CsPbBrCl Solid Solutions: Understanding the Relationship between Lattice Expansion and Optical Properties.

All-inorganic halide perovskite semiconductors have received extensive attention due to their excellent photoelectronic conversion efficiency. Prior studies have reported on compounds CsPbBr and CsPbCl. However, the transition phases between them have not been systematically studied. Here, a series of large-size single crystals of CsPbBrCl ( = 0-3) were successfully grown by the Bridgman method, which proves that the Br and Cl atoms can be miscible in any proportion in the solid solution system, and the change of lattice parameters conforms to Vegard's law. Also, the bandgap and light emission were studied. It is found that the band gap (2.90-2.29 eV) and photoluminescence characteristics (from blue light to green light) can be effectively tuned by adjusting the content of the Br atom. These results provide valuable guidance for the development and optimization of photoelectronic semiconductors that can meet different practical demands.