Cl-Assisted Perovskite Crystallization Pathway in the Confined Space of Mesoporous Metal Oxides Unveiled by In Situ Grazing Incidence Wide-Angle X-ray Scattering

The chloride ion is widely used to improve the morphology and crystallization of the perovskite film, but its influence on the crystallization pathway is still unclear. Here, the Cl-assisted perovskite crystallization pathway in the mesoporous metal oxides is unveiled by in situ grazing incidence wide-angle X-ray scattering. The in situ characterizations suggest that Cl– ions can effectively delay the formation of the intermediate MA2Pb3I8·2DMSO and shorten its existence time, promote the conversion of the intermediate to perovskite, and ultimately significantly improve the morphology and crystallinity of the perovskite in the mesoscopic structure. The photoelectric properties of Cl-assisted perovskite films are more excellent than those of the pristine MAPbI3, resulting in the efficiency increasing to 16.85% from 12.23%.