posted on 2018-03-20, 00:00authored bySebastian Nufer, Dimitrios Fantanas, Sean P. Ogilvie, Matthew J. Large, Dominik J. Winterauer, Jonathan P. Salvage, Manuela Meloni, Alice A. K. King, Pascale Schellenberger, Aleksey Shmeliov, Sandra Victor-Roman, Mario Pelaez-Fernandez, Valeria Nicolosi, Raul Arenal, Ana M. Benito, Wolfgang Maser, Adam Brunton, Alan B. Dalton
Carbon
nanofoam (CNF) is a low-density, high-surface-area material
formed by aggregation of amorphous carbon nanoparticles into porous
nanostructures. We report the use of a pulsed infrared laser to prepare
CNF from a graphene oxide (GO) target material. Electron microscopy
shows that the films consist of dendritic strings that form 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 4 orders of magnitude. The ability to measure
the conductivity of the porous structures allows electrochemical measurements
in the environment. Upon decreasing humidity, the pristine CNF exhibits
an increase in resistance with a quick response and recovery time.
By contrast, the gold-sputtered CNF showed a decrease in resistance,
indicating modification of the doping mechanism due to water adsorption.
The sensitivity to humidity is eliminated at the percolation threshold
of the metal on the CNF.