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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

alpha-Ag2-2xZnxWO4 (0 <= x <= 0.25) Solid Solutions: Structure, Morphology, and Optical Properties

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Author(s):
Pereira, Paula F. S. ; Santos, Clayane C. ; Gouveia, Amanda F. ; Ferrer, Mateus M. ; Pinatti, Ivo M. ; Botelho, Gleice ; Sambrano, Julio R. ; Rosa, Ieda L. V. ; Andres, Juan ; Longo, Elson
Total Authors: 10
Document type: Journal article
Source: Inorganic Chemistry; v. 56, n. 13, p. 7360-7372, JUL 3 2017.
Web of Science Citations: 9
Abstract

A theoretical study was elaborated to support the experimental results of the Zn-doped alpha-Ag2WO4. Theses alpha-Ag2-2xZnxWO4 (0 <= x <= 0.25) solid solutions were obtained by coprecipitation method. X-ray diffraction data indicated that all alpha-Ag2-2xZnxWO4 (0 <= x <= 0.25) microcrystals presented an orthorhombic structure. The experimental values of the micro Raman frequencies were in reasonable agreement with both previously reported and calculated results. MicroScopy images showed that the replacement of Ag+ by Zn2+ promoted a reduction in the average crystal size and modifications in the morphology, from rod-like with hexagonal shape to roll:like with; a curved surface. A theoretical methodology calculations and Wulff constructions was applied to study the particle shapes transformations and the surface energy variations in alpha-Ag2-2xZnxWO4(0 <= x <= 0.25) system. The decrease in the band gap value (from 3.18 to 3.08 eV) and the red shift in photoluminescence with the Zn2+ addition Were associated with intermediary energy levels between the valence and conduction bands. First-principles calculations with density functional theory associated with B3LYP hybrid functional were conducted. The calculated band structures revealed an indirect band gap for the alpha-Ag2-2xZnxWO4 models. The electronic properties of alpha-Ag2-2xZnxWO4 and alpha-Ag2-2xZnxWO4 microcrystals Were linked to distortion effects and oxygen vacancies (V-O(x)) present in the clusters, respectively. Finally, photoluminescence properties of alpha-Ag2WO4 and alpha-Ag2-2xZnxWO4 microcrystals were explained by means of distortional effects and oxygen vacancies (V-O(x)) in {[}AgOy] (y = 2, 4, 6, and 7) and {[}WO6] clusters, respectively, causing a red shift. Calculations revealed that the substitution for Ag+ with Zn2+ occurred randomly in the alpha-Ag2WO4 lattice, and it was more favorable on the Ag4 site, where the local coordination of Ag+,cations was four. (AU)

FAPESP's process: 13/23995-8 - Synthesis of silver tungstate doped with Eu3+ and the study of their optical, photoluminescent and photocatalytic properties
Grantee:Ivo Mateus Pinatti
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 14/14171-4 - Investigation of the crystalline structure and photoluminescence, photocatalytic and antibacterial properties of the nanocrystals (Ag2-2xZnX)WO4 with (x = 0, 0.25, 0.50, 0.75 and 1) incorporated in chitosan
Grantee:Paula Fabiana dos Santos Pereira Lima
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 16/07476-9 - Porous nanotubes of carbon and inorganic semiconductors: a computational study
Grantee:Julio Ricardo Sambrano
Support type: Regular Research Grants
FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
Grantee:Elson Longo da Silva
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC
FAPESP's process: 12/14004-5 - Investigation of the photoluminescence and photocatalytic properties of pure and Mn, Cu, and Zn-doped BaWO4 and BaMoO4 powders
Grantee:Júlio César Sczancoski
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 13/26671-9 - Theoretical and experimental study of multifunctional semiconductors
Grantee:Amanda Fernandes Gouveia
Support type: Scholarships in Brazil - Doctorate