1
|
Sanyam, Sorout P, Mondal A. Rational Design of Organic Emitters with Inverted Singlet-Triplet Gaps for Enhanced Exciton Management. J Phys Chem A 2024; 128:7114-7123. [PMID: 39159396 DOI: 10.1021/acs.jpca.4c03443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/21/2024]
Abstract
In organic light-emitting diodes (OLEDs), the pursuit of efficient molecular emitters has led to the development of thermally activated delayed fluorescence (TADF) molecules. While TADF compounds have promising properties, they face challenges such as energy gap constraints and uphill exciton transfer. Inverted emitters (INVEST) offer a novel solution with an inverted singlet-triplet energy (ΔEST) gap, enabling efficient utilization of excitons. This study examines the design and computational analysis of an array of molecules, including 23 INVEST emitters and remaining with positive energy gaps. Within the STEOM-DLPNO-CCSD framework, we explore the role of various molecular fragments in determining ΔEST. We also assess the importance of dynamic spin-polarization (DSP) obtained via the Pariser-Parr-Pople (PPP) scheme in energy gap determination. Exciting trends emerged from our results, with pentalene-containing compounds consistently manifesting negative ΔEST values while their naphthalene counterparts exhibited contrasting behavior. Moreover, we observed a negative DSP correlates with inverted singlet-triplet gaps. Overall, this research advances OLED materials through molecular design and computational analysis, offering avenues for optimizing exciton management and enhancing device performance.
Collapse
Affiliation(s)
- Sanyam
- Department of Chemistry, Indian Institute of Technology, Gandhinagar, Gujarat 382355, India
| | - Priyanshu Sorout
- Department of Chemistry, Indian Institute of Technology, Gandhinagar, Gujarat 382355, India
| | - Anirban Mondal
- Department of Chemistry, Indian Institute of Technology, Gandhinagar, Gujarat 382355, India
| |
Collapse
|
2
|
Weerasinghe RW, Dos Santos JM, Chitose Y, Matulaitis T, Warriner SL, Barman D, Chan CY, Tsuchiya Y, Zysman-Colman E, Adachi C. Molecular asymmetry and rigidification as strategies to activate and enhance thermally activated delayed fluorescence in deep-blue MR-TADF emitters. Phys Chem Chem Phys 2024; 26:21337-21341. [PMID: 39102008 DOI: 10.1039/d4cp02664k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Two novel deep-blue multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters, 1B-CzCrs and 2B-CzCrs, containing a fused carbazole unit were synthesized. The carbazole contributed to the emergence of TADF in these small molecules. Particularly, organic light-emitting diodes with 1B-CzCrs doped in the mCP host achieve a maximum external quantum efficiency of 12.8% at CIE coordinates of (0.146, 0.062).
Collapse
Affiliation(s)
- Rangani Wathsala Weerasinghe
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka 819-0395, Japan.
| | - John Marques Dos Santos
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK.
| | - Youhei Chitose
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka 819-0395, Japan.
- Department of Applied Chemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
| | - Tomas Matulaitis
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK.
| | | | - Debasish Barman
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka 819-0395, Japan.
| | - Chin-Yiu Chan
- Department of Materials Science and Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Youichi Tsuchiya
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka 819-0395, Japan.
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK.
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka 819-0395, Japan.
- Department of Applied Chemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
| |
Collapse
|
3
|
Kunze L, Froitzheim T, Hansen A, Grimme S, Mewes JM. ΔDFT Predicts Inverted Singlet-Triplet Gaps with Chemical Accuracy at a Fraction of the Cost of Wave Function-Based Approaches. J Phys Chem Lett 2024:8065-8077. [PMID: 39083761 DOI: 10.1021/acs.jpclett.4c01649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
Efficient OLEDs need to quickly convert singlet and triplet excitons into photons. Molecules with an inverted singlet-triplet energy gap (INVEST) are promising candidates for this task. However, typical INVEST molecules have drawbacks like too low oscillator strengths and excitation energies. High-throughput screening could identify suitable INVEST molecules, but existing methods are problematic: The workhorse method TD-DFT cannot reproduce gap inversion, while wave function-based methods are too slow. This study proposes a state-specific method based on unrestricted Kohn-Sham DFT with common hybrid functionals. Tuned on the new INVEST15 benchmark set, this method achieves an error of less than 1 kcal/mol, which is traced back to error cancellation between spin contamination and dynamic correlation. Applied to the larger and structurally diverse NAH159 set in a black-box fashion, the method maintains a small error (1.2 kcal/mol) and accurately predicts gap signs in 83% of cases, confirming its robustness and suitability for screening workflows.
Collapse
Affiliation(s)
- Lukas Kunze
- Mulliken Center for Theoretical Chemistry, Clausius Institute for Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
| | - Thomas Froitzheim
- Mulliken Center for Theoretical Chemistry, Clausius Institute for Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
| | - Andreas Hansen
- Mulliken Center for Theoretical Chemistry, Clausius Institute for Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Clausius Institute for Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
| | - Jan-Michael Mewes
- Mulliken Center for Theoretical Chemistry, Clausius Institute for Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms Universität Bonn, Beringstraße 4, 53115 Bonn, Germany
- beeOLED GmbH, Niedersedlitzer Str. 75c, 01257 Dresden, Germany
| |
Collapse
|
4
|
Xing L, Wang J, Chen WC, Liu B, Chen G, Wang X, Tan JH, Chen SS, Chen JX, Ji S, Zhao Z, Tang MC, Huo Y. Highly efficient pure-blue organic light-emitting diodes based on rationally designed heterocyclic phenophosphazinine-containing emitters. Nat Commun 2024; 15:6175. [PMID: 39039042 PMCID: PMC11263564 DOI: 10.1038/s41467-024-50370-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 07/09/2024] [Indexed: 07/24/2024] Open
Abstract
Multi-resonance thermally activated delayed fluorophores have been actively studied for high-resolution photonic applications due to their exceptional color purity. However, these compounds encounter challenges associated with the inefficient spin-flip process, compromising device performance. Herein, we report two pure-blue emitters based on an organoboron multi-resonance core, incorporating a conformationally flexible donor, 10-phenyl-5H-phenophosphazinine 10-oxide (or sulfide). This design concept selectively modifies the orbital type of high-lying excited states to a charge transfer configuration while simultaneously providing the necessary conformational freedom to enhance the density of excited states without sacrificing color purity. We show that the different embedded phosphorus motifs (phosphine oxide/sulfide) of the donor can finely tune the electronic structure and conformational freedom, resulting in an accelerated spin-flip process through intense spin-vibronic coupling, achieving over a 20-fold increase in the reverse intersystem crossing rate compared to the parent multi-resonance emitter. Utilizing these emitters, we achieve high-performance pure-blue organic light-emitting diodes, showcasing a top-tier external quantum efficiency of 37.6% with reduced efficiency roll-offs. This proposed strategy not only challenges the conventional notion that flexible electron-donors are undesirable for constructing narrowband emitters but also offer a pathway for designing efficient narrow-spectrum blue organic light-emitting diodes.
