Voltar
Artigo Produção Nacional Revisado por pares
BIBTEX RIS

Different Origins of Green-Light Photoluminescence Emission in Structurally Ordered and Disordered Powders of Calcium Molybdate

2008; American Chemical Society; Volume: 112; Issue: 38 Linguagem: Inglês

10.1021/jp801587w

ISSN

1520-5215

Autores

V. M. Longo, Alberthmeiry T. de Figueiredo, A.B. Campos, J.W.M. Espinosa, Antônio Carlos Hernandes, Carlton A. Taft, Júlio R. Sambrano, José Manuel Rey Varela Rey Varela, E. Longo,

Tópico(s)

Polyoxometalates: Synthesis and Applications

Resumo

A strong greenish-light photoluminescence (PL) emission was measured at room temperature for disordered and ordered powders of CaMoO4 prepared by the polymeric precursor method. The structural evolution from disordered to ordered powders was accompanied by XRD, Raman spectroscopy, and TEM imagery. High-level quantum mechanical calculations in the density functional framework were used to interpret the formation of the structural defects of disorder powders in terms of band diagram and density of states. Complex cluster vacancies [MoO3 x V(O(z))] and [CaO7 x V(O(z))] (where V(O(z)) = V(O(X)), V(O(*)), V(O(**))) were suggested to be responsible to the appearance of new states shallow and deeply inserted in the band gap. These defects give rise to the PL in disordered powders. The natural PL emission of ordered CaMoO4 was attributed to an intrinsic slight distortion of the [MoO4] tetrahedral in the short range.

Referência(s)