Synthesis and photoluminescence property of cerium-doped yttrium aluminum garnet phosphors via solid-state reaction with soft mechano-chemical assistance

A cerium-doped yttrium aluminum garnet phosphor was synthesized by a high-temperature solid state reaction method with a precursor of mixed powders (i.e., Y2O3, Al2O3 and CeO2) and NH4Cl and BaF2 as sintering aids pre-ground via a soft mechano-chemical process (by vibrating mill and stirred bead mill, respectively). The crystalline phase, microstructure/morphology and particle size of the ground samples were determined by X-ray diffraction, scanning electron microscopy and laser particle size analysis, respectively. The photoluminescence characteristics of phosphor particles synthesized were investigated by fluorescence spectrophotometry. The results indicate that the soft mechano-chemical process for pretreatment of mixed powders can effectively lower the synthesis temperature of subsequent solid state reaction process by 300℃. Compared to vibrating mill, stirred bead mill can be used to produce the more flaws and reduce the particle size. For the lattice plane of (222), stirred bead mill can reduce the crystallinity to 45.7%, while vibrating mill can reduce the crystallinity to 73.02%. As a consequence, stirred bead mill can be more effective to improve the reactivity of the mixed powders in subsequent solid state reaction process. In addition, YAG:Ce3+ phosphor sample that is pre-ground by stirred bead mill and subsequently sintered at 1300℃ for 4 h is excited by blue light, thus emitting yellow light. This phosphor can be used as a promising photoluminescence material for the application of white light emitting diode. © 2015, Editorial Department of Journal of the Chinese Ceramic Society. All right reserved.