Comprehensive study and performance analysis of an eco-friendly double perovskite Cs2AgBiBr6 on Si tandem solar cell

Abstract

With the advent of perovskites on Si technology for a tandem configuration of solar cells, it has become obligatory to take care of the toxicity content present, and proper care should be given for a stable design. Aiming at this, the present paper discusses a comprehensive analysis of lead-free all-inorganic double perovskite/c-Si tandem solar cells. The combination of double perovskite ( C s 2 A g B i B r 6 ) as a wider bandgap (2.05 eV) layer and (c-Si) as a lower bandgap (1.12 eV) layer is used for the first time, to our knowledge, and this proposed structure shows optimum device efficiency of 26.38%. Designing the tandem cell is carried out in two steps. First the top cell ( C s 2 A g B i B r 6 ) and bottom cell (c-Si) are calibrated according to the data reported so far. Simulation results reflect power conversion efficiency (PCE) values for C s 2 A g B i B r 6 and c-Si cells under an AM 1.5 spectrum to be 8.26% and 22.37%, respectively. After optimizing the performance for top and bottom cells, we evaluated the same for the tandem structure. The current matching condition for the tandem structure is obtained at 0.400 µm and 1 µm thicknesses of the absorber layer for top and bottom cells, respectively. Top and bottom cells with filtered spectra exhibit efficiencies of 8.15% and 18.23%, respectively. Overall, the C s 2 A g B i B r 6 / c - S i tandem configuration yields an impressive PCE of 26.38% with an open circuit voltage of 1.84 V.