Review Article
Recent Advancement in Functional Core-Shell Nanoparticles of Polymers: Synthesis, Physical Properties, and Applications in Medical Biotechnology
Figure 18
Upconversion spectra of original oleate-stabilized NPs in THF and PEG (2000)-phosphate coated NPs in water. (a) NaYF4:Er3+ 2 mol %, Yb3+ 20 mol% NPs. (b) NaYF4:Tm3+ 0.5 mol%, Yb3+ 30 mol% [41].