Detection of Organic Vapors by Chemiresistor Coated with gold nanoparticle/1-hexadecanthiol films

Chemiresistors are simple solid-state devices whose electrical resistance is changed by the presence of a chemical species. They typically incorporate a thin film of a semiconducting material deposited onto a pair of contacting electrodes[1]. During the past few years the vapor-sensing properties of chemiresistor coatings prepared from organically encapsulated gold nanoparticle have attracted considerable attention. In such coatings the gold nanoparticles provide electric conductivity and, thus, enable a simple electrical signal transduction. The organic film component provides sites for the selective sorption of analyte molecules [1]. A very interesting feature of these sensor materials is the possibility to control their properties through molecular level design. For example, in self-assembled gold nanoparticle films the nanoparticle cores are cross-linked with organic molecules, such as bifunctional alkanedithiols or polyfunctional dendrimers. These linker molecules form insulating barriers between the metal cores and also determine the interparticle distances. Therefore, the conductivity of the films can be controlled by the size of the linker molecules [1]. In this work, we report findings of an investigation of the design of interdigitated microelectrodes coupled with nanostructured thin films in constructing sensor for the detection of hexane and chloroform in different concentrations