We developed a “photoconductive noise microscopy” method to directly image electronic charge traps distributed on a methylammonium lead iodide perovskite film in a solar cell device. The method enabled quantitative imaging of trap densities along with local photocurrents on the solar cell film. By analyzing the imaging data, we could reveal quantitative correlations between the trap distribution and local photocurrents. The results show that the spatial density of the charge traps has a power-law relationship with the short-circuit currents during a solar cell operation as well as localized photocurrents under a sample bias, indicating that a charge trap distribution in a perovskite film can be a major factor determining the performance of the perovskite-based solar cells.

我们开发了一种“光电导噪声显微镜”方法，以直接对分布在太阳能电池设备中的甲基铵碘化铅钙钛矿膜上的电子电荷陷阱成像。该方法能够对陷阱密度以及太阳能电池膜上的局部光电流进行定量成像。通过分析成像数据，我们可以揭示陷阱分布和局部光电流之间的定量相关性。结果表明，电荷陷阱的空间密度与太阳能电池工作过程中的短路电流以及样品偏压下的局部光电流具有幂律关系，这表明钙钛矿膜中的电荷陷阱分布可以是决定钙钛矿基太阳能电池性能的主要因素。