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Weiz, Austria

Klug A.,NanoTecCenter | Schmoltner K.,NanoTecCenter | List E.J.W.,NanoTecCenter | List E.J.W.,University of Graz
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

Aside from other target applications, organic field-effect transistors (OFETs) are also promising devices for sensing various kinds of analytes, including gases, ions and biomolecules. In this work ion-sensitive polymer-based OFETs will be discussed. In detail, operational device instabilities caused by the movement of mobile ions in poly(3- hexylthiophene)-based OFETs are investigated, when (a) an ion-containing gate dielectric, polyvinyl alcohol (PVA), is applied in a top-gate architecture and (b) ions are deliberately added to the organic semiconductor in a bottom-gate architecture. The underlying mechanisms for the observed source-to-drain channel current drifts upon bias stress are thoroughly explained. In addition, device instabilities due to mobile ions within the dielectric are demonstrated with rigid and flexible PVA-based OFETs including inkjet-printed source/drain electrodes and a meander-shaped top-gate architecture, the latter enabling the realization of smart, integrated and low-cost OFET-based sensor systems. © 2010 SPIE. Source

Qin T.,Max Planck Institute for Polymer Research | Wiedemair W.,NanoTecCenter | Nau S.,NanoTecCenter | Trattnig R.,NanoTecCenter | And 9 more authors.
Journal of the American Chemical Society | Year: 2011

We present a novel core-shell-surface multifunctional structure for dendrimers using a blue fluorescent pyrene core with triphenylene dendrons and triphenylamine surface groups. We find efficient excitation energy transfer from the triphenylene shell to the pyrene core, substantially enhancing the quantum yield in solution and the solid state (4-fold) compared to dendrimers without a core emitter, while TPA groups facilitate the hole capturing and injection ability in the device applications. With a luminance of up to 1400 cd/m 2, a saturated blue emission CIExy = (0.15, 0.17) and high operational stability, these dendrimers belong to the best reported fluorescence-based blue-emitting organic molecules. © 2011 American Chemical Society. Source

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