Hydrothermal preparation and characterization of nanocrystalline: Silver gallium sulfides

Abstract The hydrothermal reaction route was developed to prepare nanocrystalline silver gallium sulfides AgGaS 2 and α-Ag 9 GaS 6 , respectively. X-ray powder diffraction patterns indicated tetragonal phase AgGaS 2 with cell constants a =5.765 and c =10.281 A, and orthorhombic phase α-Ag 9 GaS 6 with cell constants a =10.756, b =7.806, and c =7.605 A. Transmission electron microscopy images revealed that nanocrystalline AgGaS 2 consisted of uniform spherical particles with grain sizes of 6–12 nm and nanocrystalline α-Ag 9 GaS 6 displayed whisker-like particles with an average size of 20×5 nm. The room temperature photoluminescence spectrum of nanocrystalline AgGaS 2 was found to be one broad emission feature at 446 nm. A possible formation mechanism of silver gallium sulfides was proposed.