Singlet Fission Materials by Engineering Inter-Exciton Vibronic Coupling

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05629
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 35030:Organic functional materials-related
• Research Institution: Kyoto University
• Principal Investigator: Katsuyuki Shizu 京都大学, 化学研究所, 助教 (10621138)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 遅延蛍光 / 一重項励起子分裂 / 項間交差 / 逆項間交差 / 内部転換 / 多電子励起配置 / Fermiの黄金律 / 有機EL

Outline of Final Research Achievements

Radiative decays (fluorescence and phosphorescence) and nonradiative decays (internal conversion and intersystem crossing) occur simultaneously in organic materials. The competition between these electronic transitions determines material properties. Hence, if one can accurately calculate the rate constants for all the relevant electronic transitions of organic materials, one can understand the excited-state decay mechanism and realize a rapid and accurate material screening method.
In this study, we developed a method of quantitatively calculating rate constants for fluorescence, phosphorescence, internal conversion, and intersystem crossing. We applied this method to representative molecular materials used in organic light-emitting diodes and organic solar cells. We successfully reproduced experimental rate constants and confirmed the validity of our approach.

Free Research Field

材料化学

Academic Significance and Societal Importance of the Research Achievements

分子構造をインプットとして、全ての発光・熱失活過程について、速度定数を高速かつ定量的に計算できれば、励起状態からの失活過程や発光特性を高精度に予測し、材料探索のスピードを大幅に加速できる。このようなコンセプトに基づいて、本研究課題では、蛍光、りん光、内部転換および項間交差の速度定数を高速かつ定量的に計算できる理論手法を開発し、実際の有機エレクトロニクス材料（有機EL材料、有機太陽電池材料）に適用することで、計算手法の妥当性および実用性を実証した。
本研究課題の成果は、材料開発のスピードを大幅に加速し、我が国の材料開発競争力の強化に波及すると考えている。