peaks at 653 and 596 nm, respectively. The device based on deep-red BSe-DtBuTPA exhibited negligible efficiency roll-off of 18.5% at 10000 cd/m2.
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Affiliation(s)
- Xiangyu Dong
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Xie
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shaogang Shen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanyuan Qin
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhi Pang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinyi Lv
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Huang W, Zhu Y, Xie X, Tang G, Zhou K, Song L, He Z. Utilizing weakly donor-acceptor ternary π-conjugated architecture to achieve single-component white luminescence and stimulus-responsive room-temperature phosphorescence. Chem Sci 2024; 15:12316-12325. [PMID: 39118604 PMCID: PMC11304527 DOI: 10.1039/d4sc02525c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 06/20/2024] [Indexed: 08/10/2024] Open
Abstract
Purely organic room-temperature phosphorescence (RTP) has garnered substantial attention for its delayed emission, environmental sensitivity, and potential diverse applications. However, the quest for high-performance RTP materials has always been a challenge. In this study, we introduce novel weakly donor-acceptor (D-A) ternary π-conjugated architecture to construct an efficient RTP system. The strategy utilizes synergistic effects of the analogous El-Sayed rule, halogen-free heavy-atom effect, reduction of the singlet-triplet energy gap, and manipulation of flexible molecular conformation. A remarkable enhancement in the phosphorescence-to-fluorescence ratio was achieved, elevating from 0.4 in carbazole to 35.2 in DBTDBTCZ. Furthermore, the RTP system demonstrates single-component white luminescence, yielding warm and cool white colors. Intriguingly, we unveil the novel position-dependent heavy-atom effects, discerningly promoting intersystem crossing or phosphorescence decay. Benefiting from efficient RTP, multifunctional applications of real-time humidity monitoring, oxygen sensing, anti-counterfeiting labeling, and white lighting are demonstrated.
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Affiliation(s)
- Wenbin Huang
- School of Science, Harbin Institute of Technology Shenzhen Shenzhen Guangdong 518055 China
| | - Yuxin Zhu
- School of Science, Harbin Institute of Technology Shenzhen Shenzhen Guangdong 518055 China
| | - Xinwei Xie
- School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen Shenzhen Guangdong 518055 China
| | - Guanqun Tang
- School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen Shenzhen Guangdong 518055 China
| | - Kang Zhou
- Hoffman Institute of Advanced Materials, Shenzhen Polytechnic University Shenzhen Guangdong 518055 China
| | - Lijuan Song
- School of Science, Harbin Institute of Technology Shenzhen Shenzhen Guangdong 518055 China
| | - Zikai He
- School of Science, Harbin Institute of Technology Shenzhen Shenzhen Guangdong 518055 China
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Polesiak E, Makowska-Janusik M, Drapala J, Zagorska M, Banasiewicz M, Kozankiewicz B, Kulszewicz-Bajer I, Pron A. Photophysical and redox properties of new donor-acceptor-donor (DAD) compounds containing benzothiadiazole (A) and dimethyldihydroacridine (D) units: a combined experimental and theoretical study. Phys Chem Chem Phys 2024. [PMID: 39041807 DOI: 10.1039/d4cp02322f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Four donor-acceptor-donor compounds consisting of 9,9-dimethyl-9,10-dihydroacridine donors differently linked to a benzothiadiazole acceptor were designed using DFT calculations and synthesized, namely 4,7-bis(4-(9,9-dimethyl-9,10-dihydroacridine)phenyl)benzo[c][1,2,5]thiadiazole (1), 4,7-bis(2,5-dimethyl-4-(9,9-dimethyl-9,10-dihydroacridine)phenyl)benzo[c][1,2,5]thiadiazole (2), 4,7-bis(3,5-di(9,9-dimethyl-9,10-dihydroacridine)phenyl)benzo[c][1,2,5]thiadiazole (3), and 4-(3,5-di(9,9-dimethyl-9,10-dihydroacridine)phenyl)-7-(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (4). As predicted theoretically, all studied compounds were electrochemically active both in the reduction as well as in the oxidation modes. They underwent one electron quasi-reversible reduction. Oxidation of 1 and 2 