Exciton Absorption Spectrum of Thin CsPbI3 and Cs4PbI6 Films

Abstract

A method for preparing thin films of CsPbI3 and Cs4PbI6 complex compounds has been devel oped. Their absorption spectrum is investigated in the energy range of 2–6 eV at temperatures from 90 to 500 K. It is found that the CsPbI3 compound is unstable and passes to the Cs4PbI6 phase upon heating at T ≥ 400 K.