Remarkable modulation effects of Ag{sup +} ion on fluorescence of Eu{sup 3+} ion doped yttrium phosphate nanophosphors
Highlights: ► Ag{sup +} sensitized YPO{sub 4}:Eu{sup 3+} was synthesized. ► Emission band centered at 612 nm was broadened to 14 nm. ► Ag{sup +} plays a main role for the broadening of emission band of Eu{sup 3+}. ► Emission mechanisms were discussed. - Abstract: Ag{sup +} sensitized YPO{sub 4}:Eu{sup 3+} nanomaterials were successfully synthesized by hydrothermal reaction. The fluorescent spectra indicate that Ag{sup +} ion has remarkable modulation effects on the shape of the emission bands of YPO{sub 4}:Eu{sup 3+}, so that full width at half maximum (FWHM) of the {sup 5}D{sub 0} → {sup 7}F{sub 2} emission of YPO{sub 4}:Eu{sup 3+} is extended to be 14 nm, broader than that (<9 nm) of ever reported Eu{sup 3+}-doped materials. Meanwhile, it is observed that the doping of Ag+ ion leads to the lowering of the intensity ratio of {sup 5}D{sub 0} → {sup 7}F{sub 2} to {sup 5}D{sub 0} → {sup 7}F{sub 1} transition. The analysis demonstrates that doping of Ag{sup +} ion will generate the local lattice aberration and the crystal field variation of Eu{sup 3+} ion and Y{sup 3+} ions due to a fact that the ionic radius (1.31 Å) of Ag{sup +} is obviously larger than that (0.938 Å) of Eu{sup 3+} and that (0.90 Å) of Y{sup 3+}. As a result, the excitation and emission bands of Eu{sup 3+} ion are correspondingly tuned.