Fluorescence properties of polycrystalline Tm3+-activated Y3Al5O12 and Tm3+-Li+ co-activated Y3Al5O12 in the visible and near IR ranges

The photoemission properties of polycrystalline powder Tm3+-activated Y3Al5O12 and Tm3+-Li+ co-activated Y(3)A1(5)O(12) were studied in the visible and near-IR ranges at 300 K. The polycrystalline materials were obtained through a novel combustion synthesis technique that yields chemically homogeneous and small particle size(< 3.0 mu m) powders. The emission properties of Tm-3+-activated Y(3)A1(5)O(12) showed that the intensity of the blue emission is weak compared to the red emission. With the addition of Lif as a coactivator, the intensity of the blue emission increased by as much as 87%; however the red and IR emissions also increased. Efficiency measurements showed that the phosphor reached a maximum of 0.21 1m/W at a voltage of 11.7 kV and current of 1 mu A/cm(2). The optimal composition for maximum blue emission was found to be Y2.93Tm0.07Al5O12 doped with 1.0 at% Li.