Correlations between crystallite/particle size and the luminescent characteristics of submicrometer
phosphors were investigated. Spray pyrolyzed europium doped yttrium oxide (Y2O3:Eu3+) particles were
selected as a model material. Crystallite size and the particle size were controlled independently. The
morphology and crystallite structure were characterized by field-emission scanning electron microscopy,
high-resolution transmission electron microscopy, X-ray diffraction, and selected area electron diffraction.
Photoluminescence (PL) properties were examined by spectrofluorophotometry and an absolute PL
quantum efficiency (QE) measurement system. Chemical analyses and elemental mapping were conducted
by Fourier transform infrared spectrophotometry and STEM equipped with energy dispersive spectroscopy,
respectively. The results revealed that the PL properties were strongly dependent on crystallite size,
particle size, surface chemistry, and the distribution of europium inside the phosphor particles. The PL
intensities and QE increased with increasing crystallite size and particle size. The effect of crystallite
size on PL properties played a more important role than that of particle size.
Spherical Gd 2 O 3 :Eu 3+ /silica luminescent nanocomposite particles have been synthesized by spray pyrolysis of the precursor with colloidal silica nanoparticles and gadolinium and europium nitrate solutions. The as-prepared particles were characterized using field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, photoluminescence ͑PL͒ spectra, as well as Fourier transform infrared spectroscopy. The results showed that the content of silica nanoparticles has a strong effect on the size, morphology, crystallinity, and PL properties of the composite particles. By adding colloidal silica nanoparticles into the precursors, dense luminescent particles with improved characteristics were produced because the silica nanoparticles as seeds promote heterogeneous nucleation during the pyrolysis of Gd 2 O 3 :Eu 3+ . The effect of the size of silica nanoparticles on the characteristics of the composites was investigated as well. The PL intensity and crystallinity increased with increasing silica nanoparticle size and reached optimum conditions using silica nanoparticles with an average size of 50 nm for a similar volume percentage of silica. In this case, the number and the surface area of silica nanoparticles play roles in determining the characteristics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.