Synthesis and optical properties of Ce3+-doped Y3Mg2AlSi2O12 phosphors

Y3-xMg2AlSi2O12:Cex3+ (x=0.015, 0.03 and 0.06) phosphors possessing garnet crystal structure were synthesized by the sol-gel combustion technique. The samples were characterized by application of powder X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, thermal quenching (TQ) and scanning electron microscopy (SEM). Moreover, luminous efficacies (LE), color points and quantum efficiencies (QE) were calculated. Optical properties were studied as a function of Ce3+ concentration and annealing temperature. XRD analysis revealed that sintering of polycrystalline Y3Mg2AlSi2O12:Ce3+ powders at 1550 deg. C results in nearly single-phase garnet materials. Phosphors showed broad emission band in the range of 500-750 nm and had the maximum intensity at 600 nm, which results in strongly red-shifted phosphors compared with conventional YAG:Ce phosphors emitting at 560 nm. However, strong concentration quenching has also been observed, probably due to increased Stokes shift.