Haritha, P. and Martin, I. R. and Viswanath, C. S. Dwaraka and Vijaya, N. and Krishnaiah, K. Venkata and Jayasankar, C. K. and Haranath, D. and Lavin, V. and Venkatramu, V. (2017) Structure, morphology and optical characterization of Dy3+-doped BaYF5 nanocrystals for warm white light emitting devices. Optical Materials, 70. pp. 16-24. ISSN 0925-3467

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Abstract

The barium yttrium fluoride BaYF5 nanocrystalline powders doped with different concentrations of Dy3+ ions have been synthesized via a hydrothermal method and studied their structural, morphological, thermal, vibrational, and optical properties. These nanopowders have been crystallized in a single phase of the tetragonal structure with the average size of around 30 nm having spherical shape in morphology. Upon excitations at 350 and 387 nm, Dy3+ -doped BaYF5 nanocrystals exhibit strong blue and yellow emissions ascribed to the F-4(9/2) -> H-6(15/2) and F-4(9/2) -> H-6(13/2) transitions, respectively. Decay curves of the F-4(9/2) level of Dy3+ ion in BaYF5 nanocrystals exhibit non-exponential nature due to the dipole-dipole interaction between Dy3+ ions, confirmed by Inokuti-Hirayama model. The quantum yield for these nanocrystals have been found to be increased from 4.64% to 11.61% as the concentration of Dy3+ ions increases from 1.0 mol% to 2.0 mol% and then decreased to 10.68% as the dopant concentration increased to 5.0 mol%. Moreover, color coordinates and correlated color temperatures have been evaluated as a function of concentration and excitation wavelength and found to be in the warm white light region for all Dy3+ concentrations.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M\S Elsevier.
Subjects:	Materials Science Optics
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	25 Feb 2019 11:03
Last Modified:	25 Feb 2019 11:03
URI:	http://npl.csircentral.net/id/eprint/2867

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