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Kwon NY, Kwak H, Kim HY, Park SH, Park JY, Kang MJ, Koh CW, Park S, Cho MJ, Choi DH. Effect of intramolecular energy transfer in a dual-functional molecular dyad on the performance of solution-processed TADF OLEDs. Chem Sci 2024; 15:12361-12368. [PMID: 39118616 PMCID: PMC11304526 DOI: 10.1039/d4sc02357a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 07/04/2024] [Indexed: 08/10/2024] Open
Abstract
This paper introduces the design concept of a dual-functional molecular dyad tailored specifically for solution-processable organic light-emitting diodes (OLEDs). Cy-tmCPBN, characterized by an asymmetric molecular dyad structure, integrates a host unit (tmCP) and a multiple-resonance (MR) emitter (CzBN) via a non-conjugated cyclohexane linker. Cy-tmCPBN exhibited efficient intramolecular energy transfers (EnTs) from tmCP to the CzBN unit, as confirmed by time-resolved fluorescence experiments. The fluorescence lifetime of the tmCP unit was approximately three times shorter in a highly diluted solution of Cy-tmCPBN than in a mixed solution of Cy-tmCP and Cy-CzBN. In addition, Cy-tmCPBN exhibited excellent solubility and film-forming ability, making it suitable for solution processing. Notably, OLEDs utilizing Cy-tmCPBN achieved over twice the brightness and improved external quantum efficiency of 12.3% compared to OLEDs using Cy-CzBN with the same concentration of CzBN in the emitting layer. The improved OLED performance can be explained by the increased EnT efficiency from Cy-tmCP to Cy-tmCPBN and the intramolecular EnT within Cy-tmCPBN. In our dual-functional dyad, incorporating both host and emitter units in an asymmetric molecular dyad structure, we induced a positive synergy effect with the host moiety, enhancing OLED performance through intramolecular EnT.
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Affiliation(s)
- Na Yeon Kwon
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
| | - Haeun Kwak
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
| | - Ha Yeon Kim
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
| | - Su Hong Park
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
| | - Jin Young Park
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
| | - Min Ji Kang
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
| | - Chang Woo Koh
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
| | - Sungnam Park
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
| | - Min Ju Cho
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
| | - Dong Hoon Choi
- Department of Chemistry, Research Institute for Natural Sciences, Korea University 145 Anam-ro, Seongbuk-gu Seoul 02841 Republic of Korea
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Feng Y, Xu Y, Qu C, Wang Q, Ye K, Liu Y, Wang Y. Structurally Tunable Donor-Bridge-Fluorophore Architecture Enables Highly Efficient and Concentration-Independent Narrowband Electroluminescence. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2403061. [PMID: 38782371 DOI: 10.1002/adma.202403061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/05/2024] [Indexed: 05/25/2024]
Abstract
Luminescent materials with narrowband emission have extraordinary significance for developing ultrahigh-definition display. B-N-containing multiple resonance thermally activated delayed fluorescence (MR-TADF) materials are strong contenders. However, their device performances pervasively encounter detrimental aggregation-caused quenching effect that is highly vulnerable to doping concentration, complicating device fabrication. Therefore, constructing highly efficient and concentration-independent MR-TADF emitters is of pragmatic importance for improving device controllability and reproducibility, simplifying manufacturing procedures, and conserving production costs. Here, by systematic arrangement of donor triphenylamine and fluorophore BNCz on distinct bridges, a spatial confinement strategy has been developed with a donor-bridge-fluorophore architecture. Structurally fine modulation and progressive evolution to construct molecular entities with congested steric hindrance effect that can suppress intermolecular interactions without substantially affecting the luminescence tone of fluorophore BNCz, resulting in highly efficient and concentration-independent narrowband emitters; through isomer engineering, two isomers BN-PCz-TPA and TPA-PCz-BN with different crystal stacking patterns are synthesized by altering the connection mode between triphenylamine and BNCz. As a result, BN-PCz-TPA-based device showcases maximum external quantum efficiency (EQE) of 36.3% with narrow full-width at half-maximum of 27 nm at 10 wt% doping concentration. Even at 20 wt% doping concentration, the maximum EQE remains at 32.5% and the emission spectrum is almost unchanged.
