Reversible transformation between CsPbBr3 and Cs4PbBr6 nanocrystals

A reversible transformation between CsPbBr3 and Cs4PbBr6 nanocrystals through a simple treatment with extra ligands or PbBr2 (for the reverse direction) is reported. These transformations are so far the first report of direct reversibility, without a net change in morphology, between CsPbBr3 and Cs4PbBr6 and then back to CsPbBr3 nanocrystals, which provides a mechanism for flexible reorganization of the lead halide perovskite lattice.