Presentation Information
[8a-B32-10]Tunable biaxial compression of organic semiconductor thin films for robust coherent charge transport
〇(DC)Junyi Zhu1, Tomoki Furukawa1, Ryohei Kameyama1, Shohei Kumagai2, Toshihiro Okamoto2, Atsushi Shishido2, Shusaku Imajo1, Jun Takeya1,3 (1.Univ. of Tokyo, 2.Science Tokyo, 3.JST CREST)
Keywords:
biaxial strain,charge transport,organic semiconductor
Organic semiconductor single-crystal transistors are promising platforms for flexible and solution-processable electronics, where band-like charge transport can be realized owing to their highly ordered molecular packing. However, weak van der Waals interactions between molecules limit intermolecular orbital overlap, making it difficult to further enhance mobility and coherent charge transport through molecular design alone. In this study, we developed a biaxial strain platform based on a petal-shaped flexible substrate and applied uniform in-plane compressive strain to C8-DNBDT-NW single-crystal thin-film transistors. Under -2.0% biaxial compression, the room-temperature four-terminal mobility increased from 18.7 to 28.2 cm2 V-1 s-1. First-principles calculations indicate that biaxial compression reduces the band effective mass along both in-plane transport axes (b and c), unlike uniaxial strain where the Poisson effect limits the overall improvement. Furthermore, low-temperature transport measurements using electric-double-layer transistors revealed enhanced metallic transport, with Hall mobility reaching approximately 80 cm2 V-1 s-1 at 4 K and a clear transition toward Fermi-liquid behavior. These results demonstrate that biaxial compressive strain is an effective physical approach for enhancing coherent charge transport and tuning electronic correlations in organic semiconductor thin films.