(Invited) Functionalized Polymer-Sorted Carbon Nanotube Networks for Sensing Applications

Abstract

Networks of polymer-sorted, purely semiconducting single-walled carbon nanotubes (SWNTs) exhibit very high charge carrier mobilities, chemical stability and mechanical flexibility. Due to their large surface area they also permit a wide variety of modifications for sensing of gases, ions and even biomolecules. Exchanging the conjugated polymer used for the selective SWNT dispersion with specifically functionalized new wrapping polymers enables targeted sensing of analytes and improved devices performance. For example, spiropyran-functionalized polymer-nanotube hybrids can be used for dynamic optical memory devices and UV sensors (Adv. Electron. Mater. 2020, 6, 2000717). Other functional groups of the wrapping polymer promote the selective binding of copper ions and hence also the detection of the herbicide glyphosate in water by competitive binding using electrochemical SWNT network transistors. We further demonstrate how the performance of water-gated electrochemical SWNT transistors for bioelectronics (ACS Appl. Electron. Mater. 2021, 3, 3106) can be improved by exchanging the hydrophobic alkyl sidechains of the wrapping polyfluorene copolymer with hydrophilic tetraethylene glycol (TEG) groups. Thick, aerosol jet printed SWNT films with TEG sidechains show significantly increased volumetric capacitances and thus higher transconductances.