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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Silver Molybdate and Silver Tungstate Nanocomposites with Enhanced Photoluminescence

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Autor(es):
De Santana, Yuri V. B. [1] ; Cardoso Gomes, Jose Ernane [2] ; Matos, Leandro [2] ; Cruvinel, Guilherme Henrique [2] ; Perrin, Andre [3] ; Perrin, Christiane [3] ; Andres, Juan [4] ; Varela, Jose A. [2] ; Longo, Elson [1]
Número total de Autores: 9
Afiliação do(s) autor(es):
[1] Univ Estadual Paulista, UNESP, CDMF INCTMN, Araraquara, SP - Brazil
[2] Univ Fed Sao Carlos, UFSCar, CDMF INCTMN, BR-13560 Sao Carlos, SP - Brazil
[3] Univ Rennes 1, Rennes - France
[4] Univ Jaume 1, Dept Expt Sci, Castellon de La Plana - Spain
Número total de Afiliações: 4
Tipo de documento: Artigo Científico
Fonte: NANOMATERIALS AND NANOTECHNOLOGY; v. 4, AUG 1 2014.
Citações Web of Science: 43
Resumo

Silver molybdate (Ag2MoO4) and silver tungstate (Ag2WO4) nanomaterials were prepared using two complementary methods, microwave assisted hydrothermal synthesis (MAH) (pH 7, 140 degrees C) and co-precipitation (pH 4, 70 degrees C), and were then used to prepare two core/shell composites, namely alpha-Ag2WO4/beta-Ag2MoO4 (MAH, pH 4, 140 degrees C) and beta-Ag2MoO4/beta-Ag2WO4 (co-precipitation, pH 4, 70 degrees C). The shape and size of the microcrystals were observed by field emission scanning electron microscopy (FE-SEM), different morphologies such as balls and nanorods. These powders were characterized by X-ray powder diffraction and UV-vis (diffuse reflectance and photoluminescence). X-ray diffraction patterns showed that the Ag2MoO4 samples obtained by the two methods were single-phased and belonged to the beta-Ag2MoO4 structure (spinel type). In contrast, the Ag2WO4 obtained in the two syntheses were structurally different: MAH exhibited the well-known tetrameric stable structure alpha-Ag2WO4, while co-precipitation afforded the metastable beta-Ag2WO4 allotrope, coexisting with a weak amount of the alpha-phase. The optical gap of beta-Ag2WO4 (3.3 eV) was evaluated for the first time. In contrast to beta-Ag2MoO4/beta-Ag2WO4, the alpha-Ag2WO4/beta-Ag2MoO4 exhibited strongly-enhanced photoluminescence in the low-energy band (650 nm), tentatively explained by the creation of a large density of local defects (distortions) at the core-shell interface, due to the presence of two different types of MOx polyhedra in the two structures. (AU)

Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
Beneficiário:Elson Longo da Silva
Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
Processo FAPESP: 08/57872-1 - Instituto Nacional de Ciências dos Materiais em Nanotecnologia
Beneficiário:Elson Longo da Silva
Modalidade de apoio: Auxílio à Pesquisa - Temático
Processo FAPESP: 12/22823-6 - Sulfetos metálicos nanocristalinos obtidos por síntese na interface de dois solventes assistida por microondas
Beneficiário:Yuri Vinicius Bruschi de Santana
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado