Preparation and electrical properties of composites based on (Cu₆PS₅I)₁₋ₓ(Cu₇PS₆)ₓ mixed crystals

Abstract

(Cu₆PS₅I)₁₋ₓ(Cu₇PS₆)ₓ mixed crystals were grown using the direct crystallization technique from melt (Bridgman–Stockbarger technique). The polymer composites based on (Cu₆PS₅I)₁₋ₓ(Cu₇PS₆)ₓ mixed crystals were prepared. Electrical properties of composites were studied in the frequency range from 10⁻³ Hz to 2·10⁶ Hz at room temperature. The parallel equivalent circuit with a double electric layer assumed at the electrode interface was applied to analyze the frequency dependences of electrical conductivity. It has been shown that the highest value of total electric conductivity is observed for the (Cu₆PS₅I)₀.₇₅(Cu₇PS₆)₀.₂₅-based composite. The further increase of Cu₇PS₆ content leads to the monotonically decreasing values of total electric conductivity. The ratio of total ionic to electronic components demonstrates the highest value for Cu₆PS₅I-based composite.