Hexagonal boron nitride as a cationic diffusion barrier to form a graded band gap perovskite heterostructure

We demonstrate a new technique to produce graded bandgap organohalide perovskite heterostructures using hexagonal boron nitride (h-BN) as a cationic separator. With this technique, we successfully deposit CH3NH3PbI3−xBrx on CH3NH3SnI3 without cation mixing.