Thermal effects on rapid microwave synthesized Co:ZnAl2O4 spinel nanoparticles

Menon, Samvit G and Choudhari, KS and Santhosh, C and Kulkarni, Suresh D (2017) Thermal effects on rapid microwave synthesized Co:ZnAl2O4 spinel nanoparticles. Journal of Alloys and Compounds, 728. pp. 1083-1090. ISSN 0925-8388

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Abstract

A rapid (10 min) microwave-assisted synthesis of CoxZn(1-x)Al2O4 nanoparticles using metal organic precursors is reported for the first time. The nanoparticles formed at 185 �C were phase-pure in the asprepared form with an average crystallite size of ~5 nm. Sample with x ¼ 0.0025 showed intense photoluminescence (PL) emission and was used to study the effect of annealing temperature on the structural and optical properties. Annealing in air until 1200 �C gradually (i) increased the crystallite size to as much as 31 nm (ii) change of colour tone from colourless to blue which has been attributed to the diffusion of Co2þ in host lattice (iii) increase in intensity of Co2þ bands in the diffuse reflectance spectra (DRS). The emission spectra comprised of the broad 4T1(4P)/4A2(4F) spin allowed transition pertaining to tetrahedral Co2þ at ~649 nm whose intensity increased with annealing temperature. The crystal field splitting parameter (Dq) and the Racah parameter B, were calculated from the excitation spectra and the Tanabe-Sugano diagrams. The novelty of this work lies in the simplicity and swiftness of the microwaveassisted synthesis that can be extended to other ceramic phosphors suitable for lasing and sensing applications.

Item Type: Article
Uncontrolled Keywords: Phosphors ; Nanostructured materials ; Optical properties ; Luminescence.
Subjects: Departments at MU > Atomic Molecular Physics
Depositing User: KMC Library
Date Deposited: 18 Sep 2017 11:21
Last Modified: 18 Sep 2017 11:21
URI: http://eprints.manipal.edu/id/eprint/149714

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