CZTSSe thin film solar cells with two absorber layers and a PbS layer

In this paper, we simulated a novel CZTSSe (copper-zinc-tin-sulfide-selenide) thin film solar cell with two absorber layers and a PbS (a lead sulfide) layer by SCAPS-1D. We investigated the effect of changes in the thickness of the absorbing layer and the acceptor concentration on this cell. Meanwhile, we also optimized the bandgap width of CZTSSe and the thickness of PbS. Moreover, an effective method has been applied with the aim of boosting conversion efficiency by adding a BSF (back surface field) layer to the cell. The BSF layer helps to enhance optical behavior and reduces recombination losses, consequently reducing the Voc (open circuit voltage) deficit. With the highest conversion efficiency calculated in the simulation, a cell conversion efficiency of 27.70% can be achieved, which is significantly higher than the basic structure, providing a large electrical power as well as a more optimal filling factor at the same time.