Advancing CIGSe Solar Cell Efficiency Under Low-Temperature Deposition via Ag Additives

In this study, Ag was introduced into the CIGSe layer via a precursor method to enable low-temperature growth of CIGSe solar cells. Advanced device structures such as tandem and bifacial architectures are essential for further efficiency improvements, but the high growth temperature (~550°C) required for CIGSe limits their realization. We fabricated CIGSe layer at a reduced substrate temperature of 350°C. The conventional CIGSe cell showed a severely reduced efficiency of 0.143%, while the Ag-incorporated ACIGSe cell achieved 15.3%. This significant enhancement is attributed to improved film quality under low-temperature deposition owing to Ag incorporation. The developed low-temperature process is promising for high-efficiency tandem and bifacial CIGSe solar cells.