Benign Hydrogen Vacancy in Bromide-Based Organic–Inorganic Hybrid Perovskites

Bromide-based organic-inorganic hybrid perovskites (OIHPs) have emerged as one of the outstanding photovoltaic materials. We demonstrate using density functional theory and nonadiabatic molecular dynamics simulations that detrimental hydrogen vacancy (VH) in iodide-based OIHPs turns out to be benign in bromide-based OIHPs. Benign VH in MAPbBr3 [MA = CH3NH3] is mainly attributed to the absence of deep trap states. Although the VH in FAPbBr3 [FA = HC(NH2)2] has been demonstrated to be a deep-level defect, its remarkably high formation energy and low total capture coefficient (7.69 × 10-13 cm3 s-1), associated with the weak electron-phonon coupling and efficient thermal excitation, effectively suppress the nonradiative charge recombination. As a result, the long charge carrier lifetime of FAPbBr3 can be maintained. These findings reveal the intrinsic advantage owing to benign VH in bromide-based OIHPs and provide critical theoretical insights for minimizing nonradiative charge losses.