Abstract
We report the ionic liquid (IL) gating of a solution processed semiconducting polymer, poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT). IL gating relies on the poor solubility of PBTTT, which requires hot chlorinated benzenes for solution processing. PBTTT, thus, resists dissolution even in IL, which otherwise rapidly dissolves semiconducting polymers. The resulting organic thin film transistors (OTFTs) display low threshold, very high carrier mobility (>3 cm(2)/Vs), and deliver high currents (in the order of 1mA) at low operational voltages. Such OTFTs are interesting both practically, for the addressing of current-driven devices (e. g., organic LEDs), and for the study of charge transport in semiconducting polymers at very high carrier density. (C) 2014 AIP Publishing LLC.