Aerosol synthesis and characterization of nanostructured particles of Y3Al5O12:Ce3+ and Y2O3:Eu3+

Nanostructured YAG:Ce3+ and Y2O3:Eu3+ were synthesized by low temperature (320 degrees C) aerosol synthesis-LTAS and high temperature (900 degrees C) aerosol synthesis-HTAS, respectively. The synthesis included aerosol generation from a nitrate precursor solution by an ultrasonic atomizer (1.3 MHz). The obtained aerosol was introduced into a tubular flow reactor, using air as the carrier gas, where successively, on a droplet level, evaporation/drying, precipitation and thermolysis occurred. The obtained powders were collected and thermally treated at different temperatures (900-1200 degrees C). The phase development and the morphology were investigated by the X-ray powder diffraction method (XRPD) and scanning electron microscopy combined with energy dispersive spectrometry (SEM/EDS). Structural refinement was performed using the Rietveld method with the Fullprof and Koalariet programs. The average crystallite size for the Y2O3:Eu3+ system was calculated using the Profit program. It was shown that 89 wt.% of Y3Al5O12:Ce3+ was obtained by annealing (1000 degrees C/6 h) the as-prepared, amorphous powder, synthesized by the low temperature aerosol method (LTAS). High temperature spray pyrolysis (HTAS) at 900 degrees C led to the formation of the targeted cubic phase Of Y2O3:Eu3+. The microstructural parameters of the as-prepared samples of the Y2O3:Eu3+ system indicate the formation of nanostructures with crystallite size smaless than 20 nm. The substitution of lurninescent centers (Ce3+, EU3+) into a host lattice (YAG, Y2O3, respectively) was confirmed by changes in the crystal lattice parameters. Also, it was shown in both systems that good morphological characteristics (non-agglomerated, spherical, subrnicron particles) were obtained enabling improved luminescent characteristics.