Host-sensitized luminescence of Dy3+, Pr3+, Tb3+ in polycrystalline CaIn2O4 for field emission displays

CaIn2O4:Dy3+/Pr3+/Tb3+ blue-white/green/green phosphors were prepared by the Pechini sol-gel process. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), diffuse reflectance, photoluminescence (PL) and 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 deg. C and pure CaIn2O4 phase can be obtained after annealing at 900 deg. C. The FE-SEM images indicate that the CaIn2O4:Dy3+, CaIn2O4:Pr3+ and CaIn2O4:Tb3+ samples consist of spherical grains with size around 200-400 nm. Under the excitation of ultraviolet light and low-voltage electron beams (1-5 kV), the CaIn2O4:Dy3+, CaIn2O4:Pr3+ and CaIn2O4:Tb3+ phosphors show the characteristic emissions of Dy3+ (4F9/2-6H15/2 and 4F9/2-6H13/2 transitions, blue-white), Pr3+ (3P0-3H4, 1D2-3H4 and 3P1-3H5 transitions, green) and Tb3+ (5D4-7F6,5,4,3 transitions, green), respectively. All the luminescence is resulted from an efficient energy transfer from the CaIn2O4 host lattice to the doped Dy3+, Pr3+ and Tb3+ ions, and the corresponding luminescence mechanisms have been proposed. - Graphical abstract: The CaIn2O4:Dy3+/Pr3+/Tb3+ blue-white/green/green phosphors were prepared by the Pechini sol-gel process. Under the excitation of ultraviolet light and low-voltage electron beams (1-5 kV), the CaIn2O4:Dy3+, CaIn2O4:Pr3+ and CaIn2O4:Tb3+ phosphors show the characteristic emissions of Dy3+ (4F9/2-6H15/2 and 4F9/2-6H13/2 transitions, blue-white), Pr3+ (3P0-3H4, 1D2-3H4 and 3P1-3H5 transitions, green) and Tb3+ (5D4-7F6,5,4,3 transitions, green), respectively. All the luminescence is resulted from an efficient energy transfer from the CaIn2O4 host lattice to the doped Dy3+, Pr3+ and Tb3+ ions