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Affiliation(s)
- Yu Feng
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Yincai Xu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Cheng Qu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Qingyang Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Kaiqi Ye
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Yu Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Yue Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
- Jihua Laboratory, 28 Huandao South Road, Foshan, Guangdong Province, 528200, P. R. China
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3
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Yao Y, Pei M, Su C, Jin X, Qu Y, Song Z, Jiang W, Jian X, Hu F. A Small-Molecule Organic Cathode with Extended Conjugation toward Enhancing Na + Migration Kinetics for Advanced Sodium-Ion Batteries. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2401481. [PMID: 38616774 DOI: 10.1002/smll.202401481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 03/28/2024] [Indexed: 04/16/2024]
Abstract
Organic cathode materials show excellent prospects for sodium-ion batteries (SIBs) owing to their high theoretical capacity. However, the high solubility and low electrical conductivity of organic compounds result in inferior cycle stability and rate performance. Herein, an extended conjugated organic small molecule is reported that combines electroactive quinone with piperazine by the structural designability of organic materials, 2,3,7,8-tetraamino-5,10-dihydrophenazine-1,4,6,9-tetraone (TDT). Through intermolecular condensation reaction, many redox-active groups C═O and extended conjugated structures are introduced without sacrificing the specific capacity, which ensures the high capacity of the electrode and enhances rate performance. The abundant NH2 groups can form intermolecular hydrogen bonds with the C═O groups to enhance the intermolecular interactions, resulting in lower solubility and higher stability. The TDT cathode delivers a high initial capacity of 293 mAh g-1 at 500 mA g-1 and maintains 90 mAh g-1 at an extremely high current density of 70 A g-1. The TDT || Na-intercalated hard carbon (Na-HC) full cells provide an average capacity of 210 mAh g-1 during 100 cycles at 500 mA g-1 and deliver a capacity of 120 mAh g-1 at 8 A g-1.
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Affiliation(s)
- Yuxin Yao
- School of Materials Science and Engineering, State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province), Dalian University of Technology, Dalian, 116024, China
| | - Mengfai Pei
- School of Materials Science and Engineering, State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province), Dalian University of Technology, Dalian, 116024, China
| | - Chang Su
- School of Materials Science and Engineering, State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province), Dalian University of Technology, Dalian, 116024, China
| | - Xin Jin
- School of Materials Science and Engineering, State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province), Dalian University of Technology, Dalian, 116024, China
| | - Yunpeng Qu
- School of Materials Science and Engineering, State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province), Dalian University of Technology, Dalian, 116024, China
| | - Zihui Song
- School of Materials Science and Engineering, State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province), Dalian University of Technology, Dalian, 116024, China
| | - Wanyuan Jiang
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, School of Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province), Dalian University of Technology, Dalian, 116024, China
| | - Xigao Jian
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, School of Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province), Dalian University of Technology, Dalian, 116024, China
| | - Fangyuan Hu
- School of Materials Science and Engineering, State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province), Dalian University of Technology, Dalian, 116024, China
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Li MY, Wu H, Fan XC, Huang F, Yu J, Wang K, Zhang XH. Expanding Multiple-Resonance Structure of a Double-Borylated Skeleton by Fusing with Indolocarbazole a Multiple-Resonance Donor for Narrowband Green Emission. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2312098. [PMID: 38461523 DOI: 10.1002/smll.202312098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 03/01/2024] [Indexed: 03/12/2024]
Abstract
Double-borylated multiple-resonance (MR) skeletons are promising templates for high performance, while the chemical design space is relatively limited. Peripheral segments are often used to decorate/fuse MR skeletons and modulate the photophysics but they can also cause unwanted spectral broadening. Herein, a narrowband MR emitter ICzDBA by fusing an MR-featured donor segment indolocarbazole into a double-borylated MR skeleton is developed. In ICzDBA, the nitrogen atom located away from the core benzene ring can also contribute to the generation of the overall MR-featured distribution through the long-range conjugation effect, along with the other boron/nitrogen atoms on the phenyl center. Thus, ICzDBA in toluene displays a narrowband emission peaking at 507 nm with a full width at half maximum of merely 20 nm (0.09 eV). Moreover, organic light-emitting diode devices using ICzDBA emitter exhibit ultrapure green emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.27, 0.70) and a high external quantum efficiency of 32.5%. These results manifest the importance of MR characters of peripheral decorations/fusions in preserving the narrowband features of MR skeletons, which provides a solution for further expanding MR structures with well-maintained narrowband characters.
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Affiliation(s)
- Mo-Yuan Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Hao Wu
- Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Xiao-Chun Fan
- Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Feng Huang
- Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Jia Yu
- Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Kai Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Xiao-Hong Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu, 215123, P. R. China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
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5
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Zender E, Valverde D, Neubaur R, Karger S, Virovets A, Bolte M, Lerner HW, Olivier Y, Wagner M. Borylation and rearrangement reactions of azasilaanthracenes to afford B,N-doped nanographenes. Dalton Trans 2024; 53:9294-9300. [PMID: 38747255 DOI: 10.1039/d4dt01166j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
An air-stable B3,N3-containing dibenzobisanthene (8) was prepared in 29% yield by heating a 1,3,5-tri(azasilaanthryl)benzene (5) with BBr3 (180 °C). Under these conditions, the reaction does not stop after threefold SiMe2/BBr exchange but proceeds further via two rearrangement and two intramolecular C-H borylation steps. Some mechanistic details were unveiled by using smaller model systems and applying lower reaction temperatures. According to X-ray crystallography, compound 8 has a helically distorted scaffold. Due to its multiple resonance structure, it shows a narrow-band blue-green emission (λem = 493 nm; ΦPL = 84%; FWHM = 0.20 eV; THF); samples measured in PMMA gave prompt and delayed fluorescence lifetimes of 10.7 ns and 136 μs, respectively. The optical properties of 8 and of structurally related species were also investigated by quantum-chemical means: most of these compounds exhibit a small energy gap ΔEST between the lowest excited singlet (S1) and triplet (T1) states and a non-negligible spin-orbit coupling (SOC) between S1 and T1/T2, demonstrating their potential as thermally activated delayed fluorescence (TADF) emitters.
