Indium induced band gap tailoring in $AgGa1−xInxS2$ chalcopyrite structure for visible light photocatalysis

Indium was substituted at gallium site in chalcopyrite $AgGaS2$ 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 $AgGaS2$ lattice. The band gap energy of $AgGa1−xInxS2$ $(x=0–1)$ estimated from the onset of absorption edge was found to be reduced from $2.67eV$ $(x=0)$ to $1.9eV$ $(x=1)$ by indium substitution. The theoretical and experimental studies showed that the indium $s$ orbitals in $AgGa1−xInxS2$ tailored the band gap energy, thereby modified the photocatalytic activity of the $AgGa1−xInxS2$⁠.