Haritha, P. and Martin, I. R. and Viswanath, C. S. Dwaraka and Vijaya, N. and Krishnaiah, K. Venkata and Jayasankar, C. K. (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:	07 Feb 2020 07:56
Last Modified:	07 Feb 2020 07:56
URI:	http://npl.csircentral.net/id/eprint/2879

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