Highly enterprising calcium zirconium phosphate [CaZr4(PO4)6:Dy3+, Ce3+] phosphor for white light emission

Abstract

A series of CaZr₄(PO₄)₆:Dy³⁺, CaZr₄(PO₄)₆:Ce³⁺ and CaZr₄(PO₄)₆:Dy³⁺, Ce³⁺ phosphors were prepared by the solid state reaction process. The phase formation was confirmed by X-ray powder diffraction (XRD) measurements. Morphological studies were performed using scanning electron microscopy. Raman spectra were studied to identify the scattering bands associated with the normal vibrational modes of the PO₄³⁻ tetrahedron. The photoluminescence properties of the phosphors were systematically investigated. With increasing Dy³⁺ concentration in CaZr₄(PO₄)₆:Dy³⁺ phosphor, the luminescence intensity first increases, reaches the maximum, and then decreases. A similar trend is followed by CaZr₄(PO₄)₆:Ce³⁺ phosphors, with increasing Ce³⁺ concentration. A successful attempt was made to initiate the energy transfer mechanism from Ce³⁺ to Dy³⁺ ions in the CaZr₄(PO₄)₆ host lattice. The CIE chromaticity coordinates of CaZr₄(PO₄)₆:Dy³⁺ phosphor exhibited emission near the white-light region and hence, it is a potential candidate for UV excited white-LEDs (WLEDs). CaZr₄(PO₄)₆:Dy³⁺, Ce³⁺ phosphor has its CIE chromaticity coordinates in the white light region, near the standard illuminant D₆₅. Thermoluminescence (TL) studies on CaZr₄(PO₄)₆:Dy³⁺, Ce³⁺ phosphor, which was performed to test its stability against low dose of gamma-ray exposure, are also documented.