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Affiliation(s)
- Elena Zender
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany.
| | - Danillo Valverde
- Laboratory for Computational Modeling of Functional Materials, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium.
| | - Robert Neubaur
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany.
| | - Sebastian Karger
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany.
| | - Alexander Virovets
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany.
| | - Michael Bolte
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany.
| | - Hans-Wolfram Lerner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany.
| | - Yoann Olivier
- Laboratory for Computational Modeling of Functional Materials, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium.
| | - Matthias Wagner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany.
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6
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Ni F, Huang Y, Qiu L, Yang C. Synthetic progress of organic thermally activated delayed fluorescence emitters via C-H activation and functionalization. Chem Soc Rev 2024; 53:5904-5955. [PMID: 38717257 DOI: 10.1039/d3cs00871a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Thermally activated delayed fluorescence (TADF) emitters have become increasingly prominent due to their promising applications across various fields, prompting a continuous demand for developing reliable synthetic methods to access them. This review aims to highlight the progress made in the last decade in synthesizing organic TADF compounds through C-H bond activation and functionalization. The review begins with a brief introduction to the basic features and design principles of TADF emitters. It then provides an overview of the advantages and concise development of C-H bond transformations in constructing TADF emitters. Subsequently, it summarizes both transition-metal-catalyzed and non-transition-metal-promoted C-H bond transformations used for the synthesis of TADF emitters. Finally, the review gives an outlook on further challenges and potential directions in this field.
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Affiliation(s)
- Fan Ni
- National Engineering Lab of Special Display Technology, State Key Lab of Advanced Display Technology, Academy of Opto-Electronic Technology, Intelligent Interconnected Systems Laboratory of Anhui, Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronic Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China.
| | - Yipan Huang
- National Engineering Lab of Special Display Technology, State Key Lab of Advanced Display Technology, Academy of Opto-Electronic Technology, Intelligent Interconnected Systems Laboratory of Anhui, Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronic Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China.
| | - Longzhen Qiu
- National Engineering Lab of Special Display Technology, State Key Lab of Advanced Display Technology, Academy of Opto-Electronic Technology, Intelligent Interconnected Systems Laboratory of Anhui, Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronic Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China.
| | - Chuluo Yang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, Guangdong 518060, P. R. China.
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7
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Huang X, Liu J, Xu Y, Chen G, Huang M, Yu M, Lv X, Yin X, Zou Y, Miao J, Cao X, Yang C. B‒N covalent bond-involved π-extension of multiple resonance emitters enables high-performance narrowband electroluminescence. Natl Sci Rev 2024; 11:nwae115. [PMID: 38707202 PMCID: PMC11067958 DOI: 10.1093/nsr/nwae115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/12/2024] [Accepted: 03/15/2024] [Indexed: 05/07/2024] Open
Abstract
Multi-boron-embedded multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters show promise for achieving both high color-purity emission and high exciton utilization efficiency. However, their development is often impeded by a limited synthetic scope and excessive molecular weights, which challenge material acquisition and organic light-emitting diode (OLED) fabrication by vacuum deposition. Herein, we put forward a B‒N covalent bond-involved π-extension strategy via post-functionalization of MR frameworks, leading to the generation of high-order B/N-based motifs. The structurally and electronically extended π-system not only enhances molecular rigidity to narrow emission linewidth but also promotes reverse intersystem crossing to mitigate efficiency roll-off. As illustrated examples, ultra-narrowband sky-blue emitters (full-width at half-maximum as small as 8 nm in n-hexane) have been developed with multi-dimensional improvement in photophysical properties compared to their precursor emitters, which enables narrowband OLEDs with external quantum efficiencies (EQEmax) of up to 42.6%, in company with alleviated efficiency decline at high brightness, representing the best efficiency reported for single-host OLEDs. The success of these emitters highlights the effectiveness of our molecular design strategy for advanced MR-TADF emitters and confirms their extensive potential in high-performance optoelectronic devices.
