Berlin 2012 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 13: Poster II

DF 13.1: Poster

Mittwoch, 28. März 2012, 15:00–17:30, Poster E

Impedance spectroscopy of printable electrolytes: calculation of frequency dependent effective capacitance — •Anna Stoesser, Robert Kruk, Nina Schweikert, Subho Dasgupta, and Horst Hahn — Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

In this work firstly presented an ink-jet printed and electrochemically-gated inorganic oxide based FET where indium tin oxide(ITO) nanoparticles compose the active channel of the device. Due to extremely effective gating possible by the polymer electrolytes which closely follows the roughness of the nanoparticulate channel, we obtain a large value of field-effect mobility. However, a generally expressed concern is that the electrolyte-gated device speed is limited by the ionic mobility of the electrolyte. Therefore, we have investigated the conductivity and frequency dependent polarizability of the printable grade of solid polymer electrolyte using electrical impedance spectroscopy. The frequency-dependent effective capacitance of ITO electrodes is calculated. It is shown that if cut-off frequency is defined as 1/2πRC then the value of cut-off frequency for our electrolyte can be as high as 40 kHz when the thickness of the printed electrolyte is about 100 nm. Electrolyte conductivity can be foreseen with regular optimization, therefore, it may be concluded that finally electrolytes would not limit the attainable max. speed for the device-type presented here. Thus, an improvement of resolution and positional accuracy in the printing process is believed to be the key in this case to increase the speed of such transistors from kHz to MHz regime.