Alloying small quantities of silver into Cu(In,Ga)Se2 was shown to improve the efficiency for wide and low band gap solar cells. We study low band gap industrial Cu(In,Ga)(S,Se)2 absorbers, substituting less than 10% of the copper with silver, using absolute photoluminescence and cathodoluminescence spectroscopy. Silver improves the grain size and promotes the interdiffusion of Ga and In across the depth of the absorber, resulting in a smoother band gap gradient. However, a certain lateral inhomogeneity is observed near the front and back sides. The non-radiative losses in the bare absorbers are reduced by up to 30 meV.
@article{arxiv.2403.04394,
title = {Improved sequentially processed Cu(In,Ga)(S,Se)2 by Ag alloying},
author = {Aubin JC. M. Prot and Michele Melchiorre and Tilly Schaaf and Ricardo G. Poeira and Hossam Elanzeery and Alberto Lomuscio and Souhaib Oueslati and Anastasia Zelenina and Thomas Dalibor and Gunnar Kusch and Yucheng Hu and Rachel A. Oliver and Susanne Siebentritt},
journal= {arXiv preprint arXiv:2403.04394},
year = {2025}
}