Reduction in the operating voltage of organic field-effect transistors (OFETs) is sought for their successful
implementation into future portable and low-power electronic applications. Here we demonstrate OFETs with operation
below 2 V enabled by the use of self-assembled monolayer (SAM) gate dielectrics with high geometrical capacitances. A
high surface energy monolayer is chosen to allow processing of small molecule semiconductors from solution.
Impedance spectroscopy measurements of metal-insulator-semiconductor devices suggest the geometrical capacitance of
the alumina-SAM dielectric can reach ~1 μF/cm2 when accumulating charge at the semiconductor-insulator interface.
Atomic force microscopy images reveal that the glass substrates and the SAM-functionalized aluminum gate electrode
display significant roughness. Despite this, mobilities of 0.02 cm2/Vs are demonstrated. These results represent an
important step towards low-power solution processable electronics.