Collapse
Affiliation(s)
- Longjiang Xing
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou, 510006, Guangzhou, P. R. China
| | - Jianghui Wang
- State Key Laboratory of Luminescent Materials and Devices, Key Laboratory of Luminescence from Molecular Aggregates of Guangdong Province, South China University of Technology, 510640, Guangzhou, P. R. China
| | - Wen-Cheng Chen
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou, 510006, Guangzhou, P. R. China.
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, 515200, Jieyang, P. R. China.
| | - Bo Liu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou, 510006, Guangzhou, P. R. China
| | - Guowei Chen
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou, 510006, Guangzhou, P. R. China
| | - Xiaofeng Wang
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou, 510006, Guangzhou, P. R. China
| | - Ji-Hua Tan
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou, 510006, Guangzhou, P. R. China
| | - Season Si Chen
- Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, 518055, Shenzhen, P. R. China
| | - Jia-Xiong Chen
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou, 510006, Guangzhou, P. R. China
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, 515200, Jieyang, P. R. China
| | - Shaomin Ji
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou, 510006, Guangzhou, P. R. China
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, 515200, Jieyang, P. R. China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, Key Laboratory of Luminescence from Molecular Aggregates of Guangdong Province, South China University of Technology, 510640, Guangzhou, P. R. China.
| | - Man-Chung Tang
- Institute of Materials Research, Tsinghua Shenzhen International Graduate School, Tsinghua University, 518055, Shenzhen, P. R. China.
| | - Yanping Huo
- School of Chemical Engineering and Light Industry, Guangdong University of Technology Guangzhou, 510006, Guangzhou, P. R. China.
- Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, 515200, Jieyang, P. R. China.
- Analytical & Testing Center, Guangdong University of Technology, 510006, Guangzhou, P. R. China.
| |
Collapse
|
5
|
Chen X, Sun L, Sukhanov AA, Doria S, Bussotti L, Zhao J, Xu H, Dick B, Voronkova VK, Di Donato M. Photophysics and photochemistry of thermally activated delayed fluorescence emitters based on the multiple resonance effect: transient optical and electron paramagnetic resonance studies. Chem Sci 2024; 15:10867-10881. [PMID: 39027280 PMCID: PMC11253189 DOI: 10.1039/d4sc02513j] [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: 04/16/2024] [Accepted: 05/31/2024] [Indexed: 07/20/2024] Open
Abstract
The photochemistry of two representative thermally activated delayed fluorescence (TADF) emitters based on the multiple resonance effect (MRE) (DABNA-1 and DtBuCzB) was studied. No significant TADF was observed in fluid solution, although the compounds have a long-lived triplet state (ca. 30 μs). We found that these planar boron molecules bind with Lewis bases, e.g., 4-dimethylaminopyridine (DMAP) or an N-heterocyclic carbene (NHC). A new blue-shifted absorption band centered at 368 nm was observed for DtBuCzB upon formation of the adduct; however, the fluorescence of the adduct is the same as that of the free DtBuCzB. We propose that photo-dissociation occurs for the DtBuCzB-DMAP adduct, which is confirmed by femtosecond transient absorption spectra, implying that fluorescence originates from DtBuCzB produced by photo-dissociation; the subsequent in situ re-binding was observed with nanosecdon transient absorption spectroscopy. No photo-dissociation was observed for the NHC adduct. Time-resolved electron paramagnetic resonance (TREPR) spectra show that the triplet states of DABNA-1 and DtBuCzB have similar zero field splitting (ZFS) parameters (D = 1450 MHz). Theoretical studies show that the slow ISC is due to small SOC and weak Herzberg-Teller coupling, although the S1/T1 energy gap is small (0.14 eV), which rationalizes the lack of TADF.
Collapse
Affiliation(s)
- Xi Chen
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
| | - Lei Sun
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Key Laboratory of Forestry Genetics & Biotechnology of Ministry of Education, Jiangsu Provincial Key Lab for the Chemistry and Utilization of Agro-Forest Biomass, College of Chemical Engineering, Nanjing Forestry University Nanjing 210037 P. R. China
- School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang 453002 China
| | - Andrey A Sukhanov
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of RAS Kazan 420029 Russia
| | - Sandra Doria
- LENS (European Laboratory for Non-Linear Spectroscopy) Via N. Carrara 1 50019 Sesto Fiorentino (FI) Italy
- ICCOM-CNR Via Madonna del Piano 10-12 50019 Sesto Fiorentino (FI) Italy
| | - Laura Bussotti
- LENS (European Laboratory for Non-Linear Spectroscopy) Via N. Carrara 1 50019 Sesto Fiorentino (FI) Italy
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
| | - Haijun Xu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Key Laboratory of Forestry Genetics & Biotechnology of Ministry of Education, Jiangsu Provincial Key Lab for the Chemistry and Utilization of Agro-Forest Biomass, College of Chemical Engineering, Nanjing Forestry University Nanjing 210037 P. R. China
- School of Chemistry and Chemical Engineering, Henan Normal University Xinxiang 453002 China
| | - Bernhard Dick
- Lehrstuhl für Physikalische Chemie, Institut für Physikalische und Theoretische Chemie, Universität Regensburg Regensburg 93053 Germany
| | - Violeta K Voronkova
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of RAS Kazan 420029 Russia
| | - Mariangela Di Donato
- LENS (European Laboratory for Non-Linear Spectroscopy) Via N. Carrara 1 50019 Sesto Fiorentino (FI) Italy
- ICCOM-CNR Via Madonna del Piano 10-12 50019 Sesto Fiorentino (FI) Italy
| |
Collapse
|
6
|
Song S, Feng S, Wang L, Jun J, Milián-Medina B, Wannemacher R, Lee J, Kwon MS, Gierschner J. Rational Design of Color-Pure Blue Organic Emitters by Poly-Heteroaromatic Omni-Delocalization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2404388. [PMID: 39011790 DOI: 10.1002/adma.202404388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/21/2024] [Indexed: 07/17/2024]
Abstract
Current research on organic light emitters which utilize multiple resonance-induced thermally activated delayed fluorescence (MR-TADF) materials is gaining significant interest because of the materials' ability to efficiently generate color-pure blue emission. However, the underlying reasons for high color purity remain unclear. It is shown here that these emitters share a common electronic basis, which is deduced from resonance structure considerations following Clar's rule, and which is termed as "poly-heteroaromatic omni-delocalization" (PHOD). The simple and clear design rules derived from the PHOD concept allow extending the known chemical space by new structural motifs. Based on PHOD, a set of novel high-efficiency color-pure emitters with brilliant deep-blue hue is specifically designed.
