Valent control and spectral tuning by cation site engineering strategy in Eu doped Sr1−xBaxAl2Si2O8 phosphor

Control of Eu valence is one of the main issues to obtain mixed−valent Eu 2+/3+ co−doped phosphor with flexible−tunable emission spectra. In this study, for the first time, we report a simple single cation substitution strategy for controlling Eu valence. The structure of Sr 1− x Ba x Al 2 Si 2 O 8 host was tailored by Ba 2+ substitution for Sr 2+ ions. The lattice parameters show a linear evolution with increase in Ba 2+ amount. Correspondingly, the Eu 3+ emission intensity also increases over Ba 2+ amount. The spectral variation was considered to be attributed to the suppression of Eu 3+ reduction by the lattice stress, which is introduced by ion substitution. Finally, valence control of Eu and spectral tuning of Eu 3+/2+ co−doped Sr 1− x Ba x Al 2 Si 2 O 8 phosphor were realized by the proposed strategy. This study will open a novel avenue for Eu valence control and spectral tuning of mixed–valent Eu doped phosphors.