Plasma electrochemistry for nanomaterials synthesis and patterning

Summary form only given. Electrochemical reactions are typically initiated at the interface of a solid metal electrode and ionic electrolyte. A small number of experiments, dating back to more than 100 years ago, have suggested that plasmas can be used as a gaseous electrode to mediate electrochemical reactions at the surface of liquids or thin films. However, plasmas are normally operated at low pressure which limits the scope of these experiments and their applications. We have recently developed a novel microplasma source that allows a non-thermal, atmospheric-pressure plasma to be stably formed at the surface of aqueous ionic electrolytes and thin polymeric films. This has enabled 1) fundamental study of charge transfer reactions at the plasma-liquid and plasma-film interface and 2) electrochemical applications of plasmas for novel materials synthesis. In this talk, we will present several examples of plasma electrochemical reactions for nanomaterial synthesis and patterning. Colloidal metal nanoparticles are synthesized from metal salts by reduction in solution [Richmonds, C., et al., 2008]. Alternatively, metal salts dispersed in polymer films are reduced to solid metal by exposure to a scanning microplasma [Lee, S.W, et al., 2011]. This has led to the development of an extracted discharge which combined with masking techniques facilitates pattern transfer at sub-micron scales [Lee, S.W., et al., J. Vac. Sci. Technol. A, 30, pp. 010603-1]. To further reduce the size of the patterned structures, we have recently explored the reduction of metallopolymer films where the metal moieties are assembled at the molecular scale. Details of these various approaches will be discussed in detail, including materials characterization and potential applications.