Silver Molybdate and Silver Tungstate Nanocomposites with Enhanced Photoluminescence
Silver molybdate (Ag2MoO4) and silver tungstate (Ag2WO4) nanomaterials were prepared using two complementary methods, microwave assisted hydrothermal synthesis (MAH) (pH 7, 140 °C) and coprecipitation (pH 4, 70 °C), and were then used to prepare two core/shell composites, namely α-Ag2WO4/β-Ag2MoO4 (...
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2014-08-01
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| Series: | Nanomaterials and Nanotechnology |
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| Online Access: | http://www.intechopen.com/journals/nanomaterials_and_nanotechnology/silver-molybdate-and-silver-tungstate-nanocomposites-with-enhanced-photoluminescence |
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| author | Yuri V. B. De Santana José Ernane Cardoso Gomes Leandro Matos Guilherme Henrique Cruvinel André Perrin Christiane Perrin Juan Andrès José A. Varela Elson Longo |
| author_facet | Yuri V. B. De Santana José Ernane Cardoso Gomes Leandro Matos Guilherme Henrique Cruvinel André Perrin Christiane Perrin Juan Andrès José A. Varela Elson Longo |
| author_sort | Yuri V. B. De Santana |
| collection | DOAJ |
| description | Silver molybdate (Ag2MoO4) and silver
tungstate (Ag2WO4) nanomaterials were prepared using
two complementary methods, microwave assisted
hydrothermal synthesis (MAH) (pH 7, 140 °C) and coprecipitation
(pH 4, 70 °C), and were then used to prepare
two core/shell composites, namely α-Ag2WO4/β-Ag2MoO4
(MAH, pH 4, 140 °C) and β-Ag2MoO4/β-Ag2WO4 (coprecipitation,
pH 4, 70 °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 β-Ag2MoO4 structure (spinel type). In
contrast, the Ag2WO4 obtained in the two syntheses were
structurally different: MAH exhibited the well-known
tetrameric stable structure α-Ag2WO4, while coprecipitation
afforded the metastable β-Ag2WO4
allotrope, coexisting with a weak amount of the α-phase.
The optical gap of β-Ag2WO4 (3.3 eV) was evaluated for
the first time. In contrast to β-Ag2MoO4/β-Ag2WO4, the α-
Ag2WO4/β-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. |
| format | Article |
| id | doaj-art-1ac779a65e794b7496a6ea6956be4a7d |
| institution | Kabale University |
| issn | 1847-9804 |
| language | English |
| publishDate | 2014-08-01 |
| publisher | Wiley |
| record_format | Article |
| series | Nanomaterials and Nanotechnology |
| spelling | doaj-art-1ac779a65e794b7496a6ea6956be4a7d2025-02-03T06:45:38ZengWileyNanomaterials and Nanotechnology1847-98042014-08-01422http://dx.doi.org/10.5772/5892347330Silver Molybdate and Silver Tungstate Nanocomposites with Enhanced PhotoluminescenceYuri V. B. De SantanaJosé Ernane Cardoso GomesLeandro MatosGuilherme Henrique CruvinelAndré PerrinChristiane PerrinJuan AndrèsJosé A. VarelaElson LongoSilver molybdate (Ag2MoO4) and silver tungstate (Ag2WO4) nanomaterials were prepared using two complementary methods, microwave assisted hydrothermal synthesis (MAH) (pH 7, 140 °C) and coprecipitation (pH 4, 70 °C), and were then used to prepare two core/shell composites, namely α-Ag2WO4/β-Ag2MoO4 (MAH, pH 4, 140 °C) and β-Ag2MoO4/β-Ag2WO4 (coprecipitation, pH 4, 70 °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 β-Ag2MoO4 structure (spinel type). In contrast, the Ag2WO4 obtained in the two syntheses were structurally different: MAH exhibited the well-known tetrameric stable structure α-Ag2WO4, while coprecipitation afforded the metastable β-Ag2WO4 allotrope, coexisting with a weak amount of the α-phase. The optical gap of β-Ag2WO4 (3.3 eV) was evaluated for the first time. In contrast to β-Ag2MoO4/β-Ag2WO4, the α- Ag2WO4/β-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.http://www.intechopen.com/journals/nanomaterials_and_nanotechnology/silver-molybdate-and-silver-tungstate-nanocomposites-with-enhanced-photoluminescenceSilver MolybdateSilver TungstatePhotoluminescenceDecorated System |
| spellingShingle | Yuri V. B. De Santana José Ernane Cardoso Gomes Leandro Matos Guilherme Henrique Cruvinel André Perrin Christiane Perrin Juan Andrès José A. Varela Elson Longo Silver Molybdate and Silver Tungstate Nanocomposites with Enhanced Photoluminescence Nanomaterials and Nanotechnology Silver Molybdate Silver Tungstate Photoluminescence Decorated System |
| title | Silver Molybdate and Silver Tungstate Nanocomposites with Enhanced Photoluminescence |
| title_full | Silver Molybdate and Silver Tungstate Nanocomposites with Enhanced Photoluminescence |
| title_fullStr | Silver Molybdate and Silver Tungstate Nanocomposites with Enhanced Photoluminescence |
| title_full_unstemmed | Silver Molybdate and Silver Tungstate Nanocomposites with Enhanced Photoluminescence |
| title_short | Silver Molybdate and Silver Tungstate Nanocomposites with Enhanced Photoluminescence |
| title_sort | silver molybdate and silver tungstate nanocomposites with enhanced photoluminescence |
| topic | Silver Molybdate Silver Tungstate Photoluminescence Decorated System |
| url | http://www.intechopen.com/journals/nanomaterials_and_nanotechnology/silver-molybdate-and-silver-tungstate-nanocomposites-with-enhanced-photoluminescence |
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