Controlled synthesis of monodispersed AgGaS2 3D nanoflowers and the shape evolution from nanoflowers to colloids

Monodispersed AgGaS₂ three-dimensional (3D) nanoflowers have been successfully synthesized in a “soft-chemical” system with the mixture of 1-octyl alcohol and cyclohexane as reaction medium and oleylamine as surfactant. The crystal phase, morphology and chemical composition of the as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution TEM (HTEM), respectively. Results reveal that the as-synthesized AgGaS₂ nanoflowers are in tetragonal structure with 3D flower-like shape. Controlled experiments demonstrated that the shape transformation of AgGaS₂ nanocrystals from 3D nanoflowers (50 nm) to nanoparticles (10-20 nm) could be readily realized by tuning the reaction parameters, e.g., the ratio of octanol to cyclohexane, the length of carbon chain of fatty alcohol, the concentration of oleylamine, etc. The UV-vis and PL spectra of the obtained AgGaS₂ nanoflowers and colloids were researched. In addition, the photoelectron energy conversion (SPV) of AgGaS₂ nanoflowers was further researched by the surface photovoltage spectra.