Perovskite solar cells (PSCs) exhibit large, reversible, and bidirectional light-soaking effects (LSEs); however, these anomalous LSEs are poorly understood, limiting the stability engineering and commercialization. We present a unified defect theory for the LSEs in lead halide perovskites by reconciling their defect photochemistry, ionic migration, and carrier dynamics. We considered typical detrimental defects (I_Pb, I_i, V_I) and observed that two atomic configurations were favored, where the carrier lifetime of one configuration was nearly 1 order of magnitude longer than that in the other. First-principles calculations showed that light illumination promotes ion-diffusion-assisted transitions from energetically stable configurations to metastable configurations, which are converted back to stable configurations in the dark. Fermi-level-dependent formation energies of stable/metastable configurations were used to rationalize contradictory experimental results of anomalous LSEs in PSCs observed in various studies, thus providing insights for minimizing the LSE to achieve high-performance stable PSCs.

中文翻译：

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导致钙钛矿太阳能电池中巨大、可逆和双向光吸收效应的光致动态缺陷

钙钛矿太阳能电池（PSCs）表现出大的、可逆的、双向的光吸收效应（LSEs）；然而，这些异常的 LSE 知之甚少，限制了稳定性工程和商业化。我们通过协调它们的缺陷光化学、离子迁移和载流子动力学，为卤化铅钙钛矿中的 LSE 提出了统一的缺陷理论。我们认为典型的有害的缺陷（我_的Pb，我_我，V_我) 并观察到两种原子配置是有利的，其中一种配置的载流子寿命比另一种配置长近 1 个数量级。第一性原理计算表明，光照促进了离子扩散辅助从能量稳定构型到亚稳态构型的转变，亚稳构型在黑暗中转换回稳定构型。稳定/亚稳态构型的费米能级相关形成能被用于合理化在各种研究中观察到的 PSC 中异常 LSE 的矛盾实验结果，从而为最小化 LSE 以实现高性能稳定 PSC 提供见解。