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Lookup NU author(s): Dr Reda Hassanien, Professor Nick Wright, Dr Alton Horsfall, Professor Andrew HoultonORCiD, Dr Ben Horrocks
Electroless templating on DNA is established as a means to prepare high aspect ratio nanowires via aqueous reactions at room temperature. In this report we show how Pd nanowires with extremely small grain sizes (<2 nm) can be prepared by reduction of PdCl42- in the presence of lambda-DNA. In AFM images the wires are smooth and uniform in appearance, but the grain size estimated by the Scherrer treatment of line broadening in X-ray diffraction is less than the diameter of the wires from AFM (of order 10 nm). Electrical characterisation of single nanowires by conductive AFM shows ohmic behaviour, but with high contact resistances and a resistivity (similar to 10(-2) Omega cm) much higher than the bulk value for Pd metal (similar to 10(-5) Omega cm @20 degrees C). These observations can be accounted for by a model of the nanowire growth mechanism which naturally leads to the formation of a granular metal. Using a simple combing technique with control of the surface hydrophilicity, DNA-templated Pd nanowires have also been prepared as networks on an Si/SiO2 substrate. These networks are highly convenient for the preparation of two-terminal electronic sensors for the detection of hydrogen gas. The response of these hydrogen sensors is presented and a model of the sensor response in terms of the diffusion of hydrogen into the nanowires is described. The granular structure of the nanowires makes them relatively poor conductors, but they retain a useful sensitivity to hydrogen gas.
Author(s): Al-Hinai MN, Hassanien R, Wright NG, Horsfall AB, Houlton A, Horrocks BR
Publication type: Article
Publication status: Published
Journal: Faraday Discussions
Year: 2013
Volume: 164
Pages: 71-91
Print publication date: 04/03/2013
Date deposited: 26/03/2014
ISSN (print): 1359-6640
ISSN (electronic): 1364-5498
Publisher: RSC Publications
URL: http://dx.doi.org/10.1039/c3fd00017f
DOI: 10.1039/c3fd00017f
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