Lingli Wang

Synthesis and luminescent properties of Ln3+ (Ln3+ = Eu3+, Dy3+) -doped Bi2ZnB2O7 phosphors

The new phosphors Bi2ZnB2O7: Ln3+ (Ln3+ = Eu3+, Dy3+) were synthesized by solid-state reaction technique. The obtained phosphors were investigated by means of X-ray powder diffraction (XRD), photoluminescence excitation and emission spectra with the aim of enhancing the fundamental knowledge about the luminescent properties of Eu3+ and Dy3+ ions in the Bi2ZnB2O7 host lattice. XRD analysis shows that all these compounds are of a single phase of Bi2ZnB2O7. The excitation and emission spectra of Bi2ZnB2O7: Ln3+ (Ln3+ = Eu3+, Dy3+) at room temperature show the typical 4f-4f transitions of Eu3+ and Dy3+, respectively. The hypersensitive transitions of 5D0→7F2 (Eu3+) and 4F9/2→6H13/2 (Dy3+) are relatively higher than those of the insensitive transitions in Bi2ZnB2O7. It is conceivable that the Bi2ZnB2O7 structure provides asymmetry sites for activators (Eu3+, Dy3+). The optimum concentrations of Eu3+ and Dy3+ ions in Bi2ZnB2O7 phosphors are both x = 0.05.

The Influence Mechanism of Halogen Ion on the Temperature Quenching Performance of Sr 2 SiO 4 :Eu Phosphors

The luminescent properties of Sr2SiO4:Eu phosphors synthesized with and without flux have been investigated. With the co-dopation of NH4CI, the luminescent intensity of Sr2SiO4:Eu is increased and the temperature quenching property is improved. The effect of NH4Cl is analyzed not only from the crystallinity of the Sr2SiO4 crystal but also the band structure of Sr2SiO4 host, which is calculated by density functional method with the local density approximation.