involved a two electron process transforming them into dications and carrying out, in parallel, their dimerization. Oxidation of 3 and 4 resulted in their oligomerization (polymerization). The electrochemically determined ionisation potentials (IP) of 1-4 were similar, covering a narrow range of 5.28-5.33 eV and were consistent with DFT calculations. Larger differences were found for experimentally determined electron affinity (EA) values, being significantly lower for 2 (|EA| = 2.59 eV) as compared to 1, 3 and 4 whose |EA| values were higher by 0.15-0.25 eV, again consistent with DFT calculations. DFT calculations predict positive values of ΔE(S1-T1) for all compounds i.e. in the range of 0.18 eV to 0.43 eV for 1, 3 and 4 and a significantly lower value for 2 (0.06 eV), indicating a possible RISC process in this case. DFT calculations of ΔE(S1-T2) lead to negative and very small values for 2-4 implying a possible involvement of higher lying triplets in the generation of singlet excitons. The investigated derivatives exhibited fluorescence in the orange-red spectral range (550-770 nm) and were strongly dependent on the solvent polarity. The highest PLQY value of 37% was measured for 1 in toluene. The PLQY values significantly improved upon deoxygenation of the studied solutions. Solid state samples also exhibited higher PLQY values as compared to those determined for DCM solutions. These findings were rationalized by partial suppression of the vibrationally induced emission quenching in the solid state due to the intermolecular interaction confinement.
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Affiliation(s)
- Emilia Polesiak
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Malgorzata Makowska-Janusik
- Faculty of Science and Technology, Jan Dlugosz University, Al. Armii Krajowej 13/15, 42-200 Częstochowa, Poland
| | - Jakub Drapala
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Malgorzata Zagorska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Marzena Banasiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/44, 02-668, Warsaw, Poland
| | - Boleslaw Kozankiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/44, 02-668, Warsaw, Poland
| | - Irena Kulszewicz-Bajer
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
| | - Adam Pron
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
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Banerjee M, Anoop A. Exploring the Theoretical Foundations of Thermally Activated Delayed Fluorescence (TADF) Emission: A Comprehensive TD-DFT Study on Phenothiazine Systems. Chemistry 2024; 30:e202304206. [PMID: 38319588 DOI: 10.1002/chem.202304206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/28/2024] [Accepted: 02/06/2024] [Indexed: 02/07/2024]
Abstract
This study conducts a thorough theoretical investigation of Thermally Activated Delayed Fluorescence (TADF) in phenothiazine-based systems, examining ten molecular configurations recognized experimentally as TADF-active. Employing Time-Dependent Density Functional Theory (TD-DFT), our analysis spans the investigation of singlet-triplet energy gaps (ΔEST), spin-orbit coupling, and excitation characteristics using Multiwfn. This approach not only validates the adherence to El Sayed's rule across these systems but also provides a detailed understanding of charge transfer dynamics, as visualized through heat maps. A significant aspect of our study is the exploration of different oxidation states of sulfur and site substitutions on phenothiazine. This systematic variation aims to identify additional TADF-active compounds, drawing parallels with properties characterizing other known TADF emitters. Our investigation into Reverse Intersystem Crossing (rISC) rates and the analysis of dihedral angles in relation to ΔEST values offer nuanced insights into the TADF behaviours of these molecules. By integrating rigorous computational analysis with practical implications, we provide a foundational understanding that enhances the design and optimization of phenothiazine-based materials for optoelectronic applications. This work not only advances our theoretical understanding of TADF in phenothiazine derivatives but also serves as a guide for experimentalists and industry professionals in the strategic design of new TADF materials.
