Interactions between photoexcited NIR emitting CdHgTe quantum dots and graphene oxide

Jagtap, Amardeep M and Varade, Vaibhav and Konkena, Bharathi and Ramesh, KP and Chatterjee, Abhijit and Banerjee, Arup and Pendyala, Naresh Babu and Rao, Koteswara KSR (2016) Interactions between photoexcited NIR emitting CdHgTe quantum dots and graphene oxide. In: JOURNAL OF APPLIED PHYSICS, 119 (7).

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Abstract

Hydrothermally grown mercury cadmium telluride quantum dots (CdHgTe QDs) are decorated on graphene oxide (GO) sheets through physisorption. The structural change of GO through partial reduction of oxygen functional groups is observed with X-ray photoelectron spectroscopy in GO-QDs composites. Raman spectroscopy provides relatively a small change (similar to 1.1 times) in D/G ratio of band intensity and red shift in G band from 1606 cm(-1) to 1594 cm(-1) in GO-CdHgTe QDs (2.6 nm) composites, which indicates structural modification of GO network. Steady state and time resolved photoluminescence (PL) spectroscopy shows the electronic interactions between photoexcited near infrared emitting CdHgTe QDs and GO. Another interesting observation is PL quenching in the presence of GO, and it is quite effective in the case of smaller size QDs (2.6 nm) compared to the larger size QDs (4.2 nm). Thus, the observed PL quenching is attributed to the photogenerated electron transfer from QDs to GO. The photoexcited electron transfer rate decreases from 2.2 x 10(9) to 1.5 x 10(8) s(-1) with increasing particle size from 2.6 to 4.2 nm. Photoconductivity measurements on QDs-GO composite devices show nearly 3 fold increase in the current density under photo-illumination, which is a promising aspect for solar energy conversion and other optoelectronic applications. (C) 2016 AIP Publishing LLC.

Item Type:	Journal Article
Publication:	JOURNAL OF APPLIED PHYSICS
Publisher:	AMER INST PHYSICS
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	11 Jun 2016 09:38
Last Modified:	11 Jun 2016 09:38
URI:	http://eprints.iisc.ac.in/id/eprint/53920

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