First-principles Investigation of Structural, Electronic, Mechanical, Optical, and Thermodynamic Properties of Lead-Free KSrX3 (X = F, Cl, and Br) Halide Perovskites for UV Optoelectronic Applications

Rose P Abang, Auwalu Musa, Reuben A Solomon, Abdulkadir S Gidado, and Sylvester Hassan
2026-07-22 85 views 5 downloads

 

This study employed density functional theory (DFT) within Quantum ESPRESSO to investigate the structural, electronic, phonon, mechanical, optical, and thermodynamic properties of cubic KSrX? (X = F, Cl, Br) halide perovskites for UV optoelectronic applications. All compounds were found to be structurally, thermodynamically, mechanically, and dynamically stable, as confirmed by negative formation energies, appropriate Goldschmidt tolerance factors, Born stability criteria, and phonon spectra without imaginary frequencies. KSrF? exhibited a direct band gap of 5.52 eV, while KSrCl? and KSrBr? showed indirect band gaps of 4.45 and 3.75 eV, respectively, making KSrF? the most promising candidate for deep-UV applications. The compounds exhibited ductile behavior, characterized by dominant ionic bonding, low Debye temperatures indicative of low lattice thermal conductivity, and thermodynamic properties consistent with the third law of thermodynamics and Dulong–Petit’s law. Optical calculations revealed strong UV absorption and static dielectric constants of 2.02, 2.46, and 2.56 for KSrF?, KSrCl?, and KSrBr?, respectively, highlighting their potential for UV optoelectronic devices.

 

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