A numerical analysis of a high-efficiency solar cell using a DFT explored nontoxic perovskite material

In recent years, Perovskites have been a very interesting breakthrough in the field of photovoltaics because of their excellent performance with easy and less complex synthesizability, and cost-effectiveness. This instance suggests a uniquely designed solar cell with a novel perovskite, Rb
2
NaGaBr
6
. The perovskite, used as the active layer, is analyzed through the First Principle Density Functional Theory (DFT) calculation, where the cell is simulated by the SCAPS-1D simulation tool showing a power conversion efficiency (PCE) of 26.86% for this single-junction solar cell. In order to achieve optimum efficiency, the effects of defect concentration and the thickness of the absorber layer are examined and adjusted. Here, the influence of the absorber thickness and defect concentration on fill factor, short-circuit current ($\mathrm{J}_{\mathrm{sc}}$), and open-circuit voltage ($\mathrm{V}_{\mathrm{oc}}$) were also examined in addition to their impact on PCE. Based on the insights gathered from the simulation of the designed cell, $\mathrm{FTO} / \mathrm{SnO}_{2} / \mathrm{Rb}_{2} \mathrm{NaGaBr}_{6} / \mathrm{CuI} / \mathrm{W}$, the best results were obtained at a thickness of 0.8μm. The simulation indicated that $\mathrm{J}_{\mathrm{sc}}=25.02 \mathrm{~mA} / \mathrm{cm}^{2}$, a fill factor (FF) of 84.01%, and $\mathrm{V}_{\text {oc }}=1.2777 \mathrm{~V}$, that leads to a PCE of 26.86%.