Vacancy Defects’ Effects on the Optoelectronic Properties of MAPbI3

This work derived the relationship between the concentrations of Pb2+ and I- vacancies, along with MA+ vacancies, in MAPbI3 crystals and their effect on the short-circuit current of MAPbI3-based solar photovoltaic devices. First principles calculations revealed that Pb2+ and I- vacancies introduce shallow defect levels near the Fermi level, acting as non-radiative recombination centers, which significantly influence the short-circuit current and open-circuit voltage. In contrast, MA+ vacancies have a negligible effect on the optoelectronic properties of MAPbI3. Based on this correlation, we successfully elucidated the declining trend of the short-circuit current (Jsc) in MAPbI3-based devices with increasing Pb2+/I- vacancy concentrations, while uncovering the microscopic mechanism responsible for the minor performance impact of MA+ vacancies.