Indium induced band gap tailoring in Ag Ga1-x Inx S2 chalcopyrite structure for visible light photocatalysis

Indium was substituted at gallium site in chalcopyrite AgGa S2 structure by using a simple solid solution method. The spectroscopic analysis using extended x-ray absorption fine structure and x-ray photoelectron spectroscopy confirmed the indium substitution in AgGa S2 lattice. The band gap energy of Ag Ga1-x Inx S2 (x=0-1) estimated from the onset of absorption edge was found to be reduced from 2.67 eV (x=0) to 1.9 eV (x=1) by indium substitution. The theoretical and experimental studies showed that the indium s orbitals in Ag Ga1-x Inx S2 tailored the band gap energy, thereby modified the photocatalytic activity of the Ag Ga1-x Inx S2.