Enhanced performance of field-effect transistors based on C60 single crystals with conjugated polyelectrolyte

Abstract

Contact resistance at the interface between metal electrodes and semiconductors can significantly limit the performance of organic field-effect transistors, leading to a distinct voltage drop at the interface. Here, we demonstrate enhanced performance of n-channel field-effect transistors based on solution-grown C60 single-crystalline ribbons by introducing an interlayer of a conjugated polyelectrolyte (CPE) composed of poly[(9,9-bis(3′-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] dibromide (PFN+Br−). The PFN+Br− interlayer greatly improves the charge injection. Consequently, the electron mobility is promoted up to 5.60 cm2 V−1 s−1 and the threshold voltage decreased dramatically with the minimum of 4.90 V.