A Blend Approach to P3HT Based Field Effect Transistor Performance Enhancement via Inclusion of 2,5-bis(3-dodecylthiophen-2-yl)thieno[3,2-b]thiophene

Improved OFET performance through a polymer-small molecule semiconductor blend approach was demonstrated. However, a number of serious issues remain. For example, the threshold voltage (Vth) of the blend OFETs is still at a relatively high value (\textbar Vth\textbar \textgreater 10V), which is incompatible with most of portable electronics. Moreover, electrode treatment or thermal annealing is required to avoid a sacrifice in the device performance. Herein, a small molecule, 2,5-bis(3-dodecylthiophen-2-yl)thieno[3,2-b]thiophene (BTTT), is proposed to be incorporated within poly(3-hexylthiophene) (P3HT) polymer thin-films and is demonstrated to lead to overall improvement in transistor performance. The resultant blend OFETs exhibited approximately a 5-fold increase in charge carrier mobility, 10-fold increase in on-off current ratio and concomitantly, controlled the Vth as low as 1.7 V. It is worth noting that no pre- or post-treatment is required during the blend OFET fabrication process. Further, the thin-film deposition was conducted under ambient conditions using a volatile low boiling point solvent, suggesting a promising method for low-cost, high-throughput, large-area flexible device fabrication under non-stringent conditions.