Numerical Optimization and High-Performance Design of Lead-Free CsSnBr₃ Perovskite Solar Cells with Optimal Hole Transport Layer Selection

Perovskite solar cells (PSCs) are gaining popularity due to their higher photovoltaic (PV) performance than conventional PV cells. They offer several advantages, including low cost, easy production, adjustable bandgap energy, and remarkable electrical and optical characteristics. We used the SCAPS-1D modeling program to design and develop a new lead-free perovskite solar cell structure: glass/FTO/ZnSe/CsSnBr3/CBTS/Ni. The absorber layer employs the lead-free perovskite material CsSnBr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>, while other organic and inorganic hole transport layers (HTLs) were investigated to enhance efficiency and reduce expenses. The best HTL was chosen after conducting thorough simulations. The thickness and doping concentrations of the electron transport layer (ETL), hole transport layer (HTL), and absorber layers were optimized, while variations in absorber defects, interface defects, metal work function, and temperature were analyzed to assess their effects. The solar cell structure was optimized to obtain a short circuit current density ($\mathrm{Jsc}_{\text {Sc }}$) of $19.14 \mathrm{~mA} / \mathrm{cm}^{2}$, fill factor (FF) of $89.27 \%$, and an open circuit voltage (Voc) of 1.39 V. As a result, the maximum efficiency (PCE) achieved $\mathbf{2 3. 7 3 \%}$. These results suggest that, based on the simulated outcomes of this design, a stable, effective, and affordable perovskite PV cell structure could be used in the future.