Vapor Sensitivity of Networked Gold Nanoparticle Chemiresistors: Importance of Flexibility and Resistivity of the Interlinkage

Abstract

In this study we investigated the response behavior of chemiresistors made from differently interlinked networks of gold nanoparticles. Our results show that the degree of flexibility and conductivity of the interlinkage between the nanoparticles has a profound impact on the response characteristics of such sensors. 1,12-Dodecanedithiol was used as a hydrophobic, flexible linker compound. For comparison, [4]-staffane-3,3‘ ‘‘-dithiol provided a rigid, rodlike linkage, and 4,4‘-terphenyldithiol was used as a rigid linker with enhanced conductivity due to its delocalized aromatic moieties. As determined by AFM, all three sensor coatings had similar thicknesses (∼30 nm), but the degree of interlinkage, as measured by XPS, was significantly higher in the case of the flexible network. All three materials showed linear current−voltage characteristics. The vapor sensitivity was tested by dosing the sensors with toluene, 1-propanol, 4-methyl-2-pentanone, and water in the concentration range 100−5000 ppm at 0% rela...