Abstract Charge carrier dynamics and behaviors are key parameters and need to be mapped at the nanoscale in order to search for correct materials for high-performance solar cells. Unfortunately, currently, there are no existing tools or capabilities that can simultaneously map charge carrier dynamics at nanometer range in solar cells. Here we use a Transient Photo-response AFM (TP-AFM) to map for the first time apparent carrier recombination lifetime (τr), transport time (τt) and diffusion length (LD) in hybrid perovskites solar cells. These spatially resolved parameters reveal substantial variations at grain boundaries (GBs) of perovskites. Improved τr, τt and LD at GBs broaden the performance of these state-of-the-art mixed cation perovskites. Detail analysis of these parameters allow us to conclude that reduced density of trap states and recombination in mixed cation perovskites at GBs and its surrounding locations (extending to several nanometers into the grain interior) implies less ion migration. This first of its kind experimental realization of nanoscale mapping of charge carrier dynamics in photovoltaic materials can be used for applications in other optoelectronic devices.

中文翻译：

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钙钛矿太阳能电池中电荷载流子动力学的纳米级空间映射

摘要 电荷载流子动力学和行为是关键参数，需要在纳米尺度上进行映射，以便为高性能太阳能电池寻找合适的材料。不幸的是，目前没有现有的工具或能力可以同时映射太阳能电池中纳米范围内的电荷载流子动力学。在这里，我们使用瞬态光响应 AFM (TP-AFM) 首次绘制了混合钙钛矿太阳能电池中的表观载流子复合寿命 (τr)、传输时间 (τt) 和扩散长度 (LD)。这些空间解析参数揭示了钙钛矿晶界 (GB) 的显着变化。GB 上改进的 τr、τt 和 LD 拓宽了这些最先进的混合阳离子钙钛矿的性能。对这些参数的详细分析使我们能够得出结论，在 GB 及其周围位置（延伸至晶粒内部几纳米）的混合阳离子钙钛矿中陷阱态密度和复合的降低意味着离子迁移较少。这是光伏材料中电荷载流子动力学纳米级映射的首次实验实现，可用于其他光电器件。