Solution-sheared thin films of a donor-acceptor random copolymer/polystyrene blend as active material in field-effect transistors

Organic semiconductor (OSC):polymer blends are recently increasing their popularity due to the impressive performances they offer once employed as active layer in organic field-effect transistors (OFETs). Here a novel blend formulation composed by the donor-acceptor random copolymer PDPP-TT(1)-SVS(9) and polystyrene has been processed by a solution shearing technique and employed as active material in a thin film transistor. The molecular weight of the polymer binder has revealed to be fundamental for controlling the vertical phase separation and, in turn, for determining the morphological properties of the upper surface which is critical in terms of device stability. The bi-component active layer has been tested as OFET and by using a top gate as electrolyte-gated field-effect transistor (EGOFET). Our strategy based on an OSC:polymer blend processed through a solution shearing technique has demonstrated to be efficient for improving the final device performance in ambient conditions.