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 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 (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.