Year: 2025
Type: article
Abstract: Rb2KWO3F3 elpasolite was synthesized via the solid-state reaction route. The phase purity of the obtained sample was verified by the XRD analysis with Rietveld refinement in space group Fm-3m, yielding the unit cell parameter a = 8.92413 (17) Å. The electronic structure and chemical states of the constituent elements were investigated using X-ray photoelectron spectroscopy. The binding energy of the W 4f7/2 core level (34.95 eV) was found to be characteristic of the W6+ oxidation state, while the values for Rb 3d, K 2p, O 1s and F 1s levels were consistent with those reported for related oxide and oxyfluoride compounds. First-principles density functional theory calculations were performed to model the electronic structure. The fac-configuration of the WO3F3 octahedra was identified as the most energetically favorable. The calculations revealed a direct band gap of 4.38 eV, with the valence band maximum composed primarily of O 2p orbitals and the conduction band minimum formed by W 5d orbitals. This combined experimental/theoretical study shows that the electronic structure and wide bandgap of Rb2KWO3F3 are governed by the WO3F3 units and are largely insensitive to the Rb/K substitution. The wide bandgap identifies this class of oxyfluorides as a promising platform for developing new UV-transparent materials.
Source: Crystals
Institutions: Institute of Semiconductor Physics, Kemerovo State University, Siberian Branch of the Russian Academy of Sciences, V.S. Sobolev Institute of Geology and Mineralogy, Krasnoyarsk Scientific Center, Institute of Physics, Far Eastern State Transport University, Siberian Federal University, Russian Academy of Sciences
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,534
Award: G8211967352
OpenAlex ID: W7117490047