Computational Study of the Effect of Metal Change on the Structural, Electronic, and Optical Properties of Perovskites [NH3(CH2)4NH3]MCl4 (M = Co, Cd): Optoelectronic Applications

Organic–inorganic hybrid perovskites (OIHP) are currently the subject of rigorous study due to their promising utility in optoelectronics and photovoltaics. Therefore, in this work, we perform an in-depth analysis of OIHP perovskites, in particular [NH₃(CH₂)₄NH₃]MCl₄ (M = Co, Cd). We focus on structural, electronic, and optical properties and present information on this subject for the first time. Our study revealed the stable triclinic phase structure of the hybrid [NH₃-(CH₂)₄-NH₃]CoCl₄ and monoclinic of the hybrid [NH₃-(CH₂)₄-NH₃]CdCl₄ perovskites, with calculated free energies of − 10522.91 eV and − 10520.13 eV, corresponding to a relative stability difference of approximately 2.78 eV, respectively indicating their structural robustness. The semiconducting characteristics of [NH₃(CH₂)₄NH₃]CoCl₄ and [NH₃(CH₂)₄NH₃]CdCl₄ are highlighted by their wide indirect band gaps of 1.84 eV and 0.88 eV, respectively. We then examine the optical parameters, including the dielectric function, absorption coefficient, optical conductivity, refractive index, and energy loss function. Our results highlight the exceptional ability of these materials to absorb ultraviolet radiation in the electromagnetic spectrum, making them promising candidates for optoelectronic applications. The outcomes of our research catalyze deeper inquiry into the application of these materials in technologically significant contexts. Calculations were performed using a first-principles approach based on density functional theory (DFT). The electronic properties of the system were examined using the HSE06 hybrid exchange–correlation function and the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) within the CASTEP framework. Within this framework, Kramers–Kronig relations are used to obtain crucial optical parameters.