Carbon nanofoam (CNF) is a low-density, high-surface-area material formed by diffusion limited aggregation of amorphous carbon nanoparticles into porous nanostructures. This particular form of carbon is only found in a few particular environments namely in flames, in space and when carbon is interacting with a laser.<br/>This work presents the use of a pulsed infrared laser to prepare CNF from a graphene oxide target material. Electron microscopy shows that the films consist of dendritic strings which form high surface area web-like three-dimensional structures. The conductivity of these structures can be modified by using the CNF as a nanostructured scaffold for gold nanoparticles deposited by sputter coating, controllably increasing the conductivity by up to four orders of magnitude. The hybrid Au/CNF materials were incorporated into chemiresistor structures for sensor applications.<br/>When the pristine CNF film is exposed to a dry environment the conductivity of the film decreases by 50% but rapidly recovers when exposed to ambient. When the Au/CNF network is exposed to the same dry environment the conductivity increases by 30% and still shows excellent recovery times. An exposed pristine sputtered coated gold film shows 7 % change in conductivity exposed to the dry environment highlighting the influence of the surface area in sensing applications. The change in sensing mechanism shows the characteristics of the 3D network can be modified by sputter coating while maintaining the high surface area properties.

Volumetric, percolating metallic structures templated by laser-deposited carbon nanofoams: Applications in humidity sensing

255th National Meeting (2018)

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