Continuous single-step fabrication of nonaggregated, size-controlled and cubic nanocrystalline Y2O3:Eu3+ phosphors using flame spray pyrolysis

Continuous single-step fabrication of cubic nanocrystalline Y2O3:Eu3+ successfully conducted without any post-heat treatments. The morphology of the as-prepared particles was spherical and nonaggregated. The mean size of as-prepared particles was easily controlled by adjusting the precursor concentration. On varying the overall concentration of the precursor solution from 0.01 to 0.5 M, the crystallite size and geometric mean particle diameter varied from 38.4 nm to 50.6 nm and 263 nm to 741 nm, respectively. XRD spectra of as-prepared particles indicated that all products, regardless of the precursor concentration, showed the cubic phase with high crystallinity without any post-treatments, although residence times in the flame were very short. Upon excitation with 254 nm light, all of the as-prepared particles showed bright red emission due to the 4f-4f transitions of Eu3+ ions, and the highest photoluminescent intensity at 611 nm was found at a Eu3+ content of about 12 mol%. These results indicate the possibility of the fabrication of cubic nanocrystalline Y2O3:Eu3+ phosphors with a high production rate and high purity.