Optimization of Absorber Layer Cs ₂ TiBr ₆ Dimension Based on Portia Spider Algorithm for Efficient Lead-Free Perovskite Solar Cell

The Photovoltaic industry has recently shown a great deal of interest in lead-based Perovskite Solar cells (PSCs) because of their special properties, high absorption coefficient, and large bandgap. Still, the limited longevity, instability, and toxicity of inorganic-organic lead-based PSCs have hindered their application. These concerns are addressed by the proposed design, which utilizes a La-doped BaSnO 3 as ETL and optimizes a Cs 2 TiBr 6 perovskite layer-based lead-free PSC to improve the efficiency of power conversion. The lead-free perovskite solar cell (PSC) is structured with a transparent glass substrate, which ensures that sunlight passes through, while also providing mechanical support. A fluorine-doped tin oxide (FTO) layer is used to assist light to pass through it and allow electrons to transport through it. A copper oxide (Cu 2 O) Hole Transport Layer (HTL) assists in directing positive charge carriers into the anode. The Cs 2 TiBr 6 perovskite layer employs sunlight-absorbing properties and creates electron-hole pairs, where they separate into free charge carriers. The La-doped BaSnO 3 Electron Transport Layer (ETL) plays a crucial role in allowing electrons to freely travel on the cathode side of the solar cell; meanwhile, the HTL avoids recombination, and aluminium functions as the electrode metal. Furthermore, the Portia Spider Algorithm (PSA) focuses on the architecture of the cell to determine the optimal thickness of the perovskite layer, which can improve the overall performance of the solar cell. In addition, the performance parameters of the Cs 2 TiBr 6 -based lead-free PSCs proposed for this work are assessed and compared against the existing materials used in the ETL, perovskite layer, and HTL. The results show that a perovskite layer thickness of 200[Formula: see text]nm is a viable option to allow for a lead-free PSC and obtain a [Formula: see text] of 1.5[Formula: see text]V, [Formula: see text] 36.1[Formula: see text]mA/cm 2 , FF of 83%, PCE of 33.78% and quantum efficiency of 87%. Thus, the proposed design ensures efficient sunlight conversion into electrical energy and also increases stability by minimizing recombination, making it a cost-effective and environmentally safe solution than conventional solar technology.