Theoretical optimization of eco-friendly Ba3NCl3 perovskite solar cells with CeOX ETL and V2O5 HTL

Nowadays, perovskite material is dominating the photovoltaic (PV) research sector. However, the researchers' primary concerns are the hazardous nature and stability issue of commonly used lead-based perovskites. Recently, a Pb-free perovskite family, A₃BX₃ (A = Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, BN³⁻, As³⁻, P^3–, Sb³⁻, and X = halide ions) has gained popularity for its direct bandgap, electrical characteristics, durability, etc. Among these materials, Ba₃NCl₃ has garnered particular interest due to its exceptional optoelectronic properties and stability, with an energy bandgap of 1.2 eV. Through numerical simulation, the performance of Ba₃NCl₃-based PSCs with TiO₂ and CeO_X as the electron transport layers (ETLs) for nine different hole transport layers (HTLs), has been thoroughly examined in this study. V₂O₅ has demonstrated the best performance among these HTLs, whereas CeO_X has overperformed TiO₂ as ETL. The optimal values of the Ba₃NCl₃'s thickness and defect density, the CeO_X/Ba₃NCl₃ and Ba₃NCl₃/V₂O₅ interface defect densities, the energy band positions and bandgaps of CeO_X and V₂O₅, the carrier density of Ba₃NCl₃, and cell's series resistance have been achieved through a series of simulations. As a result, the optimized PSC has recorded a V_OC of 0.951 V, J_SC of 25.28 mA/cm², FF of 82.4 %, and PCE of 19.81 %. These findings pave the way for the proposal that Ba₃NCl₃-based perovskite solar cells could significantly contribute to the PV research industry, especially in light of stability, environmental concerns, and the global push for clean energy as outlined in the United Nations' Sustainable Development Goal 7 (SDG 7). Moreover, CeO_X and V₂O₅ have demonstrated as promising ETL and HTL, respectively.