Spectra Analysis of Nd3+ Sensitized NaYF4:Yb@NaYF4:Ho Upconversion Nanoparticles

Upconversion nanoparticles are widely used in bioimaging and biomarkers because of their excellent penetration depth and strong luminescence. Mono dispersed core-shell structured NaYF4:Yb@NaYF4:Ho nanoparticles with sizes of about 50 nm were synthesized. It was found by spectral analysis that these nanoparticles emitted light centered at a wavelength of 650 nm under the 980 nm laser excitation. Further Nd3+ doping caused the NaYF4:Yb@NaYF4:Ho nanoparticles to emit strong red light under the 800 nm laser excitation. By analyzing the fluorescence spectra of the Nd3+ doped NaYF4:Yb@NaYF4:Ho nanoparticles with different structures, it was found that the emission intensity of the NaYF4:Yb@NaYF4:Ho, Nd nanoparticles was the strongest, indicating that doping Nd3+ ions into the shell layer of the NaYF4:Yb@NaYF4:Ho nanoparticles was optimal choice. Finally, the Nd3+ concentration of the NaY4:Yb(3+)50%@NaYF4:Ho(3+)1%, Nd(3+)x% nanoparticles was optimized. The experimental results show that the optimized concentration of Nd3+ ions is 30%, the luminescence intensity of the NaYF4: Yb(3+)50%@NaYF4:Ho(3+)1%,Nd(3+)30% nanoparticles is strongest under an 800 nm laser excitation.