Structure–composition–luminescence correlations in Sr2.5−3x/2Ba0.5SmxAl1−yInyO4F (0.001≤x, y≤0.1) oxyfluorides

Luminescent materials composed of Sr2.5−3x/2Ba0.5SmxAl1−yInyO4F (0.001≤x, y≤0.1) were prepared by the solid-state reaction method. After the replacement of Sr2+ and Al3+ ions by Sm3+ and In3+ ions in Sr2.5Ba0.5AlO4F host structure, a novel charge-transfer band centered around 304 nm shifted from 240 nm is monitored; moreover, sharp and well-resolved emission peaks in the 4G5/2→6HJ transitions of the Sm3+ activator are observed. The diverse excitation and emission photoluminescence spectra of Sr2.5−3x/2Ba0.5SmxAl1−yInyO4−αF1−δ (0.001≤x, y≤0.1) phosphors originated by the charge-transfer of the host to the Sm3+ activator, the f–f transitions in the Sm3+ ions, and the defect-induced self-activation are also introduced.