Preparation and properties of dual-mode luminescent NaYF4:Yb,Tm@SiO2/carbon dot nanocomposites

Herein, NaYF4:Yb,Tm@SiO2/carbon dot nanocomposites have been successfully fabricated by a facile route. The structure and morphology of the nanocomposites were characterized by SEM, TEM, XRD, FT-IR and XPS measurements. It was demonstrated that carbon dots were embedded well in the silica layer coating on the surface of NaYF4:Yb,Tm nanoparticles, leading to a relatively stable structure of the nanocomposites. The nanocomposites showed interesting dual-mode luminescence properties, i.e. blue green light under a 365 nm UV lamp and blue purple light under a 980 nm laser. They were utilized to achieve light conversion films, ion detection probes and cell imaging, suggesting their great potential in the fields of anti-counterfeiting and bioapplications.