Negative capacitance in photovoltaic devices has been observed and reported in several cases, but its origin, at low or intermediate frequencies, is under debate. Here we unambiguously demonstrate a direct correlation between the observation of this capacitance and a corresponding decrease in performance of a halide perovskite (HaP; CsPbBr₃)-based device, expressed as reduction of open-circuit voltage and fill factor. We have prepared highly stable CsPbBr₃ HaPs that do not exhibit any degradation over the duration of the impedance spectroscopy measurements, ruling out degradation as the origin of the observed phenomena. Reconstruction of current–voltage curves from the impedance spectroscopy provided further evidence of the deleterious role of negative capacitance on photoconversion performance.

中文翻译：

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负电容对卤化物钙钛矿太阳能电池性能的有害影响

在几种情况下，已经观察到并报道了光伏器件中的负电容，但是其起源是在中低频还是在争论中。在这里，我们明确地证明了对这种电容的观察与基于卤化钙钛矿（HaP; CsPbBr ₃）的器件性能的相应降低之间的直接相关性，表示为开路电压和填充因子的降低。我们准备了高度稳定的CsPbBr ₃在阻抗谱测量过程中没有表现出任何降解的HaP，排除了降解是观察到的现象的根源。通过阻抗谱重建电流-电压曲线，进一步提供了负电容对光转换性能的有害作用的证据。