Effect of thermal annealing on dual photoluminescence emission characteristics of chemically synthesized uncapped Mn2+ doped ZnS quantum dots

Kole, Arup Kanti and Tiwary, Chandra Sekhar and Kumbhakar, Pathik (2014) Effect of thermal annealing on dual photoluminescence emission characteristics of chemically synthesized uncapped Mn2+ doped ZnS quantum dots. In: JOURNAL OF LUMINESCENCE, 155 . pp. 359-367.

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Abstract

Dual photoluminescence (PL) emission characteristics of Mn2+ doped ZnS (ZnS:Mn) quantum dots (QDs) have drawn a lot of attention recently. However, here we report the effect of thermal annealing on the PL emission characteristics of uncapped ZnS:Mn QDs of average sizes similar to 2-3 nm, synthesized by simple chemical precipitation method by using de-ionized (DI) water at room temperature. As-synthesized samples show dual PL emissions, having one UV PL band centred at similar to 400 nm and the other in the visible region similar to 610 nm. But when the samples are isochronally annealed for 2 h at 100-600 degrees C temperature range in air, similar to 90% quenching of Mn2+ related visible PL emission intensity takes place at the annealing temperature of 600 degrees C. X-ray diffraction data show that the as-synthesized cubic ZnS has been converted to wurtzite ZnO at 600 degrees C annealing temperature. The nanostructural properties of the samples are also determined by transmission electron micrograph, electron probe micro-analyser and UV-vis spectrophotometry. The photocatalytic property of the annealed ZnS:Mn sample has been demonstrated and photo-degradation efficiency of the as-synthesized and 600 degrees C annealed ZnS:Mn sample has been found out to be similar to 35% and similar to 61%, respectively, for the degradation of methylene blue dye under visible light irradiation. The synthesized QDs may find significant applications in future optoelectronic devices. (C) 2014 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	JOURNAL OF LUMINESCENCE
Additional Information:	Copy right for this article belongs to the ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	15 Oct 2014 04:41
Last Modified:	15 Oct 2014 04:41
URI:	http://eprints.iisc.ac.in/id/eprint/50006

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