Lithographically defined porous carbon electrodes.

The special nature of the C C bond can lead to various polymorphic forms of carbon such as graphite, glassy-carbon, fullerenes (such as buckyballs), carbon nanotubes, and diamond. Electrodes made from carbon exhibit many useful properties including wide potential windows, low background capacitance, resistance to fouling, and catalytic activity for manyanalytes compared to solidmetal electrodes. In addition to the intrinsic material properties of carbon, functionalized films can be produced through chemical modification using a wide range of chemistries. Because of this flexibility and utility, fabrication of both macroand microporous carbon films, with their commensurate increase in surface area, continues to receive significant research interest. Some of the specific applications for porous carbon materials include fuel cells, electrochemical double layer capacitors, high surface area catalytic supports, water purification, and gas separation. Recently, it has been found that pyrolyzed photoresist films (PPFs) have the same unique properties of carbon electrodes with an advantage that they canbe lithographically defined. The goal of this work was to create lithographically defined porous pyrolyzedcarbonelectrodesandcharacterize thedepositionand electrochemical properties of metal nanoparticles on these electrodes. We report a robust fabrication method capable of producing large area ( 100s cm) submicrometer porous carbon films. In our approach, interferometric lithography (IL) is used topattern thickphotoresist films into 3Dperiodic lattices. These structures are then converted to carbon via pyrolysis under flowing forming gas. During pyrolysis, the non-carbon species in the resist polymer backbone are removed, while the bulk of the carbon remains. The patterned structures undergo significant shrinkage, but remarkably maintain their morphology and adhesion to the substrate. The degree of carbonization is a function of the pyrolysis temperature, which has a profound