Enhanced charge transport via Fe-doped brookite TiO2 ETLs for eco-friendly perovskite solar cells

Abstract

Through detailed simulation studies, essential material properties—such as bandgap energy (Eg), dielectric constant (ε), effective density of states for both conduction (Nc) and valence (Nv) bands, and the thermal velocities of charge carriers (Vthe for electrons and Vthh for holes)—were obtained via density functional theory (DFT) calculations. These properties served as inputs for Solar Cell Capacitance Simulator in 1 Dimension (SCAPS-1D) simulations to assess and enhance the efficiency of perovskite solar cells (PSCs) featuring Fe-doped brookite titanium dioxide (TiO2) as the electron transport layer (ETL). The study involved optimizing both the absorber and ETL to achieve improved charge transport and overall efficiency. Key device metrics, including current-voltage (JV) curves and quantum efficiency (QE) were thoroughly examined. Simulation outcomes indicate that Fe doping significantly boosts the electron transport properties of brookite TiO2, leading to better interface characteristics and enhanced charge carrier mobility. The optimized device demonstrated a remarkable power conversion efficiency (PCE) of 31.40%, underscoring the promise of Fe-doped brookite TiO2 as a stable, efficient, and environmentally friendly ETL material for next-generation lead-free perovskite solar cell (PSC). This study highlights the value of integrating first-principles calculations with device-level modeling to drive innovation in solar energy technologies.