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 ) is investigated as a powerful strategy for morphology control. Low T values cause extended polymer aggregation in solution and induce larger nanofibrils in a monolayer network with more pronounced π-π 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 with a value approaching 1 cm  V  s . Besides that, the solution kinetics reveal a higher growth rate of aggregates at low T , and filtration experiments further confirm that the dependence of the fibril width in monolayers on T is consistent with the aggregate size in solution. The generalizability of the T 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.