Color-tunable luminescence from single-phased Sr${}_3$YNa(PO${}_4$)${}_3$F:Tb${}^{3+}$, Eu${}^{3+}$ phosphors with good energy transfer efficiency for white light emitting diodes

A novel Sr${}_3$YNa(PO${}_4$)${}_3$F:Tb${}^{3+}$, Eu${}^{3+}$ phosphor was prepared by high-temperature solid-state reaction method. The optical properties and luminescence mechanism were investigated in detail. The emission spectra and lifetime curve of Sr${}_3$Y${}_{0.92-y}$Na(PO${}_4$)${}_3$F:0.08Tb${}^{3+}$, yEu${}^{3+}$ phosphors indicate that there is efficient energy transfer between Tb${}^{3+}$ and Eu${}^{3+}$, and the mechanism is confirmed as dipole–quadrupole interaction. By adjusting the Tb${}^{3+}$, Eu${}^{3+}$ doping ratio, Sr${}_3$Y${}_{0.8}$Na(PO${}_4$)${}_3$F:0.08Tb${}^{3+}$, 0.12Eu${}^{3+}$ showed warm white light at color coordinates (0.3244, 0.3316). White light evidently relates to visible range.