Electrical conductivity, electrochemical and optical properties of Cu 7GeS5I-Cu7GeSe5I superionic solid solutions

Abstract

Single crystals of Cu7GeS5I-Cu7GeSe 5I superionic solid solutions were grown by chemical transport. Their electrical conductivity in the frequency range 1.0·10 6-1.2·109 Hz and in the temperature range 100-300 K was measured; the compositional dependences of the electrical conductivity and activation energy were obtained. Electrochemical studies of Cu 7GeS5I-Cu7GeSe5I solid solutions were performed, the character of compositional variation of the electrode potential and the range of the electrochemical stability at S→Se substitution were determined. The optical absorption edge of Cu 7GeS5I-Cu7GeSe5I superionic solid solutions in the temperature range 77-300 K were studied; the compositional dependences of the optical pseudogap and Urbach energy were obtained. © 2009 Lithuanian Physical Society.