Jiayan Li

Facile sonochemical synthesis of CePO4 : Tb/LaPO4 core/shell nanorods with highly improved photoluminescent properties

A simple, efficient and quick method has been established for the synthesis of CePO(4):Tb nanorods and CePO(4):Tb/LaPO(4) core/shell nanorods via ultrasound irradiation of inorganic salt aqueous solution under ambient conditions for 2xa0h. The as-prepared products were characterized by means of powder x-ray diffraction (PXRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), x-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectra and lifetimes. TEM micrographs show that all of the as-prepared cerium phosphate products have rod-like shape, and have a relatively high degree of crystallinity and uniformity. HRTEM micrographs and SAED results prove that these nanorods are single crystalline in nature. The emission intensity and lifetime of the CePO(4):Tb/LaPO(4) core/shell nanorods increased significantly with respect to those of CePO(4):Tb core nanorods under the same conditions. A substantial reduction in reaction time as well as reaction temperature is observed compared with the hydrothermal process.

Sonochemical synthesis and photoluminescent property of YVO4:Eu nanocrystals

YVO4 nanocrystals doped with 10.0 mol% Eu3+ have been synthesized from an aqueous solution of (Y,Eu)(NO3)3 and NH4VO3 with or without ultrasonic irradiation. The ultrasonic irradiation has a strong effect on the morphology of the YVO4:Eu particles. The spindle-like particles with an equatorial diameter of 90–150 nm and a length of 250–300 nm could be obtained with ultrasonic irradiation, whereas only nanoparticles were produced without ultrasonic irradiation. The photoluminescence intensity of YVO4:Eu of the spindle-like particles was largely improved compared with that of the nanoparticles. The possible formation mechanism of the spindle-like particles of YVO4:Eu with the application of ultrasonic irradiation was discussed in this paper.

Single-crystalline nanowires of SiC synthesized by carbothermal reduction of electrospun PVP/TEOS composite fibres

Nanowires of SiC were synthesized by carbothermally reducing PVP/TEOS composite fibres obtained by electrospinning. High-resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED) indicated that the SiC nanowires are single crystalline in nature. Both Fourier-transformed infrared spectroscopy and HRTEM indicated that a thin layer of SiO2 was formed on the outer surface of the nanowire as a result of post-heat treatment for the removal of residual carbon. Such SiO2 layer protects the inner SiC fibre from further oxidation. The formation mechanism of single-crystalline SiC nanowires was proposed based on our understanding and characterizations. The growth of the nanowire is believed to be along the (111) of its cubic cell.