Comprehensive Analysis of Optoelectronic Properties and Photovoltaic Performance of Rb2CuAsZ6 (Z = Br and Cl) Double Perovskites Using DFT and SCAPS-1D Modelling

Rb2CuAsZ6 (Z = Br, Cl) double perovskites were studied for their optoelectronic and photovoltaic properties using a comprehensive density functional theory (DFT) analysis. Using the HSE06 functional for electronic band structure calculations, Rb2CuAsBr6 and Rb2CuAsCl6 exhibit indirect band gaps (Eg) of 0.64 eV and 1.09 eV, respectively. Moreover, the analysis of the optical properties revealed substantial absorption (α) around 105 in both the visible and near-infrared regions, highlighting their suitability for solar cell and optoelectronic applications. Moreover, we utilised the absorber layer Rb2CuAsCl6 to construct an n-i-p structure perovskite and modelled it Using the SCAPS-1d program, this calculation was performed with a thickness of 400 nm of Rb2CuAsCl6, yielding remarkable performance: an open-circuit voltage (Voc) of 0.81 V, a short-circuit current density (Jsc) of 38.33 mA/cm², a fill factor (FF) of 68.65%, and a power conversion efficiency (PCE) of 20.63%.