Abstract:

In recent years， counterfeit and shoddy products have emerged in an endless stream， which has become a major issue in the global food safety and medicine fields. In order to effectively crack down on counterfeit and shoddy products and protect consumers' rights， researchers have paid great attention to fluorescent materials with high concealment and excellent anti-counterfeiting performance among many anti-counterfeiting technologies. A series of CsLu（MoO₄）₂∶Ln³⁺ （Ln³⁺=Yb³⁺/Er³⁺， Yb³⁺/Ho³⁺， Yb³⁺/Tm³⁺， Er³⁺， Dy³⁺， Dy³⁺/Eu³⁺） phosphors were synthesized by high-temperature solid-state reaction. X-ray diffraction （XRD）， up-conversion spectra and down-conversion spectra were used to characterize the phases and luminescence properties of the obtained samples. Under the excitation of UV， the multi-color regulation was successfully realized by using the energy transfer between Dy³⁺ and Eu³⁺. Moreover， under the excitation of NIR， CsLu（MoO₄）₂∶Yb³⁺/Er³⁺， Yb³⁺/Ho³⁺， Yb³⁺/Tm³⁺ phosphors realized green， red and blue upconversion emissions， respectively. Finally， under the excitation of 254， 365 or 980 nm， highly distinguishable luminescent images were obtained using various CsLu（MoO₄）₂∶Ln³⁺ phosphors for the application in multicolor fluorescent anticounterfeiting.

Key words: CsLu（MoO₄）₂∶Ln³⁺ phosphors, Energy transfer, Tunable luminescence, Anti-counterfeiting