Photoluminescence study of activator ions (Eu, Tb) co-doped in different host environments (CaO, CaSiO3, CaAl2O4 and CaSiAl2O6)

The present paper mainly reports on how the co-doped RE activator ions behaves especially the excitation and emission wavelengths, in different host environments. For this purpose, we have taken Eu and Tb rare-earth ions as activators or dopants at 1.5 mol%, 1.0 mol% respectively. These dopants are co-doped in different host materials like CaO, CaSiO3, CaAl2O4 and CaSiAl2O6 compounds and were synthesized by the standard solid state reaction method. The structure, morphology of the phosphors was characterized by X-ray diffraction and scanning electron microscopy. Luminescence properties of all the phosphors were investigated by the excitation and emission spectroscopy at the room temperature. The excitation spectra of all the synthesized phosphors monitored at 614nm wavelength were composed of a broadband around 310nm with high intensity which is attributed to charge transfer (CT) band from Eu - O and a series of sharp peaks with less intensity at 395nm and 467nm are observed which are assigned to f-f transitions of Eu ion. The emission spectra of prepared phosphors had transitions of Eu3+ ions i.e. D-5(0) -> F-7(1) (590nm), D-5(0) -> F-7(2) (614nm). CIE analysis and CCT were also done to see the colour coordinates and temperature of the phosphors. The prepared materials had bright red emitting optical properties that could be suitably applied in various display devices under UV excitation and also for w-LED applications under nUV, blue excitation. (C) 2019 Elsevier Ltd. All rights reserved.