AgIn x Ga 1−x S 2 solid solution nanocrystals: synthesis, band gap tuning and photocatalytic activity

AgInxGa1−xS2 (x = 0, 0.3, 0.5, 0.7 and 1) solid solutions with a size of 25–100 nm have been synthesized in a mixed solvent system via a solvothermal process. The crystal structure of the solid solutions gradually transforms from tetragonal to orthorhombic, along with the chemical composition (x value changes from 0 to 1), and the band gap of the solid solutions can be tuned from 2.37 eV to 1.62 eV. Further studies revealed that the obtained AgInxGa1−xS2 solid solutions show improved photocatalytic activities under visible light irradiation compared with AgGaS2 and AgInS2, and the AgIn0.3Ga0.7S2 solid solution exhibits the best photocatalytic performance for its optimized band gap and energy structure.