New Progress in Multi-Exciton Generation Reactions Using Organic Materials

2021 Fiscal Year Final Research Report

• Project/Area Number: 18H01957
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 32020:Functional solid state chemistry-related
• Research Institution: Keio University
• Principal Investigator: Hasobe Taku 慶應義塾大学, 理工学部(矢上), 教授 (70418698)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 多励起子生成反応

Outline of Final Research Achievements

Singlet fission (SF) is a photophysical process in which two individual triplet states generation from one-photon absorption via correlated triplet pair. Most of the examples of highly efficient SF are discussed by using pentacene derivatives.The triplet excitation energy of pentacene is extremely small (0.86 eV) as compared to the conventional organic molecules. Considering the photovoltaic and photocatalytic applications, tetracene is a good candidate because tetracene has a high E(T1) = 1.3 eV and a long lifetime of T1 (τ = 0.63 ms). In this work, we demonstrated high-yield individual triplet excited states together with sequential photoinduced process of SF with electron transfer or singlet oxygen generation. The detail synthesis and evaluation of phoinduced process is discussed here.

Free Research Field

光化学

Academic Significance and Societal Importance of the Research Achievements

従来の光化学反応では吸収光子数に対するエネルギー変換過程の最大量子収率は100％である。一方、近接二分子間での一光子の吸収過程から二つの三重項励起子を生成する一重項分裂を用いることで量子収率は最大200％となる。本研究では、励起子生成の量子収率を向上させるだけでなく、電子移動や一重項酸素発生などの逐次反応系の構築にも成功した。