Widening the emission spectrum of Eu~(2+) in Na_3Sc_2(PO_4)_3 to full-color via controlling the multi-emission centers by equivalent substitution of Sc-Al and PO_4-BO_3

摘要

Single-doped color tunable phosphors Na3Sc2-xAlx(PO4)(3-y)(BO3)(y):Eu2+ are synthesized by conventional high temperature solid-state reaction method. Both the excitation and emission spectra of Eu2+ in Na3Sc2(PO4)(3) can be effectively tailored by equivalent substitution. The equivalent cation substitution of Sc3+ by Al3+ and unit substitution of (PO4)(3-) by (BO3)(3-) results in the significant distortion of the local environment neighboring the Na-O polyhedral, which enables the modulation of Eu2+ occupation on three kinds of Na sites. Besides the original occupation of Na1 site by Eu2+, equivalent cation and unit substitutions open a way for Na2 and Na3 sites to be occupied by Eu2+ ions, which leads to the significant widening of the Eu2+ emission spectrum to full-color. The mechanism of widening the Eu2+ emission spectrum is elucidated. Furthermore, the different thermal stability behaviors that Eu1 emission is better than that of Eu2 and Eu3 ions are also discussed.