Grain size adjustion in organic field-effect transistors for chemical sensing performance improvement

Various nanostructures of the organic semiconductor (OSC) films have been reported to enhance the organic field-effect transistors (OFETs) sensing performance. However, complicated fabrication processes hinder their applications. In this work, we have effectively enhanced the sensitivity of the OFET-based sensors only by adjusting substrate temperature in OSC preparation and surface treatment of the dielectric layer. The relative sensitivity of the device can be enhanced by 5 times. The flexible sensors with polymer dielectric also exhibit high sensitivity because the less smooth surface of the polymer provides the OSCs with smaller grain size. Therefore, this work reveals the trade-off effects of the OSCs grain size on both transistor characteristic and chemical sensing performance, and provides a simple and extensively applicable strategy for OFETs sensitivity improvement.