Crystallization optimization of the 40GeSe2–40Sb2Se3–20CuI glass for improvement of photoelectric properties

•Heterojunction networks enhance the photoelectric properties of glass-ceramics.•Two-stage heat treatment is developed to control the crystallization process.•Nucleation condition is optimized by differential scanning calorimeter analysis.•The influence of crystallization process is systematically studied.

A novel photoelectric glass-ceramic with the heterojunction microstructure was prepared by controlling the growth of nanocrystals in the 40GeSe2–40Sb2Se3–20CuI glass. The DSC, XRD, SEM, and photo-electrochemical measurement were adopted to investigate the influence of different crystallization processes on the microstructure and properties of as-prepared glass-ceramics. The results show that the optimum nucleation temperature and duration are respectively around 225 °C and 90 min, and the Sb2Se3 rods crystallize firstly in the matrix, followed by the in-situ growth of conductive Cu2GeSe3 nanocrystals on the Sb2Se3, leading to interconnected conductive channels. These conductive channels are essential for improving the conductivity and the photocurrent.