Evaluation of design and device parameters for lead-free Sr3PBr3/Sr3NCl3 duel-layer perovskite photovoltaic device technology

The study looks into how Sr₃PBr₃ and Sr₃NCl₃ double perovskite materials can be used as absorbers in perovskite solar cells (PSCs). Computational Sr₃PBr₃ and Sr₃NCl₃ simulations were employed to assess the performance of each absorber together with electron transport layers (ETL), with a particular emphasis on optimizing ETL thickness to improve charge transport and synchronize current outputs. The simulations yielded valuable insights into the electronic and optical characteristics of the individual absorbers. Subsequently, a tandem simulation was performed to adjust each layer's thickness, ensuring that both devices' current outputs were aligned for maximum system efficiency. The findings revealed that the tandem configuration of Sr₃PBr₃ and Sr₃NCl₃ surpassed the performance of the individual absorber setups, attributed to the optimized ETL thicknesses that enhanced charge transport and facilitated effective current matching. This study makes a significant contribution to the design and optimization of tandem PSCs utilizing Sr₃PBr₃ and Sr₃NCl₃ absorbers, paving the way for improved overall device efficiency. We investigated three device configurations to find the optimum structure. FTO/SnS₂/Sr₃PBr₃/Ni, FTO/SnS₂/Sr₃NCl₃/Ni, and FTO/SnS₂/Sr₃PBr₃/Sr₃NCl₃/Ni are considered as Device-I, II, and III. In Device-I, the execution parameters are power conversion efficiency (PCE) of 24.26%, an open-circuit voltage (V_OC) of 1.23 V, a short-circuit current density (J_SC) of 24.65 mA cm⁻², and a fill factor (FF) of 87.42%. For Device-II, PCE, FF, V_OC, and J_SC are correspondingly 20.35%, 87.91%, 1.28 V, and 18.07 mA cm⁻². The further refined tandem configuration achieved a PCE of 30.32%, with a V_OC of 1.27 V, an FF of 90.14%, and a J_SC of 26.44 mA cm⁻², demonstrating the potential of this methodology in enhancing PSC performance.