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Affiliation(s)
- Moumita Banerjee
- Department of Chemistry, Indian Institute of Technology Kharagpur, West Bengal, 721302, India
| | - Anakuthil Anoop
- Department of Chemistry, Indian Institute of Technology Kharagpur, West Bengal, 721302, India
- School of Digital Sciences, Kerala University of Digital Sciences, Innovation and Technology, Thiruvananthapuram, Kerala, 695317, India
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Liu Z, Chen J, Chen L, Liu H, Yang D, Ma D, Tang BZ, Zhao Z. Simultaneously Realizing High Efficiency and High Color Rendering Index for Hybrid White Organic Light-Emitting Diodes by Ultra-Thin Design of Delayed Fluorescence Sensitized Phosphorescent Layers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2305589. [PMID: 37828633 DOI: 10.1002/smll.202305589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/25/2023] [Indexed: 10/14/2023]
Abstract
In consideration of energy economization and light quality, concurrently attaining high external quantum efficiency (ηext ) and high color rendering index (CRI) is of high significance for the commercialization of hybrid white organic light-emitting diodes (WOLEDs) but is challenging. Herein, a blue luminescent molecule (2PCz-XT) consisting of a xanthone acceptor and two 3,6-diphenylcarbazole donors is prepared, which exhibits strong delayed fluorescence, short delayed fluorescence lifetime, and excellent electroluminescence property, and can sensitize green, orange, and red phosphorescent emitters efficiently. By employing 2PCz-XT as sensitizer and phosphorescent emitters as dopants, efficient two-color and three-color WOLED architectures with ultra-thin phosphorescent emitting layers (EMLs) are proposed and constructed. By incorporating a thin interlayer to modulate exciton recombination zone and reduce exciton loss, high-performance three-color hybrid WOLEDs are finally achieved, providing a high ηext of 26.8% and a high CRI value 83 simultaneously. Further configuration optimization realizes a long device operational lifetime. These WOLEDs with ultra-thin phosphorescent EMLs are among the state-of-the-art hybrid WOLEDs in the literature, demonstrating the success and applicability of the proposed device design for developing robust hybrid WOLEDs with superb efficiency and color quality.
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Affiliation(s)
- Zhangshan Liu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Jinke Chen
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Letian Chen
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Hao Liu
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Dezhi Yang
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
| | - Ben Zhong Tang
- School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
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6
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Zhao S, Yang Z, Zhang X, Liu H, Lv Y, Wang S, Yang Z, Zhang ST, Yang B. A functional unit combination strategy for enhancing red room-temperature phosphorescence. Chem Sci 2023; 14:9733-9743. [PMID: 37736641 PMCID: PMC10510757 DOI: 10.1039/d3sc03668e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 08/21/2023] [Indexed: 09/23/2023] Open
Abstract
Red room-temperature phosphorescence (RTP) materials based on non-metallic organic compounds are less reported compared to the commonly found green RTP materials. Here, we propose a novel approach to obtain red RTP materials by integrating and combining two functional units, resembling a jigsaw puzzle. In this approach, benzo[c][2,1,3]thiadiazole (BZT) serves as the red RTP unit, while a folding unit containing sulphur/oxygen is responsible for enhancing spin-orbit coupling (SOC) to accelerate the intersystem crossing (ISC) process. Three new molecules (SS-BZT, SO-BZT, and OO-BZT) were designed and synthesized, among which SS-BZT and SO-BZT with folded geometries demonstrate enhanced red RTP in their monodisperse films compared to the parent BZT. Meanwhile, the SS-BZT film shows a dual emission consisting of blue fluorescence and red RTP, with a significant spectral separation of approximately 150 nm, which makes the SS-BZT film highly suitable for applications in optical oxygen sensing and ratiometric detection. Within the oxygen concentration range of 0-1.31%, the SS-BZT film demonstrates a quenching constant of 2.66 kPa-1 and a quenching efficiency of 94.24%, indicating that this probe has the potential to accurately detect oxygen in a hypoxic environment.
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Affiliation(s)
- Shuaiqiang Zhao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 China
| | - Zhiqiang Yang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 China
| | - Xiangyu Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 China
| | - Haichao Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 China
| | - Yingbo Lv
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 China
| | - Shiyin Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 China
| | - Zhongzhao Yang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 China
| | - Shi-Tong Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 China
| | - Bing Yang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun 130012 China
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De R, Sharma S, Sengupta S, Kumar Pal S. Discs to a 'Bright' Future: Exploring Discotic Liquid Crystals in Organic Light Emitting Diodes in the Era of New-Age Smart Materials. CHEM REC 2022; 22:e202200056. [PMID: 35594033 DOI: 10.1002/tcr.202200056] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/29/2022] [Indexed: 11/09/2022]
Abstract
With the advent of a new decade and the paradigm shift of every sphere of urban life to virtual platforms, it has become imperative for the global researcher community to channelize efforts into upgradation of the existing display-technology. In this context, discotic liquid crystals (DLCs) are a class of self-assembling organic materials that are recently being explored in fabricating the emissive layers of organic light emitting diodes (OLEDs). With their unique inherent structural and functional properties, they have the potential to challenge the currently prevailing OLED-emitters. Yet the applications of this promising class of materials in OLEDs have not been comprehensively reviewed in literature till now. In this account, we present an overview of the developments in the field of luminescent DLC-based emitters, supported by their associated photophysical phenomena and their performance parameters as emitters in fabricated OLED devices.
