Degradation mechanisms of the blue-emitting phosphor BaMgAl10O17:Eu2+ under baking and VUV-irradiating treatments

The luminescent properties of an Eu2+-activated hexagonal aluminate, BaMgAl10O17 (BAM), were studied under 147- and 254-nm excitations. The BAM samples were thermally treated by baking and then irradiated in vacuum ultraviolet (VUV) rays. The results show that the emission efficiency of Eu2+ in BAM under 147-nm excitation degraded seriously after baking or VUV-irradiating treatments, while no significant degradation was observed under 254-nm excitation. The degree of degradation depended on the excitation wavelength, and the absorption edge of the BAM host was suggested to be close to 175 nm (7.2 eV). The differences between the thermal-induced and the VUV-irradiation-induced degradations, and their mechanisms are discussed for the color plasma display applications.