Abstract
A series of CaTiO3: Eu3+, Eu3+/Dy3+, Eu3+/Dy3+/xGd3+, and Eu3+/Dy3+/Gd3+/M (M = Li+, Mg2+, Sr2+) perovskite micro phosphors have been prepared via solid-state reaction method. The structural, morphological, and spectral properties were systematically characterized by XRD, MEB, FT-IR, UV-V absorption, PL, and PLE. The prepared micro powders exhibited a single-phase orthorhombic structure with Pbnm space group. The MEB images revealed grain size ranging from 5 to 20 μm. The CaTiO3 band gap energy decreases by introducing the doping elements and changes from 3.581 eV for the undoped to 2.847 eV for Eu/Dy/Gd/Li doped sample. The photoluminescence properties of Eu3+, Eu3+/Dy3+, and Eu3+/Dy3+/xGd3+ doped CaTiO3 phosphors were investigated through excitation and emission spectra. Under 365 nm excitation, Eu3+/Dy3+ co-doped samples exhibit blue emission, which is turned to near white region by introducing Gd3+ ions. In order to enhance the luminescence properties, (Li+, Mg2+, Sr2+) ions are doped into CaTiO3 Eu3+/Dy3+/Gd3+ phosphors to ensure the host charge compensation. The charge compensators not only provide luminescence enhancement but also modify the local environment of the lanthanide ions and then adjust the emission to tune the ratio of each color in the spectrum. The photometric parameters such as CIE-coordinate and correlated color temperature (CCT) were calculated, which depend on the ion charge and on the ionic radii. These perovskite phosphors can be applied for solid-state lighting applications.
Published Version
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