First Principle Investigation of CuCdX ₃ (X = F, Cl, Br) Halide Perovskites: Structural Stability and Optoelectronic Potential for Energy Applications

First-principle density functional theory (DFT) calculations within the generalized gradient approximation were employed to investigate the structural, mechanical, electronic, and optical properties of cubic CuCdX 3 (X = F, Cl, Br) perovskites. The systematic theoretical investigations about CuCdX 3 family are provided for the first time to elucidate the structureproperty relationships and halogen-dependent tunability. The CuCdX 3 (X = F, Cl, Br) perovskites exhibit structural stability within the ideal perovskite range, along with ductile mechanical behavior and tunable stiffness governed by the halogen substitution. All compounds displayed indirect semiconducting band gaps having band gap values of: CuCdF 3 = 0.029 eV; CuCdCl 3 = 0.795 eV; and CuCdBr 3 = 0.532 eV. Partial density of states analysis indicates that the valence band is mainly composed of Cu-d and halogen-p states, while Cd-d and halogen-p states dominate the conduction band. Optical studies revealed strong absorption and high dielectric response in the visible-UV region, confirming the efficient lightmatter interaction. Overall, these materials provided strong potential for flexible optoelectronic and photovoltaic applications owing to the mechanical tenability and favorable optical response.