Collapse
Affiliation(s)
- Sunwu Song
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Siyang Feng
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, C/ Faraday 9, Ciudad Universitaria de Cantoblanco, Madrid, 28049, Spain
| | - Liangxuan Wang
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, C/ Faraday 9, Ciudad Universitaria de Cantoblanco, Madrid, 28049, Spain
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Jinwon Jun
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Seoul National University, Seoul, 08826, Republic of Korea
| | - Begoña Milián-Medina
- Department for Physical Chemistry, Faculty of Chemistry, University of Valencia, Burjassot, Valencia, 46100, Spain
| | - Reinhold Wannemacher
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, C/ Faraday 9, Ciudad Universitaria de Cantoblanco, Madrid, 28049, Spain
| | - Jaesang Lee
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Seoul National University, Seoul, 08826, Republic of Korea
| | - Min Sang Kwon
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Johannes Gierschner
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, C/ Faraday 9, Ciudad Universitaria de Cantoblanco, Madrid, 28049, Spain
| |
Collapse
|
7
|
Jin P, Wei X, Yin B, Xu L, Guo Y, Zhang C. Stepwise Charge/Energy Transfer in MR-TADF Molecule-Doped Exciplex for Ultralong Persistent Luminescence Activated with Visible Light. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2400158. [PMID: 38847332 DOI: 10.1002/adma.202400158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 05/31/2024] [Indexed: 06/15/2024]
Abstract
Organic long-persistent luminescence (OLPL), which relies on energy storage for delayed light emission by the charge separation state, has attracted intense attention in various optical applications. However, charge separation (CS) is efficient only under ultraviolet excitation in most OLPL systems because it requires a driving force from the large energy difference between the local excited (LE) and charge transfer (CT) states. In this study, a multiresonance thermally activated delayed fluorescence (MR-TADF) molecule is incorporated into an exciplex system to achieve efficient OLPL in a composite material activated by visible light via a stepwise charge/energy transfer process. The enhanced absorption of the composite material facilitated a tenfold increase in the duration of the OLPL, which can last for several hours under visible light excitation. The excited state of the MR-TADF molecule tends to charge transfer to the acceptor, followed by energy transfer to the exciplex, which benefits from the small difference between the LE and CT states owing to the inherent CS characteristics of the opposing resonance effect. Afterglow displays of these composite materials are fabricated to demonstrate their considerable potential in encryption patterns and emergency lights, which take advantage of their excellent processability, visible light activation, and tunable luminescence properties.
Collapse
Affiliation(s)
- Pengfei Jin
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaofang Wei
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, China
| | - Baipeng Yin
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, China
| | - Lixin Xu
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yunlong Guo
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, China
| | - Chuang Zhang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, China
| |
Collapse
|
8
|
Weerasinghe RW, Madayanad Suresh S, Hall D, Matulaitis T, Slawin AMZ, Warriner S, Lee YT, Chan CY, Tsuchiya Y, Zysman-Colman E, Adachi C. A Boron, Nitrogen, and Oxygen Doped π-Extended Helical Pure Blue Multiresonant Thermally Activated Delayed Fluorescent Emitter for Organic Light Emitting Diodes That Shows Fast k RISC Without the Use of Heavy Atoms. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2402289. [PMID: 38581139 DOI: 10.1002/adma.202402289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/03/2024] [Indexed: 04/08/2024]
Abstract
Narrowband emissive multiresonant thermally activated delayed fluorescence (MR-TADF) emitters are a promising solution to achieve the current industry-targeted color standard, Rec. BT.2020-2, for blue color without using optical filters, aiming for high-efficiency organic light-emitting diodes (OLEDs). However, their long triplet lifetimes, largely affected by their slow reverse intersystem crossing rates, adversely affect device stability. In this study, a helical MR-TADF emitter (f-DOABNA) is designed and synthesized. Owing to its π-delocalized structure, f-DOABNA possesses a small singlet-triplet gap, ΔEST, and displays simultaneously an exceptionally faster reverse intersystem crossing rate constant, kRISC, of up to 2 × 106 s-1 and a very high photoluminescence quantum yield, ΦPL, of over 90% in both solution and doped films. The OLED with f-DOABNA as the emitter achieved a narrow deep-blue emission at 445 nm (full width at half-maximum of 24 nm) associated with Commission Internationale de l'Éclairage (CIE) coordinates of (0.150, 0.041), and showed a high maximum external quantum efficiency, EQEmax, of ≈20%.
Collapse
Affiliation(s)
- Rangani Wathsala Weerasinghe
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Subeesh Madayanad Suresh
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - David Hall
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Tomas Matulaitis
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Alexandra M Z Slawin
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Stuart Warriner
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Yi-Ting Lee
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Chin-Yiu Chan
- Department of Materials Science and Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, 000-000, China
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, 000-000, China
| | - Youichi Tsuchiya
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Motooka, Nishi, Fukuoka, 819-0395, Japan
| |
Collapse
|
9
|
Kang S, Kim T. Comparative study of TDDFT and TDDFT-based STEOM-DLPNO-CCSD calculations for predicting the excited-state properties of MR-TADF. Heliyon 2024; 10:e30926. [PMID: 38779014 PMCID: PMC11109791 DOI: 10.1016/j.heliyon.2024.e30926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
The time dependent density functional theory (TDDFT) and TDDFT/similarity transformed EOM domain-based local pair natural orbital CCSD (STEOM-DLPNO-CCSD) calculations were explored to estimate their validity in predicting the excited-state properties of multi-resonant thermally activated delayed fluorescence (MR-TADF) materials. Obviously, it was demonstrated that TDDFT calculation is inadequate to provide the quantitative prediction of the lowest singlet excited-state (S1), the lowest triplet excited-state (T1), and ΔEST. On the other hand, TDDFT/STEOM-DNLPNO-CCSD calculation reveals the superior prediction of S1, T1, and ΔEST that are in quantitative agreement with experiments. More importantly, it was found that TD-LC-⎤ * HPBE/STEOM-DLPNO-CCSD calculation provides the most accurate prediction of S1, T1, and ΔEST. Accordingly, we suggest that TD-LC-⎤ * HPBE/STEOM-DLPNO-CCSD calculation should be utilized to compute the excited-states properties of MR-TADF materials accurately.
