Role of organic cations on hybrid halide perovskite CH3NH3PbI3 surfaces

Optimized stable structure [top view from (001) direction] of (a) the cubic, (b) orthorhombic, (c) tetragonal phases of CH3NH3PbI3 with CH3NH3 cation along [100] direction, respectively. (d) Surface termination diagram of tetragonal CH3NH3PbI3 with CH3NH3 cation along [100] direction.135