Synthesis of High-Efficiency CuGaS2 Quantum Dots for Photocatalysis by Fine Modulation of the Reaction Temperature

CuGaS2 quantum dots (CGS QDs) with a chalcopyrite crystal structure were synthesized by a hot-injection method. The structural and optical characteristics of the obtained nanocrystals were investigated in the reaction temperature range of 210 °C to 260 °C, it was found that the CuGaS2 QDs were governed by the surface groups functionalized with 1-dodecanethiol capping ligands in the reaction system. The appropriate reaction temperature favored the decomposition of the surface ligand. CGS QDs synthesized at 230 °C exhibited a narrow particle size distribution and good crystallinity. In terms of the optical spectra, with an increase in the reaction temperature, the excitonic absorption peaks and band gap emission peaks were systematically red-shifted, thus exhibiting a quantum confinement effect. A mechanism for the growth and formation of nanoparticles on the basis of the reaction temperature is proposed. Furthermore, the obtained CGS QDs showed promising visible-light-driven photocatalytic activity during degradation of rhodamine 6G.