Component-controllable Synthesis of Stable Planar-structure Perovskite CH3NH3Pb(I1−xBrx)3 Thin Films

The pure-phase Br-doped CH3NH3PbI3 films with a planar structure have been fabricated by evaporating a mixed powder with different proportions of CH3NH3I and CH3NH3Br, and the component-controllable CH3NH3Pb(I1−xBrx)3 thin films can be successfully obtained. The study results indicated that the component change in CH3NH3Pb(I1−xBrx)3 films not only affects the color and band gaps, but also influences the stability of the perovskite films. When the Br content in CH3NH3Pb(I1−xBrx)3 films reaches 0.5, the perovskite films display an excellent stability. We demonstrate efficient solar cells exhibiting 6.8% power conversion efficiency under AM 1.5G illumination.