Dielectric Behavior of α-Ag2WO4 and its Huge Dielectric Loss Tangent

Abstract

The microwave-assisted hydrothermal method was used to obtain α-Ag 2 WO 4 . Rietveld refinement confirmed that α-Ag 2 WO 4 is stable in the orthorhombic phase, without secondary phase. However, fieldeffect scanning electron microscope analysis showed that α-Ag 2 WO 4 nanorods surfaces contain silver nanoparticles, confirmed by the X-ray photoelectron spectroscopy by the peak observed at 374.39 eV. In addition to metallic Ag, other Ag oxidation states were also observed on the surface. Hence, Ag (I) as Ag 2 O and Ag (I) as Ag 2 WO 4 also were identified. DC measurements exhibited a high capacity of charge storage, nevertheless, with a large loss tangent (0.12 µC.cm -2 .V -1 ) and no residual polarization for the voltage range between -100 V and +100 V. AC measurements at frequencies less than 275 Hz, revealed that ionic polarization is dominant, whereas at frequencies higher than 275 Hz, the electronic behavior predominates. The potential of electromagnetic energy conversion in thermal was observed from loss tangent analysis.

Ag2–xCuxWO4 Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation

“…Table summarizes the lattice parameters, unit cell volume, and crystallite size for α-Ag 2 WO 4 and α-Ag 1.98 Cu 0.02 WO 4 samples obtained by Rietveld refinement results and those reported in the literature. ,− …”

“…Several applications are reported for silver tungstate microcrystals, mainly related to the alpha phase. In this context, we can highlight photocatalytic, − antimicrobial, , and fungal properties in addition to applications in semiconductor technology as capacitors, light-emitting devices (LEDs), and gas sensors . These applications are intrinsically dependent on the obtaining methods, particle size and morphology, doping elements, and crystalline defects. ,,− Also, the optical band gap near 3.1 eV for pure silver tungstate (α-Ag 2 WO 4 ) is a factor that limits the photocatalytic applications to the ultraviolet region.…”

Disclosing the Biocide Activity of α-Ag2−2xCuxWO4 (0 ≤ x ≤ 0.16) Solid Solutions

“…Transition metal tungstates belong to an important family of inorganic functional materials with potential applications in various fields [1] and have been widely studied [2][3][4] due to their unique structures and photoluminescence emissions at room temperature [5]. Among them, alpha silver tungstate (α-Ag 2 WO 4 ) has received special attention from the scientific community because of its interesting properties, including photoluminescence emission [5][6][7][8][9][10], antimicrobial activity [11][12][13][14][15][16][17][18], and photocatalytic properties [11,13,[19][20][21][22][23][24][25].…”