Mid-Infrared Photothermal Imaging of Photochemically Patterned Polymer Gate Dielectrics for Organic Thin-Film Transistors

Mid-infrared photothermal (MIP) microscopy has recently attracted increasing attention for use in super-resolution infrared (IR) absorption imaging in a broad range of fields, including polymer sciences, owing to its high detection sensitivity and nanoscale spatial resolution. In this study, we present submicron IR imaging of ultrathin photopatternable polymer layers using MIP microscopy to visualize photochemically reacted micropatterns. Because micropatterning of ultrathin polymeric layers is beneficial for gate dielectrics to achieve operating organic thin-film transistors (OTFTs), we have demonstrated high-performance OTFTs with photopatterning of ultrathin polymer gate dielectrics and also examined the photochemical micropatterns by super-resolution IR imaging, which proved the successful photopatterning of ultrathin polymer gate dielectrics and provided direct spectroscopic insights into high-performance OTFTs in support of our experimental results. The present results demonstrate that MIP microscopy enables us to study the interfacial properties of photopatternable functional layers in electronic devices at the submicrometer scale and gain in-depth insights into engineering photolithographic base materials for electronics, thus accelerating the development of electronic devices.