Controlling the Microstructure of Conjugated Polymers in High-Mobility Monolayer Transistors via the Dissolution Temperature

It remains a challenge to precisely tailor the morphology of polymer monolayers to control charge transport. Herein, the effect of the dissolution temperature (T-dis) is investigated as a powerful strategy for morphology control. Low T-dis values cause extended polymer aggregation in solution and induce larger nanofibrils in a monolayer network with more pronounced pi-pi stacking. The field-effect mobility of the corresponding monolayer transistors is significantly enhanced by a factor of four compared to devices obtained from high T-dis with a value approaching 1 cm(2)V(-1) s(-1). Besides that, the solution kinetics reveal a higher growth rate of aggregates at low T-dis, and filtration experiments further confirm that the dependence of the fibril width in monolayers on T-dis is consistent with the aggregate size in solution. The generalizability of the T-dis effect on polymer aggregation is demonstrated using three other conjugated polymer systems. These results open new avenues for the precise control of polymer aggregation for high-mobility monolayer transistors.