First principal investigation of Structural optical and thermoelectric properties of hybrid organic-inorganic perovskite [NH₃-(CH₂)₄-NH₃]CdCl₄ compound

The structural, thermoelectric, and optical properties of [NH₃-(CH₂)₄-NH₃]CdCl₄ were studied using Density Functional Theory (DFT) within the ABINIT code. The GGA-PBE functional, plane wave pseudopotentials, a kinetic energy cutoff of $35Ha$, and an 11x8x8 Monkhorst-Pack k-point grid were employed. The material comprises inorganic [CdCl₄]²⁻ sheets, organic [NH₃-(CH₂)₄-NH₃]²⁺ layers, and $N-H-Cl$ hydrogen bonds, ensuring sublattice cohesion. Structural optimization used reference crystal data, enabling analysis of alkylene-diammonium chain conformation, intermolecular interactions, and crystal stability. The study highlights the role of $Cd$ in influencing optical and thermoelectric properties. Temperature-induced changes lead to a reduced band gap and enhanced optical absorption, indicating significant electronic structure modifications. These findings propose [NH₃-(CH₂)₄-NH₃]CdCl₄ as a promising candidate for optoelectronic applications, particularly after thermal cycling, due to its improved performance under varying conditions.