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Networks of DNA-templated palladium nanowires: structural and electrical characterisation and their use as hydrogen gas sensors

Lookup NU author(s): Dr Reda Hassanien, Professor Nick Wright, Dr Alton Horsfall, Professor Andrew Houlton, Dr Ben Horrocks

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Abstract

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.


Publication metadata

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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