Mobile Ion Induced Slow Carrier Dynamics in Organic–Inorganic Perovskite CH3NH3PbBr3

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• 作者：Sheng Chen ; Xiaoming Wen ; Rui Sheng ; Shujuan Huang ; Xiaofan Deng ; Martin A. Green ; Anita Ho-Baillie
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 2, 2016
• 年：2016
• 卷：8
• 期：8
• 页码：5351-5357
• 全文大小：445K
• ISSN：1944-8252

文摘

Here, we investigate photoluminescence (PL) and time-resolved photoluminescence (TRPL) in CH₃NH₃PbBr₃ perovskite under continuous illumination, using optical and electro-optical techniques. Under continuous excitation at constant intensity, PL intensity and PL decay (carrier recombination) exhibit excitation intensity dependent reductions in the time scale of seconds to minutes. The enhanced nonradiative recombination is ascribed to light activated negative ions and their accumulation which exhibit a slow dynamics in a time scale of seconds to minutes. The observed result suggests that the organic–inorganic hybrid perovskite is a mixed electronic–ionic semiconductor. The key findings in this work suggest that ions are photoactivated or electro-activated and their accumulation at localized sites can result in a change of carrier dynamics. The findings are therefore useful for the understanding of instability of perovskite solar cells and shed light on the necessary strategies for performance improvement.