Side-chain effect of organic semiconductors in OFET-based chemical sensors

Abstract

Organic field-effect transistors (OFETs) offer great potential applications in chemical and biological sensing for homeland security, environmental monitoring, industry manufacturing, and medical/biological detection. Many studies concentrate on sensitivity and selectivity improvement of OFET-based sensors. We report four organic semiconductors with different alkyl side chain lengths but the same π-conjugated core structure for OFETs. Our work focuses on the molecular structure of organic semiconductors (OSCs). Alkyl side chains can hinder the diffusion of ammonia into the OSCs layer, which blocks the interaction between ammonia and conducting channel. The result also reveals the relationship between the alky chain and the film thickness in sensitivity control. These results are expected to be a guide to the molecular design of organic semiconductors and the choice of OSCs.