Towards a better understanding of the use of additives in Zn(S,O,OH) deposition bath for high efficiency Cu(In,Ga)Se2-based solar cells

CBD-Zn(S,O,OH) remains one the most studied and promising Cd-free buffer layer for Cu(In,Ga)Se₂-based solar cells, and has already demonstrated its potential to lead to high-efficiency solar cells. However Zn(S,O,OH) deposition time and metastable behavior of the final devices remain critical to outperform CdS-based devices. The aim of this work is to study and understand the influence of additives such as H₂O₂ on the deposition bath and on the surface of the absorber. These results will be related with final performances of the devices. A new promising additive, persulfate S₂O₈^2-, will be presented and could be the key to go beyond CdS-based solar cell records.