Disclosing the electronic structure and optical properties of Ag₄V₂O₇crystals: experimental and theoretical insights

Abstract

This work combines experimental and computational techniques to exploit the best of both methodologies and thus provide a tool for understanding the geometry, cluster coordination, electronic structure, and optical properties of Ag4V2O7 crystals. This tool has been developed to create structural models and enable a much more complete and rapid refinement of 3D (Third Dimension) structures from limited data, aiding the determination of structure-property relationships and providing critical input for materials simulations. Ag4V2O7 crystals were synthesized by a simple precipitation method from aqueous solution at 30 °C for 10 min. The obtained crystals were characterized by X-ray diffraction (XRD) and Rietveld refinement, and micro-Raman spectroscopy. The crystal morphology was determined by field emission scanning electron microscopy (FESEM), and the optical properties were investigated by ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy and photoluminescence (PL) measurements. The geometric and electronic structures of Ag4V2O7 crystals were investigated by first-principles quantum-mechanical calculations based on the density functional theory. The theoretical results meet the experimental data to confirm that Ag4V2O7 crystals have an orthorhombic structure, and that the building blocks of the lattice comprise two types of V clusters, [VO4] and [VO5], and two types of Ag clusters, [AgO5] and [AgO6]. This type of fundamental studies, which combine multiple experimental methods and first-principles calculations, have been proved valuable to obtain a basic understanding of the local structure, bonding, electronic, and optical properties of Ag4V2O7 crystals.

Uncovering the metastable γ-Ag2WO4phase: a joint experimental and theoretical study

“…This combination has previously been applied to the investigation of complex materials such as b-Ag 2 WO 4 , 35 Ag 2 CrO 4 , 37 and Ag 4 V 2 O 7 (ref. 38) crystals. To the best of our knowledge, combination of theoretical and experimental studies on the structure of g-Ag 2 WO 4 crystals is inexistent.…”

Photoluminescence and thermal expansion of zirconium vanadate

“…Cavalcante et al. assumed that the distorted VO 4 tetrahedra and VO 5 trigonal bipyramidal are the responsible for the electronic transitions between the conduction band (CB) and the valence band (VB) . The one at the lowest energy shows a red shift until 130 K (Figure A).…”

Effect of metallic Ag growth on the electrical resistance of 3D flower‐like Ag4V2O7 crystals

“…The before and after exposure to electron beam enhances the formation of e′‐h • pairs leading to electron transfer within the band gap. The cluster‐to‐cluster charge‐transfer (CCCT) in a crystal, containing more than one kind of cluster, is characterized by excitations involving electronic transitions from one cluster to another, which is possible according to Equations :…”

“…The before and after exposure to electron beam enhances the formation of e 0 -h • pairs leading to electron transfer within the band gap. The cluster-to-cluster charge-transfer (CCCT) in a crystal, containing more than one kind of cluster, 14 is characterized by excitations involving electronic transitions from one cluster to another, which is possible according to Equations (1)(2)(3)(4)(5)(6):…”