No abstract

Solution-processed organic semiconductors (OSCs) promote the development of the next generation of large-area, low-cost flexible electronics. To date, the properties of the flexible substrates such as chemical compatibility, roughness, and surface energy are still big challenges for the solution process, especially for high-performance ultrathin monolayer OSCs. Herein, van der Waals assembled organic field-effect transistors (OFETs) with layerby-layer lamination processes are reported. The active layer is an ultrathin single molecular layer 2,9-Didecyldinaphtho[2,3-b:2′,3′-f ]thieno[3,2-b] thiophene (C 10 -DNTT) which maintains decent electrical fidelity with mobility of 10.4 cm 2 V -1 s -1 after transfer. With the active layer transfer technique, the bias stability of OFETs can be significantly improved by tuning diverse hydrophobic self-assembly monolayers (SAMs) onto the dielectric which is a challenging task before the solution processing organic monolayer. A small subthreshold swing (SS) of 63 mV decade −1 is achieved by low surface energy phosphonic acid SAMs on high-κ AlO x dielectric. We further demonstrate a high-gain organic inverter amplifier that can be powered up by a coin cell on the 1.5 µm conformal parylene substrate and apply it for high-resolution electrocardiograph (ECG) sensing. The ECG sensors can provide a signal-tonoise ratio as high as 34 dB. It is believed that our device demonstrates the prospect of continuous monitoring for human health management.