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

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.