1
|
Mamada M, Aoyama A, Uchida R, Ochi J, Oda S, Kondo Y, Kondo M, Hatakeyama T. Efficient Deep-Blue Multiple-Resonance Emitters Based on Azepine-Decorated ν-DABNA for CIE y below 0.06. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2402905. [PMID: 38695744 DOI: 10.1002/adma.202402905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 04/19/2024] [Indexed: 05/23/2024]
Abstract
Ultrapure deep-blue emitters are in high demand for organic light-emitting diodes (OLEDs). Although color coordinates serve as straightforward parameters for assessing color purity, precise control over the maximum wavelength and full-width at half-maximum is necessary to optimize OLED performance, including luminance efficiency and luminous efficacy. Multiple-resonance (MR) emitters are promising candidates for achieving ideal luminescence properties; consequently, a wide variety of MR frameworks have been developed. However, most of these emitters experience a wavelength displacement from the ideal color, which limits their practical applicability. Therefore, a molecular design that is compatible with MR emitters for modulating their energy levels and color output is particularly valuable. Here, it is demonstrated that the azepine donor unit induces an appropriate blue-shift in the emission maximum while maintaining efficient MR characteristics, including high photoluminescence quantum yield, narrow emission, and a fast reverse intersystem crossing rate. OLEDs using newly developed MR emitters based on the ν-DABNA framework simultaneously exhibit a high quantum efficiency of ≈30%, luminous efficacy of ≈20 lm W-1, exceptional color purity with Commission Internationale de l'Éclairage coordinates as low as (0.14, 0.06), and notably high operational stability. These results demonstrate unprecedentedly high levels compared with those observed in previously reported deep-blue emitters.
Collapse
Affiliation(s)
- Masashi Mamada
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Akio Aoyama
- Department of Chemistry, Graduate School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan
| | - Ryota Uchida
- 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
| | - Susumu Oda
- Department of Applied Chemistry, Graduate School of Science and Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama, 350-8585, Japan
| | - Yasuhiro Kondo
- SK JNC Japan Co., Ltd., 5-1 Goi Kaigan, Ichihara, Chiba, 290-8551, Japan
| | - Masakazu Kondo
- JNC Co., Ltd., 5-1 Goi Kaigan, Ichihara, Chiba, 290-8551, Japan
| | - Takuji Hatakeyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| |
Collapse
|
2
|
Tsuchiya Y, Mizukoshi K, Saigo M, Ryu T, Miyata K, Onda K, Adachi C. Luminescence mechanism analysis of a TADF molecule showing peculiar thermal behavior. Faraday Discuss 2024; 250:233-250. [PMID: 38031437 DOI: 10.1039/d3fd00151b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
In recent years, much attention has been paid to the development of thermally activated delayed fluorescence (TADF) materials with short delayed-fluorescence lifetimes to improve the device performances of OLEDs. In principle, by reducing the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) overlap, while the energy difference between S1-T1 (ΔEST) and activation energy (Ea) can be reduced, and the reverse intersystem crossing rate constant (kRISC) can be accelerated, a decrease in the radiative rate constant happens, necessitating an advanced molecular design. Furthermore, a molecule based on heptazine as a parent skeleton has recently been found to have a peculiar temperature dependence of luminescence decay, suggesting a negative gap (NG) material. In this report, we show that 9-[1,4]benzoxaborino[2,3,4-kl]phenoxaborine-7-yl-1,3,6,8-tetramethyl-9H-carbazole (TMCz-BO), a donor-acceptor linked TADF molecule with a very short delay lifetime of 750 ns, exhibits a peculiar thermal behavior similar to that of NG materials based on the temperature dependence of its luminescence decay in solution.
Collapse
Affiliation(s)
- Youichi Tsuchiya
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
| | - Keito Mizukoshi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
| | - Masaki Saigo
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Tomohiro Ryu
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Kiyoshi Miyata
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Ken Onda
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
- International Institute for Carbon Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Sumida A, Onishi T, Imoto H, Naka K. Synthesis, structures, and photophysical properties of π-extended arsaborins. Dalton Trans 2024; 53:1706-1713. [PMID: 38168688 DOI: 10.1039/d3dt03798c] [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
In this study, various (hetero)arene-fused arsaborins were synthesized. All the synthesized arsaborins were stable under ambient conditions and allowed for the chemical modification of the lone pair of the arsenic atom. Experimental and computational studies revealed that these compounds possessed planar structures and weak anti-aromatic properties. Fluorescence with large Stokes shifts was observed due to drastic structural relaxation at 298 K, whereas intense phosphorescence due to the heavy-atom effect of arsenic was observed at 77 K. Furthermore, a thiophene-fused derivative demonstrated a temperature-dependent emission color change in the solid state, attributable to the gradual alteration in the ratio of monomer fluorescence, excimer fluorescence, and phosphorescence.
Collapse
Affiliation(s)
- Akifumi Sumida
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
| | - Tomoharu Onishi
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
| | - Hiroaki Imoto
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
- FOREST, JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012, Japan
| | - Kensuke Naka
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
- Materials Innovation Lab, Kyoto Institute of Technology, Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| |
Collapse
|