A new design and optimization of SnSe-based dual absorber solar cell with efficiency above 28%

Tin selenide (SnSe)-based solar cells are gaining significant interest from researchers due to their exceptional semiconductor properties. The primary aim of this study is to enhance the performance of the newly proposed Cu/FTO/CdS/SnSe/Sb₂Se₃/Au solar cell and to analyze the effects of the Sb₂Se₃ second absorber layer and CdS buffer layer on key performance metrics such as open circuit voltage (V_OC), short circuit current density (J_SC), fill factor (FF), and power conversion efficiency (PCE). SCAPS-1D simulation software was used for this investigation. Various factors were examined to improve performance, including the impacts of thickness variation, carrier concentration, bulk defect concentration in each layer, interface defects, operating temperature, and the placement of front and rear electrodes. The reference structure (Cu/FTO/CdS/SnSe/Au) showed a PCE of 26.15%, V_OC of 0.79 V, J_SC of 36.36 mA/cm², and FF of 85.94%. By adding the Sb₂Se₃ layer as a second absorber in the proposed structure (Cu/FTO/CdS/SnSe/Sb₂Se₃/Au), the performance improved to a PCE of 28.18%, V_OC of 0.84 V, J_SC of 38.42 mA/cm², and FF of 86.57%. This study offers valuable insights and a practical approach to developing economically viable SnSe-based thin-film solar cells.