Enhanced Gas Sensing Performance of Organic Field‐Effect Transistors by Modulating the Dimensions of Triethylsilylethynyl‐Anthradithiophene Microcrystal Arrays

Abstract This paper systematically compares the gas sensing properties of organic field‐effect transistors (OFETs) based on patterned 5,11‐bis(triethylsilylethynyl)anthradithiophene (TES‐ADT) films, by adopting TES‐ADT crystal arrays of various shapes and dimensions. The patterning and crystallization of spin‐cast TES‐ADT layers are achieved by the use of a solvent‐containing engraved polydimethylsiloxane (PDMS) mold. Decreasing width of the TES‐ADT pattern enhances gas sensing performance, as well as field‐effect mobility of OFETs. The decreased grain boundary density at narrower line width contributes to the increase of field‐effect mobility. On the other hand, the increased sensing performance is mainly due to the increased area of crystal edges, which provides a diffusion pathway for gas molecules to arrive at the semiconductor‐dielectric interface. This study provides new perspectives on the diffusion pathway of gas molecules in OFET‐based gas sensor, and will be useful for the design of active channel to boost the gas sensing properties of OFETs.