Bandgap Engineering, Device Optimization, and Performance Analysis of a Perovskite Solar Cell using Sr‐Doped La₂NiMnO₆ as an Absorber Layer: A Promising Material for Next‐Generation Perovskite Solar Cells

The study explored the role of doping Sr in double perovskite La 2 NiMnO 6 to tune the bandgap of the host material thereby revealing a considerable decrease, indicating its usefulness in solar cell device fabrication. To authenticate the experimental findings revealing the bandgap tuning to 1.37 eV by Sr doping, close to 1.4 eV, an optimum value for achieving better efficiencies in solar cell devices, we focus on the performance analysis of Sr‐doped based perovskite solar cell by performing the device optimization using LNMO and Sr‐doped LNMO as the light‐absorbing material in the SCAPS‐1D simulation tool. The best SC configuration during device optimization turned out to be FTO/WS 2 /LNMO/CFTS/C, where FTO was the substrate, WS 2 was the electron transport layer, LNMO was the absorber, CFTS was the hole transport layer, and C was the carbon contact. The SC was optimized for the thickness of all these constituent layers to obtain the best PV parameters. The impact of Sr‐doped LNMO in the devices was very significant, as it enhanced the power conversion efficiency (PCE) from 13.90% in the pure LNMO to 19.62% in the Sr‐doped LNMO, supporting the experimental results. The cell parameters of the Sr‐doped‐based optimized SC device were V OC = 1.15 V, J SC = 31.96 mA/cm 2 , FF = 53.48%, and PCE = 19.62%, in comparison to those of the pure LNMO‐based optimized SC device, which were V OC = 1.35V, J SC = 21.99 mA/cm 2 , FF = 46.74%, and PCE = 13.90%, showing a considerable enhancement in the efficiency of the device. Significant variation in photovoltaic parameters with the density of defects of absorber layer reveals that the optimal doping along with minimum defect density is important to maximizing perovskite solar cell efficiency.