Tunable and White-Light Emission from Single-Phase Ca2YF4PO4:Eu2+,Mn2+Phosphors for Application in W-LEDs

Novel phosphors, Ca2YF4PO4:Eu2+,Mn2+, have been prepared by high-temperature solid-state reactions. XRD and XPS techniques were used to investigate the purity and composition of the as-prepared samples. The Ca2YF4PO4:Eu2+,Mn2+ phosphors exhibit broad excitation spectra ranging from 275420 nm and the emission spectra show a broad blue emission band centered at 455 nm and a yellow emission band centered at 570 nm, which originate from the Eu2+ and Mn2+ ions, respectively. Energy transfer from the Eu2+ to Mn2+ ions in the Ca2YF4PO4 host matrix was observed and studied by luminescence spectrosccopy as well as the lifetime of the Eu2+ ions. The emission color of the Ca2YF4PO4:Eu2+,Mn2+ samples can be adjusted from blue to yellow under excitation by UV radiation of 375 nm by adjusting the Eu2+ and Mn2+ concentrations, and white-light emission with chromaticity coordinates (0.327, 0.312) was obtained with the Ca2YF4PO4:0.015Eu2+,0.015Mn2+ sample. In addition, the temperature-dependent photoluminescence of the as-prepared phosphors has been investigated in detail. The results revealed that the Ca2YF4PO4 host has good thermal stability. The stable structure of the host and tunable luminescence suggest that Ca2YF4PO4:Eu2+,Mn2+ could be regarded as a good candidate for UV LED-based white-light emitting diodes.