Layer-number tailoring and template-induced orientation control of 2D perovskites on 3D perovskites by adopting the Dion–Jacobson phase

Abstract

Orientation-controlled 2D perovskites consisting of octahedral monolayers have been realized on 3D perovskites. By bar-coating a Dion–Jacobson (DJ) phase 2D perovskite precursor solution onto 3D perovskite thin films, the conversion of the top layer of 3D perovskite to 2D perovskite was promoted, and the optimal 2D/3D heterostructure could be fabricated. The orientation of the DJ 2D perovskite could be controlled horizontally or obliquely according to the 3D perovskite template thin films; the 2D perovskite was obliquely oriented on (200)/(112)-oriented CH3NH3PbI3, and horizontally oriented on (110)-oriented CH3NH3PbI2.5Cl0.5. This approach would boost the stability and power conversion efficiency of 2D/3D heterostructures.