Combustion Synthesis and Luminescent Properties of Nano and Submicrometer-Size Gd_2O_3:Dy~3+ Phosphors for White LEDs

摘要

Monoclinic phase Dy~3+:Gd_2O_3 nanophosphors were synthesized by a combustion method using glycine followed by sintering to obtain submicrometer-size phosphors. The X-ray diffraction patterns confirmed the monoclinic structure of Gd_2O_3:Dy~3+ phosphors. The phosphors were characterized by a transmission electron microscope, Raman, Fourier transform infrared, and fluoresence spectroscopy. The sizes of the phosphor particles are in the range from nearly 35 to 93 nm. It was observed that the emission intensities are varied with the excitation wavelength and concentration. The mechanism responsible for concentration quenching was discussed. The enhancement of emission intensities was observed while increasing the sintering temperature of the phosphor. Moreover, the CIE chromaticity coordinates of Dy~3+-doped Gd_2O_3 phosphors fall in the white light domain of the chromaticity diagram. The above characteristics indicate that these phosphors may be potential candidates for the application of near-ultraviolet-based white-light-emitting diodes.