Abstract
Lead-free halide double perovskite (LFHDP) Cs(2)AgBiBr(6) has emerged as a promising alternative to traditional lead-based perovskites (LBPs), offering notable advantages in terms of chemical stability and non-toxicity. However, the efficiency of Cs(2)AgBiBr(6) solar cells faces challenges due to their wide bandgap (E(g)). As a viable strategy to settle this problem, we consider optimization of the optical and photovoltaic properties of Cs(2)AgBiBr(6) by Gallium (Ga) substitution. The synthesized Cs(2)Ag(0.95)Ga(0.05)BiBr(6) is rigorously characterized by means of X-ray diffraction (XRD), UV-vis spectroscopy, and solar simulator measurements. XRD analysis reveals shifts in peak positions, indicating changes in the crystal lattice due to Ga substitution. The optical analysis demonstrates a reduction in the E(g), leading to improvement of the light absorption within the visible spectrum. Importantly, the Cs(2)Ag(0.95)Ga(0.05)BiBr(6) solar cell exhibits enhanced performance, as evidenced by higher values of open circuit voltage (V(oc)), short-circuit current (J(sc)), and fill factor (FF), which are 0.94 V, 6.01 mA cm(-2), and 0.80, respectively: this results in an increased power conversion efficiency (PCE) from 3.51% to 4.52%. This research not only helps to overcome film formation challenges, but also enables stable Cs(2)Ag(0.95)Ga(0.05)BiBr(6) to be established as a high-performance material for photovoltaic applications. Overall, our development contributes to the advancement of environmentally friendly solar technologies.