Tuning the structure of nanowires through controlled segmenting

A common production method for nanowires is based on electrodeposition into cylindrical channels of a nanoporous template. Since the nanostructures adopt the morphology given by the host material as they are created by reduction from an electrolyte solution, the deposition step can be considered as the most important factor that determines the structure. Pt nanostructures are of particular interest because of their great potential for applications including catalysts, sensors, and electronic devices. While several shape-controlled Pt nanostructures have been reported, the synthesis of additional types is highly desirable. 4 Our approach to controlled nanostructuring gives rise to segmented all-Pt nanowires. As templates we used ion track-etched polycarbonate membranes. Pulse-reverse (PR) electrodeposition in combination with a suitably chosen electrolyte-template system influences the local electrolyte distribution inside the nanochannels. This method generates segments linked to nanowires by a novel growth mechanism. It allows the design of nanowires with a preset number of segments and interfaces. SEM images of segmented nanowires produced by PR deposition using constant anodic and cathodic pulse durations (ta and tc) reveal their characteristic structure (Figure 1). Sharp and striking interfaces can be identified. Shape and dimensions of the segments are homogeneous along most of the total wire length.