Investigation of hybrid SnSe/SnS bilayer absorber for application in solar cells

The vapor-transport deposition of SnS and SnSe can help achieve low-cost and scalable photovoltaic devices. However, the performance of SnS- and SnSe-based solar cells is limited by shunt losses and low open-circuit voltage. Single SnS absorber based solar cells exhibit a high open-circuit voltage and low short-circuit current density, whereas single SnSe based solar cells demonstrate higher short-circuit current and low open-circuit voltage. In this study, we introduce a hybrid bilayer absorber configuration combining SnSe and SnS and fabricate a solar cell device using this structure (Mo/SnSe/SnS/CdS/ZnO/AZO/Al). Specifically, we establish this bilayer absorber configuration and a heterojunction device using CdS as the buffer layer. The bilayer-absorberbased device exhibits a higher open-circuit voltage than SnS based devices, along with a short-circuit current density comparable to those of SnSe based device. The optimal device featuring the bilayer absorber exhibits an efficiency of 3.65%, representing a considerable improvement over single SnS (2.87%) and SnSe (1.4%) absorber-based solar cells.