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Affiliation(s)
- Xingyu Huang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Jiahui Liu
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Yulin Xu
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Guohao Chen
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Manli Huang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Mingxin Yu
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Xialei Lv
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Xiaojun Yin
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Yang Zou
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Jingsheng Miao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Xiaosong Cao
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
| | - Chuluo Yang
- Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
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8
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Cho HH, Congrave DG, Gillett AJ, Montanaro S, Francis HE, Riesgo-Gonzalez V, Ye J, Chowdury R, Zeng W, Etherington MK, Royakkers J, Millington O, Bond AD, Plasser F, Frost JM, Grey CP, Rao A, Friend RH, Greenham NC, Bronstein H. Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs. NATURE MATERIALS 2024; 23:519-526. [PMID: 38480865 PMCID: PMC10990937 DOI: 10.1038/s41563-024-01812-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 01/18/2024] [Indexed: 03/21/2024]
Abstract
Hyperfluorescence shows great promise for the next generation of commercially feasible blue organic light-emitting diodes, for which eliminating the Dexter transfer to terminal emitter triplet states is key to efficiency and stability. Current devices rely on high-gap matrices to prevent Dexter transfer, which unfortunately leads to overly complex devices from a fabrication standpoint. Here we introduce a molecular design where ultranarrowband blue emitters are covalently encapsulated by insulating alkylene straps. Organic light-emitting diodes with simple emissive layers consisting of pristine thermally activated delayed fluorescence hosts doped with encapsulated terminal emitters exhibit negligible external quantum efficiency drops compared with non-doped devices, enabling a maximum external quantum efficiency of 21.5%. To explain the high efficiency in the absence of high-gap matrices, we turn to transient absorption spectroscopy. It is directly observed that Dexter transfer from a pristine thermally activated delayed fluorescence sensitizer host can be substantially reduced by an encapsulated terminal emitter, opening the door to highly efficient 'matrix-free' blue hyperfluorescence.
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Affiliation(s)
- Hwan-Hee Cho
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Daniel G Congrave
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
| | | | - Stephanie Montanaro
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Haydn E Francis
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, UK
| | - Víctor Riesgo-Gonzalez
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, UK
| | - Junzhi Ye
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | | | - Weixuan Zeng
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Marc K Etherington
- Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Ellison Place, Newcastle upon Tyne, UK
| | - Jeroen Royakkers
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Oliver Millington
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Andrew D Bond
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Felix Plasser
- Department of Chemistry, Loughborough University, Loughborough, UK
| | | | - Clare P Grey
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, UK
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | | | - Neil C Greenham
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Hugo Bronstein
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
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9
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Zhao X, Liu H, Mu Q, Fan J, Xu Y, Cai L. Modulating excited state properties of thermally activated delayed fluorescence molecules by hybrid long-range and short-range charge transfer strategy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 308:123684. [PMID: 38039645 DOI: 10.1016/j.saa.2023.123684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/08/2023] [Accepted: 11/21/2023] [Indexed: 12/03/2023]
Abstract
Balancing the rapid radiative decay process and the fast reverse intersystem crossing (RISC) process of thermally activated delayed fluorescence (TADF) molecule remains a great challenge and efficient molecular design strategies are highly desired. Herein, from a theoretical perspective, excited state properties of three reported TADF molecules (1TICz, 1BOICz and 2BOICz) are investigated based on density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations coupled with the thermal vibration correlation function (TVCF) method. Results indicate that, by introducing the multi-resonance (MR) acceptor, 1BOICz possesses hybrid long-range and short-range charge transfer features, balanced small energy gap (ΔEST) and large oscillator strength (f) is obtained. Furthermore, by incorporating double equivalent MR acceptors in 2BOICz, largely enhanced f with slightly changed ΔEST is achieved, inner mechanism for remarkable photophysical property is illustrated. Keep this strategy, seven new TADF molecules (2pDBA-bICz-1, 2pDBA-bICz-2, 2OSBA-bICz, 2DQAO-bICz, 2QAO-bICz, 2SQAO-bICz and 2OQAO-bICz) are theoretically designed, detailed physical parameters are analyzed and excited state energy consumption process is studied. Strong electrophilicity on acceptor is determined and the strength of nucleophilic sites on the bridge-phenyl of 2DQAO-bICz, 2QAO-bICz, 2SQAO-bICz and 2OQAO-bICz is increased, this promotes the short-range charge transfer property. In addition, the excitation processes for all studied molecules are dominated by long-range charge transfer from donor to acceptors, and supplemented by the short-range charge transfer on the bridge-phenyl with MR effect. Compromise energy gap and oscillator strength as well as large spin orbit coupling (SOC) constant are obtained for designed molecules. Thus, by regulating the long-range and short-range charge transfer ratios, excited state properties are successfully modulated and new efficient TADF molecules are proposed. Our research aims to provide deeper insight into long-range and short-range charge transfer features in balancing small ΔEST and large f, which could facilitate the development of novel efficient TADF molecules.
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Affiliation(s)
- Xin Zhao
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Materials and Clean Energy, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Huanling Liu
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Materials and Clean Energy, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Qingfang Mu
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Materials and Clean Energy, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Jianzhong Fan
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Materials and Clean Energy, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China.
| | - Yuanyuan Xu
- School of Science, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Lei Cai
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Materials and Clean Energy, School of Physics and Electronics, Shandong Normal University, Jinan 250014, China.
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10
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Mamada M, Hayakawa M, Ochi J, Hatakeyama T. Organoboron-based multiple-resonance emitters: synthesis, structure-property correlations, and prospects. Chem Soc Rev 2024; 53:1624-1692. [PMID: 38168795 DOI: 10.1039/d3cs00837a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Boron-based multiple-resonance (MR) emitters exhibit the advantages of narrowband emission, high absolute photoluminescence quantum yield, thermally activated delayed fluorescence (TADF), and sufficient stability during the operation of organic light-emitting diodes (OLEDs). Thus, such MR emitters have been widely applied as blue emitters in triplet-triplet-annihilation-driven fluorescent devices used in smartphones and televisions. Moreover, they hold great promise as TADF or terminal emitters in TADF-assisted fluorescence or phosphor-sensitised fluorescent OLEDs. Herein we comprehensively review organoboron-based MR emitters based on their synthetic strategies, clarify structure-photophysical property correlations, and provide design guidelines and future development prospects.
