Synthesis and Luminescence Properties of Mg-Si Co-doped Tb_3Al_5O_(12): Ce~(3+) Phosphors with Blue Excitation for White LEDs

摘要

Tb_(2.94)Mg_xAl_(5-2x)Si_xO_(12):Ce_(0.06)~(3+) (TMASG: Ce) were synthesized by high temperature Solid-State Reaction (SSR) at different temperatures from 1650℃ to 1550℃. Samples with x = 0.1, 0.2, 0.3, 0.6 were fabricated and characterized using powder X-ray diffraction (XRD) and room-temperature photo-luminescence spectroscopy. In this work, the excitation and emission spectra indicate that the phosphor can be excited effectively by the blue light (450-550 nm) and exhibit a satisfactory orange-yellow emission from 550 to 575 nm. The reasons of the red-shift of the phosphor have been discussed. A crystal field analysis of the Ce ~(3+) 5d energy levels is conducted to explain the correlation between the TMASG:Ce lattice expansion and the Ce~(3+) energy level changes. The chromaticity coordinates of the phosphors are tuned from (0.465, 0.527) to (0.512, 0.483). This indicates a prospective for application of this novel phosphor in white light emitting diodes (LEDs).