Organic field-effect transistors (OFETs) have attracted great attention as key elements in Internet-of-Thing (IoT) devices due to their advantages of low cost and mass producibility made possible by printing technology. Such devices require organic semiconductors (OSCs) that intrinsically possess high carrier mobility and air stability. In addition, the demand for low-voltage operation and low power consumption has been increasing because the potential power sources for actual devices are implementable energy harvesters that supply low power and low voltages. Based on recently developed high-performance single-crystal p-type and n-type OSCs, this work demonstrated air-stable, high-mobility OFETs with low-voltage operation by using an insulating polymer-blend printing method. By comparing two acrylic polymers poly(methyl methacrylate) and poly(adamantyl methacrylate) (PADMA), having remarkably different thermal properties, we found that PADMA showing a high glass transition temperature >200 °C was suitable for device fabrication, enhancing the flexibility of OSC materials. Also, PADMA spontaneously produced good charge-transport interfaces with the OSC single crystals, leading to high carrier mobilities of 6.6 and 2.2 cm2 V−1 s−1 in p-channel and n-channel OFETs at ≤1.5 V, respectively. The current electron mobility was the highest among low voltage-operation OFETs reported so far. These high-mobility OFETs were integrated into a complementary inverter, for which a low static power consumption of 6.6 pW was confirmed. Therefore, this study reports an advantage of polymer-blend printing for OFETs with enhanced processability and performance suitable for IoT applications.
PhC2-BQQDI was purchased from FUJIFILM Wako Pure Chemical Corporation. T.M. and A.Y. were supported by a Grant-in-Aid through a Japan Society for the Promotion of Science (JSPS) Research Fellowship. T.O. acknowledges support from PRESTO-JST through the project “Scientific Innovation for Energy Harvesting Technology” (Grant No. JPMJPR17R2). S.W. acknowledges support from the Leading Initiative for Excellent Young Researchers of JSPS. This work was also supported in part by JSPS KAKENHI grants (Nos. JP17H06123, JP17H06200, and JP17H03104).
Title: Low-voltage complementary inverters using solution-processed, high-mobility organic single-crystal transistors fabricated by polymer-blend printing
Publication: Applied Physics Letters
Author: Taiki Sawada, Tatsuyuki Makita, Akifumi Yamamura, Mari Sasaki, Yasunari Yoshimura, Teruaki Hayakawa, Toshihiro Okamoto, Shun Watanabe, Shohei Kumagai, Jun Takeya
Published Online: 22 July 2020