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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.)

Silver-controlled evolution of morphological, structural, and optical properties of three-dimensional hierarchical WO3 structures synthesized from hydrothermal method

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Lopes, L. F. [1] ; Pontes, F. M. [1] ; Garcia, L. O. [1] ; Pontes, D. S. L. [1] ; Padovani, D. [1] ; Chiquito, A. J. [2] ; Teixeira, S. R. [3] ; Colmenares, Y. N. [4] ; Mastelaro, V. R. [4] ; Longo, E. [5]
Total Authors: 10
[1] Univ Estadual Paulista, UNESP, Dept Chem, POB 47, BR-17033360 Bauru, SP - Brazil
[2] Univ Fed Sao Carlos, NanO LaB, Dept Phys, Via Washington Luiz, Km 235, POB 676, BR-13565905 Sao Carlos, SP - Brazil
[3] Univ Estadual Paulista, FCT, Dept Phys, Rua Roberto Simonsen 305, BR-19060900 Presidente Prudente, SP - Brazil
[4] Univ Sao Paulo, Phys Inst Sao Carlos IFSC, Sao Carlos, SP - Brazil
[5] Univ Fed Sao Carlos, Dept Chem, CDMF, LIEC, Via Washington Luiz, Km 235, POB 676, BR-13565905 Sao Carlos, SP - Brazil
Total Affiliations: 5
Document type: Journal article
Source: Journal of Alloys and Compounds; v. 736, p. 143-151, MAR 5 2018.
Web of Science Citations: 4

Hierarchical structures of self-assembled three-dimensional (3D) WO3-Ag were synthesized via hydrothermal growth using precursor solutions of peroxopolytungstic acid with different amounts of Ag. The as-grown samples were analyzed by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy. The XRD and Raman studies showed that as the amount of Ag was varied from 0 to 10 wt% in the hydrothermal growth solution, the crystal phase gradually changed from orthorhombic WO3 center dot 0.33H(2)O to hexagonal WO3. The FTIR and TGA studies revealed different hydration levels, supporting the XRD and Raman results. By controlling the amount of Ag in the precursor solution, platelet-like building blocks and hexagonal building blocks were obtained, highlighting the role of Ag in the hydrothermal growth of 3D WO3 center dot 0.33H(2)O and WO3 microcrystals. In addition, high-magnification FESEM images showed that the Ag nanoparticles were anchored on the surface of the 3D hierarchical WO3-Ag structures, and the UV-vis measurements demonstrated that the 3D hierarchical structures gradually absorbed more light when the Ag content was increased. Moreover, the band-gap energy decreased when the Ag content was increased from 0 wt% (Eg = 2.65 eV) to 10 wt% (Eg = 2.26 eV). These experimental results demonstrate that the amount of Ag played a crucial role in determining the building blocks' morphology, and the hydration level, optical properties, and crystal phase of the WO3 center dot nH(2)O microcrystals. (C) 2017 Published by Elsevier B.V. (AU)

FAPESP's process: 11/20536-7 - Multifunctional ferroelectric materials: studies of optical, electrical and photoluminescent properties
Grantee:Debora da Silva Lima Pontes
Support type: Scholarships in Brazil - Post-Doctorate
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: 12/14106-2 - Designe multifunctional oxides with perovskite architecture (Pb, Sr, La, BI) (Ti, Fe) O3
Grantee:Fenelon Martinho Lima Pontes
Support type: Regular Research Grants