M.  Nakamura, Yamaguchi, K., Kimoto, Y., Yasaki, Y., Kato, T., and Sugimoto, H., ?Cd-Free Cu(In,Ga)(Se,S)2 Thin-Film Solar Cell With Record Efficiency of 23.35%?, IEEE Journal of Photovoltaics, vol. 9, pp. 1863-1867, 2019.