Stable High-Performance Perovskite Solar Cells via Passivation of the Grain Boundary and Interface

The carrier recombination at the perovskite grain boundary and layer interface is the main factor that limits the efficiency of the perovskite solar cells (PSCs). Herein, such recombination loss is significantly improved by inducing a new adduct [lead(II) iodide–tetramethylene sulfoxide (PbI2–TMSO)] into the perovskite precursor solution (this adduct can stably exist in the solution). After annealing, the grain boundary of the perovskite film can be passivated by the annealed-remaining PbI2. Notably, PbI2–TMSO changes the crystallization kinetics, resulting in large grain size and high crystallinity of the perovskite film. Subsequently, phenethylammonium iodide (PEAI) is further used to passivate the interface between perovskite and hole transporting layer for an excellent efficiency (22.84%). The two-dimensional perovskite formed by the reaction of PEAI and the residual PbI2 (on the surface) improves the thermal stability. Moreover, a larger-area module (substrate: 4 × 4 cm2, active area: 7.2 cm2) with an efficiency of 16.82% is assembled successfully, indicating its scalability in passivation for PSCs.