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

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 I-i and antisites I-Cs, 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.

Automated summary

It is demonstrated that hydrogen impurities incorporated in all-inorganic perovskite CsPbI3 can act as efficient nonradiative recombination centers, contributing to a higher nonradiative efficiency loss compared to native deep defects. Additionally, it is proposed that iodine-moderate growth conditions can effectively reduce detrimental hydrogen ions.