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Affiliation(s)
- Masashi Mamada
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
| | - Masahiro Hayakawa
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
| | - Junki Ochi
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
| | - Takuji Hatakeyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
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11
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Zender E, Karger S, Neubaur R, Virovets A, Lerner HW, Wagner M. Green-Emitting Extended B 3,N 2-Doped Polycyclic Aromatic Hydrocarbon with Multiple Resonance Structure. Org Lett 2024; 26:939-944. [PMID: 38266241 DOI: 10.1021/acs.orglett.3c04283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
An air-stable B3,N2-PAH (B3N2; nine annulated six-membered rings) was synthesized from 1-X-2,6-di(azasilaanthryl)benzenes (X = Cl, I) via lithiation/borylation, electrophilic aromatic borylation, and Si/B exchange. The heteroatom distribution in B3N2 meets the requirements for multiple resonance thermally activated delayed fluorescence (MR-TADF). Indeed, B3N2 emits green light (λem = 523 nm; ΦPL = 85%; CHCl3) with a small fwhm of 0.15 eV. Lifetimes for prompt (7.8 ns) and delayed (60 μs) fluorescence were measured in PMMA.
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Affiliation(s)
- Elena Zender
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Sebastian Karger
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Robert Neubaur
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Alexander Virovets
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Hans-Wolfram Lerner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
| | - Matthias Wagner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt (Main), Germany
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12
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Meng G, Zhou J, Huang T, Dai H, Li X, Jia X, Wang L, Zhang D, Duan L. B-N/B-O Contained Heterocycles as Fusion Locker in Multi-Resonance Frameworks towards Highly-efficient and Stable Ultra-Narrowband Emission. Angew Chem Int Ed Engl 2023; 62:e202309923. [PMID: 37584379 DOI: 10.1002/anie.202309923] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 08/17/2023]
Abstract
Fusing condensed aromatics into multi-resonance (MR) frameworks has been an exquisite strategy to modulate the optoelectronic properties, which, however, always sacrifices the small full width at half maxima (FWHM). Herein, we strategically embed B-N/B-O contained heterocycles as fusion locker into classical MR prototypes, which could enlarge the π-extension and alleviate the steric repulsion for an enhanced planar skeleton to suppress the high-frequency stretching/ scissoring vibrations for ultra-narrowband emissions. Sky-blue emitters with extremely small FWHMs of 17-18 nm are thereafter obtained for the targeted emitters, decreased by (1.4-1.9)-fold compared with the prototypes. Benefiting from their high photoluminescence quantum yields of >90 % and fast radiative decay rates of >108 s-1 , one of those emitters shows a high maximum external quantum efficiency of 31.9 % in sensitized devices, which remains 25.8 % at a practical luminance of 1,000 cd m-2 with a small FWHM of merely 19 nm. Notably a long operation half-lifetime of 1,278 h is also recorded for the same device, representing one of the longest lifetimes among sky-blue devices based on MR emitters.
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Affiliation(s)
- Guoyun Meng
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Jianping Zhou
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Tianyu Huang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Hengyi Dai
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Xiao Li
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Xiaoqin Jia
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Lu Wang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Dongdong Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Lian Duan
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing, 100084, P. R. China
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13
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Wu Z, Zhang Q, Wang X, Zhang K, Li X, Li R, Song Y, Fan J, Wang CK, Lin L, Wang Z. Multi-resonance thermally activated delayed fluorescence molecules with intramolecular-lock: theoretical design and performance prediction. Phys Chem Chem Phys 2023; 25:24406-24416. [PMID: 37621260 DOI: 10.1039/d3cp02255b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
Multi-resonance thermally activated delayed fluorescence (MR-TADF) molecules with narrow full width at half maximum (FWHM) have attracted much attention recently. In this work, 36 borane/amine (B/N) type MR-TADF molecules were theoretically designed by using an intramolecular-lock strategy and systematically studied based on first-principles calculations. It was found that intramolecular-lock at different positions and in different manners could induce different luminescent properties. The calculated oscillator strengths for PXZ-L2 and PTZ-L2 locking systems are weaker than that for 2DPABN (without intramolecular-lock), while the Cz-L1 and TMCZ-L1 locking could result in stronger oscillator strength. Though the calculated FWHM of all the systems with intramolecular-lock is higher than that of 2DPABN, the Cz, TMCz and DMAC locking at L1 or L2 would induce relatively small FWHM which is comparable to that of 2DPABN. Our calculation results indicate that intramolecular-lock could enhance the SOC values and decrease the energy gap between the first singlet excited state and the first triplet excited state, which is quite favorable to reverse intersystem crossing. The Cz, TMCz and DMAC locking systems could realize comparable and higher efficiency than 2DPABN, thus higher quantum efficiency could be obtained. Our calculation results indicate that the intramolecular-lock strategy is an effective method to realize the design of highly efficient MR-TADF emitters.
