Kiani, Reza, et al. “An Effect of Band Gap Engineering, Absorber Layer Type, and Ga (Ga+In) Ratio Variation on the Performance of CIGS Thin-Film Solar Cells”. International Journal of Natural and Engineering Sciences, vol. 20, no. 2, Oct. 2026, pp. 52-62, https://www.ijnes.org/index.php/ijnes/article/view/934.