Computational design of GUA0.5X0.5SrI3 (X = Cs, K) perovskites: exploring the potential for optoelectronic applications

Abstract

In this study, the structural, electronic, and optical properties of GUA_0.5X_0.5SrI₃ (X = Cs, K) halide perovskite materials were theoretically analyzed using the CASTEP (Cambridge Serial total energy package) software package, which employs density functional theory (DFT). DFT is a powerful computational method that allows for the accurate prediction of material properties, enabling the rational design of novel compounds. The structural analysis of the lattice constants and stable cell volume at different cutoff energies confirmed the stability of the cubic compounds, which is driven by the synergistic interactions between guanidinium (GUA), cesium (Cs), potassium (K), and strontium (Sr). The electronic properties, including the band structure and density of states, indicate that these perovskite compounds exhibit semiconductor behavior, as evidenced by the calculated band structures and density of states. Furthermore, the optical properties quantified through the dielectric function, extinction coefficient, refractive index, absorption coefficient, reflectivity, energy-loss function, and optical conductivity offer a detailed understanding of their optical performance. This work underscores the potential of GUA_0.5X_0.5SrI₃ materials in advancing high-performance, environmentally friendly solar cell technologies, effectively addressing critical challenges related to efficiency and long-term stability in perovskite-based systems.