Printed transistors employing both the bench-mark polymer semiconductor poly(3-hexyl-thiophene) and ultra-high capacitance ion gel gate insulators exhibit unusually large hole mobilities near 1 cm2/Vs at high charge densities (0.2 holes/ring). The large mobility suggests delocalized carriers and the possibility of observing the Hall effect and insulator-metal transition. Postdoc Shun Wang has measured the Hall effect, the first time that the Hall effect has been observed in polymer transistors. The Hall voltage has the expected sign and scaling with magnetic field strength and carrier type. This work appeared in Nature Communications. Future work aims to observe the Hall effect in other polymers and to better understand transport in the high carrier density regime near the insulator-metal transition.
