High Thermal Stability Apatite Phosphors Ca(2)La(8)(SiO(4))(6)O(2):Dy(3+)/Sm(3+) for White Light Emission: Synthesis, Structure, Luminescence Properties and Energy Transfer

What ideal w-LED phosphors always aim to do is to achieve a single phase near-sunlight emission phosphor simultaneously with both high luminescence efficiency and high thermal stability at operation temperature. And It is well known that apatite compound phosphors are one of the most promising optical materials to realize those above because of their unique structure enhanced luminescence properties and thermal stability. Here, we synthesized a co-doped single phase apatite phosphors Ca(2)La(8)(SiO(4))(6)O(2):Dy(3+)/Sm(3+) (CLSO:Dy(3+)/Sm(3+)) for white light emission, which was provided with excellent thermal stability and of which luminescence intensity at 150 °C still was 92 percentage of that at room temperature. Moreover, X-ray diffraction technique, Fourier transform infrared spectroscopy, scanning electron microscope were employed to characterization of phase structure and morphology, and consequently pure apatite structure and gravel-like morphology of phosphors were proved. Analysis of photoluminescence spectra indicated that concentration quenching effect exist in single-doped CLSO:Dy(3+) phosphors owing to dipole-dipole interaction between Dy(3+) ions. It is revealed that maybe exist Dy(3+) ↔ Sm(3+) bilateral non-radiative energy transfer processes in Dy(3+)/Sm(3+) co-doped CLSO system by PL spectra and decay curves. And variation of Sm(3+) ion concentration can control color emission, namely CIE chromaticity coordinates and correlated color temperature, finally to achieve white light emission (0.309,0.309) with CCT 6848 K, able to be a potential candidate for commercial lighting applications.