Tunable Luminescence Properties of CaIn2O4:Eu3+ Phosphors

CaIn 2 O 4:Eu 3+ phosphors were prepared by a Pechini sol−gel process. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL), cathodoluminescence (CL) spectra as well as lifetimes were utilized to characterize the samples. The XRD results reveal that the samples begin to crystallize at 800 °C, and the crystallinity increases upon raising the annealing temperature. The FE-SEM images indicate that the CaIn 2 O 4:Eu 3+ samples consist of fine and spherical grains with size around 200−400 nm. Under the excitation of ultraviolet light and low-voltage electron beams, the CaIn 2 O 4:Eu 3+ phosphors show the characteristic emissions of Eu 3+ ( 5 D J − 7 F J ‘ J, J ‘ = 0, 1, 2, 3 transitions). The luminescence color can be tuned from white to orange to red by adjusting the doping concentration of Eu 3+ . The corresponding luminescence mechanisms have been proposed.