Organic field-effect transistors (OFETs) are the most fundamental device units in organic electronics. Interface engineering at the semiconductor/dielectric interface is an effective approach for improving device performance, particularly for enhancing charge transport in conducting channels. Here, we report flat-lying molecular monolayers that exhibit good uniformity and high crystallinity at the semiconductor/dielectric interface, deposited through slow thermal evaporation. Transistor devices achieve high carrier mobility up to 2.80 cm2 V-1 s-1, which represents a remarkably improvement in device performance compared with devices that are completely based on fast-evaporated films. Interfacial flat-lying monolayers benefit charge transport by suppressing the polarization of dipoles and narrowing the broadening of trap density of states. Our work provides a promising strategy for enhancing the performance of OFETs by using interfacial flat-lying molecular monolayers.
Keywords: DNTT; OFET; charge transport; interfacial layer; thermal evaporation.