Searching for the dopant ion in Eu2+-activated BaMgAl10O17 phosphor with synchrotron diffraction

Searching for the multiple sites predicted in the literature for the europium activator in the BaMgAl10O17:Eu2+ phosphor, we undertook a detailed structural study using synchrotron powder diffraction. Three different positions were found for Eu2+ in the Beevers–Ross site, near the mid-oxygen position and in substitution for the interblocks Al–O–Al bridge. By favoring the migration of the activator ion, the resulting vacancies in the Beevers–Ross sites may be a major cause of the degradation of the phosphor.