High efficiency CZTSSe solar cells enabled by dual Ag-passivation approach via aqueous solution process

Abstract

Ag substitution in Cu2ZnSn(S,Se)4 (CZTSSe) is a promising way to mitigate Cu/Zn related defects, electrostatic fluctuations and Shockley-Read-Hall (SRH) recombination centers. However, high performance ACZTSSe solar cells are generally demonstrated with more Ag amounts and strenuous fabrication processes, which are not ideal when using cheap constituent materials CZTSSe. To reduce the Ag amount (2%–3%), local Ag substitutions into CZTSSe at front (F), back (B) and dual front/back (FB) were proposed. Experimental results revealed that F-passivation effectively reduced the Cu/Zn related defects and further limits the interface/bulk recombination whereas B-passivation improved the grain growth at the back interface and further allows enhanced transport of charge carriers. By employing the dual Ag-passivation approach, the final ACZTSSe device parameters were significantly improved and remarkable power conversion efficiency (PCE) of 12.43% was achieved with eco-friendly aqueous solution process. © 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences