Field of Expertise: Advanced Material Science

Electrolyte-gated organic field-effect transistor for sensing applications in aqueous media
Kerstin Schmoltner
NanoTecCenter Weiz Forschungsgesellschaft m.b.H.
14:00 - 14:40 Thursday 24 October 2013 AT02002J

Organic field-effect transistors (OFETs) are highly promising candidates for chemical and biological sensing. Owing to their intrinsic amplification, OFET based sensors typically reveal a high sensitivity. In conjunction with the outstanding features of organic electronic devices such as economic production, integration on flexible substrates and biocompatibility, low-cost disposable sensor assemblies are not a future vision anymore. Asides from the key features of sensors such as sensitivity, selectivity, reversibility and response time, the device stability is another important factor. Within this context a novel air stable heterotriangulene polymer as an active layer in bottom-gate/bottom-contact p-channel OFETs and its detailed investigation concerning morphological, optical, electrical and interface related properties will be presented.
In addition to the air stable performance, a water-stable operation of OFET sensor elements is crucial when it comes to the detection of ions or biological molecules in aqueous media. Here electrolyte-gated OFETs (EGOFETs) will be discussed as the devices of choice. Due to the formation of an electric double layer at the electrolyte/organic semiconductor interface, they exhibit a very high capacitance allowing for a low voltage operation and thus a water-stable operation. In this regard, a novel ion sensor concept based on electrolyte gated poly(3hexylthiophene) thin film transistors in combination with a state-of-the-art ion selective membrane for selective and reversible ion detection will be demonstrated. This novel potentiometric sensor showed a sensitive linear response for a broad detection range between 10^-6 M and 10^-1 M Na+ and a selective as well as reversible response without a complex recovering process was achieved.