Synthesis and Application in Anticounterfeiting of RGB Upconversion Nanoparticles

Figure 5

(a) The upconversion spectrum of the mixed white NPs (mixing of KMnF₃:Yb³⁺,Er³⁺ NPs, NaYF₄:Yb³⁺,Tm³⁺ NPs, and NaYF₄:Yb³⁺,Er³⁺ NPs with a mass percentage of 42%, 54%, and 4%, respectively) in 980 nm excitation. Embedded in the figure is the picture of white NP cyclohexane solution without or with 980 nm excitation. (b) The CIE color coordinates of the mixed white NPs.

(a)

(b)