Preparation and characterization of CaAl2O4:Eu2+,Nd3+ luminous phosphor synthesized by coprecipitation-sol-gel method

In this study, Eu2+ doped and Nd3+ co-doped rare-earth strontium aluminates CaAl2O4:Eu2+,Nd3+ luminous phosphor was prepared by coprecipitation-sol-gel(CSG) and high temperature solid-state(HTS) method. The rare-earth strontium aluminates CaAl2O4:Eu2+,Nd3+ powder was investigated in terms of material composition, crystalline phase, morphology and luminescence property by x-ray diffraction (XRD), Scanning Electron Microscope (SEM), fluorescence spectrophotometer, long afterglow phosphors tester and CIE chromaticity respectively. XRD analysis shows that doping a small amount of rare earth ions in the raw materials had no effect on the crystal texture of CaAl2O4 and the required temperature of solid phase method is higher than CSG reaction. The images of SEM show that the particle size of the phosphor made by CSG is smaller and more uniform than that of HTS. The excitation spectrum of the luminescent phosphor is a 240–360 nm broad band caused by ground state 4f7(8s7/2) to 4f65d excited state of Eu2+ and the spectrum peaks of nanometer material moved to the longwave region slightly. The strong emission peak near 440 nm caused by excited state 4f65d to the ground state 4f7(8s7/2) of Eu2+ and also shifts to the longwave region slightly in keeping with the changes of the CIE coordinates. The luminous fiber prepared by the CaAl2O4:Eu2+,Nd3+ powder of CSG method have great optical and mechanical properties.