Optical absorption and exciton-phonon interaction in solid solutions Cu6PS5I1 − x Cl x

Abstract

We have studied the optical absorption edge of solid solutions Cu 6 PS 5 I 1 -x Cl x at high absorption levels in the temperature range of 77-320 K. In a superionic state, we have revealed the Urbach behavior of the absorption edge, determined its parameters, and studied their temperature and concentration variations. We consider exciton-phonon interaction as a mechanism by which the Urbach bundle is formed and show that this bundle can be described in terms of the Dow-Redfield model.