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Affiliation(s)
- Ritobrata De
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), 140306, Mohali, Punjab, India
| | - Sushil Sharma
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), 140306, Mohali, Punjab, India
| | - Sanchita Sengupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), 140306, Mohali, Punjab, India
| | - Santanu Kumar Pal
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), 140306, Mohali, Punjab, India
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Sudyoadsuk T, Funchien P, Petdee S, Loythaworn T, Chasing P, Waengdongbung W, Saenubol A, Hadsadee S, Jungsuttiwong S, Promarak V. Benzothiadiazole-based fluorophores as efficient non-doped emitters for solution-processed organic light-emitting diodes. NEW J CHEM 2022. [DOI: 10.1039/d2nj04354h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
New HLCT fluorophores are synthesized and successfully applied as non-doped emissive layers in solution-processed double-layered OLEDs. These devices exhibit intense yellow-green emission colors with superior performance.
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Affiliation(s)
- Taweesak Sudyoadsuk
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Patteera Funchien
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Sujinda Petdee
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Thidarat Loythaworn
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Pongsakorn Chasing
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Wijitra Waengdongbung
- Research Network of NANOTEC-VISTEC on Nanotechnology for Energy, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Atthapon Saenubol
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Sarinya Hadsadee
- Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Warinchumrap, Ubon Ratchathani 34190, Thailand
| | - Siriporn Jungsuttiwong
- Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Warinchumrap, Ubon Ratchathani 34190, Thailand
| | - Vinich Promarak
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
- Research Network of NANOTEC-VISTEC on Nanotechnology for Energy, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
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Jiang YY, Zhang K, Zhou MS, Gao PF, Fu HR. A fluorescence/phosphorescence dual-emitting metal-organic framework exhibiting two approaches for single-phase white-light emission. J SOLID STATE CHEM 2021. [DOI: 10.1016/j.jssc.2021.122563] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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10
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Zhang Y, Wu C, Zhu M, Miao J. High Performance Near-Infrared Emitters with Methylated Triphenylamine and Thiadiazolo[3,4-g]quinoxaline-Based Fluorophores. Molecules 2021; 26:6386. [PMID: 34770795 PMCID: PMC8588353 DOI: 10.3390/molecules26216386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022] Open
Abstract
Three near-infrared emitters (2TPA-QBT, 2MeTPA-BT and TPA-QBT-MeTPA) were rationally designed and synthesized. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations showed that the introduction of mono- or di-methyl groups between the donors and acceptor could result in the spatial configuration changing greatly for 2MeTPA-QBT and TPA-QBT-MeTPA compared to their parent compound 2TPA-QBT. The emission of TPA-QBT-MeTPA had a more obvious hybridized local and charge transfer feature (HLCT) based on the influence of the steric hindrance of the methyl substituent. Attributed to their different spatial configurations and luminescence mechanisms, different emission wavelengths with photoluminescent quantum yields of 26%, 38% and 34% in toluene, as well as 24%, 27% and 31% in 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) doped film, were observed for 2TPA-QBT, 2MeTPA-QBT and TPA-QBT-MeTPA, respectively. The constructed organic light-emitting devices (OLEDs) displayed electroluminescence with emission peaks at 728, 693 and 710 nm, with maximum external quantum efficiencies of 1.58%, 1.33% and 3.02% for the 2TPA-QBT, 2MeTPA-QBT and TPA-QBT-MeTPA-doped OLEDs, respectively. This work illustrated the effect of spatial configuration changes on the luminescence properties of donor-acceptor-type organic emitters.
