Low-cost and environmentally friendly CuZnSnSSe (CZTSSe)-based solar cells suffer low conversion efficiencies. On the other hand, perovskite B-γ-CsSnI₃-based cells, may yield higher performance, but still lower than anticipated, and involve the costly cesium. This study aims at lowering the B-γ-CsSnI₃ perovskite solar cell costs, without sacrificing performance, by adding a CZTSSe absorbing layer to a thinned perovskite layer. The proposed lead-free cell structure is: ZnO-Al/i-ZnO/CdS/CZTSSe/B-γ-CsSnI₃/MoSe₂/Mo. This strategy is novel and has not been described for cost lowering in B-γ-CsSnI₃ based systems. Density Functional Theory is used to predict the crystalline structure, the electronic and the optical parameters that are in turn used in the SCAPS simulation software. Layer thicknesses are varied for CZTSSe (1-2 μm) and the perovskite (0.1-2 μm), while the doping concentrations are varied from 1×10¹⁵ to 1×10¹⁹ cm^-3. With doping concentration 1×10¹⁷ cm^-3, the bi-absorber cell exhibits high efficiency of 23.80% at 0.1 µm perovskite thickness.  At thickness 1.0 µm, the efficiency is 29.20%.  These values are higher than literature B-γ-CsSnI₃ mono-absorber layer cells of similar thicknesses. The results highlight the added value of CZTSSe layer inclusion, in costly solar cells, while exhibiting higher efficiency.

Title

Journal of Electroanalytical Chemistry

Publisher

Elsevier

Publisher Country

Netherlands

Indexing

Thomson Reuters

Impact Factor

4.1

Publication Type

Both (Printed and Online)

Volume

990

Year

2025

Pages

119369