Achieving high mobilities in solution-processable organic FETs by minimizing contact effects

Contact effects in OFETs often play an important role and care must be taken to distinguish contact-limited charge injection from bulk-limited charge transport. We report on charge transport in organic field-effect transistors based on (2,5-bis(3- tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) as the active polymer layer with saturation field-effect mobilities as large as 1 cm
²
V
^-1
s
^-1
. The dependence of mobility on transistor channel length is investigated for devices with Au or Pt as the source and drain electrodes.