Title: Synthesis, characterisation and spectroscopic properties of GdOF:Eu3+ phosphors and their Judd-Ofelt analysis
Authors: N. Dhananjaya; S.R. Yashodha; C. Shivakumara
Addresses: Department of Physics, B.M.S. Institute of Technology and Management, Bangalore – 560 064, India ' Department of Physics, Sai Vidya Institute of Technology, Bangalore – 560 064, India ' Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore – 560012, India
Abstract: A series of Eu3+-doped gadolinium oxyfluoride (GdOF) phosphors (1-9 mol%) were successfully prepared by a low temperature solid state method. The phosphors were characterised by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), UV-Visible (UV-Vis) absorption and photoluminescence (PL) spectroscopy. Rietveld refinement of PXRD data confirmed that all the compounds were crystallised in the rhombohedral structure. The photoluminescence properties were investigated under 254 nm excitation wavelengths. On substitution of Eu3+ ion to Gd3+-site in GdOF, the photoluminescence spectra exhibit 5D0 → 7F0 (579 nm), 5D0 → 7F1 (593 nm), 5D0 → 7F2 (612, 620 nm), 5D0 → 7F3 (651 nm) and 5D0 → 7F4 (705 nm) transitions. Judd-Ofelt theory was applied to evaluate the intensity parameters (Ω2, Ω4) of Eu3+-doped GdOF phosphors. The transition probabilities (AT), radiative lifetime (τrad), and branching ratio (β) were investigated by using the intensity parameters. CIE colour coordinates confirmed that the Eu3+-doped GdOF phosphors exhibit red luminescence. The obtained results revealed that the present phosphors can be a potential candidate for red component in white LEDs applications.
Keywords: gadolinium oxyfluoride; GdOF; phosphors; Judd-Ofelt analysis; CIE chromaticity; white LEDs.
International Journal of Nanotechnology, 2017 Vol.14 No.9/10/11, pp.727 - 738
Received: 08 May 2021
Accepted: 12 May 2021
Published online: 23 Jun 2017 *