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Affiliation(s)
- Zhimin Wu
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Qun Zhang
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Xiaofei Wang
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Kai Zhang
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Xiaofang Li
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Rui Li
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Yuzhi Song
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Jianzhong Fan
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Chuan-Kui Wang
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Lili Lin
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
| | - Zhongjie Wang
- Shandong Key Laboratory of Medical Physics and Image Processing & Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China.
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Park SW, Kim D, Rhee YM. Overcoming the Limitation of Spin Statistics in Organic Light Emitting Diodes (OLEDs): Hot Exciton Mechanism and Its Characterization. Int J Mol Sci 2023; 24:12362. [PMID: 37569740 PMCID: PMC10418923 DOI: 10.3390/ijms241512362] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
Triplet harvesting processes are essential for enhancing efficiencies of fluorescent organic light-emitting diodes. Besides more conventional thermally activated delayed fluorescence and triplet-triplet annihilation, the hot exciton mechanism has been recently noticed because it helps reduce the efficiency roll-off and improve device stability. Hot exciton materials enable the conversion of triplet excitons to singlet ones via reverse inter-system crossing from high-lying triplet states and thereby the depopulation of long-lived triplet excitons that are prone to chemical and/or efficiency degradation. Although their anti-Kasha characteristics have not been clearly explained, numerous molecules with behaviors assigned to the hot exciton mechanism have been reported. Indeed, the related developments appear to have just passed the stage of infancy now, and there will likely be more roles that computational elucidations can play. With this perspective in mind, we review some selected experimental studies on the mechanism and the related designs and then on computational studies. On the computational side, we examine what has been found and what is still missing with regard to properly understanding this interesting mechanism. We further discuss potential future points of computational interests toward aiming for eventually presenting in silico design guides.
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Affiliation(s)
- Soo Wan Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Dongwook Kim
- Department of Chemistry, Kyonggi University, Suwon 16227, Republic of Korea
| | - Young Min Rhee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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15
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Kim HS, Cheon HJ, Lee D, Lee W, Kim J, Kim YH, Yoo S. Toward highly efficient deep-blue OLEDs: Tailoring the multiresonance-induced TADF molecules for suppressed excimer formation and near-unity horizontal dipole ratio. SCIENCE ADVANCES 2023; 9:eadf1388. [PMID: 37256963 PMCID: PMC10413681 DOI: 10.1126/sciadv.adf1388] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 04/24/2023] [Indexed: 06/02/2023]
Abstract
Boron-based compounds exhibiting a multiresonance thermally activated delayed fluorescence are regarded promising as a narrowband blue emitter desired for efficient displays with wide color gamut. However, their planar nature makes them prone to concentration-induced excimer formation that broadens the emission spectrum, making it hard to increase the emitter concentration without raising CIE y coordinate. To overcome this bottleneck, we here propose o-Tol-ν-DABNA-Me, wherein sterically hindered peripheral phenyl groups are introduced to reduce intermolecular interactions, leading to excimer formation and thus making the pure narrowband emission character far less sensitive to concentration. With this approach, we demonstrate deep-blue OLEDs with y of 0.12 and full width at half maximum of 18 nm, with maximum external quantum efficiency (EQE) of ca. 33%. Adopting a hyperfluorescent architecture, the OLED performance is further enhanced to EQE of 35.4%, with mitigated efficiency roll-off, illustrating the immense potential of the proposed method for energy-efficient deep-blue OLEDs.
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Affiliation(s)
- Hyung Suk Kim
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Hyung Jin Cheon
- Department of Chemistry and RIGET, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Donggyun Lee
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Woochan Lee
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Junho Kim
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Yun-Hi Kim
- Department of Chemistry and RIGET, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Seunghyup Yoo
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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16
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Istiqomah IN, Jang JH, Lee T, Lee YH, Kim C, Jung J, Lee JH, Lee MH. Impact of π-Expanded Boron-Carbonyl Hybrid Acceptors on TADF Properties: Controlling Local Triplet Excited States and Unusual Emission Tuning. ACS APPLIED MATERIALS & INTERFACES 2023; 15:15758-15767. [PMID: 36930863 DOI: 10.1021/acsami.3c00047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Three donor-acceptor-type thermally activated delayed fluorescence (TADF) emitters (PXZBAO (1), PXZBTO (2), and PXZBPO (3)) comprising a phenoxazine (PXZ) donor and differently π-expanded boron-carbonyl (BCO) hybrid acceptor units are proposed. The emitters exhibit red (1) to orange (3) emissions with an increase in the π-expansion in the BCO acceptors. The control of the strength of local aromaticity for the BCO unit and the corresponding LUMO level is attributed to inducing the unusual emission color shifts. The photoluminescence quantum yield and delayed fluorescence lifetime of the emitters are also adjusted by the π-expansion. Notably, although 1 possesses a 3nπ* state in the acceptor unit as a local triplet excited state (3LE, T2), the T2 states of 2 and 3 mainly comprise a 3ππ* state in the acceptor. Consequently, all of the emitters exhibit strong spin-orbit coupling between their T2 and excited singlet (S1) states, leading to a fast reverse intersystem crossing with rate constants of ∼106 s-1. By employing the emitters as dopants, we realize efficient red-to-orange TADF-OLEDs. Maximum external quantum efficiencies of 17.7% for the yellowish-orange (3), 15.5% for the orange (2), and 13.9% for the red (1) devices are achieved, and the values are very close to the theoretical limit predicted from the optical simulation.
