skip to main content

SciTech ConnectSciTech Connect

Title: Defect correlated fluorescent quenching and electron phonon coupling in the spectral transition of Eu{sup 3+} in CaTiO{sub 3} for red emission in display application

This paper reports on the defect correlated self-quenching and spectroscopic investigation of calcium titanate (CaTiO{sub 3}) phosphors. A series of CaTiO{sub 3} phosphors doped with trivalent europium (Eu{sup 3+}) and codoped with potassium (K{sup +}) ions were prepared by the solid state reaction method. The X-ray diffraction results revealed that the obtained powder phosphors consisted out of a single-phase orthorhombic structure and it also indicated that the incorporation of the dopants/co-dopants did not affect the crystal structure. The scanning electron microscopy images revealed the irregular morphology of the prepared phosphors consisting out of μm sized diameter particles. The Eu{sup 3+} doped phosphors illuminated with ultraviolet light showed the characteristic red luminescence corresponding to the {sup 5}D{sub 0}→{sup 7}F{sub J} transitions of Eu{sup 3+}. As a charge compensator, K{sup +} ions were incorporated into the CaTiO{sub 3}:Eu{sup 3+} phosphors, which enhanced the photoluminescence (PL) intensities depending on the doping concentration of K{sup +}. The concentration quenching of Eu{sup 3+} in this host is discussed in the light of ion-ion interaction, electron phonon coupling, and defect to ion energy transfer. The spectral characteristics and the Eu-O ligand behaviour were determined using the Judd-Ofelt theory from the PL spectra instead of the absorptionmore » spectra. The CIE (International Commission on Illumination) parameters were calculated using spectral energy distribution functions and McCamy's empirical formula. Photometric characterization indicated the suitability of K{sup +} compensated the CaTiO{sub 3}:Eu{sup 3+} phosphor for pure red emission in light-emitting diode applications.« less
Authors:
; ; ; ;  [1] ; ; ; ;  [2]
  1. Department of Physics, University of the Free State, Box 339, Bloemfontein 9300 (South Africa)
  2. Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India)
Publication Date:
OSTI Identifier:
22275531
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION SPECTRA; CALCIUM COMPOUNDS; CONCENTRATION RATIO; DOPED MATERIALS; ELECTRON-PHONON COUPLING; ENERGY SPECTRA; ENERGY TRANSFER; EUROPIUM IONS; FLUORESCENCE; LIGHT EMITTING DIODES; ORTHORHOMBIC LATTICES; PHOSPHORS; PHOTOLUMINESCENCE; POTASSIUM IONS; QUENCHING; SCANNING ELECTRON MICROSCOPY; TITANATES; ULTRAVIOLET RADIATION; VISIBLE RADIATION; X-RAY DIFFRACTION