Photoluminescent and low-voltage cathodoluminescent blue-emitting phosphors with high colour purity

Tungstate phosphor synthesized by a polyol method exhibits characteristic emission of Tm3+in the blue region when excited either by ultraviolet light or by a low-voltage electron beam. The emission at 453 nm predominates in both spectra, which is attributed to the exceptionally large probability of transition1D2→3F4. In the photoluminescence and cathodoluminescence spectra, this blue-emitting phosphor has chromaticity coordinates (0.1556, 0.0316) with a dominant wavelength of 455 nm and (0.1498, 0.0383) with a dominant wavelength of 460 nm, respectively. The colour purities are both as high as 97%. These values are superior to those reported for the blue-emitting phosphors. The changes in luminescent intensity of visible and near-infrared emission with annealing temperatures under low-voltage electron beam excitation were discussed.