SCAPS-1D Simulation of High-Performance NaZn₀․₇Ag₀․₃Br₃ Double Perovskite Solar Cells with Optimized Transport Layers

Abstract This study presents a comprehensive SCAPS-1D simulation of a lead-free double-perovskite solar cell based on 
NaZn₀.₇Ag₀.₃Br₃ as the absorber layer. Various electron transport layers (CdZnS, MZO, Nb₂O₅, and SnS₂) were 
systematically evaluated to optimize device performance. Among the investigated configurations, the 
FTO/SnS₂/NaZn₀.₇Ag₀.₃Br₃/CuAlO₂/Pt structure exhibited superior photovoltaic characteristics due to improved 
band alignment and reduced recombination losses. Under ideal radiative-loss-free conditions (B = 0), a maximum 
power conversion efficiency (PCE) of 30.56% was obtained. However, after incorporating a realistic radiative 
recombination coefficient (B = 2.3 × 10⁻⁹ cm³/s), the optimized device achieved a PCE of 29.92%, with minimal 
variation in short-circuit current density and a moderate reduction in open-circuit voltage. The results confirm that 
the proposed lead-free perovskite configuration maintains strong photovoltaic performance under physically 
realistic recombination conditions, highlighting its potential for high-efficiency and environmentally benign solar 
cell applications.