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White light tunable emissions from ZnS: Eu3+ nanophosphors over 330–465nm excitation range for white LED applications

Ahemen, I and De, Dilip Kumar and Dejen, F. B. and Viana, B. (2016) White light tunable emissions from ZnS: Eu3+ nanophosphors over 330–465nm excitation range for white LED applications. Materials Research Express, 3 (4). pp. 1-13.

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Abstract

(ZnS: Eu3+ -CMC) nanophosphors of cubic (zinc blende) structure were synthesized using a precipitation technique with doping concentrations of Eu3+ ions 1 mol% and 5 mol%. The crystal sizes were 2.56 nmand 2.91 nmrespectively. Annealing at 300 °Cin a sulfur-rich atmosphere altered the crystal size to 4.35 nmand 3.65 nmrespectively and the band gap from 4.2 eV to 3.76 eV and 3.81 eV respectively. The as-synthesized samples gave pure orange-red emission when excited at wavelengths of 394 nmand 465 nm. After thermal annealing of the samples, a broad emission band in the blue-green region assigned to defect related states emerged or were enhanced. Also enhanced were the emission lines of Eu3+ ions in the orange-red region. A combination of these two transitions gave white light of different shades (recorded on the CIE 1931 chromaticity diagram) from cool white through day-light to warm white light, depending on Eu3+ concentration and the excitation wavelengths (UV-330 to blue 465 nm), thus showing great potential of these nano-phosphors in the generation of high quality white light.

Item Type: Article
Uncontrolled Keywords: high quality white light, photoluminescence, zinc sulfide, europium, nano-particles, synthesis, structural and optical characterization
Subjects: Q Science > Q Science (General)
Q Science > QC Physics
Divisions: Faculty of Engineering, Science and Mathematics > School of Physics
Depositing User: Mrs Patricia Nwokealisi
Date Deposited: 16 Aug 2016 08:27
Last Modified: 16 Aug 2016 08:27
URI: http://eprints.covenantuniversity.edu.ng/id/eprint/6909

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