University of Twente Student Theses


Determining the properties of DEME-TFSI for gating purposes

Daling, Gerben (2013) Determining the properties of DEME-TFSI for gating purposes.

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Abstract:In this bachelor assignment, the characteristics of the ionic liquid DEME-TFSI are studied for gating purposes. This bachelor thesis was initiated in the hope ionic liquid gating might be able to up the charge carrier concentration in a thin layer of a adjacent material more than any conventional methods using dielectric layers will. This might in some materials create a transition from an isolating state to another state. In the experiments conducted to characterize the ionic liquid, it was found the breakdown voltage is somewhere between 4 and 6 volts, matching literature values. Also, it was determined that the ionic liquid does solidify at around 182 K, but one needs to take care during experiments with the probe station to assure the ionic liquid does actually cool down to the temperature of the cold �nger. The measurements performed at low temperatures are likely to have taken place at a higher temperature because of these conduction problems. Possible solutions to these conduction problems have been found but could not be applied in time. Despite no accurate measurements have been done in the case of low temperature, there have been measurements at lower-than-room temperature that still showed strong indications of a lower current at lower temperatures. Qualitatively, vacuum does not seem to in uence the condition of the ionic liquid (the ionic liquid still solidi�es at low temperatures) but quantitatively, the measurements are strongly in uenced by the pressure. It has to be found out if this change is caused by change in geometry (droplet becoming atter because of bubbling in the ionic liquid) or whether the ionic liquid itself changes, as the bubbling at low pressure seems to suggest. The question if the bubbling is caused by evaporating water (which might reduce the mobility of the ions) or if it is caused by another e�ect, one that perhaps is internally damaging to the ionic liquid, is still unanswered. The assumed inverse proportional relation between current and distance between the electrodes has not been found; it is not clear if this is caused by the limited amount of measurements or if a fundamental theoretical mistake is the cause of this error. In general, the more quantitative treatment of this assignment has su�ered under the limited number of measurements performed, caused by the long time required for each measurement. It is however hoped that the qualitative treatment is still able to help research in the area of ionic liquids, and helps to prevent the pitfalls that might occur during research with ionic liquids.
Item Type:Essay (Bachelor)
Faculty:TNW: Science and Technology
Subject:33 physics
Programme:Applied Physics BSc (56962)
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