Morphology and Blue Photoluminescence Emission of PbMoO4 Processed in Conventional Hydrothermal

• Published in: Journal of physical chemistry. C 2009-04, Vol.113 (14), p.5812-5822
• Main Authors: Sczancoski, J. C., Bomio, M. D. R., Cavalcante, L. S., Joya, M. R., Pizani, P. S., Varela, J. A., Longo, E., Li, M. Siu, Andrés, J. A.
• Format: Article
• Language: eng ; jpn
• Subjects: C: Electron Transport, Optical and Electronic Devices, Hard Matter
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp810294q

PbMoO4 micro-octahedrons were prepared by the coprecipitation method at room temperature without the presence of surfactants and processed in a conventional hydrothermal at different temperatures (from 60 to 120 °C) for 10 min. These micro-octahedrons were structurally characterized by X-ray diffraction (XRD) and micro-Raman (MR) spectroscopy, and its morphology was investigated by field-emission gun scanning electron microscopy (FEG-SEM). The optical properties were analyzed by ultraviolet−visible (UV−vis) absorption spectroscopy and photoluminescence (PL) measurements. XRD patterns and MR spectra confirmed that the PbMoO4 micro-octahedrons are characterized by a scheelite-type tetragonal structure. FEG-SEM micrographs points out that these structures present a polydisperse particle size distribution in consequence of a predominant growth mechanism via aggregation of particles. In addition, it was observed that the hydrothermal conditions favored a spontaneous formation of micro-octahedrons interconnected along a common crystallographic orientation (oriented-attachment), resulting in self-organized structures. An intense blue PL emission at room temperature was observed in these micro-octahedrons when they were excited with a 350 nm wavelength. The origin of the PL emissions as well as its intensity variations are explained by means of a model based on both distorted [MoO4] and [PbO8] clusters into the lattice.