Synthesis of CaWO4:Eu3+ phosphor powders via a combustion process and its optical properties

Using citric acid as chelating agent and fuel, ammonium nitrate as fuel, boric acid as flux material and silica as supports, persistent phosphor CaWO4:Eu3+ has been prepared via a combustion process, which formed voluminous white powder. The persistent phosphor was further investigated by X-ray diffractometer (XRD), fluorescence spectrophotometer (PL) and transmission electron microscopy (TEM). XRD analyses indicate that the crystalline calcium tungstate has been synthesized when ignited at 500 °C. The PL results showed the highest intensity of emission spectrum obtained at 800 °C, the optimal contents is 0.7CaWO4:0.3Eu3+ incorporated into silica which could enhance luminescence intensity of CaWO4:Eu3+. The average particle sizes as measured by TEM are ranged in 50 to 100 nm, which could extend the application of this phosphor.