Co-Precipitation Synthesis and Photoluminescence Properties of Ce3+ Activated Terbium Aluminum Garnet (Tb1-xCex)3Al5O12 (0≤x≤0.05) Yellow Phosphors

Ce3+ activated terbium aluminum garnet ((Tb1-xCex)(3)Al5O12, 0 <= x <= 0.05) phosphors have been converted from their precursors synthesized via co-precipitation from mixed solutions of aluminum and rare earth nitrates with ammonium hydrogen carbonate (AHC) as the precipitant. Detailed characterizations of the precursors and the phosphor oxides were performed by the combined techniques of X-ray diffractometry, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, differential scanning calorimetry/thermogravimetry, and photoluminescence spectroscopy. The co-precipitated precursors possess a general composition of (NH4)(x)(Tb,Ce)(3)Al-5(CO3)(y)(OH)(z)center dot nH(2)O, and the particles, having diameters of about 50nm, are well dispersed. Calcining the precursors at 1000 degrees C for 4 h in the air and then reducing in a hydrogen atmosphere at 1000 degrees C for 2 h yielded a phase-pure garnet solid-solution of (Tb1-xCex)(3)Al5O12. The cubic lattice of garnet allows the Ce3+ activators to reside at the dodecahedral interstitial sites. The resultant garnet phosphors with various Ce3+ contents exhibit nearly identical positions of the PLE/PE bands, but significantly different intensities. Upon blue-light excitation at 470nm, the garnet phosphors exhibit broad band emissions peaking at 560nm. The garnet phosphors show a luminescence quenching concentration of 1.5at% for Ce3+.