Bai Zhaohui

Preparation and characterization of bismuth silicate nanopowders

Bismuth silicate (Bi4Si3O12) nanopowders were prepared by the sol-gel method. Tetraethyl orthosilicate (TEOS) and Bi2O3 were used as the starting materials. The precursors were heat-treated at 750°C for 2 h. The size distribution of Bi4Si3O12 nanopowders is 40–100 nm. The thermogravimetry and differential thermal analysis (TG-DTA) curves, the X-ray diffraction (XRD) patterns and the transmission electron microscopy (TEM) microphotograph of Bi4Si3O12 were discussed. Compared with crystal materials, the excitation and emission spectra of Bi4Si3O12 nanopowders indicated a blue shift.

Preparation and Study on Spectrum Characteristics of Sr0.99 Ce0.01 HfO3 Nanopowders

Abstract The Sr 0.99 Ce 0.01 HfO 3 nanopowders were synthesized by the co-precipitation method. The calcination temperature and time of the powders were 1200 °C and 2 h, respectively. The powder size of Sr 0.99 Ce 0.01 HfO 3 nanopowders was 15 × 30 nm. There were two excitation bands in the excitation spectra of the Sr 0.99 Ce 0.01 HfO 3 nanopowders, which peaking at 216 and 309 nm, respectively. There were two emission bands in the emission spectra excited by the 220 nm light, which peaking at 398 and 467 nm. And they were corresponding to the 5d→ 2 F 5/2 and the 5d→ 2 F 7/2 transitions of Ce 3+ ions. But there was only one emission band in the emission spectrum excited by the 309 nm light which peaking at 392 nm.

Preparation and Characterization Upconversion Luminescence Material of Yttrium Aluminate Doped with Rare Earth

Abstract Low phonon energy yttrium aluminate was adopted as matrix and the upconversion materials yttrium aluminate co-doped with Yb3+ and Er3+ was synthesized by solid-state reaction method. The X-ray diffraction spectra and the upconversion emission spectra of various samples were measured and the effect of Er3+ concentration, sensitization, fluxing agent and calcining temperature on the luminescence properties was studied. Research results showed that the sample could emit green light at 543 and 570 nm when excited 980 nm laser; the optimum concentration of Er3+ should be 1.0%; sensitization of Yb3+ could enhance luminescent effects of Er3+ obviously; the optimum content of F3BO3 fluxing agent should be 8% and the optimum calcining temperature should be 1500 °C.