Hydrogen-Induced Nonradiative Recombination in All-Inorganic CsPbI3 Perovskite Solar Cells

Abstract

All-inorganic halide perovskites have thus far exhibited better thermal stability but lower power conversion efficiency (PCE), compared with their organic–inorganic hybrid counterparts. The experimentally observed nonradiative recombination loss is commonly attributed to the prevalence of native deep defects, yet the exact microscopic origin remains elusive. Based on density functional theory calculations, it is demonstrated that hydrogen impurities may incorporate in the prototypical all-inorganic perovskite CsPbI3 with a high density and serve as a new source of efficient nonradiative recombination centers. The resultant nonradiative efficiency loss can be significantly higher than those induced by native deep defects, namely interstitials (Formula presented.) and antisites (Formula presented.), contributing to the subdued performance of the CsPbI3-based devices. Furthermore, it is proposed that the iodine-moderate growth conditions can effectively reduce the detrimental hydrogen ions. These results highlight the impact of unintentionally incorporated impurities and offer insights into the optimal synthetic route and practical operating protocols in the field of all-inorganic perovskite solar cells.