Earth-Abundant CZTSSe Thin Film Solar Cells on Flexible Stainless Steel Foil Substrates

We fabricated Cu
₂
ZnSn(S,Se)
₄
(CZTSSe) thin film solar cells on flexible stainless steel foil substrates (SUS). The absorber layers are deposited by magnetron sputtering followed by sulfo-selenization process. The fabricated cell structure was Al/Ni/AZO/i-ZnO/CdS/CZTSSe/Mo/Cr/SUS. The best device represents an open-circuit voltage of 363.4 mV, a short-circuit current density of 29.6 mA/cm
²
, a fill factor of 44.7%, and a power conversion efficiency of 4.8%.