Collapse
Affiliation(s)
- Sunwoo Kang
- Department of Chemistry, Dankook University, Cheonan, Chungnam, 31116, South Korea
| | - Taekyung Kim
- Department of Materials Science and Engineering, Hongik University, Sejongsi, 30016, South Korea
- Department of Information Display Engineering, Hongik University, Seoul, 04066, South Korea
| |
Collapse
|
10
|
Di Maiolo F, Phan Huu DKA, Giavazzi D, Landi A, Racchi O, Painelli A. Shedding light on thermally-activated delayed fluorescence. Chem Sci 2024; 15:5434-5450. [PMID: 38638233 PMCID: PMC11023041 DOI: 10.1039/d4sc00033a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 02/17/2024] [Indexed: 04/20/2024] Open
Abstract
Thermally activated delayed fluorescence (TADF) is a hot research topic in view of its impressive applications in a wide variety of fields from organic LEDs to photodynamic therapy and metal-free photocatalysis. TADF is a rare and fragile phenomenon that requires a delicate equilibrium between tiny singlet-triplet gaps, sizable spin-orbit couplings, conformational flexibility and a balanced contribution of charge transfer and local excited states. To make the picture more complex, this precarious equilibrium is non-trivially affected by the interaction of the TADF dye with its local environment. The concurrent optimization of the dye and of the embedding medium is therefore of paramount importance to boost practical applications of TADF. Towards this aim, refined theoretical and computational approaches must be cleverly exploited, paying attention to the reliability of adopted approximations. In this perspective, we will address some of the most important issues in the field. Specifically, we will critically review theoretical and computational approaches to TADF rates, highlighting the limits of widespread approaches. Environmental effects on the TADF photophysics are discussed in detail, focusing on the major role played by dielectric and conformational disorder in liquid solutions and amorphous matrices.
Collapse
Affiliation(s)
- Francesco Di Maiolo
- Dept. Chemistry, Life Science and Environmental Sustainability, University of Parma Parco Area delle Scienze 17/A 43124 Parma Italy
| | - D K Andrea Phan Huu
- Dept. Chemistry, Life Science and Environmental Sustainability, University of Parma Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Davide Giavazzi
- Dept. Chemistry, Life Science and Environmental Sustainability, University of Parma Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Andrea Landi
- Dept. Chemistry, Life Science and Environmental Sustainability, University of Parma Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Ottavia Racchi
- Dept. Chemistry, Life Science and Environmental Sustainability, University of Parma Parco Area delle Scienze 17/A 43124 Parma Italy
| | - Anna Painelli
- Dept. Chemistry, Life Science and Environmental Sustainability, University of Parma Parco Area delle Scienze 17/A 43124 Parma Italy
| |
Collapse
|
11
|
Wu S, Hu YN, Sun D, Wang K, Zhang XH, Zysman-Colman E. A fluorene-bridged double carbonyl/amine multiresonant thermally activated delayed fluorescence emitter for efficient green OLEDs. Chem Commun (Camb) 2024; 60:2489-2492. [PMID: 38196344 DOI: 10.1039/d3cc05761e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Herein, we report a fluorene-bridged double carbonyl/amine-based MR TADF emitter DDiKTa-F, formed by locking the conformation of the previously reported compound DDiKTa. Using this strategy, DDiKTa-F exhibited narrower, brighter, and red-shifted emission. The OLEDs with DDiKTa-F emitted at 493 nm and showed an EQEmax of 15.3% with an efficiency roll-off of 35% at 100 cd m-2.
Collapse
Affiliation(s)
- Sen Wu
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, UK.
| | - Ya-Nan Hu
- Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China.
| | - Dianming Sun
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, UK.
| | - Kai Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China.
| | - Xiao-Hong Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China.
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, UK.
| |
Collapse
|
12
|
Hagai M, Inai N, Yasuda T, Fujimoto KJ, Yanai T. Extended theoretical modeling of reverse intersystem crossing for thermally activated delayed fluorescence materials. SCIENCE ADVANCES 2024; 10:eadk3219. [PMID: 38295171 PMCID: PMC10830100 DOI: 10.1126/sciadv.adk3219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/29/2023] [Indexed: 02/02/2024]
Abstract
Thermally activated delayed fluorescence (TADF) materials and multi-resonant (MR) variants are promising organic emitters that can achieve an internal electroluminescence quantum efficiency of ~100%. The reverse intersystem crossing (RISC) is key for harnessing triplet energies for fluorescence. Theoretical modeling is thus crucial to estimate its rate constant (kRISC) for material development. Here, we present a comprehensive assessment of the theory for simulating the RISC of MR-TADF molecules within a perturbative excited-state dynamics framework. Our extended rate formula reveals the importance of the concerted effects of nonadiabatic spin-vibronic coupling and vibrationally induced spin-orbital couplings in reliably determining kRISC of MR-TADF molecules. The excited singlet-triplet energy gap is another factor influencing kRISC. We present a scheme for gap estimation using experimental Arrhenius plots of kRISC. Erroneous behavior caused by approximations in Marcus theory is elucidated by testing 121 MR-TADF molecules. Our extended modeling offers in-depth descriptions of kRISC.
Collapse
Affiliation(s)
- Masaya Hagai
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Aichi, Japan
| | - Naoto Inai
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Aichi, Japan
| | - Takuma Yasuda
- Institute for Advanced Study, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Kyushu, Japan
- Department of Applied Chemistry, Graduate School of Engineering, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Kyushu, Japan
| | - Kazuhiro J. Fujimoto
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Aichi, Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Aichi, Japan
- Integrated Research Consortium on Chemical Science (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Aichi, Japan
| | - Takeshi Yanai
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Aichi, Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Aichi, Japan
- Integrated Research Consortium on Chemical Science (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Aichi, Japan
| |
Collapse
|
13
|
Bedogni M, Giavazzi D, Di Maiolo F, Painelli A. Shining Light on Inverted Singlet-Triplet Emitters. J Chem Theory Comput 2024; 20:902-913. [PMID: 37992126 PMCID: PMC10809715 DOI: 10.1021/acs.jctc.3c01112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 11/24/2023]
Abstract
The inversion of the lowest singlet and triplet excited states, observed in several triangle-shaped organic molecules containing conjugated carbon and nitrogen atoms, is an astonishing result that implies the breakdown of Hund's rule. The phenomenon attracted interest for its potential toward triplet harvesting in organic LEDs. On a more fundamental vein, the singlet-triplet (ST) inversion sheds new light on the role of electron correlations in the excited-state landscape of π-conjugated molecules. Relying on the celebrated Pariser-Parr-Pople model, the simplest model for correlated electrons in π-conjugated systems, we demonstrate that the ST inversion does not require triangle-shaped molecules nor any specific molecular symmetry. Indeed, the ST inversion does not require strictly non-overlapping HOMO and LUMO orbitals but rather a small gap and a small exchange integral between the frontier orbitals.
