High efficiency Cu2ZnSnS4 solar cells over FTO substrates and their CZTS/CdS interface passivation via thermal evaporation of Al2O3

Sulfur kesterite (CZTS) solar cells on transparent substrate (FTO) showing η = 7.3% and V_oc = 700 mV (structure: SLG/FTO/Mo (20 nm)/CZTS/Al₂O₃/CdS/i-ZnO/ITO) and η = 7.7% and V_oc = 677 mV (structure: SLG/FTO/Mo (20 nm)/CZTS/CdS/i-ZnO/ITO).