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Affiliation(s)
| | | | | | - Jingsheng Miao
- Shenzhen Key Laboratory of Polymer Science and Technology, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China; (Y.Z.); (C.W.); (M.Z.)
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Ajantha J, Yuvaraj P, Karuppusamy M, Easwaramoorthi S. Single-Molecule White-Light-Emitting Starburst Donor-Acceptor Triphenylamine Derivatives and Their Application as Ratiometric Luminescent Molecular Thermometers. Chemistry 2021; 27:11319-11325. [PMID: 34043253 DOI: 10.1002/chem.202100748] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Indexed: 01/07/2023]
Abstract
White-light emission (WLE) from a single molecule is a highly desirable alternative to a complex mixture of complementary colour emitters, which suffers from poor stability and reproducibility for potential use in organic electronic devices and lighting applications. We report single-molecule WLE both in solution and thin films by judiciously controlled π-electron delocalisation between the triarylamine subchromophoric units. Triphenylamine (TPA) forms the central core, and the phenyl rings are substituted with the electron-deficient acceptor 3-ethylrhodanine (Rh) and electron-rich donors triphenylamine or carbazole. The enforced biphenyl configuration of the TPA core and the other donors renders the π-conjugation across the entire chromophore poor, thus the individual subchromophoric units retain their individual emission characteristics, which cover all three primary colour emissions, that is, red, green and blue (RGB). TPA-Rh units exhibit broad fluorescence in the green-red region originating from the local excited (LE) state and intramolecular charge transfer state (ICT), strongly influenced by the solvent, water, and temperature. Different fluorescence parameters, including spectral maxima, ratiometric changes in ICT emission at the expense of blue emission from terminal donor units, and changes in lifetime, have a linear relationship with temperature between 180-330 K, thus the molecules can function as a multiparameter luminescent molecular thermometer. A temperature coefficient of 0.19 K-1 in ratiometric fluorescence changes along with a spectral shift of 0.3 nm K-1 and their workability over the wide temperature makes these molecules promising materials for potential applications. At lower temperatures, individual subchromophoric properties subside because of the reduced dihedral angle of biphenyl, and fluorescence from the whole molecule becomes dominant.
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Affiliation(s)
- Joseph Ajantha
- Inorganic & Physical Chemistry Laboratory, CSIR-Central Leather Research Institute Adyar, Chennai, 600020, India
- University of Madras, Chepauk, Chennai, 600005, India
| | - Palani Yuvaraj
- Inorganic & Physical Chemistry Laboratory, CSIR-Central Leather Research Institute Adyar, Chennai, 600020, India
- University of Madras, Chepauk, Chennai, 600005, India
| | - Masiyappan Karuppusamy
- Inorganic & Physical Chemistry Laboratory, CSIR-Central Leather Research Institute Adyar, Chennai, 600020, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-CLRI Campus, Chennai, 600020, India
| | - Shanmugam Easwaramoorthi
- Inorganic & Physical Chemistry Laboratory, CSIR-Central Leather Research Institute Adyar, Chennai, 600020, India
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Liu T, Chen X, Zhao J, Wei W, Mao Z, Wu W, Jiao S, Liu Y, Yang Z, Chi Z. Hybridized local and charge-transfer excited state fluorophores enabling organic light-emitting diodes with record high efficiencies close to 20. Chem Sci 2021; 12:5171-5176. [PMID: 34163754 PMCID: PMC8179597 DOI: 10.1039/d1sc00272d] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Pure organic emitters with full utilization of triplet excitons are in high demand for organic light-emitting diodes (OLEDs). Herein, through modulation of electron donors and introduction of phenyl rings as π spacers, we present three pure organic fluorophores (BCz, BTCz and BPTCz) with the hybridized local and charge-transfer (HLCT) excited state feature for OLED fabrication. Importantly, the introduction of π spacers in BPTCz not only enhances locally excited character with a