Collapse
Affiliation(s)
- Matteo Bedogni
- Department of Chemistry, Life Science
and Environmental Sustainability, Università
di Parma, 43124 Parma, Italy
| | - Davide Giavazzi
- Department of Chemistry, Life Science
and Environmental Sustainability, Università
di Parma, 43124 Parma, Italy
| | - Francesco Di Maiolo
- Department of Chemistry, Life Science
and Environmental Sustainability, Università
di Parma, 43124 Parma, Italy
| | - Anna Painelli
- Department of Chemistry, Life Science
and Environmental Sustainability, Università
di Parma, 43124 Parma, Italy
| |
Collapse
|
14
|
Sanyam, Khatua R, Mondal A. Cost-Effective Approach for Modeling of Multiresonant Thermally Activated Delayed Fluorescence Emitters. J Chem Theory Comput 2023; 19:9290-9301. [PMID: 38096547 DOI: 10.1021/acs.jctc.3c01147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Multiresonant thermally activated delayed fluorescence (MR-TADF) emitters have recently attracted great interest for application in organic light-emitting diodes due to their remarkable electroluminescent efficiency and narrow emission spectra. It is therefore essential to establish computational methodologies that can accurately model the excited states of these materials at manageable computational costs. With regard to MR-TADF design and their associated photophysics, previous works have highlighted the importance of wave function-based methods, at much higher computational costs, over the traditional time-dependent density functional theory approach. Herein, we employ two independent techniques built on different quantum mechanical frameworks, highly correlated wave function-based STEOM-DLPNO-CCSD and range-separated double hybrid density functional, TD-B2PLYP, to investigate their performance in predicting the excited state energies in MR-TADF emitters. We demonstrate a remarkable mean absolute deviation (MAD) of ∼0.06 eV in predicting ΔEST compared to experimental measurements across a large pool of chemically diverse MR-TADF molecules. Furthermore, both methods yield superior MAD in estimating S1 and T1 energies over earlier reported SCS-CC2 computed values [J. Chem. Theory Comput. 2022, 18, 4903]. The short-range charge-transfer nature of low-lying excited states and narrow fwhm values, hallmarks of this class of emitters, are precisely captured by both approaches. Finally, we show the transferability and robustness of these methods in estimating rates of radiative and nonradiative events with adequate agreement against experimental measurements. Implementing these cost-effective computational approaches is poised to streamline the identification and evaluation of potential MR-TADF emitters, significantly reducing the reliance on costly laboratory synthesis and characterization processes.
Collapse
Affiliation(s)
- Sanyam
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Rudranarayan Khatua
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Anirban Mondal
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| |
Collapse
|
15
|
Pu YJ, Valverde D, Sancho-García JC, Olivier Y. Computational Design of Multiple Resonance-Type BN Molecules for Inverted Singlet and Triplet Excited States. J Phys Chem A 2023; 127:10189-10196. [PMID: 38011598 DOI: 10.1021/acs.jpca.3c06573] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
A computational design of linearly extended multiple resonance (MR)-type BN molecules based on DABNA-1 is proposed herein in the quest to find potential candidates that exhibit a negative singlet-triplet gap (ΔEST) and a large oscillator strength value. The impact of a proper account of the electron correlation in the lowest singlet and triplet excited states is systematically investigated by using double-hybrid functionals within the TD-DFT framework, as well as wavefunction-based methods (EOM-CCSD and SCS-CC2), since this contribution plays an essential role in driving the magnitude of the ΔEST in MR-TADF and inverted singlet-triplet gap compounds. Our results point out a gradual reduction of the ΔEST gap with respect to the increasing sum of the number of B and N atoms, reaching negative ΔEST values for some molecules as a function of their size. The double-hybrid functionals reproduce the gap with only slight deviation compared to available experimental data for DABNA-1, ν-DABNA, and mDBCz and nicely agree with high-level quantum mechanical methods (e.g., EOM-CCSD and SCS-CC2). Larger oscillator strengths are found compared to the azaphenalene-type molecules, also exhibiting the inversion of their singlet and triplet excited states. We hope this study can serve as a motivation for further design of the molecules showing negative ΔEST based on boron- and nitrogen-doped polyaromatic hydrocarbons.
Collapse
Affiliation(s)
- Yong-Jin Pu
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Danillo Valverde
- Laboratory for Computational Modeling of Functional Materials, Namur Institute of Structured Matter, Université de Namur, Rue de Bruxelles, 61, B-5000 Namur, Belgium
| | | | - Yoann Olivier
- Laboratory for Computational Modeling of Functional Materials, Namur Institute of Structured Matter, Université de Namur, Rue de Bruxelles, 61, B-5000 Namur, Belgium
| |
Collapse
|
16
|
Sanyam, Khatua R, Mondal A. Constructing Multiresonance Thermally Activated Delayed Fluorescence Emitters for Organic LEDs: A Computational Investigation. J Phys Chem A 2023. [PMID: 38048094 DOI: 10.1021/acs.jpca.3c05056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Multiple resonance thermally activated delayed fluorescence (MR-TADF) materials have acquired substantial attention due to their high electroluminescence efficiency with narrow emission spectra. However, the existing MR-TADF emitters suffer from substantial efficiency roll-off due to insufficient rate constants of the reverse intersystem crossing (kRISC) process compared to the traditional TADF materials. Herein, we employ the DLPNO-STEOM-CCSD method, which is computationally less expensive than the wave function-based EOM-CCSD method, to evaluate the electronic and photophysical properties of MR-TADF materials accurately. The predicted singlet-triplet energy gap (ΔEST), one of the critical parameters governing the TADF efficiency, exhibits remarkable agreement with the experimental measurement, with a standard deviation value of 0.026 eV (obtained based on five experimentally synthesized MR-TADF systems). The proposed technique was utilized to determine the suitability of 15 newly designed MR-TADF emitters via their computed radiative and nonradiative rates, luminescence efficiencies, and exciton characteristics. Moreover, most conceived molecules exhibit blue emission with decent to strong oscillator strengths, making them potential candidates for practical light-emitting applications. The proposed computational route will undoubtedly accelerate the designing and prescreening of potential MR-TADF emitters before their expensive laboratory synthesis and characterization.
Collapse
Affiliation(s)
- Sanyam
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Rudranarayan Khatua
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Anirban Mondal
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| |
Collapse
|
17
|
Sandoval-Salinas ME, Ricci G, Pérez-Jiménez AJ, Casanova D, Olivier Y, Sancho-García JC. Correlation vs. exchange competition drives the singlet-triplet excited-state inversion in non-alternant hydrocarbons. Phys Chem Chem Phys 2023; 25:26417-26428. [PMID: 37522306 DOI: 10.1039/d3cp02465b] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
In this work, we focus on the understanding of the driving force behind the S1-T1 excited-state energy inversion (which would thus violate Hund's rule, making the S1 state lower in energy than the T1 state) of two non-benzenoid non-alternant hydrocarbons, composed of odd-membered rings. The molecules considered here have identical chemical composition but different atomic configuration in space. The delicate interplay between structural and electronic factors that might induce inversion and its energy extension, only by a few meV, is systematically investigated here by state-of-the-art calculations. Qualitative and quantitative accurate predictions are obtained employing post-HF methods, thanks to the balanced and careful inclusion of electron correlation effects. The obtained results might guide and rationalize new searches for molecules violating Hund's rule, concomitantly demonstrating the importance of key contributions from the theoretical method of choice.
Collapse
Affiliation(s)
- M E Sandoval-Salinas
- Department of Physical Chemistry, University of Alicante, E-03080 Alicante, Spain.
