An effective combination reaction involved with sputtered and selenized Sb precursors for efficient Sb2Se3 thin film solar cells

Sputtering followed by post annealing is extensively used for fabrication of copper indium gallium selenide (CIGS), copper zinc tin sulfide (CZTS) and copper zinc tin sulfur selenide (CZTSSe) thin film solar cells. In this work, Sb2Se3 as an emerging alternative absorber was fabricated by an effective combination reaction of annealing sputtered Sb metallic precursors under Se vapor. Self-assembled growth of Sb2Se3 thin films consist of large grains that across the whole films have been successfully fulfilled via this combination reaction. Sb2Se3 thin films with desired orientation, stoichiometric composition and high-quality Sb2Se3/CdS heterojunction could be achieved once a proper selenization scenario was employed. Further, by selecting Sb films as precursors, the thickness of interfacial MoSe2 located at the back-contact region can be well controlled, leading to a significant enhancement in fill factor (FF) of the devices. This is in good accordance with our DFT simulation results which demonstrated Se vapor would be prone to react with the Sb lattice thermodynamically and thus limiting the thickness of the MoSe2 layer. Finally, a champion Sb2Se3 thin film solar cell with power conversion efficiency of 6.15% was achieved, which represents the highest efficiency of sputtered Sb2Se3 solar cells.