Nanomaterial Host Bands Effect on the Photoluminescence Properties of Ce-Doped YAG Nanophosphor Synthesized by Sol-Gel Method

Cerium trivalent (Ce3+) doped YAG nano-sized phosphors have been successfully synthesized by sol-gel method using different annealing temperatures. The samples have been characterized by X-ray diffraction (XRD), thermogravimetry (TG), differential scanning calorimetry (DSC) analysis, Fourier transform infrared (FTIR) spectroscopy, and steady photoluminescence (PL) spectroscopy. X-ray diffraction analysis indicates that the pure cubic phase YAG was formed and strongly depends on the cerium content and the annealing temperature. It was found that the grain size ranges from 30 to 58 nm depending on the calcination temperature. The YAG:Ce nanophosphors showed intense, green-yellow emission, corresponding to Ce3+ 5d(1) -> F-2(5/2), F-2(7/2) transitions and its photoluminescence excitation spectrum contains the two Ce3+ 4f(1) -> 5d(1), 5d(2) bands. The crystal filed splitting energy levels positions 5d(1) and 5d(2) and the emission transitions blue shift with annealing temperatures have been discussed. It was found that the Ce3+ 4f(1) ground state position relative to valence band maximum of YAG host nanomaterial decreases with increasing the temperature.