Synthesis, characterization and optical properties of nanocrystalline lead molybdate

Lead molybdate (PbMoO4) finds wide practical application due to its acousto-optic and luminescent properties. In the present study, nanoparticles of PbMoO4 of different grain sizes were synthesized through chemical precipitation technique. Precipitation reactions carried out in non-aqueous media below room temperature were used for the synthesis of samples of two lower grain sizes. The crystal structure and grain size of the samples were determined using X-ray diffraction and transmission electron microscopy. UV-Visible absorption spectra showed a broad absorption peak for the sample with average grain size of 52 nm which is blue shifted considerably as the average grain size was reduced to 14 nm. The fundamental absorption follows an exponential edge indicating Urbach-like behaviour. The temperature dependence of Urbach parameter is also determined. The micro-Raman spectra and FT Raman spectra of the samples were recorded and the features in the Raman spectra are discussed. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim