Zn-doped CaTiO3:Eu(3+) red phosphors for enhanced photoluminescence in white LEDs by solid-state reaction.

Abstract

Zn-doped CaTiO3:Eu(3+) red phosphors for enhanced photoluminescence in white light-emitting diodes (LEDs) were synthesized by a solid-state method. The structure and morphology of the obtained phosphor samples were observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the impact of Ca, Zn and Eu content on their photoluminescence properties was studied. The results indicated that Zn not only participates in the formation of defects in suitable lattice matrices but also has a role in flux in the transformation from ZnO to Zn2TiO4, which is beneficial for the enhancement of photoluminescence properties. Photoluminescence test data showed that the Zn-doped phosphor is excited efficiently by near-ultraviolet (NUV) light at wavelengths around 398 nm and emits an intense red light with a broad peak around 616 nm corresponding to the (5) D0 →(7) F2 transition of Eu(3+). The intensity of this phosphor emission is three times stronger than that without Zn-doping. Furthermore, this phosphor has very good thermal stability, high color purity and a low sintered temperature, all of which suggest its potential as a promising red phosphor for white LEDs.