Effective Molecular Alignment of Semiconducting Polymer and Its Application to Photopatterned Stretchable Transistors

Abstract Intrinsically stretchable organic transistors are promising solutions for realizing stretchable electronic systems, such as skin‐like wearables and next‐generation displays. Nevertheless, applying stretchable organic thin‐film transistors to high‐end display backplanes requires enhancing key electrical properties, including mobility and off‐current, beyond the amorphous Si level, particularly for short channel lengths. Herein, enhanced performances of intrinsically stretchable organic transistors with a high degree of molecular alignment in stretchable semiconductor composites, comprising a diketopyrrolopyrrole‐based polymer and polystyrene‐block‐poly(ethylene‐ran‐butylene)‐block‐polystyrene‐elastomer, utilizing the solution shearing process on nanogrooved surfaces is reported. The density and shapes of the nano grooves are controlled by the number of rubbings with a 0.1 µm diamond lapping film, achieving mobility values exceeding 3 cm 2 Vs −1 on SiO 2 /Si—three‐fold higher than that of the conventional spin‐coating method. This process improves the crystalline structure of semiconductor films, facilitating π–π stacking and large‐sized crystalline structures. Additionally, the solvent treatment on the surface of stretchable Au electrodes effectively reduces the contact resistance with highly oriented polymer semiconductors in intrinsically stretchable transistors, exhibiting 2.66 cm 2 Vs −1 mobility and 0.96 pA off‐current at 10 µm short channel length. The electrical properties of stretchable transistors yield only minor variations under 50% strain conditions and after 1000 cycles at 40% strain.