PNNL

Abstract

The exploration of nanoparticle-structured thin films as sensing materials desires maximum accessibility of analytes and effective mass transport within the nanostructure. This paper explores the viability of creating nanoparticle-carbon nanotube (CNTs) as composite interfacial materials to enhance such properties. We report findings of an investigation of the assembly of monolayer-protected gold nanoparticles on multi-walled CNTs. A simple and effective route has been demonstrated for assembling nanoparticles of 2-5 nm core sizes onto CNTs with controllable coverage and interparticle spatial properties. The composite nanomaterials can be dispersed in organic solvent and cast on interdigitated microelectrode surface. The skeleton-like nanocomposite materials have been examined for chemiresistor sensing of volatile organic compounds. The response profiles and sensitivities of the nanocomposites determined for the sorption of a series of vapors have been shown to exhibit different or enhanced sensing properties in comparison with similar but nanotube-free nanoparticle assemblies. The observation of these results can be attributed to a combination of three factors, the increased accessibility of analytes to the nanostructure, the enhanced mass transport characteristics, and the unique electronic properties of the nanocomposite materials. Implications of the findings to the design of nanostructured sensing materials are also discussed.