A Study of Photoinduced Charge Separation for TiO2–TCNQ Surface Complex

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05289
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: The University of Tokyo
• Principal Investigator: Jono Ryota 東京大学, 先端科学技術研究センター, 客員研究員 (10586936)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 界面電荷移動遷移 / 光電変換 / 太陽電池 / 理論化学 / 分光

Outline of Final Research Achievements

We found the color variation of the TiO2-TCNQ surface complex showing photo-induced direct charge transfer transitions. The charge separation is achieved at the same time of the photon absorp-tion in this mechanism, while usual charge separation mechanisms appeared in photo-catalysis and solar cells need two steps of reac-tions: generation of electronic excited states by photon absorption and injection of electrons from donor to acceptor. The color varia-tion of the TiO2-TCNQ surface complexes enabled us to reveal the relation between interfacial structures and photo properties by measurements of absorption spectrum and FT-IR spectrum with DFT calculations. DFT calculations predicted no dependency of colorations of TiO2-TCNQ surface complex on photo-electron conversion, and it was experimentally confirmed by observation of incident photon-to-current conversion efficiency spectra (IPCE). This agreement supports that the DFT calculation explain all the experiments in this work.

Free Research Field

計算科学・分光

Academic Significance and Societal Importance of the Research Achievements

電子移動反応はあらゆる化学反応の基本であり，特に光誘起電荷移動反応は光合成を代表とする生物におけるエネルギー生産や太陽電池・光触媒などの基礎として幅広く展開されてきた．本研究で注目した界面電荷移動遷移は，光照射によって直接電荷分離状態に達する反応であるが，光合成や太陽電池・光触媒とは異なる全く新しいメカニズムを用いていることから，このメカニズムの解明によって太陽電池や光触媒と並ぶ電子移動反応の新領域の開拓が期待できる．