1. Bipolar electrochemistry. An electrically isolated conductor immersed in an electrolyte can act as a bipolar electrode–as both an anode and a cathode–if a sufficiently large potential difference is applied across the solution. The applied voltage generates an interfacial potential difference that varies in a predictable way along the length of the conductor. If the electrolyte contains appropriate redox couples, electrodeposition reactions can occur at the electrode/solution interface. We use bipolar electrochemistry to generate a one-dimensional solid-state chemical composition gradients and solid-state materials libraries.

2. Electrosynthesis of semiconductor nano films. The advantages of electrodeposition include growth at ambient temperature and pressure, deposition onto surfaces with complex topographies, and low cost. The widespread application of electrosynthesis hinges on overcoming two limitations: polycrystalline growth and contaminated deposits. We are attempting to address these two issues through achieving atomic-level control of the deposition process. We are currently investigating approaches based on the electrochemical analogs of atomic layer deposition and atomic layer epitaxy.

3. Polyoxometalate monolayers as model oxide surfaces. Polyoxometalates (POMs) are highly symmetric, stable, nanometer scale clusters with characteristic sizes and shapes that resemble discrete fragments of bulk metal oxide phases. POMs adsorbed on metal substrates are good models of metal oxide surfaces and excellent catalysts in their own right. Our interest stems from their use as electrocatalysts, with potential applications as general oxidation catalysts, and components of fuel cells and dye-sensitized solar cells.

4. Surface Enhanced Raman Spectroscopy. Recent advances in the growth of size monodisperse metal nanoparticles and nanoparticle arrays with well-defined optical properties has lead to renewed interest SERS as an analytical technique. We are investigating the use of SERS to probe chemical and biological interactions relevant in analytical chemistry.