Tetramethylammonium Iodide Additive for Enhancing the Charge Carrier Mobilities of Diketopyrrolopyrrole-Based Conjugated Polymer in Ambipolar Organic Field-Effect Transistors†

Diketopyrrolopyrrole (DPP) is one of the most promising building blocks for constructing polymer semiconductors with high charge-carrier mobilities in organic field-effect transistors (OFETs). In this study, a novel DPP-based conjugated polymer, PDPPy-BDD, was designed and synthesized. The ambipolar field-effect transistor characteristics were realized with the average hole and electron mobilities of 3.5 x 10(-3) and 3.07 x 10(-2) cm(2) V-1 s(-1), respectively. Both the hole and electron mobilities could be successfully enhanced by using a tetramethylammonium iodide (NMe4I) additive. Such an enhancement was attributed to the formation of stronger interchain pi-pi stackings, the weakening of the face-on packing orientation in the thin film state, and the higher channel conductivities in the OFETs.

Automated summary

A novel DPP-based conjugated polymer, PDPPy-BDD, was synthesized and showed ambipolar field-effect transistor characteristics with average hole and electron mobilities of 3.5 x 10(-3) and 3.07 x 10(-2) cm(2) V-1 s(-1), respectively. The addition of tetramethylammonium iodide (NMe4I) successfully enhanced both the hole and electron mobilities by promoting stronger interchain pi-pi stackings, weakening face-on packing orientation in the thin film state, and increasing channel conductivities in the OFETs.