Chengcheng Wang

Synthesis of a novel core-shell nanocomposite Ag@SiO2@Lu2O3:Gd/Yb/Er for large enhancing upconversion luminescence and bioimaging.

Upconversion nanocrystals have many advantages over other fluorescent materials. However, their upconversion luminescence intensities are not desirable, limiting their applications for highly sensitive detection. Therefore, it is really important to enhance upconversion luminescent intensities of upconversion nanocrystals. In the present study, a novel Ag core and upconversion nanocrystal shell based nanocomposite Ag@SiO2@Lu2O3:Gd/Yb/Er for metal-enhanced upconversion luminescence was fabricated successfully, and its morphology, crystalline phase, composition, optical property, and cell imaging application were investigated. It was found that a maximum upconversion luminescence enhancement of 30-fold was obtained in comparison with the control without a silver core, and the nanocomposite exhibited bright upconversion luminescence when it was used for imaging with HeLa cells. This enhancement potentially increases the overall upconversion nanocrystal detectability, endowing the nanocomposite with a potential capability for highly sensitive biological, medical, and optical detection.

Preparation of NaLuF4:Gd, Yb, Tm–TiO2 nanocomposite with high catalytic activity for solar light assisted photocatalytic degradation of dyes and wastewater

A new nanocomposite NaLuF4:Gd, Yb, Tm–TiO2 photocatalyst was developed. Its morphology, size, crystalline phase, composition, absorbance and emission spectra were characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray analysis, ultraviolet-visible absorbance and fluorescence spectroscopy. The photocatalytic degradation of dyes including rhodamine B (RhB), methyl blue (MB) and methyl orange (MO), dye mixtures and dye wastewater under simulated solar light irradiation were evaluated. The degradation ratios and the removal ratios of chemical oxygen demand (COD) of the dyes and dye wastewater after the photo-degradation were measured. The results show that the as-prepared nanocomposite exhibits high photocatalytic activity, and it can not only efficiently degrade single dyes, but also mixtures and dye wastewater.