Abstract

Thedevelopment of crystals with bipolar transport characteristics is essential forhigh-performance organic field effect transistor (OFET) devices. In this work,we theoretically investigated the bipolar transport behaviors in CnBTBT–FmTCNQcocrystals. It is found that bipolar transport can be realized in C8BTBT–TCNQand C12BTBT–TCNQ cocrystals with room-temperature electron/hole mobility up to1.8/0.75 and 2.5/1.8 cm²V^–1s^–1, respectively.The comparable electron- and hole-transfer integrals between thenearest-neighbor molecule pairs as well as the small hole reorganization energyof the TCNQ molecule are responsible for the balanced electron and holemobilities. Moreover, because of the π–π stacking between neighboringmolecules, all cocrystals show strong anisotropic transport characteristic forboth electron and hole transport with the mobility along the π–π stackingdirection much larger than those along the other two directions. This workprovides the possibility of high-performance OFET engineering and also enrichesthe OFET families with bipolar transport characteristics.