Tuned Transport Behavior of the IPA-Treated PEDOT:PSS Flexible Temperature Sensor via Screen Printing

A flexible temperature sensor based on poly-(3, 4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) with isopropyl alcohol (IPA) treatment is successfully fabricated by screen printing. The distribution of PEDOT is investigated by the SEM, AFM, and Raman techniques. It can be found that the microstructure is manipulated by the ratio of the PEDOT:PSS to IPA content. Raman spectra demonstrate that the transition between quinoid and benzoid structures of PEDOT are tuned by IPA treatment as well. The temperature dependence of resistance for IPA-treated PEDOT:PSS film is found to be well fitted by non-adiabatic small polaron hopping transport. Moreover, a constant temperature coefficient of resistance (TCR) value can be obtained by the optimized ratio of IPA to PEDOT:PSS. Therefore, this paper suggests that the tuned microstructure of PEDOT:PSS film can be realized by IPA treatment, which plays an important role in the physical properties of the temperature sensor based on PEDOT:PSS.