Characterization of Cu–Bi–S Powders Synthesized by Polyol Method

Abstract

Cu–Bi–S powders were synthesized by a polyol method at 180°C and a speed of 600 rpm for 70 min. X-ray diffraction patterns of the Cu–Bi–S powders showed that single-phase Cu₃BiS₃ was obtained at a thiourea concentration of 197 mmol·L⁻¹. Microstructural analysis of the Cu–B–S powders revealed that the sizes of the Cu–Bi–S particles with single-phase Cu₃BiS₃ were 200–400 nm and their composition was Cu-poor, Bi-rich, and slightly S-poor. From the optical measurement by an ultraviolet-visible-near infrared spectroscopy, the optical bandgap of the Cu–B–S powder with single-phase Cu₃BiS₃ was estimated to be 1.24 eV. Based on the obtained results, the influences of thiourea concentration on synthesis of Cu₃BiS₃ were discussed.