Synthesis and luminescent properties of nano-sized Y3Al5O12:Eu3+ phosphors

Nano-sized Eu3+-activated yttrium aluminum garnet (Y3Al5O12, YAG) phosphors were prepared via a simple sol–gel process at as low a temperature as 900 °C. In comparison with the conventional solid-state reaction process, this sol–gel process not only reduced the temperature required for synthesizing YAG:Eu3+ powders, but also decreased their particle size to the nanometer range. In the sol–gel process, citric acid and ethylene glycol formed numerous tiny enclosures that trapped the constituent cations, leading to a reduction of the interdiffusion length and an enhancement of the reactivity of the precursors. The photoluminescence intensity of the sol–gel-prepared YAG:Eu3+ phosphors was markedly greater than that of the samples derived from the solid-state reaction. This is attributed to the increased crystallinity and improved compositional homogeneity in the sol–gel-derived powders. The photoluminescence characteristics of YAG:Eu3+ phosphors were demonstrated to substantially depend on their morphology and particle size.