Cesium Lead Bromides—Structural, Electronic and Optical Properties

In recent years, it has been found that lowering the dimensionality of halide perovskites leads to enhanced photoluminescence and stability than their three-dimensional counterparts. Further, the change in the dimensionality of an inorganic halide perovskite can evoke surprising ramifications to its intrinsic behavior. The dimensionality in perovskites is governed by its octahedral cages. In zero-dimensional perovskites, the octahedral cages are discrete, whereas in two-dimensional perovskites, they are connected with one another resulting in the formation of a layer. Likewise, in three-dimensional perovskites, the octahedral cages share the corner atoms with each other. This study describes the two-dimensional counterpart of cesium lead bromide perovskites. The structural, electronic and optical properties, in conjunction with their three-dimensional structure, are presented. The emergence of new physical phenomena with respect to the decreasing dimensionality of cesium lead bromide perovskites is analyzed.