Synthesis and luminescence properties of microemulsion-derived Y3Al5O12: Eu3+ Phosphors

Europium-ion doped yttrium aluminum garnet (YAG: Eu3+) phosphors were prepared via both the solid-state-reaction method and the microemulsion process. The solid-state-reaction-derived powders required repeated calcination at 1600 °C to produce phase-pure YAG: Eu3+, and the formed phosphors had irregular morphology and a broad particle-size distribution. The microemulsion route was demonstrated to significantly lower the synthesis temperature of pure garnet phase to 1400 °C, and substantially reduce the particle size to submicron order. With a rise in the calcination temperature, the peak intensities in the excitation and emission spectra also increased as a result of increased amount of YAG phase. Synchrotron radiation-excited luminescence studies indicate that YAG: Eu3+ exhibited broad excitation peaks in vacuum ultraviolet (VUV) range and strong red emission peaks at 590 nm. The VUV-excited emission spectra demonstrate that the microemulsion-derived YAG: Eu3+ phosphors generated more intense luminescence than the solid-state-derived specimens. The enhanced luminescence characteristics are considered to be attributed to the reduced particle size and improved morphology of the microemulsion-derived phosphors.