Luminescent properties of LuAG:Ce phosphors with different Ce contents prepared by a sol–gel combustion method

Nanosized LuAG:Ce phosphors with different Ce concentrations were prepared by the sol–gel combustion method. Phase evolution, morphology and luminescent properties of the obtained materials were characterized by XRD, TEM, photoluminescent and radioluminescent spectra excited by blue light and X-ray, respectively. The purified crystalline phase of LuAG:Ce was obtained at 820 °C by directly crystallizing from amorphous materials. Both the photoluminescence and radioluminescence are the well-known Ce emissions located in the 470–600 nm consisting of two emission bands due to the transitions from the lowest 5d excited state (2D) to the 4f ground state of Ce3+, which matches well with the sensitivity curve of the Si-photodiode. The luminescent intensity of LuAG:Ce phosphors varies with the Ce contents and reaches the maximum at 0.5 at.% doped. There is a little red shift for the main emission component from blue light-excited emission spectra to X-ray-excited ones. The luminescent intensity of LuAG:Ce phosphors increases with increasing the calcining temperatures due to the improved crystallization.