Photocarrier dynamics in perovskite solar cells and their constituent materials and analysis of their electronic structure

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15521
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 32020:Functional solid state chemistry-related
• Research Institution: Kobe City College of Technology (2020-2021); Kobe University (2019)
• Principal Investigator: Morihiko Hamada 神戸市立工業高等専門学校, その他部局等, 講師 (70827948)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 光化学 / 電荷分離 / ペロブスカイト / 磁気共鳴 / 有機薄膜太陽電池

Outline of Final Research Achievements

methylammonium Lead iodide (MAPbI3) has been intensively investigated for perovskite solar cells, but the charge separation state, which is the basis of the photoelectric conversion mechanism, has not been observed. In this study, we attempted to directly observe the charge-separation state of MAPbI3 by time-resolved electron paramagnetic resonance spectroscopy (TREPR). However, we couldn't observe the charge-separated state.
We considered that the electrons produced by charge separation are trapped at the trap site, and started to study the release of charge from the trap site. Specifically, we developed a two-color TREPR method. For the sample, we used a mixed thin film of PTzBT-BOHD and PC71BM, which were developed as candidates for organic thin film solar cell materials. Currently, we have obtained the results of charge release from the trap sites and are in the process of developing an analysis program.

Free Research Field

光化学

Academic Significance and Societal Importance of the Research Achievements

本研究ではMAPbI3の電荷分離状態の直接観察にまでは至らなかったが、2色TREPR法の開発は完了しており、今後は解析プログラムの開発と一般化によりさまざまな試料における電化分離状態の詳細な構造解析が可能になることが本研究の学術的意義である。一方、詳細な構造解析結果の実現は、その後の各種デバイス開発前に多量の知識を蓄えられるため、今以上に効率的に材料選定できるようになる。これが本研究の社会的意義である。