Facile synthesis of NaYF4:Ln/NaYF4:Eu composite with up-conversion and down-shifting luminescence

Herein, a series of novel dual-mode NaYF4:Ln/NaYF4:Eu (Ln = Yb, Er, Tm) composites involving up-conversion and down-shifting luminescence have been prepared by a facile synthetic method. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis, up-conversion and down-shifting fluorescence spectrometer were used to characterize the materials. By doping different lanthanide ions and tailoring the molar ratio of the doped lanthanide ions, three kinds of composites were obtained which could exhibit three-primary-color (red-green-blue, abbreviating as RGB) up-conversion luminescence under the irradiation of 980 nm laser, and generate red down-shifting color under the excitation of 393 nm. The composites show excellent photoluminescence properties, which attribute to NaYF4 served as a major matrix for both the up-conversion and down-shifting materials. Moreover, the work provides a promising material for anti-counterfeiting application.