Temperature and compositional behaviour of electrical conductivity and optical absorption edge in Cu7Ge(S1−xSex)5I mixed superionic crystals

Influence of cation substitution on electrical conductivity and optical absorption edge in Cu7(Ge1–xSix)S5I mixed crystals

“…It is shown that the electrical conductivity of Cu 7 GeSe 5 I crystal at room temperature was found to be rather high (64 S/m at 295 K and 10 6 Hz) and typical for advanced superionic conductors [5,6]. At SSe anionic substitution, the nonlinear increase of the electric conductivity by more than an order of magnitude was observed in   I Se S Ge Cu 5 x x 1 7  mixed crystals [7]. Optical studies have shown that the absorption edge of Cu 7 GeS(Se)S 5 I crystals and mixed crystals based on them exhibits Urbach behaviour in a wide temperature range [3,[5][6][7].…”

“…Optical studies have shown that the absorption edge of Cu 7 GeS(Se)S 5 I crystals and mixed crystals based on them exhibits Urbach behaviour in a wide temperature range [3,[5][6][7]. A nonlinear decrease of the optical pseudogap in the   I Se S Ge Cu 5 x x 1 7  mixed crystals at SSe anionic substitution is observed [7]. mixed crystals were presented in the paper [8].…”

“…Cu 7 GeS 5 I and Cu 7 SiS 5 I superionic crystals belong to argyrodite family compounds [1]. Due to their high ionic conductivity, these crystals are attractive materials for applications in different functional elements of solid state ionics [2].…”

“…Structural, electrical and optical properties of Cu 7 GeS(Se) 5 I and mixed crystals based on them were studied in papers [3][4][5][6][7]. It is shown that the electrical conductivity of Cu 7 GeSe 5 I crystal at room temperature was found to be rather high (64 S/m at 295 K and 10 6 Hz) and typical for advanced superionic conductors [5,6].…”

“…At SSe anionic substitution, the nonlinear increase of the electric conductivity by more than an order of magnitude was observed in   I Se S Ge Cu 5 x x 1 7  mixed crystals [7]. Optical studies have shown that the absorption edge of Cu 7 GeS(Se)S 5 I crystals and mixed crystals based on them exhibits Urbach behaviour in a wide temperature range [3,[5][6][7]. A nonlinear decrease of the optical pseudogap in the   I Se S Ge Cu 5 x x 1 7  mixed crystals at SSe anionic substitution is observed [7].…”