Exciton spectra of Cs1–xRbxPbCl3 solid solution thin films

Abstract

The exciton spectra of Cs1–xRbxPbCl3 solid solution thin films are studied in a range of 2–6 eV. The formation of solid solutions stable at room temperature was detected in range of concentrations 0 ≤ х ≤ 0.7. A linear dependence of the exciton band and bandgap width parameters on the concentration was found. Kinks are observed along the temperature dependences of the spectral position Em(T) (x > 0) of the long-wave exciton band at 310 and 320 K that are characteristic of second-order phase transitions. The exciton excitations in CsPbCl3 are found to have a three-dimensional nature, while in Cs1–xRbxPbCl3 (x > 0) solid solutions they are found to be two-dimensional.