ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

First-principles insights into cation-dependent properties of Na₂CuRhF₆ and Rb₂CuRhF₆ double perovskites for UV optoelectronic applications

Hadjer Bendjilali, Debidatta Behera, Aiswarya Priyambada, Kalpana Sahoo, Sanat Kumar Mukherjee, and Adnène Arbi

Dielectric Materials and Polymers Team, Laboratory of Materials Physics, Faculty of Physics, University of Science and Technology Houari Boumediene USTHB, El Alia, Algiers, Algeria

E-mail: hadjer.bendjilali@yahoo.com

Received: 21 March 2026  Accepted: 1 May 2026

Abstract:

Density functional theory was used to evaluate the structural, mechanical, electrical and optical properties of Na₂CuRhF₆ and Rb₂CuRhF₆ perovskite fluorides. According to the structural relaxation the two compounds were stable with cubic double-perovskite structure. The computed elastic parameters meet Born stability criteria that show the mechanical stability of the studied compounds. Furthermore, the computed poison ratio of the Na₂CuRhF₆ and Rb₂CuRhF₆ compounds were found to be 0.32 and 0.27 respectively reflecting their ductile nature. According to their electronic band structures, both materials, Na₂CuRhF₆ and Rb₂CuRhF₆ are indirect semiconducting with band gap 0.94 eV and 0.77 eV respectively. Their valence band and conduction band are due to Cu-3d, Rh-4d, and F-2p orbitals. Substitution of the larger Rb cation by Na results in the lattice structure being opened somewhat, and the band gap and electronic states near the Fermi level undergo some small changes. According to the outcomes, the electronic properties of fluorinated double perovskites depend on the size of the A-site cation. Based on the optical analysis, the two substances have a high UV absorption. The dielectric function has the real and imaginary components which provide it with distinctive properties that change the refractive index spectrum. The high-energy absorption edge of the materials suggests the prospects of radioactivated technology and optical electrotechnology with UV applications.

Keywords: DFT; Double perovskites; Electronic properties; Refractive index

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04996-y

Chemical Papers 80 (9) 10131–10146 (2026)