DC Hall-effect measurement for inkjet-deposited films of poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) by using microscale gap electrodes

•DC Hall-effect measurements for inkjet-deposited PEDOT/PSS films were performed.•The PEDOT/PSS films were site-selectively prepared onto microscale gap electrodes.•Hall voltages were detected under reversal of current flow and magnetic field.•A sign anomaly in the Hall voltage appeared probably due to hopping transport.•Carrier concentration of the PEDOT/PSS containing ethylene glycol was estimated.

DC Hall-effect measurements were performed for inkjet-deposited p-type poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS) films, site-selectively fabricated onto micrometer-scale van der Pauw electrode gap patterns. A commercially-available ink of high conductivity grade PEDOT/PSS was utilized. Carrier concentration and Hall mobility of the PEDOT/PSS containing ethylene glycol were in the order of 1021 cm−3 and 0.1 cm2/(Vs), respectively, derived from the repeated Hall voltage measurements under reversal of current flow and magnetic field. The Hall voltage showed an n-type behavior, while the thermoelectric measurement indicated p-type. This sign anomaly of the Hall voltage, which is often observed in such low-mobility materials as amorphous silicon and chalcogenide glasses, may be due to hopping carrier transport in the PEDOT/PSS, although non-uniformities in the sample structure should be noted. Nonetheless this study suggests that the combination of microscale electrodes and inkjet deposition may be useful in high-sensitivity detection of Hall voltages for organic conducting films.

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