Preparation and fluorescence properties of Eu3+-doped strontium chloroapatite nanocrystals

Strontium chloroapatite nanocrystals doped with trivalent europium ions wer e prepared by an aqueous colloidal method. The mean diameter of the crystal was found to be similar to 3 nm by transmission electron microscopy, altho ugh, for the most part, they were agglomerated. The X-ray diffraction patte rns show that the lattice constants of nanocrystals are contracted by simil ar to 2% compared to the corresponding bulk counterpart, and also that they further decrease by annealing at 200-300 degrees C. The fluorescence spect rum of nanocrystals exhibited blue shifts of both the D-5(0)-F-7(2) transit ion and the charge transfer excitation band, and an apparent enhancement in the strength of the hypersensitive D-5(0)-F-7(2) transition. (C) 2000 Else vier Science B.V. All rights reserved.