Water-Soluble NaYF4:Yb,Er(Tm)/NaYF4/Polymer Core/Shell/Shell Nanoparticles with Significant Enhancement of Upconversion Fluorescence

摘要

Research on NaYF4:Yb,Er and NaYF4:Yb,Tm,especially preparation and upconversion fluorescence of their nanocrystals,has been active due to potential applications as sensitive bio-probes.NaYF4:Yb,Er(Tm) is one of the most efficient 980 nm near-infrared (NIR) to visible (green and blue) upconversion phosphors.As bio-probes for imaging and detection,conceivable advantages include improved signal-to-noise ratio due to absence of autofluo-rescence and reduction of light scattering,easy in vivo imaging by noninvasive and deep penetration of NIR radiation,low photobleaching,and feasibility of multiple labeling with different emissions under the same excitation.A compact,power-rich,and inexpensive 980 nm NIR laser may be used as the excitation source,potentially replacing the currently expensive ultrafast pulse laser in the multipho-ton fluorescent microscopy.