Mobile Charge-Induced Fluorescence Intermittency in Methylammonium Lead Bromide Perovskite

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• 作者：Xiaoming Wen ; Anita Ho-Baillie ; Shujuan Huang ; Rui Sheng ; Sheng Chen ; Hsien-chen Ko ; Martin A. Green
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：July 8, 2015
• 年：2015
• 卷：15
• 期：7
• 页码：4644-4649
• 全文大小：388K
• ISSN：1530-6992

文摘

Organic鈥搃norganic halide perovskite has emerged as a very promising material for solar cells due to its excellent photovoltaic enabling properties resulting in rapid increase in device efficiency over the last 3 years. Extensive knowledge and in-depth physical understanding in the excited state carrier dynamics are urgently required. Here we investigate the fluorescence intermittency (also known as blinking) in vapor-assisted fabricated CH₃NH₃PbBr₃ perovskite. The evident fluorescence blinking is observed in a dense CH₃NH₃PbBr₃ perovskite film that is composed of nanoparticles in close contact with each other. In the case of an isolated nanoparticle no fluorescence blinking is observed. The 鈥淥N鈥?probability of fluorescence is dependent on the excitation intensity and exhibits a similar power rule to semiconductor quantum dots at higher excitation intensity. As the vapor-assisted fabricated CH₃NH₃PbBr₃ perovskite film is a cluster of nanoparticles forming a dense film, it facilitates mobile charge migration between the nanoparticles and charge accumulation at the surface or at the boundary of the nanoparticles. This leads to enhanced Auger-like nonradiative recombination contributing to the fluorescence intermittency observed. This finding provides unique insight into the charge accumulation and migration and thus is of crucial importance for device design and improvement.