Sr₃Al₂O₆: Eu Phosphor Synthesized By Solid State Reaction Method

As one of the composition of tricolor luminescence powdery, the red luminescence material containing rare-earth elements, has played an important role in PDP, new lamp-house, phototube and fibre communications, but it is expensive because of its high rare-earth elements content. Aluminates luminescence materials, with high brilliance, chemical stability and low cost, have been widely used, but they always emit blue or green light, lack of red one. So there is a great require to synthesis excellent red aluminates luminescence material.In this paper, Sr₃Al₂O₆:Eu³⁺ red phosphor was prepared by using solid state reaction method with SrCO₃ and Al₂O₃ as raw materials, and characterized by means of X-ray diffraction analysis and fluorescence spectrometer analysis, the factors which affect the phase and luminescence properties of Sr₃Al₂O₆:Eu³⁺ samples were investigated, too. So the synthesized temperature, Eu³⁺ content and the quantity of adding B₂O₃ flux were ascertained. That is, when SrCO₃/Al₂O₃=1.5, Eu₂O₃ content is 1% and B₂O₃ is 10%, the sample with better performance can be obtained. There are two broadband excitation peak in 200-340nm for the samples, and three high intensity red light emitting peak at wavelength of 590nm, 620nm and 703nm when excited by 250nm and 312nm ultraviolet.In order to enhance the phosphor emission intensity at 620nm, Ce³⁺, Mg²⁺ and Ca²⁺ were added into Sr₃Al₂O₆.Eu³⁺, and even carbon thermal reducing atmosphere has been used. It is shown that there are three special emitting peaks of Eu³⁺ and a broadband emitting peak near 380nm when excited by 250nm ultraviolet for the sample co-doped by Ce³⁺, but no similar phenomena has been observed when excited by 312nm ultraviolet in the same sample. There is only blue shift of emission peak for the samples doped by Mg²⁺ or Ca²⁺ , but no intensity enhancement for the special emission peak of Eu³⁺. For the sample synthesized in reducing atmosphere, there are three special emission peaks of Eu³⁺ and two broadband emission peaks near 400nm and 520nm when excited by 240nm. When excited by 240nm ultraviolet, it will express red emission belong to Eu³⁺, but there is only one broadband emission peak near 520nm when excited by 345nm ultraviolet.