The improved performance for KI incorporated perovskite solar cells are clarified from the point view of grain boundry and interface passivation.

Tin oxide SnO₂films were prepared by RF magnetron sputtering. The effects of oxygen partial pressure percentage on the SnO₂property have been investigated to obtain relatively high-resistivity SnO₂films which could be used as buffer layers to optimize the performance of CdTe/CdS solar cells. The oxygen partial pressure percentage varied in the range of 1%~10%. The results show that the introduction of oxygen would suppress the deposition and growth of SnO₂films. Electrical measurement suggests that the film resistivity decreases with the increase of oxygen pressure. The SnO₂films with resistivity of 232 Ω cm were obtained in pure Ar atmosphere. All SnO₂films fabricated with different oxygen partial pressure percentage have almost the same optical band gap.