Hydrothermal synthesis and photoluminescence of the monophosphate LaPO4:Eu(5%)

Hexagonal LaPO(4 center dot)nH(2)O and monoclinic LaPO4 doped with Eu3+ powder phosphors were prepared through hydrothermal reaction, respectively, at 100 degrees C and 200 degrees C under fine control of the acidity in the starting materials based on lanthanide oxides and phosphoric acid. X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, thermal treatment, scanning electron microscopy and fluorescence spectroscopy have been used to characterize these materials. The structural, morphological, and luminescent changes of the products due to the heating temperature are studied. The effect of the thermal treatment on the colorimetric characteristic of the red emission of the Eu3+ was investigated. The Commission Internationale de L'Eclairage (CIE) chromatic coordinates, dominant wavelength, and colour purity were determined, discussed and compared to other products like Eu3+ doped zinc aluminate (ZnAl2O4) and yttrium oxide (Y2O3). (C) 2008 Elsevier B.V. All rights reserved.