Hydrothermal preparation and characterization of nanocrystalline Silver gallium sulfides

摘要

The hydrothermal reaction route was developed to prepare nanocrystalline silver gallium sulfides AgGaS_2 and #alpha#-Ag_9GaS_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 #alpha#-Ag_9GaS_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 #alpha#-Ag_9GaS_6 displayed whisker-like particles with an average size of 20 X 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.