Structural refinement and photoluminescence properties of irregular cube-like (Ca-1_Cu-x(x))TiO3 microcrystals synthesized by the microwave-hydrothermal method
Nenhuma Miniatura disponível
Data
2012-09-14
Orientador
Coorientador
Pós-graduação
Curso de graduação
Título da Revista
ISSN da Revista
Título de Volume
Editor
Elsevier B.V. Sa
Tipo
Artigo
Direito de acesso
Acesso restrito
Resumo
In this paper, calcium copper titanate (Ca-1_Cu-x(x))TiO3 microcrystals with (x = 0, 0.01 and 0.02) were synthesized by the microwave-hydrothermal method at 140 degrees C for 30 min. These crystals were analyzed by X-ray diffraction (XRD), Rietveld refinement, X-ray absorption near-edge structure spectroscopy (XANES), micro-Raman spectroscopy, field emission scanning electron microscopy (FE-SEM). Its optical properties were investigated by ultraviolet-visible (UV-vis) absorption and photoluminescence (PL) measurements. XRD patterns, Rietveld refinement and micro-Raman spectroscopy indicated that these crystals present a perovskite-type orthorhombic structure. The Rietveld refinement data, micro-Raman and XANES spectra suggested that the substitution of Ca by Cu in A-site promoted a displacement of Ti atoms to off-center symmetric, which leads distortions on the cuboctahedral [CaO12] clusters neighboring and consequently promotes a strain into the CaTiO3 lattice. FE-SEM images showed that these cube-like microcrystals have an irregular shape due to Ostwald-ripening and self-assembly of plates and cubes in growth process. The defects and distortions into lattice at medium- and short-range on the[CaO12]/[TiO6]clusters promotes the structural order-disorder responsible by the intense PL properties of these microcrystals. The microcrystals are promising candidates for future applications in optical devices. (C) 2012 Elsevier B.V. All rights reserved.
Descrição
Palavras-chave
Idioma
Inglês
Como citar
Materials Chemistry and Physics. Lausanne: Elsevier B.V. Sa, v. 136, n. 1, p. 130-139, 2012.