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pH-triggered conduction of amine-functionalized single ZnO wire integrated on a customized nanogap electronic platform

Valentina Cauda1*, Paolo Motto2, Denis Perrone1, Gianluca Piccinini2 and Danilo Demarchi12

Author Affiliations

1 Center for Space Human Robotics, Istituto Italiano di Tecnologia, Turin 10129, Italy

2 Department of Electronics, Politecnico di Torino, Turin 10129, Italy

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Nanoscale Research Letters 2014, 9:53  doi:10.1186/1556-276X-9-53

Published: 31 January 2014


The electrical conductance response of single ZnO microwire functionalized with amine-groups was tested upon an acid pH variation of a solution environment after integration on a customized gold electrode array chip. ZnO microwires were easily synthesized by hydrothermal route and chemically functionalized with aminopropyl groups. Single wires were deposited from the solution and then oriented through dielectrophoresis across eight nanogap gold electrodes on a platform single chip. Therefore, eight functionalized ZnO microwire-gold junctions were formed at the same time, and being integrated on an ad hoc electronic platform, they were ready for testing without any further treatment. Experimental and simulation studies confirmed the high pH-responsive behavior of the amine-modified ZnO-gold junctions, obtaining in a simple and reproducible way a ready-to-use device for pH detection in the acidic range. We also compared this performance to bare ZnO wires on the same electronic platform, showing the superiority in pH response of the amine-functionalized material.

ZnO wire; Aminopropyl functionalization; Nanogap electrodes; pH-responsive behavior; Gold-ZnO-gold junction