Shape and phase evolution from CsPbBr₃ perovskite nanocubes to tetragonal CsPb₂Br₅ nanosheets with an indirect bandgap

Abstract

Tetragonal CsPb₂Br₅ nanosheets were obtained by an oriented attachment of orthorhombic CsPbBr₃ nanocubes, involving a lateral shape evolution from octagonal to square. Meanwhile, the experimental results, together with DFT simulation results, indicated that the tetragonal CsPb₂Br₅ is an indirect bandgap semiconductor that is PL-inactive with a bandgap of 2.979 eV.