Papers by Author: Xin He

Abstract: A series of Ba1.91-xSrxSiO4:Eu2+, Dy3+phosphors were synthesized by the high-temperature solid-state reaction. The structure of powder samples were characterized by X-ray powder diffraction. The photoluminescence emission and excitation spectra are also studied. It can be proved the formation of the solid solution of Ba1.91-xSrxSiO4:Eu2+, Dy3+ compounds, and the phosphors can be efficiently excited by UV-visible light from 300 to 480 nm. The as-synthesized Ba1.91-xSrxSiO4:Eu2+, Dy3+ phosphors are promising candidates applicable to near-UV and blue LEDs for solid-state lighting.

Abstract: Silver nanowires with lenghths of several hundred micrometers and diameters of 90~150 nm were prepared by glucose and Fe3+ in the presence of poly (vinyl pyrrolidone). The results show that the concentration of poly (vinyl pyrrolidone), Fe3+ and AgNO3 are the vital factors to determine the shape of the final products. The growth kinetics of the as-synthesized silver nanowires with high aspect ratios are also discussed in this work. This silver nanowires are expected to form the network used for excellent conductors or electrodes.

Abstract: We demonstrated the fabrication of the flower-like silver nanoplate micro-assemblies in high yields by a facile hydrothermal method. This novel nanostructure was synthesized in the presence of poly (vinyl pyrrolidone) (PVP) and ascorbic acid (AsA) at 150 °C for 10 h. The microassemblies with average size of 1~2 μm are consisted of several uniform nanoplates and show face centered cubic structure. The effects of the concentration of reactants, molar ratio of silver nitrate to ascorbic acid on the formation of the flower-like silver micro-assemblies were also presented.

Abstract: We described a facile approach to controllably synthesize silver nanoparticles with various morphologies using N, N-dimethylformamide (DMF) in the presence of poly (vinyl pyrrolidone) (PVP). Triangular/hexagonal nanoplates, chain-like nanoplate assemblies, and nanobelts could be selectively obtained. On the basis of the experimental results, the concentration of poly (vinyl pyrrolidone) and AgNO3, reactive temperature and time were the vital factors to determine the shape of final products. Reasonable mechanisms for the formation of silver nanoparticles with various morphologies were proposed. Fluorescence modulation of dye rhodamine B (RhB) and fluorescein (FI) in the presence of silver nanoparticles were studied. Addition of silver nanoparticles could produce fluorescence enhancement and show self-quenching release of RhB, while the fluorescence intensity of FI decreased due to the presence of the silver nanoparticles. The effects of silver nanoparticles on the fluorescence properties of dyes were dependent on the competition between the local field enhancement and non-radiation energy transfer from the molecule to the metallic nanoparticles.