Preparation and luminescence properties of Eu2+-doped CaSi 2O2-dN2+2/3d phosphors

Abstract

Eu2+-doped CaSi2O2-dN2+2/3d phosphors for white LED lamps were prepared by solid-state reaction, and the effects of heat-treatment conditions and the overall composition of host lattice on the optical properties have been discussed. Eu2+-doped CaSi 2O2-dN2+2/3d displayed a single broad emission band peak at 540 nm, which could be assigned to the allowed transition of Eu2+ from the lowest crystal field component of 4f65d to 4f7 ground-state level. The excitation band of samples, extending from UV to blue, is extremely wide, so the phosphors are suitable for white LED lamps in combination with a UV or blue LED dies. The highest PL intensity is found for the sample sintered at 1400 °C. Moreover, the emission intensity decreases when N partially replaces O. A red shift of emission wavelength did not occur with increasing of the N content. © 2009 IOP Publishing Ltd.