Photoluminescence degradation mechanism of BaMgAl₁₀O₁₇:Eu²⁺ phosphor by vacuum ultraviolet irradiation

A real high power vacuum ultraviolet light source is applied to the investigation on the vacuum ultraviolet irradiation degradation of BaMgAl₁₀O₁₇:Eu²⁺ phosphor. The degradations of emission intensity and colour quality of sample are clearly observed after irradiation. It reveals that the oxidation of Eu²⁺ during irradiation is partly responsible for the degradations. The excitation and absorption spectra show that some traps generated during irradiation have negative influence on the luminescence of sample and these traps have been identified as positively charged oxygen vacancies by positron annihilation. The investigations on host emission and decay curve further confirm that these oxygen vacancies are involved in the perturbation of energy transfer from host to Eu²⁺ and finally result in the degradation.