Propriedade fotoluminescente do Ca1-(x+y)YbxTmyTiO3 obtido pelo método hidrotérmico assistido por micro-ondas
Data
2014-01-27
Autores
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Universidade Federal de Goiás
Resumo
In recent years, the perovskite type oxides doped with rare-earth ions has attracted great interest in the research, especially in the field of photoluminescence (PL). This property has always attracted the interest of the scientific community, especially since their discovery room temperature. The present work aims to study the PL property CaTiO3 (CT) doped with rare-earth ions Yb (III) and Tm (III). Samples of CT pure and doped with rare-earth ions, Ca1-(x+y)YbxTmyTiO3 (x and y = 0, 0,01, 0,0075, 0,005, ou 0,0025 ), were obtained by co-precipitation method and processing using hydrothermal system assisted by microwave , which was used to be a relatively new, promising little used method of processing. The samples were characterized by different techniques, the X-ray diffraction confirmed to obtain a single phase material of orthorhombic perovskite type structure, confirming that the hydrothermal synthesis method is effective in the samples of interest in shorter periods of time. Ultraviolet-visible absorption spectroscopy, allowed calculation of the "gap" optic, confirming the presence of intermediate levels between the valence band and the conduction in the doped samples. The characterization by SEM and EDX confirmed, respectively, obtaining approximately cubic particles and exclusive presence of the cations of interest. PL results show that the doping of CT formation leads of defects to high and low energy in the samples. The highest FL intensity occurs when the doping is performed in proportion to the doping.
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Palavras-chave
Perovsquita, Terras-raras, Síntese hidrotérmica assistida por micro-ondas, Fotoluminescência, Perovskite, Rare earths, Hydrothermal synthesis assisted by microwave, Photoluminescence
Citação
PEREIRA, Sandra de Cássia. Propriedade fotoluminescente do Ca1-(x+y)YbxTmyTiO3 obtido pelo método hidrotérmico assistido por micro-ondas. 2014. 78 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Goiânia, 2014.