Solution‐Processed Ambipolar Thin Film Transistors‐Based Inverters for Circuit Applications

ABSTRACT Fully solution‐processed ambipolar organic thin‐film transistors (OTFTs) are attractive for flexible, large‐area, and low‐cost electronics; however, their circuit‐level implementation has remained limited by mobility imbalance, trap‐induced instability, and complex fabrication. This study employs bulk‐heterojunction blends of the benchmark n‐type polymer N2200 and the high‐mobility donor polymer DPP‐DTT as a single active semiconductor platform for ambipolar OTFTs and complementary‐like logic. Systematically tuning the DPP‐DTT:N2200 composition enables balanced electron and hole transport, high on/off current ratios of ∼10 ⁵ , and threshold voltages suitable for rail‐to‐rail operation, with the 5:95 blend providing the optimal compromise between mobility symmetry and operational stability. The optimized ambipolar behavior is attributed to a semi‐intermixed morphology with bi‐continuous percolation pathways and controlled crystallinity, as confirmed by correlated optical, energetic, and structural characterizations. Using a simple top‐gate device architecture and geometry‐scaled channel widths, all‐polymer ambipolar inverters exhibited sharp switching voltage‐transfer characteristics and high small‐signal gains of up to 19 at an optimized width ratio of 2:1. This study establishes a manufacturing‐compatible strategy for co‐engineering blend composition, microstructure, and device geometry, enabling scalable printed organic logic using a single bulk heterojunction semiconductor rather than separate p‐type and n‐type materials.