Microwave-assisted hydrothermal synthesis of Ag-2(W1-xMox)O-4 heterostructures: Nucleation of Ag, morphology, and photoluminescence properties
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2016-01-15
Autores
Silva, M. D. P.
Goncalves, R. F.
Nogueira, I. C.
Longo, V. M.
Mondoni, L.
Moron, M. G.
Santana, Y. V.
Longo, E. [UNESP]
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Elsevier B.V.
Resumo
Ag2W1-xMoxO4 (x = 0.0 and 0.50) powders were synthesized by the co-precipitation (drop-by-drop) method and processed using a microwave-assisted hydrothermal method. We report the real-time in situ formation and growth of Ag filaments on the Ag2W1-xMoxO4 crystals using an accelerated electron beam under high vacuum. Various techniques were used to evaluate the influence of the network-former substitution on the structural and optical properties, including photoluminescence (PL) emission, of these materials. X-ray diffraction results confirmed the phases obtained by the synthesis methods. Raman spectroscopy revealed significant changes in local order-disorder as a function of the network-former substitution. Field-emission scanning electron microscopy was used to determine the shape as well as dimensions of the Ag2W1-xMoxO4 heterostructures. The PL spectra showed that the PL-emission intensities of Ag2W1-xMoxO4 were greater than those of pure Ag2WO4, probably because of the increase of intermediary energy levels within the band gap of the Ag2W1-xMoxO4 heterostructures, as evidenced by the decrease in the band-gap values measured by ultraviolet-visible spectroscopy. (C) 2015 Elsevier B.V. All rights reserved.
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Ag2WO4, Ag2MoO4, Photoluminescence, Morphology, Raman spectroscopy
Como citar
Spectrochimica Acta Part A-molecular And Biomolecular Spectroscopy. Oxford: Pergamon-elsevier Science Ltd, v. 153, p. 428-435, 2016.