Huaqiang He

Influence of La3+ and Dy3+ on the properties of the long afterglow phosphor CaAl2O4: Eu2+, Nd3+

The long afterglow phosphor CaAl2O4: Eu(superscript 2+), Nd(superscript 3+) was prepared by the high temperature solid-state reaction method, and the influence of La(superscript 3+) and Dy(superscript 3+) on the properties of the long afterglow phosphor was studied by X-ray diffraction (XRD), photoluminescence (PL), and thermolu-minescence (TL). The XRD pattern shows the host phase of CaAl2O4 is produced and no impurity phase appears. The peak wavelength of the phosphor does not vary with La(superscript 3+) and Dy(superscript 3+) doping. It implies that the crystal field, which affects the 5d electron states of Eu(superscript 2+), is not changed dramatically after doping of La(superscript 3+) and Dy(superscript3+). The TL spectra indicate that the phosphor doped with La(superscript 3+) or Dy(superscript 3+) produces different depths of trap energy level. In the mechanism of long afterglow luminescence, it is considered that La(superscript 3+) or Dy(superscript 3+) works as trap energy level. The decay time lies on the number of electrons in the trap energy level and the rate of the electrons returning to the excitation level.

Facile synthesis of high purity anhydrous complex rare earth halides by the modified mixed-salt-dehydration method

A novel and facile method to produce high purity anhydrous complex rare earth halides was introduced. The method was named modified mixed-salt-dehydration, which was proved to be a universal route to various types of complex rare earth halides with both high purity and low cost.

41.2: Influence of Doping on the Crystal Structures and Luminescent Properties of Aluminate Phosphors for Plasma Display Panel

BaAl12O19: Mn2+ doped with Mg2+, Sr2+ and La3+ cations and BaMgAl10O17: Eu2+ doped with Ca2+ and Sr2+ cations were synthesized by the high temperature solid state reaction method. The crystal structures and luminescent properties of these phosphors have been studied by XRD and luminescent spectra especially excited by vacuum ultraviolet.