Luminescence and crystallinity of flame-made Y2O3:Eu~(3+) nanoparticles

摘要

Cubic and/or monoclinic Y2O3:Eu~(3+) nanoparticles (10-50 nm) were made continuously without post-processing by single-step,flame spray pyrolysis (FSP).These particles were characterized by X-ray diffraction,nitrogen adsorption and transmission electron microscopy.Photolumines-cence (PL) emission and time-resolved PL intensity decay were measured from these powders.The influence of particle size on PL was examined by annealing (at 700-1300°C for 10 h) as-prepared,initially monoclinic Y2O3:Eu~(3+) nanoparticles resulting in larger 0.025-1 urn,cubic Y2O3:Eu~(3+).The influence of europium (Eu~(3+)) content (1-10 wt%) on sintering dynamics as well as optical properties of the resulting powders was investigated.Longer high-temperature particle residence time during FSP resulted in cubic nanoparticles with lower maximum PL intensity than measured by commercial micron-sized bulk Y2O3:Eu~(3+) phosphor powder.After annealing as-prepared 5 wt% Eu-doped Y2O3 particles at 900,1100 and 1300°C for 10 h,the PL intensity increased as particle size increased and finally (at 1300°C) showed similar PL intensity as that of commercially available,bulk Y2O3:Eu~(3+) (5 mu m particle size).Eu doping stabilized the monoclinic Y2O3 and shifted the monoclinic to cubic transition towards higher temperatures.