Linhui Gao

Fe3O4–Au and Fe2O3–Au Hybrid Nanorods: Layer-by-Layer Assembly Synthesis and Their Magnetic and Optical Properties

A layer-by-layer technique has been developed to synthesize FeOOH–Au hybrid nanorods that can be transformed into Fe2O3–Au and Fe3O4–Au hybrid nanorods via controllable annealing process. The homogenous deposition of Au nanoparticles onto the surface of FeOOH nanorods can be attributed to the strong electrostatic attraction between metal ions and polyelectrolyte-modified FeOOH nanorods. The annealing atmosphere controls the phase transformation from FeOOH–Au to Fe3O4–Au and α-Fe2O3–Au. Moreover, the magnetic and optical properties of as-synthesized Fe2O3–Au and Fe3O4–Au hybrid nanorods have been investigated.

Hydrothermal synthesis of blue-emitting YPO4:Yb3+ nanophosphor

The blue-emitting YPO4 phosphors doped with Yb3+ were prepared by a simple hydrothermal method. All the products were characterized by XRD and TEM, which revealed that they were zircon structure with leaf-like morphology. According to the analysis of photoluminescence spectra, upon ultraviolet (275 nm) excitation, the Yb3+ doped YPO4 phosphor showed an intense blue emission composed of two main bands at 420 and 620 nm assigned to charge transfer state (CTS) → 2F5/2 and CTS → 2F7/2, respectively. Moreover, the optimum doping concentration of Yb3+ in YPO4 phosphor was 1%, which exhibited the maximum emission intensity. The possible physical mechanism of concentration quenching was discussed, and the critical transfer distance determined to be 23.889 Å. In particular, the color purity of the as-synthesized Yb3+ doped YPO4 phosphor was as high as 83%, which made it an excellent candidate for blue-emitting materials.