Luminescent emission in calcium titanate doped with rare-earth ions

Through the polymeric precursor method were synthesized samples Ca sub(0.98)Sr sub(0.01)X sub(0.01)TiO sub(3) (X= Eu super(3+), Sm super(3+) and Pr super(3+)), which under different heat treatments were obtained with levels of distinct structural order-disorder. The synthesized materials were charac...

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Bibliographic Details
Published in:Cerâmica (São Paulo) 2014-03, Vol.60 (353), p.77-82
Main Authors: Pereira, S C, Paranhos, M M, Eduardo, A C, Santos, M A B, Li, M S, Longo, E, Motta, F V, de Figueiredo, A T
Format: Magazinearticle
Language:Portuguese
Subjects:
Charge transfer
Crystallites
Dopants
Emission
Order disorder
Photoluminescence
Polymeric precursors
Rare earth metals
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Summary:Through the polymeric precursor method were synthesized samples Ca sub(0.98)Sr sub(0.01)X sub(0.01)TiO sub(3) (X= Eu super(3+), Sm super(3+) and Pr super(3+)), which under different heat treatments were obtained with levels of distinct structural order-disorder. The synthesized materials were characterized by X-ray diffraction, confirming the obtaining of ahomogeneous material with perovskite-type orthorhombic structure. This characterization allowed evaluating the average crystallite size of the samples that varies depending on the rare-earth ion. The results of photoluminescence emission confirmed the presence of this optical phenomenon at room temperature and its relationship to the level of order-disorder structural system. The photoluminescence emission is more intense in samples annealed at 500 parallel C (independent on the dopant ion), the variation of the dopant influence on the emission intensity due to charge transfer between the host and emitting rare-earth ion, where the doped with Pr super(3+) ion has chargeOriginal Abstract: Atraves do metodo dos precursores polimericos foram sintetizadas amostras de Ca sub(0,98)Sr sub(0,01)X sub(0,001)TiO sub(3) (X= Eu super(3+), Sm super(3+) ou Pr super(3+)), que submetidas a diferentes tratamentos termicos foram obtidas com niveis de ordem-desordem estrutural distintos. Os materiais sintetizados foram caracterizados por difracao de raios X, confirmando a obtencao de um material homogeneo com estrutura perovsquita do tipo ortorrombica. Essa caracterizacao permitiu ainda calcular o tamanho medio de cristalito das amostras, que varia em funcao do ion terra-rara presente. Os resultados da emissao fotoluminescente confirmaram a presenca desse fenomeno optico a temperatura ambiente e sua relacao com o nivel de ordem-desordem estrutural do sistema. A emissao fotoluminescente mais intensa ocorre nas amostras tratadas termicamente a 500 [degrees]C (independente do ion dopante), a variacao do dopante influencia na intensidade da emissao devido a transferencia de carga entre a matriz hospedeira e o ion terra-rara emissor, onde a amostra dopada com ion Pr super(3+) apresenta transferencia de carga mais eficiente e consequentemente maior intensidade na emissao fotoluminescente. Outro fator que favorece a propriedade optica das amostras e a compensacao de carga, pois contribui para o aumento da desordem estrutural devido a formacao de vacancias do ion Ca super(2+).
ISSN:0366-6913