Abstract
Crystalline silicon (c-Si) solar cells dominate the global market, and the development of eco-friendly and cost-effective c-Si compound solar cells with carrier-selective passivated contacts has attracted increasing attention. This work investigated the impact of oxygen vacancies (V(O)) and vanadium (V) doping on molybdenum trioxide (MoO(X)), using a combination of first-principles calculations and device simulations. These V(O) defects accumulated from bulk to surface with lower energy barrier of 1.7 eV, compared to 3.4 eV on surface and 3.8 eV from surface to bulk. The surface V(O) significantly decreased MoO(X) work function from 6.1 eV to 4.8 eV，considering alteration in surface charges from +4 µC cm(-2) to -8 µC cm(-2). Vanadium doping increased V(O) transport barrier by 0.1 eV, suppressing defect migration. Meanwhile, it raised work function by 0.26 eV and widened the bandgap by 0.6 eV. As hole transport layer, V-doped MoO(X) on illuminated side of c-Si solar cells boosted absolute efficiency by 1.0%, compared to MoO(X) on rear side; of this increase, 0.2% was attributed to higher work function and 0.8% was due to reduced optical losses. These findings emphasize V-doped MoO(X) in enhancing c-Si compound solar cell performance and in promoting the development of efficient photovoltaic technologies.