A comparative DFT study of CdKF3 and CdKCl3 halide perovskite materials for energy harvesting applications

Abstract

Lead-free halide perovskites have been investigated as promising materials for energy harvesting and thermoelectric device applications. The current article thoroughly explains the electronic behavior, stability, optical and thermoelectric characteristics of CdKF3 and CdKCl3 halide perovskite. For structural stability, the elastic constant and phonon dispersion of both halides are investigated. Additionally, thermodynamic stability is demonstrated by the investigation of formation energy (-2.45 to −1.89 eV). The ductile nature of both halides is confirmed by calculating the Poisson ratio, and their significance for the manufacturing of devices. The direct bandgap nature (2.65 eV and 0.9 eV) of both halides is observed through electronic band structures using mBJ-GGA, which has been employed to obtain more precise results for optoelectronic applications. Both halides show remarkable optoelectronic performance, with low reflectivity, high optical absorption, and conductivity. Thermal and electrical conductivity are also used to study the thermoelectric characteristics. Both halides show the figure of merit (ZT) near unity, ZT indices highlight their importance for thermoelectric devices.

Keywords

• Perovskites CdKCl3 and CdKF3
• Density Functional Theory
• Elastic parameters
• Energy gap
• Optical properties
• Figure of merit (ZT)