The role of hydrogen in nonradiative recombination in CsPbI₃: a first-principles investigation

Abstract Defect-induced nonradiative recombination is the main factor hindering the efficiency improvement in CsPbI3 perovskite solar cells. It has been recently claimed that the unintentionally incorporated hydrogen impurity can potentially cause nonradiative losses because of the deep levels. Using first-principles approaches, we show that, as a matter of fact, the hydrogen impurity has a negligible effect on carrier recombination in CsPbI3 due to its small nonradiative capture coefficient and low density. This insight rationalizes why the addition of hydriodic acid does not reduce carrier lifetime and could prevent acidic additives being discarded as potential candidates for assisting film growth.