Molecule upgrading metal-semiconductor buried contacts for high-performance and high-ideality single-crystal organic thin-film transistors.

Abstract

Achieving high-quality electrical contact at metal/organic semiconductor interfaces is crucial for unlocking the full potential of single-crystal organic thin-film transistors (SC OTFTs). However, the delicate nature of organic single-crystalline films (OSCFs) and the harsh metal deposition process often introduce trap states at the interface, limiting SC-OTFT performance. Here, we present a transparent electrical contact concept that leverages the in situ spontaneous reaction of fluorinated thiol molecules with the electrode, enhancing the buried metal/OSCF contacts. This method significantly lowers the Schottky barrier height by 73.3% and mitigates the Fermi-level pinning effect, resulting in over a 16-fold reduction in contact resistance. As a result, 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene ([Formula: see text]-BTBT) OTFTs achieve a high average reliable mobility ([Formula: see text]) of 13.2 [Formula: see text] and a reliability factor up to 89%, surpassing previously reported values. Device simulations indicate that the concentration of tail and deep states is nearly two orders of magnitude lower than that of free states contributing to charge transport, suggesting near-ideal trap-free charge transport. These findings position our molecular contact upgrading method as a promising technology for advancing organic electronics.