- School of Physical and Chemical Science, Queen Mary University of London, London, UK
| | - G Ricci
- Unité de Chimie Physique Théorique et Structurale, & Laboratoire de Physique du Solid, Namur Institute of Structured Matter, Université de Namur, B-5000 Namur, Belgium.
| | - A J Pérez-Jiménez
- Department of Physical Chemistry, University of Alicante, E-03080 Alicante, Spain.
| | - D Casanova
- Donostia International Physics Center (DIPC), E-20018 Donostia, Euskadi, Spain.
- IKERBASQUE-Basque Foundation for Science, E-48009 Bilbao, Euskadi, Spain
| | - Y Olivier
- Unité de Chimie Physique Théorique et Structurale, & Laboratoire de Physique du Solid, Namur Institute of Structured Matter, Université de Namur, B-5000 Namur, Belgium.
| | - J C Sancho-García
- Department of Physical Chemistry, University of Alicante, E-03080 Alicante, Spain.
| |
Collapse
|
18
|
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.
Collapse
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.
| |
Collapse
|
19
|
Kang J, Jeon SO, Kim I, Lee HL, Lim J, Lee JY. Color Stable Deep Blue Multi-Resonance Organic Emitters with Narrow Emission and High Efficiency. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2302619. [PMID: 37424040 PMCID: PMC10502835 DOI: 10.1002/advs.202302619] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/19/2023] [Indexed: 07/11/2023]
Abstract
The development of highly efficient and deep blue emitters satisfying the color specification of the commercial products has been a challenging hurdle in the organic light-emitting diodes (OLEDs). Here, deep blue OLEDs with a narrow emission spectrum with good color stability and spin-vibronic coupling assisted thermally activated delayed fluorescence are reported using a novel multi-resonance (MR) emitter built on a pure organic-based molecular platform of fused indolo[3,2,1-jk]carbazole structure. Two emitters derived from 2,5,11,14-tetrakis(1,1-dimethylethyl)indolo[3,2,1-jk]indolo[1',2',3':1,7]indolo[3,2-b]carbazole (tBisICz) core are synthesized as the MR type thermally activated delayed fluorescence emitters realizing a very narrow emission spectrum with a full-width-at-half-maximum (FWHM) of 16 nm with suppressed broadening at high doping concentration. The tBisICz core is substituted with a diphenylamine or 9-phenylcarbazole blocking group to manage the intermolecular interaction for high efficiency and narrow emission. The deep blue OLEDs achieve high external quantum efficiency (EQE) of 24.9%, small FWHM of 19 nm, and deep blue color coordinate of (0.16, 0.04) with good color stability with increase in doping concentration. To the authors' knowledge, the EQE in this work is one of the highest values reported for the deep blue OLEDs that achieve the BT.2020 standard.
Collapse
Affiliation(s)
- Jihoon Kang
- School of Chemical EngineeringSungkyunkwan University2066, Seobu‐ro, Jangan‐guSuwonGyeonggi16419Republic of Korea
| | - Soon Ok Jeon
- Material Research Center, Samsung Advanced Institute of TechnologySamsung Electronics Co., Ltd.130 Samsung‐ro, Yeongtong‐guSuwonGyeonggi16678Republic of Korea
| | - Inkoo Kim
- Innovation CenterSamsung Electronics Co., Ltd.HwaseongGyeonggi18448Republic of Korea
| | - Ha Lim Lee
- School of Chemical EngineeringSungkyunkwan University2066, Seobu‐ro, Jangan‐guSuwonGyeonggi16419Republic of Korea
| | - Junseop Lim
- School of Chemical EngineeringSungkyunkwan University2066, Seobu‐ro, Jangan‐guSuwonGyeonggi16419Republic of Korea
| | - Jun Yeob Lee
- School of Chemical EngineeringSungkyunkwan University2066, Seobu‐ro, Jangan‐guSuwonGyeonggi16419Republic of Korea
- SKKU Advanced Institute of Nano TechnologySungkyunkwan University2066, Seobu‐ro, Jangan‐guSuwonGyeonggi16419Republic of Korea
- SKKU Institute of Energy Science and TechnologySungkyunkwan University2066, Seobu‐ro, Jangan‐guSuwonGyeonggi16419Republic of Korea
| |
Collapse
|
20
|
Suresh SM, Zhang L, Matulaitis T, Hall D, Si C, Ricci G, Slawin AMZ, Warriner S, Beljonne D, Olivier Y, Samuel IDW, Zysman-Colman E. Judicious Heteroatom Doping Produces High-Performance Deep-Blue/Near-UV Multiresonant Thermally Activated Delayed Fluorescence OLEDs. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2300997. [PMID: 37140188 DOI: 10.1002/adma.202300997] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/26/2023] [Indexed: 05/05/2023]
Abstract
Two multiresonant thermally activated delayed fluorescence (MR-TADF) emitters are presented and it is shown how further borylation of a deep-blue MR-TADF emitter, DIDOBNA-N, both blueshifts and narrows the emission producing a new near-UV MR-TADF emitter, MesB-DIDOBNA-N, are shown. DIDOBNA-N emits bright blue light (ΦPL = 444 nm, FWHM = 64 nm, ΦPL = 81%, τd = 23 ms, 1.5 wt% in TSPO1). The deep-blue organic light-emitting diode (OLED) based on this twisted MR-TADF compound shows a very high maximum external quantum efficiency (EQEmax ) of 15.3% for a device with CIEy of 0.073. The fused planar MR-TADF emitter, MesB-DIDOBNA-N shows efficient and narrowband near-UV emission (λPL = 402 nm, FWHM = 19 nm, ΦPL = 74.7%, τd = 133 ms, 1.5 wt% in TSPO1). The best OLED with MesB-DIDOBNA-N, doped in a co-host, shows the highest efficiency reported for a near-UV OLED at 16.2%. With a CIEy coordinate of 0.049, this device also shows the bluest EL reported for a MR-TADF OLED to date.
