Growth of (Ag,Cu)(In,Ga)Se2 Absorbers under Band Gap Variation and Characterization with a Focus on Optical Spectroscopy

Whilst Cu(In,Ga)Se2 (CIGSe) is an extremely promising material for solar cell fabrication, the widening of band gap beyond standard 1.1 eV highly desirable semitransparent applications. By replacing Cu with Ag and increasing Ga content, we fabricate ACIGSe absorbers gaps ranging from 1.27–1.55 eV. An Ag/(Ag + Cu) ratio 0.36–1.00 chosen, as well a Ga/(Ga In) 0.25–0.59. The larger contents lead to expected widening, which is, together high sub-gap transparency, essential crystalline properties are confirmed by Raman spectroscopy X-ray diffraction, both reveal peak shifts according composition variations: higher content results in lower angles diffraction main peaks due mass compared lattice constant Ag-rich compounds. Increased open circuit voltages decreased short current densities gaps. overall trend increased power conversion efficiency related devices future research wide Ag-chalcopyrites their application.