Synthesis and luminescence properties of RE3+ (re = eu3+, Dy3+) activated CaSr2(PO4)2 phosphors for lighting and dosimetric applications

Abstract

A series of RE3+ (RE = Eu3+, Dy3+) activated CaSr2(PO4)2 phosphors were successfully synthesized by the Solid-State Diffusion method at high temperature. X-ray diffraction (XRD) pattern and Fourier transform infrared (FT-IR) spectra explained the structural properties and crystalline nature of the prepared sample. The Scanning Electron Microscopy (SEM) study represents particle size and morphological behavior of the prepared sample. The luminescence properties of the prepared phosphor were investigated by Photoluminescence (PL) and Thermoluminescence (TL) techniques. The PL properties of Eu3+ activated CaSr2(PO4)2 phosphors monitored under near-ultraviolet excitation at 395 nm, exhibited two strong, orange and red emission peaks at 593 nm and 615 nm respectively corresponding to the characteristic 5D0→7F1 and 5D0→7F2 transitions of Eu3+ ions. Further, Dy3+ activated CaSr2(PO4)2 phosphors monitored under 350 nm excitation wavelength, exhibited two strong, blue, and yellow emission peaks at 481 nm and 572 nm respectively, corresponding to the characteristic 4F9/2→6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ion. The CIE chromaticity diagram shows high color purity and excellent chromaticity coordinates and it also shows the presence of emission bands in the visible spectrum. The TL properties of (RE = Eu3+, Dy3+) activated CaSr2(PO4)2 phosphors were investigated after irradiating the samples with 75 MeV Oxygen ion beam and Gamma rays. CaSr2(PO4)2:Eu samples show TL response linearity in the fluence range 5 × 1010 ions/cm2 to 1 × 1011 ions/cm2 whereas CaSr2(PO4)2:Dy samples show linearity in the range 5 × 1010 ions/cm2 to 5 × 1011 ions/cm2 when irradiated with 75 MeV O6+ ion beam. Further γ-ray irradiated CaSr2(PO4)2 samples show TL response linearity for dose range 1.75 kGy to 21.06 kGy when activated by Eu and 0.116 kGy to 2.32 kGy when activated by Dy. So, CaSr2(PO4)2 activated by RE3+ (RE = Eu3+, Dy3+) phosphor is a promising candidate for lighting and dosimetric applications.