Collapse
Affiliation(s)
- Subeesh Madayanad Suresh
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Le Zhang
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK
| | - Tomas Matulaitis
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - David Hall
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
- Laboratory for Chemistry of Novel Materials, University of Mons, Mons, 7000, Belgium
| | - Changfeng Si
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Gaetano Ricci
- Laboratory for Computational Modeling of Functional Materials, Namur Institute of Structured Matter, Université de Namur, Rue de Bruxelles, 61, Namur, 5000, Belgium
| | - Alexandra M Z Slawin
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Stuart Warriner
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons, Mons, 7000, Belgium
| | - Yoann Olivier
- Laboratory for Chemistry of Novel Materials, University of Mons, Mons, 7000, Belgium
- Laboratory for Computational Modeling of Functional Materials, Namur Institute of Structured Matter, Université de Namur, Rue de Bruxelles, 61, Namur, 5000, Belgium
| | - Ifor D W Samuel
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| |
Collapse
|
21
|
Wu S, Zhang L, Wang J, Kumar Gupta A, Samuel IDW, Zysman‐Colman E. Merging Boron and Carbonyl based MR-TADF Emitter Designs to Achieve High Performance Pure Blue OLEDs. Angew Chem Int Ed Engl 2023; 62:e202305182. [PMID: 37193649 PMCID: PMC10952889 DOI: 10.1002/anie.202305182] [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: 04/12/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 05/18/2023]
Abstract
Multiresonant thermally activated delayed fluorescence (MR-TADF) compounds are attractive as emitters for organic light-emitting diodes (OLEDs) as they can simultaneously harvest both singlet and triplet excitons to produce light in the device and show very narrow emission spectra, which translates to excellent color purity. Here, we report the first example of an MR-TADF emitter (DOBDiKTa) that fuses together fragments from the two major classes of MR-TADF compounds, those containing boron (DOBNA) and those containing carbonyl groups (DiKTa) as acceptor fragments in the MR-TADF skeleton. The resulting molecular design, this compound shows desirable narrowband pure blue emission and efficient TADF character. The co-host OLED with DOBDiKTa as the emitter showed a maximum external quantum efficiency (EQEmax ) of 17.4 %, an efficiency roll-off of 32 % at 100 cd m-2 , and Commission Internationale de l'Éclairage (CIE) coordinates of (0.14, 0.12). Compared to DOBNA and DiKTa, DOBDiKTa shows higher device efficiency with reduced efficiency roll-off while maintaining a high color purity, which demonstrates the promise of the proposed molecular design.
Collapse
Affiliation(s)
- Sen Wu
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
| | - Le Zhang
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
- Organic Semiconductor CentreSUPA School of Physics and AstronomyUniversity of St AndrewsSt AndrewsKY169SSUK
| | - Jingxiang Wang
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
| | - Abhishek Kumar Gupta
- Organic Semiconductor CentreSUPA School of Physics and AstronomyUniversity of St AndrewsSt AndrewsKY169SSUK
| | - Ifor D. W. Samuel
- Organic Semiconductor CentreSUPA School of Physics and AstronomyUniversity of St AndrewsSt AndrewsKY169SSUK
| | - Eli Zysman‐Colman
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY16 9STUK
| |
Collapse
|
22
|
Madayanad Suresh S, Zhang L, Hall D, Si C, Ricci G, Matulaitis T, Slawin AMZ, Warriner S, Olivier Y, Samuel IDW, Zysman-Colman E. A Deep-Blue-Emitting Heteroatom-Doped MR-TADF Nonacene for High-Performance Organic Light-Emitting Diodes. Angew Chem Int Ed Engl 2023; 62:e202215522. [PMID: 36480790 PMCID: PMC10107802 DOI: 10.1002/anie.202215522] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 12/13/2022]
Abstract
We present a p- and n-doped nonacene compound, NOBNacene, that represents a rare example of a linearly extended ladder-type multiresonant thermally activated delayed fluorescence (MR-TADF) emitter. This compound shows efficient narrow deep blue emission, with a λPL of 410 nm, full width at half maximum, FWHM, of 38 nm, photoluminescence quantum yield, ΦPL of 71 %, and a delayed lifetime, τd of 1.18 ms in 1.5 wt % TSPO1 thin film. The organic light-emitting diode (OLED) using this compound as the emitter shows a comparable electroluminescence spectrum peaked at 409 nm (FWHM=37 nm) and a maximum external quantum efficiency (EQEmax ) of 8.5 % at Commission Internationale de l'Éclairage (CIE) coordinates of (0.173, 0.055). The EQEmax values were increased to 11.2 % at 3 wt % doping of the emitter within the emissive layer of the device. At this concentration, the electroluminescence spectrum broadened slightly, leading to CIE coordinates of (0.176, 0.068).
Collapse
Affiliation(s)
- Subeesh Madayanad Suresh
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Le Zhang
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK.,Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK
| | - David Hall
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Changfeng Si
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Gaetano Ricci
- Laboratory for Computational Modeling of Functional Materials & Solid State Physics Laboratory, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, 5000, Namur, Belgium
| | - Tomas Matulaitis
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Alexandra M Z Slawin
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Stuart Warriner
- School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Yoann Olivier
- Laboratory for Computational Modeling of Functional Materials & Solid State Physics Laboratory, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, 5000, Namur, Belgium
| | - Ifor D W Samuel
- Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| |
Collapse
|
23
|
Oparina LA, Kolyvanov NA, Ushakov IA, Nikitina LP, Petrova OV, Sobenina LN, Petrushenko KB, Trofimov BA. Contributing to Biochemistry and Optoelectronics: Pyrrolo[1',2':2,3]imidazo[1,5- a]indoles and Cyclohepta[4,5]pyrrolo[1,2- c]pyrrolo[1,2- a]imidazoles via [3+2] Annulation of Acylethynylcycloalka[ b]pyrroles with Δ 1-Pyrrolines. Int J Mol Sci 2023; 24:ijms24043404. [PMID: 36834813 PMCID: PMC9959468 DOI: 10.3390/ijms24043404] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/02/2023] [Accepted: 02/05/2023] [Indexed: 02/11/2023] Open
Abstract
Available pyrrolylalkynones with tetrahydroindolyl, cycloalkanopyrrolyl, and dihydrobenzo[g]indolyl moieties, acylethynylcycloalka[b]pyrroles, are readily annulated with Δ1-pyrrolines (MeCN/THF, 70 °C, 8 h) to afford a series of novel pyrrolo[1',2':2,3]imidazo[1,5-a]indoles and cyclohepta[4,5]pyrrolo[1,2-c]pyrrolo[1,2-a]imidazoles functionalized with an acylethenyl group in up to an 81% yield. This original synthetic approach contributes to the arsenal of chemical methods promoting drug discovery. Photophysical studies show that some of the synthesized compounds, e.g., benzo[g]pyrroloimidazoindoles, are prospective candidates for TADF emitters of OLED.
Collapse
|
24
|
Curtis K, Adeyiga O, Suleiman O, Odoh SO. Building on the strengths of a double-hybrid density functional for excitation energies and inverted singlet-triplet energy gaps. J Chem Phys 2023; 158:024116. [PMID: 36641391 DOI: 10.1063/5.0133727] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
It is demonstrated that a double hybrid density functional approximation, ωB88PTPSS, that incorporates equipartition of density functional theory and the non-local correlation, however with a meta-generalized gradient approximation correlation functional, as well as with the range-separated exchange of ωB2PLYP, provides accurate excitation energies for conventional systems, as well as correct prescription of negative singlet-triplet gaps for non-conventional systems with inverted gaps, without any necessity for parametric scaling of the same-spin and opposite-spin non-local correlation energies. Examined over "safe" excitations of the QUESTDB set, ωB88PTPSS performs quite well for open-shell systems, correctly and fairly accurately [relative to equation-of-motion coupled-cluster singles and doubles (EOM-CCSD) reference] predicts negative gaps for 50 systems with inverted singlet-triplet gaps, and is one of the leading performers for intramolecular charge-transfer excitations and achieves near-second-order approximate coupled cluster (CC2) and second-order algebraic diagrammatic construction quality for the Q1 and Q2 subsets. Subsequently, we tested ωB88PTPSS on two sets of real-life examples from recent computational chemistry literature-the low energy bands of chlorophyll a (Chl a) and a set of thermally activated delayed fluorescence (TADF) systems. For Chl a, ωB88PTPSS qualitatively and quantitatively achieves DLPNO-STEOM-CCSD-level performance and provides excellent agreement with experiment. For TADF systems, ωB88PTPSS agrees quite well with spin-component-scaled CC2 (SCS-CC2) excitation energies, as well as experimental values, for the gaps between the S1 and T1 excited states.
