Comparative study of exciton properties in CsSnX3(X=Cl, Br, I) halide perovskite thin films

Abstract CsSnX 3 (X = Cl, Br, I) inorganic perovskites exhibit excellent stability and optoelectronic properties. This study establishes a quantitative correlation the regulation of their fundamental physical properties by layers. As X-site atoms increase, the lattice becomes constant, and optimized volume grows. The band gap decreases and absorption spectra shift red as layer thickness increases, without altering the direct bandgap nature. Exciton properties are influenced by X atoms and layer number, with the maximum exciton binding energy decreasing and the Bohr radius increasing as the X atom size grows.