Combustion Synthesis Of A Series Calcium Aluminate Phosphors Doped With Other Ions

In this paper, the current situation and development of solid luminescent materials were summarized. Especially, the current situation, development, characteristic of phosphors, theory of the luminescence and preparation of the photoluminescence doped with rare earth were emphasized elaborately.Long lasting phosphorescence of alkaline earth aluminate doped with rare earth as a non-radioactive phosphor has excellent luminescent property and not environmental pollution in the process of preparation, so it has a wide application prospect. However, its cost is so high that its application is restricted seriously. In this paper, new method and technique of preparation were studied in order to decrease the cost and to simplify the process. We gained the productions as following:1 When we have chosen the aluminum oxide, calcium carbonate, europium oxide and neodymium oxide as raw materials, boric acid as flux, grainy active carbon for the ratio of 1:10 as reductant. Under the condition of sintering for 4 h at 1350℃ and naturally lowering the temperature, the long afterglow blue-purple color phosphor product -CaAl2O4:Eu2+, Nd3+ can be prepared.It was found that the phosphor's exciting spectrum and emission spectrum is broad spectrum by measuring. It belongs to the special luminescence of Eu2+. It was found that the phosphor's best exciting peak wavelength is 290nm corresponding emission peak wavelength 450nm and the phosphor attains the strongest luminescent intensity simultaneously.2 A new synthetic method-combustion synthesis were used to prepare the phosphor, CaAl2O4:Eu2+, Nd3+. The influence of the temperature of furnace, the content of the activator, the assistant activator, the flux and the combustibles, etc. upon the properties of the sample is studied. We confirmed the better technics parameters to prepare the excellent luminescent intensity of the CaAl2O4 Eu2+, Nd3+ phosphor.The results show that we opted for the aluminum nitrate and calcium nitrate solution as raw materials, borate acid (0.12 mol fraction) as flux, the quantity of urea for 2.2 times as much as theoretic quantity as reductant, doping with Eu2+ for the mol fraction of 0.018 and the quantity of Dy3+ for the mol fraction of 0.01. A newhigh-quality long lasting phosphor- CaAl2O4:Eu2+,Nd3+ was prepared by combustion synthesis at 600℃ of igniting temperature in the furnace. It was found that the phosphor's best exciting peak wavelength is 290nm corresponding emission peak wavelength 450nm by measuring the exciting spectra and the emitting spectra. The phosphor luminescent intensity is strongest under this exciting condition.3 In order to find the better method to improve the phosphor's luminescent brightness, we replaced the atomic Sr, Zr and Ce of Al, and attained the excellent luminescent phosphors. We analyzed the exciting spectra and the emitting spectra of the phosphors. The results are as following. The emission peak wavelength is still 450nm doped with a few Sr; With increasing the fraction of Sr the emitting wavelength of the phosphor transfered toward the longer wavelength; With the increasing of the content of Zr, the wavelength didn't change, but the luminescent intensity had a change that the intensity is enhanced, then reached the strongest and weakened finally. When the content of doped-Ce3+ is low, the emission peak wavelength doesn't transfer, but the luminescent intensity of doped-Eu2+ was enhanced.