1
|
Bae J, Imai-Imada M, Kim HS, Lee M, Imada H, Tsuchiya Y, Hatakeyama T, Adachi C, Kim Y. Visualization of Multiple-Resonance-Induced Frontier Molecular Orbitals in a Single Multiple-Resonance Thermally Activated Delayed Fluorescence Molecule. ACS NANO 2024; 18:17987-17995. [PMID: 38934571 DOI: 10.1021/acsnano.4c04813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
The spatial distribution and electronic properties of the frontier molecular orbitals (FMOs) in a thermally activated delayed fluorescence (TADF) molecule contribute significantly to the TADF properties, and thus, a detailed understanding and sophisticated control of the FMOs are fundamental to the design of TADF molecules. However, for multiple-resonance (MR)-TADF molecules that achieve spatial separation of FMOs by the MR effect, the distinctive distribution of these molecular orbitals poses significant challenges for conventional computational analysis and ensemble averaging methods to elucidate the FMOs' separation and the precise mechanism of luminescence. Therefore, the visualization and analysis of electronic states with the specific energy level of a single MR-TADF molecule will provide a deeper understanding of the TADF mechanism. Here, scanning tunneling microscopy/spectroscopy (STM/STS) was used to investigate the electronic states of the DABNA-1 molecule at the atomic scale. FMOs' visualization and local density of states analysis of the DABNA-1 molecule clearly show that MR-TADF molecules also have well-separated FMOs according to the internal heteroatom arrangement, providing insights that complement existing theoretical prediction methods.
Collapse
Affiliation(s)
- Jaehyun Bae
- Surface and Interface Science Laboratory (SISL), RIKEN, Wako, Saitama 351-0198, Japan
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Miyabi Imai-Imada
- Surface and Interface Science Laboratory (SISL), RIKEN, Wako, Saitama 351-0198, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Hyung Suk Kim
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Minhui Lee
- Surface and Interface Science Laboratory (SISL), RIKEN, Wako, Saitama 351-0198, Japan
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 118-8656, Japan
| | - Hiroshi Imada
- Surface and Interface Science Laboratory (SISL), RIKEN, Wako, Saitama 351-0198, Japan
| | - Youichi Tsuchiya
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Takuji Hatakeyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Sakyo 606-8502, Japan
| | - Chihaya Adachi
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
- Department of Applied Chemistry, 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
| | - Yousoo Kim
- Surface and Interface Science Laboratory (SISL), RIKEN, Wako, Saitama 351-0198, Japan
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 118-8656, Japan
| |
Collapse
|
2
|
Omar Ö, Xie X, Troisi A, Padula D. Identification of Unknown Inverted Singlet-Triplet Cores by High-Throughput Virtual Screening. J Am Chem Soc 2023; 145:19790-19799. [PMID: 37639703 PMCID: PMC10510316 DOI: 10.1021/jacs.3c05452] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Indexed: 08/31/2023]
Abstract
Molecules where the energy of the lowest excited singlet state is found below the energy of the lowest triplet state (inverted singlet-triplet molecules) are extremely rare. It is particularly challenging to discover new ones through virtual screening because the required wavefunction-based methods are expensive and unsuitable for high-throughput calculations. Here, we devised a virtual screening approach where the molecules to be considered with advanced methods are pre-selected with increasingly more sophisticated filters that include the evaluation of the HOMO-LUMO exchange integral and approximate CASSCF calculations. A final set of 7 candidates (0.05% of the initial 15 000) were verified to possess inversion between singlet and triplet states with state-of-the-art multireference methods (MS-CASPT2). One of them is deemed of particular interest because it is unrelated to other proposals made in the literature.
Collapse
Affiliation(s)
- Ömer
H. Omar
- Department
of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.
| | - Xiaoyu Xie
- Department
of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.
| | - Alessandro Troisi
- Department
of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.
| | - Daniele Padula
- Dipartimento
di Biotecnologie, Chimica e Farmacia, Università
di Siena, Via A. Moro
2, Siena 53100, Italy
| |
Collapse
|
3
|
Wang Y, Zhao W, Ma Z, Li L, Ma L, Tian G. Theoretical study on the vibrational structures in the conductance spectra of a weakly coupled polycyclic aromatic hydrocarbon molecule. Chem Phys Lett 2023. [DOI: 10.1016/j.cplett.2022.140272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
4
|
Bergmann K, Hojo R, Hudson ZM. Uncovering the Mechanism of Thermally Activated Delayed Fluorescence in Coplanar Emitters Using Potential Energy Surface Analysis. J Phys Chem Lett 2023; 14:310-317. [PMID: 36602966 DOI: 10.1021/acs.jpclett.2c03425] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Planarized emitters exhibiting thermally activated delayed fluorescence (TADF) have attracted attention due to their narrow emission spectra, improved photostability, and high quantum yields, but with large singlet-triplet energy gaps (ΔEST) and no heavy atoms, the origin of their TADF remains a subject of debate. Here we prepare two isomeric, coplanar donor-acceptor compounds, with HMAT-2PYM performing dual TADF and room-temperature phosphorescence but with HMAT-4PYM exhibiting only prompt fluorescence. Although conventional TADF design principles suggest that neither isomer should exhibit TADF, we reveal differences in the excited state potential energy surfaces that enable spin-flip processes in only one isomer. We also find that hydrogen bonding is absent between the planar units of these emitters, despite earlier claims of intramolecular hydrogen bonding in similar compounds. Overall, this work demonstrates that potential energy surface analysis is a practical strategy for designing coplanar TADF materials that might otherwise be overlooked by conventional TADF design metrics.
Collapse
Affiliation(s)
- Katrina Bergmann
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Ryoga Hojo
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Zachary M Hudson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| |
Collapse
|
5
|
Wei K, Louis H, Emori W, Idante PS, Agwamba EC, Cheng CR, Eno EA, Unimuke TO. Antispasmodic activity of carnosic acid extracted from rosmarinus officinalis: Isolation, spectroscopic characterization, DFT studies, and in silico molecular docking investigations. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.132795] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|