fast radiative decay but also promotes intermolecular interactions to suppress non-radiative decays, contributing to a high solid-state fluorescence efficiency over 90%. Significantly, BPTCz not only endows its doped OLEDs with an external quantum efficiency (EQE) up to 19.5%, but also its non-doped OLED with a high EQE of 17.8%, and these outstanding efficiencies are the state-of-the-art performances of HLCT-based OLEDs. Three purely organic fluorophores with a hybridized local and charge-transfer excited state feature are presented and enabled organic light-emitting diodes with record high external quantum efficiencies close to 20%.![]()
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Affiliation(s)
- Tiantian Liu
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology, Research Center for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of OEMT, School of Chemistry, Sun Yat-sen University Guangzhou 510275 China
| | - Xiaojie Chen
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology, Research Center for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of OEMT, School of Chemistry, Sun Yat-sen University Guangzhou 510275 China
| | - Juan Zhao
- State Key Laboratory of OEMT, School of Materials Science and Engineering, Sun Yat-sen University Guangzhou 510275 China
| | - Weichun Wei
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology, Research Center for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of OEMT, School of Chemistry, Sun Yat-sen University Guangzhou 510275 China
| | - Zhu Mao
- Shenzhen Institute of Advanced Electronic Materials, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences Shenzhen 518055 China
| | - William Wu
- R&D Center, Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd Shenzhen 518132 China
| | - Shibo Jiao
- R&D Center, Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd Shenzhen 518132 China
| | - Yang Liu
- R&D Center, Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd Shenzhen 518132 China
| | - Zhiyong Yang
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology, Research Center for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of OEMT, School of Chemistry, Sun Yat-sen University Guangzhou 510275 China
| | - Zhenguo Chi
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology, Research Center for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of OEMT, School of Chemistry, Sun Yat-sen University Guangzhou 510275 China .,State Key Laboratory of OEMT, School of Materials Science and Engineering, Sun Yat-sen University Guangzhou 510275 China
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Zhang Y, Song J, Qu J, Qian PC, Wong WY. Recent progress of electronic materials based on 2,1,3-benzothiadiazole and its derivatives: synthesis and their application in organic light-emitting diodes. Sci China Chem 2020. [DOI: 10.1007/s11426-020-9901-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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14
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Zhang Y, Li J, Quan Y, Ye S, Cheng Y. Solution-Processed White Circularly Polarized Organic Light-Emitting Diodes Based on Chiral Binaphthyl Emitters. Chemistry 2020; 27:589-593. [PMID: 32881099 DOI: 10.1002/chem.202003721] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/01/2020] [Indexed: 11/08/2022]
Abstract
By combining the blue and orange CPL or functionalized bis-benzoxanethones emitters (S-/R-BN-tCz and S-/R-BN-PXZ), warm white CP-OLEDs were fabricated using solution-processed single emitting layer strategy. The successful realization of white CP-EL benefited from the same stable binaphthyl chirality and similar rigid structure of the two emissive CPL emitters. The devices exhibited the low turn-on voltage of ≈4.3 V, maximum luminance of ≈10200 cd m-2 and maximum current efficiency of ≈2.0 cd A-1 . Most significantly, the devices with CIE coordinates of (0.32, 0.45) displayed intense CP-EL signals in the spectral range of 450 to 650 nm, and showed stable gEL values of ≈10-3 as the luminance increased from 100 to 6000 cd m-2 . To the best of our knowledge, this work provides for the first time a simple and feasible strategy to fabricate solution-processed white CP-OLEDs based on the co-doping of the CPL emitters.