Collapse
Affiliation(s)
- Kevin Curtis
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, USA
| | - Olajumoke Adeyiga
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, USA
| | - Olabisi Suleiman
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, USA
| | - Samuel O Odoh
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, USA
| |
Collapse
|
25
|
Wu S, Kumar Gupta A, Yoshida K, Gong J, Hall D, Cordes DB, Slawin AMZ, Samuel IDW, Zysman‐Colman E. Highly Efficient Green and Red Narrowband Emissive Organic Light-Emitting Diodes Employing Multi-Resonant Thermally Activated Delayed Fluorescence Emitters. Angew Chem Int Ed Engl 2022; 61:e202213697. [PMID: 36300809 PMCID: PMC10100094 DOI: 10.1002/anie.202213697] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Indexed: 11/05/2022]
Abstract
Herein, we demonstrate how judicious selection of the donor decorating a central multi-resonant thermally activated delayed fluorescence (MR-TADF) core based on DiKTa can lead to very high-performance OLEDs. By decorating the DiKTa core with triphenylamine (TPA) and diphenylamine (DPA), 3TPA-DiKTa and 3DPA-DiKTa exhibit bright, narrowband green and red emission in doped films, respectively. The OLEDs based on these emitters showed record-high performance for this family of emitters with maximum external quantum efficiencies (EQEmax ) of 30.8 % for 3TPA-DiKTa at λEL of 551 nm and 16.7 % for 3DPA-DiKTa at λEL =613 nm. The efficiency roll-off in the OLEDs was improved significantly by using 4CzIPN as an assistant dopant in hyperfluorescence (HF) devices. The outstanding device performance has been attributed to preferential horizontal orientation of the transition dipole moments of 3TPA-DiKTa and 3DPA-DiKTa.
Collapse
Affiliation(s)
- Sen Wu
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsFifeKY16 9STSt AndrewsUK
| | - Abhishek Kumar Gupta
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsFifeKY16 9STSt AndrewsUK
- Organic Semiconductor CentreSUPA School of Physics and AstronomyUniversity of St AndrewsKY16 9SSSt AndrewsUK
| | - Kou Yoshida
- Organic Semiconductor CentreSUPA School of Physics and AstronomyUniversity of St AndrewsKY16 9SSSt AndrewsUK
| | - Junyi Gong
- Organic Semiconductor CentreSUPA School of Physics and AstronomyUniversity of St AndrewsKY16 9SSSt AndrewsUK
| | - David Hall
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsFifeKY16 9STSt AndrewsUK
| | - David B. Cordes
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsFifeKY16 9STSt AndrewsUK
| | - Alexandra M. Z. Slawin
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsFifeKY16 9STSt AndrewsUK
| | - Ifor D. W. Samuel
- Organic Semiconductor CentreSUPA School of Physics and AstronomyUniversity of St AndrewsKY16 9SSSt AndrewsUK
| | - Eli Zysman‐Colman
- Organic Semiconductor CentreEaStCHEM School of ChemistryUniversity of St AndrewsFifeKY16 9STSt AndrewsUK
| |
Collapse
|
26
|
Lee HL, Jeon SO, Kim I, Kim SC, Lim J, Kim J, Park S, Chwae J, Son WJ, Choi H, Lee JY. Multiple-Resonance Extension and Spin-Vibronic-Coupling-Based Narrowband Blue Organic Fluorescence Emitters with Over 30% Quantum Efficiency. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2202464. [PMID: 35762112 DOI: 10.1002/adma.202202464] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Achieving narrow-bandwidth emission and high external quantum efficiency (EQE) simultaneously is a challenge for next-generation blue-emitting organic light-emitting diodes (OLEDs). In this study, novel multiple-resonance thermally activated delayed fluorescence (MR-TADF) emitters are developed by fusing an indolocarbazole unit with two carbazole skeletons using para-oriented nitrogen atoms. The resulting rigid and planar π-system without electron-accepting atoms exhibits pure blue photoluminescence at 470 nm, reaching a 100% quantum yield with a full-width-at-half-maximum (FWHM) of 25 nm. Higher-level quantum chemistry calculations confirm an MR effect within the extended π-conjugation and an enhanced triplet-to-singlet crossover (104 s-1 ) through a reduced energy gap (ΔEST ) coupled with large spin-vibronic coupling mediated by low-lying triplet excited states. An OLED fabricated using the MR-TADF emitter with CIE color coordinates of (0.12, 0.16) exhibits a record high EQE of 30.9% and a small FWHM of 23 nm. With further optimization of the device structure, a high EQE of 33.8% is achieved without additional outcoupling enhancements owing to the near-perfect horizontal alignment of the emitting dipoles.
Collapse
Affiliation(s)
- Ha Lim Lee
- School of Chemical Engineering, Sungkyunkwan University 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| | - Soon Ok Jeon
- Samsung Advanced Institute of Technology, Samsung Electronics, 130 Samsung-ro, Suwon, Gyeonggi, 16678, Republic of Korea
| | - Inkoo Kim
- Innovation Center, Samsung Electronics, Hwaseong, 18448, Republic of Korea
| | - Seung Chan Kim
- School of Chemical Engineering, Sungkyunkwan University 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| | - Junseop Lim
- School of Chemical Engineering, Sungkyunkwan University 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| | - Joonghyuk Kim
- Samsung Advanced Institute of Technology, Samsung Electronics, 130 Samsung-ro, Suwon, Gyeonggi, 16678, Republic of Korea
| | - Sangho Park
- Samsung Advanced Institute of Technology, Samsung Electronics, 130 Samsung-ro, Suwon, Gyeonggi, 16678, Republic of Korea
| | - Jun Chwae
- Samsung Advanced Institute of Technology, Samsung Electronics, 130 Samsung-ro, Suwon, Gyeonggi, 16678, Republic of Korea
| | - Won-Joon Son
- Innovation Center, Samsung Electronics, Hwaseong, 18448, Republic of Korea
| | - Hyeonho Choi
- Samsung Advanced Institute of Technology, Samsung Electronics, 130 Samsung-ro, Suwon, Gyeonggi, 16678, Republic of Korea
| | - Jun Yeob Lee
- School of Chemical Engineering, Sungkyunkwan University 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 16419, Republic of Korea
| |
Collapse
|