Synthesis and luminescence properties of new red-emitting phosphors YGe0.5M0.5O4:Eu3+ (M=Mo, W)

Abstract

A series of Eu3+ doped YGe0.5M0.5O4:Eu3+ (M=Mo, W) red-emitting phosphors were synthesized by high-temperature solid-phase method. The phase formation, morphology and luminescence properties were analyzed in detail. X-ray powder diffraction (XRD) patterns verified the successful phase formation of the YGe0.5M0.5O4:Eu3+ (M=Mo, W) phosphors. The scanning electron microscope (SEM) images showed the irregular shape of the sample. The results of the photoluminescence excitation (PLE) and photoluminescence (PL) spectra indicated that the sample can be effectively excited by near-ultraviolet light and exhibits a strong red emission at the 5D0→7F2 transition (electric dipole transition). By calculation, the concentration quenching mechanism of Eu3+ in the sample was attributed to exchange coupling. The temperature-dependent spectra showed that the PL efficiency of the Y0.4Ge0.5W0.5O4:0.60Eu3+ phosphor at 423 K remained at 93.3% (Compared to room temperature). All results indicate that synthetic phosphors have potential applications in white light-emitting diodes (w-LEDs).