Up-Conversion Luminescence of NaYF4:Yb~(3+)/Er~(3+) Nanoparticles Embedded into PVP Nanotubes with Controllable Diameters

摘要

NaYF4:Yb~(3+)/Er~(3+)/polyvinylpyrrolidone (PVP) up-conversion (UC) luminescent nanotubes were synthesized by the electrospinning technique. The diameters of the nanotubes were controllable by changing the electrospinning voltages. The structure and the optical properties were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra, and fluorescence microscope. The NaYF4:Yb~(3+)/Er~(3+)/PVP nanocomposites simultaneously possessed UC luminescent property, active surfaces and tubular structure. PVP molecules were found to have an important influence on the UC luminescence of NaYF4:Yb~(3+)/Er~(3+)/PVP nanotubes. Compared with those in pure NaYF4:Yb~(3+)/Er~(3+) nanoparticles, the relative intensities of violet, blue, and green to red emissions were increased in NaYF4:Yb~(3+)/Er~(3+)/PVP nanotubes. It is owing to the existence of PVP molecules, which might produce the passivation on NaYF4:Yb~(3+)/Er~(3+) nanoparticles and reduce the nonradiative relaxation of Er~(3+) ion. The luminescent nanotubes with desirable UC properties are expected to be applied in biomedicine.