Single-particle reaction observation of organic-inorganic perovskite solar cells

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H03771
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Physical chemistry
• Research Institution: Kobe University
• Principal Investigator: Tachikawa Takashi 神戸大学, 分子フォトサイエンス研究センター, 准教授 (20432437)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 有機無機ペロブスカイト / 単一粒子分光 / 電子移動 / ナノ粒子 / フォトルミネッセンス / 太陽電池

Outline of Final Research Achievements

Using single-particle photoluminescence (PL) imaging and spectroscopy, we have studied the size and composition-dependent photo-charge dynamics. From the PL spectra and the corresponding TEM images, it was found that smaller particles, especially less than 10 nm, exhibited quantum confinement effect. Spectral and lifetime analyses of PL revealed that that the photogenerated electrons were equilibrated between the inner bulk CH3NH3PbBr3 and the outer CH3NH3PbIxBr3-x domains with 0 < x < 1 during halide exchange reaction, while stationary holes resided at CH3NH3PbIxBr3-x domains. Moreover, emission signals appeared with a duration of several dozen milliseconds. These are attributable to the PL from individual nanometer-scale iodide-rich domains with x = 2, and their lifetimes are suggested to be limited by reaction with diffusing halide vacancies. Our findings will help to understand the operating principle of perovskite-based devices and facilitate their applications.

Free Research Field

光化学