Metal nanostructures: electrochemical and photonic properties
Munini, Fabio (2006) Metal nanostructures: electrochemical and photonic properties. Master of Science thesis, Dublin City University.
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The aim of the work is to fabricate nanoporous gold electrodes of controllable structure and texture. These nanostructures were created by self-assembling colloidal polystyrene latex nanospheres into closed-packed arrays on a fluorine-doped thin oxide glass surface, followed by electrodeposition of gold within the interstitial voids and finally removing the template. The nanospheres diameters were 240, 430, 600 and 820 nm Dip-coating technique was exploited to create ordered arrays Latex polystyrene opals were produced by slowly withdrawing hydrophilic FTO glass slides from a 2-10% (w/w) nanospheres suspensions with feedrate and acceleration ranging from 0 001 to 0 006 mm s 1 and from 0 003 to 0 018 mm s'2, respectively Electrochemical reduction of metal complex ions, obtained from Techni Gold 25 plating bath and NaAuCU solutions, was performed by applying an overpotential between -0 1 and -1 0 V with respect to a Ag/AgCl reference electrode. The final material, a photonic crystal with an inverse opal morphology arranged in a multidomain (polycrystalline) structure with the domain size between 10 and 10 (im. The nanoporous gold electrodes were found to have a surface area at least 2 orders of magnitude greater than the flat metal surfaces, corroborating the possibility of being applied for electrocatalysis. Furthermore, preliminary investigation using trans- 1,2-two (4-pyndyl) ethylene (BPE) as test molecule lead to significant SERS response of these nanostructures, confirming their potential use for Raman-based sensing applications.
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