Temperature-Dependent Performance of Printed Field-Effect Transistors with Solid Polymer Electrolyte Gating.

Printable, physical, and air-stable composite solid polymer electrolytes (CSPEs) with high ionic conductivity have been established as a suitable alternative to standard dielectric gate insulators for printed field-effect transistors (FETs) and logics. We have performed a stress and temperature stability study involving several CSPEs. Mechanical tensile and shear tests have been performed to determine the physical condition of CSPEs. A comprehensive temperature dependent study has been conducted within the working temperature range which electric double layer (EDL) capacitors or CSPE-gated FETs may typically experience during their lifetime. Moreover, calorimetric measurements have been performed to investigate the CSPEs stability, especially at low temperatures. Mechanical characterizations have shown tensile strength and shear modulus of the material that is typical for solid polymer electrolytes while DSC measurements show no change in the physical state within the measured temperature range. An expected increase in ionic conductivity of the CSPEs of nearly 1 order of magnitude has been observed with an increase in temperature, while an anomalous positive temperature relationship to EDL capacitance has also been noticed. Interestingly, the transistor performance characteristics, namely, on-current and threshold voltage, are found to be quite independent of the temperature, thus ensuring a large and stable operation temperature window for CSPE-gated FETs. The other parameters, subthreshold slope and the device mobility, have varied following the classical semiconductor behavior. In fact, the present study not only provides a detailed understanding of temperature dependence of the CSPE-gated FETs but also offers an insight into the physical and electrical properties of the CSPEs itself. Therefore, these results may very well help to comprehend and improve EDL capacitors, supercapacitors, and other devices that use CSPEs as the active material.