Electrodeposition and characterisation of thin films and nanostructures based on bismuth, silver and iodine

Electrodeposition is used to produce thin film and nanostructured materials based on bismuth, silver and iodine. X-ray and probe microscopy techniques are employed to determine the structure of electrodeposited Bi films on Au(111) substrates. Analyses of multilayer films reveal that they are deposited epitaxially, with the Bi(012) plane parallel to the underlying Au(111) surface, and require no annealing to achieve single-crystal domains. The bulk film/substrate structure has been modelled and compared with in situ Scanning Tunneling Microscopy (STM) images of the growing epitaxial films. Models of the multilayer arrangement provide structural evidence for the proposed anisotropic growth mode.; Electrodeposition of silver and copper on iodine-covered and bare polycrystalline Pt electrodes is studied with the Electrochemical Quartz-Crystal Microbalance (EQCM). Voltammetry of silver on the iodine-covered surface shows single deposition and stripping peaks, with masses appropriate for silver. This is an ideal calibration system. A lower mass than the ideal silver mass for multilayer silver electrodeposition (in the absence of iodine) is attributed to increased smoothing of the electrode.; The EQCM and a Rotating Ring-Disk Electrode (RRDE) are used to study the behaviour of iodate interactions at Pt polycrystalline electrodes. Comparison of results between 0.2 and 1 mM iodate solutions point to significant contributions from solution-based reactions throughout the formation and dissolution of the iodine adlayer. Direct reduction from the iodate anion appears to be responsible for the formation of the adlayer.; Electrodeposition of silver iodide films and layered structures is investigated using coreduction of silver and iodate ions in a single bath onto platinum EQCM electrodes. Iodate concentration is shown to significantly affect the rate of film formation and plays a crucial role in determining film thickness. High relative concentrations of IO-3 result in significant solution-based charge transfer reactions that complicate analysis of the film structure using the microbalance. A simple model based on the EQCM response is employed to determine the structure of films formed in these solutions at more negative potentials. These films exhibit an AgIx (x < 1) structure. A pulsed potential scheme is employed to create a layered material of the form AgIx/AgIy.