Structure, particle size, and annealing of gas phase-condensed Eu3+:Y2O3 nanophosphors

This paper reports the phase distribution and particle size of Eu3+ :Y2O3 nanoparticles prepared by gas-phase condensation as a function of preparation conditions and annealing. Annealing improves the crystallinity of the as-prepared nanoparticles but also increases the particle size. Gas-phase condensation at a low pressure (10Torr) produces 5-nm Eu3+ :Y2O3 in multiple phases. Annealing the 5-nm nanoparticles produces single-phase material in the cubic structure with a doubling of the particle size. Higher chamber pressures produce larger particles. A pressure of 400Torr produces 13-nm Eu3+ :Y2O3 in the monoclinic structure. Annealing the 13-nm particles produces a mixture of monoclinic and cubic phase material with a 50% increase in average particle size. We also report preliminary attempts to disperse Eu3+ :Y2O3 and Eu2O3 nanoparticles in different surfactant and polymer solutions. (C) 2002 Elsevier Science (USA). All rights reserved.