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1.3 PHYSICAL SCIENCES
We demonstrate a technology platform that enables the development of new, surface-sensitised organic transistor sensors. We show that an organic semiconductor can still be gated by an electric double layer within the electrochemical window of water after the deposition of up to four Langmuir- Schäfer calixarene layers onto its surface. Since many calixarenes are known to selectively bind waterborne cations, this facilitates sensitising a conventional organic semiconductor with a physically deposited layer for specific cation recognition. When at least two Langmuir-Schäfer layers are deposited, these also block the electrochemical doping of the organic semiconductor, which otherwise competes with the field effect in water-gated organic transistors. Carrier mobility is reduced by the application of calixarene layers, but transistor current measurement remains accessible by simple methods. We find that for the present purpose, Langmuir-Schäfer-printed surface layers perform better than those deposited by Langmuir-Blodgett deposition.
Puzzovio, D., Al Naim, A. & Hague, L. (2012). Technology Platform for Sampling Water with Electrolyte-Gated Organic Transistors Sensitised with Langmuiur-Deposited Calixarene Surface Layers. Journal of Surfaces and Interfaces of Materials, vol. 1, pg. 1–6. doi:0.1166/jsim.2012.1007 doi:10.1166/jsim.2012.1007