Performance Analysis of Perovskite Solar Cells Using DFT-Extracted Parameters of Metal-Doped TiO₂ Electron Transport Layer

The performance of perovskite solar cells (PSCs) depends heavily on the electronic and optical properties of the electron transport layer (ETL). Density functional theory (DFT) uses a quantum-mechanical approach to accurately predict the properties of different layers in PSCs, including the ETL. Titanium dioxide (TiO₂) is a widely used material for the ETL in PSCs. In this work, we use first-principles calculations based on DFT to obtain the electronic and optical properties of pristine rutile TiO₂ and TiO₂ doped with tin (Sn) and zinc (Zn). DFT-extracted carrier mobility, band gap, and the absorption spectrum of TiO₂ are used in the SCAPS-1D device simulator to evaluate the performance of the solar cell device, with respect to dopant concentration and thickness of TiO₂. PSCs with 3.125 mol % Sn-doped TiO₂ achieve a maximum power conversion efficiency (PCE) of 17.14 versus 13.70% with undoped TiO₂. We have also compared the performance of PSCs with Sn-doped and Zn-doped TiO₂. For the same dopant concentration, Sn-doped TiO₂ offers 0.63% higher PCE than the Zn-doped counterpart. The results are in good agreement with reported experimental findings and provide a reliable means of evaluating PSC performance by combining first-principles (DFT) calculations with conventional device simulations.