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.

Orientation Control of Semiconducting Polymers Using Microchannel Molds

“…Through the POM analysis, it was confirmed that the P3HT aggregates are accumulated at certain saturated levels in the 5 and 10 μm-width channels in ∼50 and ∼380 s, respectively, which is determined by comparing the time taken to reach a certain birefringent intensity (Figure 5). 34 Numerical Simulations of Diffusion Rate Depending on PDMS Channel Widths. In addition to the time sequential POM measurements following the solution diffusion, we conducted numerical simulations of P3HT molecule transport of each PDMS channel width condition (Figure 6).…”

Solution-processing of semiconducting organic small molecules: what we have learnt from 5,11-bis(triethylsilylethynyl)anthradithiophene

“…Indeed, the discovery of isomeric guest-host systems of TES ADT using blends of the two pure isomers provided further, detailed insight on the polymorph development of TES ADT. 51 Apart from high performance transistors, moreover, new applications of TES ADT are being explored, including gas sensors 52,53 and the use of this semiconducting small molecule in photon-upconversion. 54 These new research frontiers open new opportunities for TES ADT and other semiconducting small molecules and requires further insights into their solidification and controlled fabrication towards specific structures produced for targeted applications.…”

Recent progress in organic field‐effect transistor‐based chem/bio‐sensors

“…Lee et al systematically compared the gas sensing performances of NO 2 sensors on the basis of various types of patterned 5,11-bis(triethylsilylethynyl)anthradithiophene (TES-ADT) films. 60 Three types of TES-ADT crystal arrays were successfully achieved using engraved polydimethylsiloxane mold (Figure 7D,E). The type C device with decreased width of TES-ADT pattern displayed the highest NO 2 gas sensing property.…”