Comparative study of vapor- and solution-crystallized perovskite for planar heterojunction solar cells

Organometal halide perovskite (CH3NH3PbI3) could be crystallized by exposing PbI2 to either CH3NH3I solution or CH3NH3I vapor. Though high performance was achieved in both approaches, it was still not clear which approach would be more desirable for device performance in principle. Herein, we addressed this issue by investigating the influence of crystallization condition on perovskite morphology, and subsequently on device performances. We found that vapor-crystallized perovskite devices demonstrated smoother surface morphology, better light absorption, lower charge recombination, and thus much higher conversion efficiency than solution-crystallized devices, which would give some useful enlightenment to develop high-performance planar perovskite solar cells.