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Affiliation(s)
- Ina Nur Istiqomah
- Department of Chemistry, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Jee-Hun Jang
- Department of Materials Science and Engineering and 3D Convergence Center, Inha University, Incheon 22212, Republic of Korea
| | - Taehwan Lee
- Department of Chemistry, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Young Hoon Lee
- Department of Chemistry, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Chaerin Kim
- Department of Chemistry, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Jaehoon Jung
- Department of Chemistry, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Jeong-Hwan Lee
- Department of Materials Science and Engineering and 3D Convergence Center, Inha University, Incheon 22212, Republic of Korea
| | - Min Hyung Lee
- Department of Chemistry, University of Ulsan, Ulsan 44610, Republic of Korea
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Wang Z, Yan Z, Chen Q, Song X, Liang J, Ye K, Zhang Z, Bi H, Wang Y. Toward Narrowband and Efficient Blue Fluophosphors by Locking the Stretching Vibration of Indolocarbazole Skeletons. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 36890783 DOI: 10.1021/acsami.2c23278] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Developing efficient and color-saturated deep-blue emitting molecules with small Commission Internationale de L'Eclairage (CIE) y values is challenging and has great potential for wide-color gamut displays. Herein, we introduce an intramolecular locking strategy to restrain molecular stretching vibrations of the emission spectral broadening. By cyclizing rigid fluorenes and connecting electron-donating groups to the indolo[3,2,1-jk]-indolo[1',2',3':1,7]indolo[2,3-b]carbazole (DIDCz) framework, the in-plane swing of peripheral bonds and stretching vibrations of the indolocarbazole skeleton are restricted due to an increased steric hindrance from cyclized groups and diphenylamine auxochromophores. As a result, reorganization energies at the high-frequency region (1300-1800 cm-1) are reduced, realizing pure blue emission with a small full-width-at-half-maximum (FWHM) of 30 nm by suppressing shoulder peaks of polycyclic aromatic hydrocarbon (PAH) frameworks. The fabricated bottom-emitting organic light-emitting diode (OLED) exhibits an efficient external quantum efficiency (EQE) of 7.34% and deep-blue coordinates of (0.140, 0.105) at a high brightness of 1000 cd/m2. The FWHM of the electroluminescent spectrum is only 32 nm, which is one of the narrowest electroluminescent emissions among the reported intramolecular charge transfer fluophosphors. Our current findings provide a new molecular design strategy to conceive efficient and narrowband emitters with small reorganization energies.
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Affiliation(s)
| | - Zhiping Yan
- Ji Hua Laboratory, Foshan 528200, P. R. China
| | - Qishen Chen
- Ji Hua Laboratory, Foshan 528200, P. R. China
| | - Xiaoxian Song
- Ji Hua Laboratory, Foshan 528200, P. R. China
- Jihua Hengye Electronic Materials Co. Ltd., Foshan, Guangdong Province 528200, P. R. China
| | - Jie Liang
- Ji Hua Laboratory, Foshan 528200, P. R. China
| | - Kaiqi Ye
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Zuolun Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China
| | - Hai Bi
- Ji Hua Laboratory, Foshan 528200, P. R. China
- Jihua Hengye Electronic Materials Co. Ltd., Foshan, Guangdong Province 528200, P. R. China
| | - Yue Wang
- Ji Hua Laboratory, Foshan 528200, P. R. China
- Jihua Hengye Electronic Materials Co. Ltd., Foshan, Guangdong Province 528200, P. R. China
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18
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Zhang Y, Li Y, Quan Y, Ye S, Cheng Y. Remarkable White Circularly Polarized Electroluminescence Based on Chiral Co-assembled Helix Nanofiber Emitters. Angew Chem Int Ed Engl 2023; 62:e202214424. [PMID: 36331071 DOI: 10.1002/anie.202214424] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Indexed: 11/06/2022]
Abstract
White circularly polarized organic light-emitting diodes (CP-WOLEDs) are of great significance in potential lighting sources and full-color 3D displays. However, High-performance white CP-EL sources are almost unexplored. We have constructed full-color CP-EL devices based on chiral co-assemblies by using three achiral conjugated pyrene-based dyes (BP, w-WP and c-WP) doped with chiral binaphthyl-based enantiomers (S-/R-M) as the EMLs through an intermolecular chirality induction mechanism. (S-/R-M)0.2 -(c-WP)0.8 films exhibit regular helix nanofibers under annealing treatment and emit strong white CPL. Significantly, remarkable CP-WOLEDs based on (S-/R-M)0.2 -(c-WP)0.8 were achieved with |gEL | values as high as 6.2×10-2 and an excellent CRI of 98 at the CIE coordinates of (0.33, 0.33). These are the highest gEL and CRI values of reported CP-WOLEDs to date. This is the first achievement of CP-WOLEDs based on chiral co-assembled helix nanofiber emitters, and provides a valuable strategy with which to develop white CP-EL for future practical applications.
