In situ Spectroscopy of Solid-State Chemical Reaction in PbBr₂-Deposited CsBr Crystals

Abstract

It is possible to measure the fundamental optical absorption spectra of CsPbBr₃ and Cs₄PbBr₆, whose stability is predicted by the study of phase diagram in the binary system CsBr–PbBr₂, by means of in situ optical absorption and reflection spectroscopy of thermally induced solid-state chemical reaction in PbBr₂-deposited CsBr crystals. On heavy annealing of the crystals, the Pb²⁺ ions are uniformly dispersed in the crystal matrix. The present experiment provides a novel method for measuring intrinsic optical absorption of ternary metal halides and also for in situ monitoring of doping metal halide crystal with impurities (metal ions or halogen ions).