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Affiliation(s)
- Yu Zhang
- Key Laboratory of High Performance Polymer Materials and Technology, of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China.,Key Lab of Mesoscopic Chemistry of MOE and Jiangsu Key Laboratory, of Advanced Organic Materials, School of Chemistry and Chemical, Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Jie Li
- Key Laboratory of High Performance Polymer Materials and Technology, of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China.,Key Lab of Mesoscopic Chemistry of MOE and Jiangsu Key Laboratory, of Advanced Organic Materials, School of Chemistry and Chemical, Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Yiwu Quan
- Key Laboratory of High Performance Polymer Materials and Technology, of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China.,Key Lab of Mesoscopic Chemistry of MOE and Jiangsu Key Laboratory, of Advanced Organic Materials, School of Chemistry and Chemical, Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Shanghui Ye
- Key Laboratory of High Performance Polymer Materials and Technology, of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China.,Key Lab of Mesoscopic Chemistry of MOE and Jiangsu Key Laboratory, of Advanced Organic Materials, School of Chemistry and Chemical, Engineering, Nanjing University, Nanjing, 210023, P. R. China.,Key Laboratory for Organic Electronics & Information Displays, (KLOEID), Institute of Advanced Materials, National Synergistic Innovation, Center, for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, Nanjing, 210023, P. R. China
| | - Yixiang Cheng
- Key Laboratory of High Performance Polymer Materials and Technology, of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China.,Key Lab of Mesoscopic Chemistry of MOE and Jiangsu Key Laboratory, of Advanced Organic Materials, School of Chemistry and Chemical, Engineering, Nanjing University, Nanjing, 210023, P. R. China
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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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Lee HY, Yen SW, Lee CT. Polymer hybrid white quantum dots light-emitting diodes with a nanostructured electron injection layer. OPTICS EXPRESS 2020; 28:17299-17306. [PMID: 32679940 DOI: 10.1364/oe.392915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
In this study, poly(N-vinylcarbazole) (PVK) polymer was blended with various dimensional CdSe/ZnS core-shell quantum dots to be used as a single emissive layer of white quantum dots light-emitting diodes (WQLEDs). Besides, the nanostructured ITO/ZnO nanorod array was used as electron transport/injection layer to shorten carrier transport distance, accelerate carrier transport velocity, and enhance carrier transport surface area. Consequently, luminance and luminous efficiency were increased by the resulting increase of the carrier injection current density and the hole-electron recombination opportunity. The CIE of (0.329, 0.331) was obtained for the WQLEDs by using the weight ratio of 1.5:1.3:2.2 of the red, green, and blue (RGB) quantum dots. Compared with the WQLEDs without the nanorod array, the WQLEDs with the 1.5-µm-periodic ITO/ZnO nanorod array obtained an increased luminance of 16333 cd/m2 (compared with 7191 cd/m2) and an increased luminous efficiency of 3.13 cd/A (compared with 2.30 cd/A).
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Liu Y, Liu H, Bai Q, Du C, Shang A, Jiang D, Tang X, Lu P. Pyrene[4,5- d]imidazole-Based Derivatives with Hybridized Local and Charge-Transfer State for Highly Efficient Blue and White Organic Light-Emitting Diodes with Low Efficiency Roll-Off. ACS APPLIED MATERIALS & INTERFACES 2020; 12:16715-16725. [PMID: 32180398 DOI: 10.1021/acsami.0c01846] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A family of pyrene[4,5-d]imidazole derivatives, PyPA, PyPPA, PyPPAC, and PyPAC, with different excited states are successfully developed. Among them, PyPPA and PyPPAC possess hybridized local and charge-transfer (HLCT) state, endowing them with pure blue fluorescence as well as high quantum yields. The nondoped organic light-emitting diode (OLED) based on PyPPA displays Commission Internationale de L'Eclairage coordinates of (0.14, 0.13) and achieves a maximum external quantum efficiency (EQE) of 8.47%, which are among the highest value reported to date for nondoped blue HLCT OLEDs. The nondoped OLED based on PyPPAC exhibits a maximum luminance of 50,046 cd m-2 located in the blue region with CIE coordinates of (0.15, 0.21) and an EQE of 6.74% even when the luminance reached over 10,000 cd m-2. In addition, they both reveal ultimate exciton utilizing efficiencies of nearly 100%. The potential of a blue emitter of PyPPA with an HLCT character for application in white OLED (WOLED) is further tested. The efficient two-color hybrid warm WOLED is successfully achieved, which provides the total EQE, power efficiency, and current efficiency of up to 21.19%, 61.46 lm W-1, and 62.13 cd A-1, respectively. The nondoped blue OLEDs and hybrid WOLEDs present good color stabilities with low efficiency roll-offs. Our results prove that taking advantage of the HLCT state, nondoped blue OLEDs as well as hybrid WOLEDs with high performance could be realized, which have a promising prospect for the displays and lightings in the future.
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Affiliation(s)
- Yulong Liu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
- Department of Applied Chemistry, Northeast Agricultural University, Harbin 150030, China
| | - Hui Liu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Qing Bai
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Chunya Du
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Anqi Shang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Dongyan Jiang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Xiangyang Tang
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
| | - Ping Lu
- State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, Changchun 130012, China
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