High-Quality Mixed-Organic-Cation Perovskites from a Phase-Pure Non-stoichiometric Intermediate (FAI)1-x-PbI2 for Solar Cells

A high-quality mixed-organic-cation perovskite (MA)(x)(FA)(1-x)PbI3 is prepared from a phase-pure non-stoichiometric intermediate complex (FAI)(1-x)-PbI2. The phase-pure (FAI)(1-x)-PbI2 probably facilitates homogenous nucleation and modulates the growth kinetics during the crystallization of (MA)(x)(FA)(1-x)PbI3. This strategy can be expected to pave the way for the development of mixed-organic-cation perovskite solar cells.