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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, 210023, Nanjing, China
| | - Yupeng Li
- Key Laboratory for Organic Electronics & Information Displays (KLOEID) and Institute of Advanced Materials, National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 210023, Nanjing, China
| | - Yiwu Quan
- Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, 210023, Nanjing, China
| | - Shanghui Ye
- Key Laboratory for Organic Electronics & Information Displays (KLOEID) and Institute of Advanced Materials, National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, 210023, Nanjing, China
| | - Yixiang Cheng
- Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, 210023, Nanjing, China
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19
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Lian M, Ye Z, Mu Y, Hu D, Liu Y, Zhang H, Ji S, Huo Y. Progress on Blue-Emitting Hot Exciton Materials. CHINESE J ORG CHEM 2023. [DOI: 10.6023/cjoc202207042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
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Cheon HJ, Woo SJ, Baek SH, Lee JH, Kim YH. Dense Local Triplet States and Steric Shielding of a Multi-Resonance TADF Emitter Enable High-Performance Deep-Blue OLEDs. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2207416. [PMID: 36222388 DOI: 10.1002/adma.202207416] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/26/2022] [Indexed: 05/12/2023]
Abstract
Multi-resonance thermally activated delayed fluorescence (MR-TADF) molecules based on boron and nitrogen atoms are emerging as next-generation blue emitters for organic light-emitting diodes (OLEDs) due to their narrow emission spectra and triplet harvesting properties. However, intermolecular aggregation stemming from the planar structure of typical MR-TADF molecules that leads to concentration quenching and broadened spectra limits the utilization of the full potential of MR-TADF emitters. Herein, a deep-blue MR-TADF emitter, pBP-DABNA-Me, is developed to suppress intermolecular interactions effectively. Furthermore, photophysical investigation and theoretical calculations reveal that adding biphenyl moieties to the core body creates dense local triplet states in the vicinity of S1 and T1 energetically, letting the emitter harvest excitons efficiently. OLEDs based on pBP-DABNA-Me show a high external quantum efficiency (EQE) of 23.4% and a pure-blue emission with a Commission Internationale de L'Eclairage (CIE) coordinate of (0.132, 0.092), which are maintained even at a high doping concentration of 100 wt%. Furthermore, by incorporating a conventional TADF sensitizer, deep-blue OLEDs with a CIE value of (0.133, 0.109) and an extremely high EQE of 30.1% are realized. These findings provide insight into design strategies for developing efficient deep-blue MR-TADF emitters with fast triplet upconversion and suppressed self-aggregation.
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Affiliation(s)
- Hyung-Jin Cheon
- Department of Chemistry and RINS, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Seung-Je Woo
- Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul, 08826, Republic of Korea
| | - Seung-Hyun Baek
- Department of Materials Science and Engineering, Inha University, Incheon, 22212, Republic of Korea
| | - Jeong-Hwan Lee
- Department of Materials Science and Engineering, Inha University, Incheon, 22212, Republic of Korea
- 3D Convergence Center, Inha University, Incheon, 22212, Republic of Korea
| | - Yun-Hi Kim
- Department of Chemistry and RINS, Gyeongsang National University, Jinju, 52828, Republic of Korea
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Lee H, Braveenth R, Park JD, Jeon CY, Lee HS, Kwon JH. Manipulating Spectral Width and Emission Wavelength towards Highly Efficient Blue Asymmetric Carbazole Fused Multi-Resonance Emitters. ACS APPLIED MATERIALS & INTERFACES 2022; 14:36927-36935. [PMID: 35920715 DOI: 10.1021/acsami.2c10127] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The novel carbazole-based multiresonance types of thermally activated delayed fluorescence (MR-TADF) emitters of mICz-DABNA and BFCz-DABNA are reported, and their spectroscopic properties are investigated with the inductive effect on the central nitrogen atom for pure and deep blue emission. With the introduction of electron-donating/-withdrawing properties of substituents, emitters exhibited the bathochromic/hypsochromic shifted emission, respectively, compared to simple carbazole-based MR-TADF. Moreover, their spectral bandwidths became narrower. Theoretical calculation indicated that the meta-positioned bulky moiety restricts the molecular geometry discrepancy and reduces the Huang-Rhys factors. Particularly, the organic light-emitting diode (OLED) with 3% BFCz-DABNA exhibited the maximum external quantum efficiency of 28.0% with the Commission International de l'Éclairage (CIE) of (0.13, 0.09), which is the best record value among single-boron MR-TADF devices of CIE y < 0.10.
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Affiliation(s)
- Hyuna Lee
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Ramanaskanda Braveenth
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Jae Do Park
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Chae Yeon Jeon
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Hyun Seung Lee
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Jang Hyuk Kwon
- Organic Optoelectronic Device Lab (OODL), Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
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