Electrochemical 3D printing of silver and nickel microstructures with FluidFM

Electrochemical 3D printing of conductors with microscale resolution holds a great promise for a wide range of applications, but the choice of suitable metals for these technologies remains limited. Most efforts so far have been focused on deposition of copper, however, other metals are also of interest, especially when tuning of mechanical, electrical, or optical properties is required for a given application. Here we address the issue of a limited materials choice in electrochemical 3D printing by extending the materials library to silver and nickel. Free-standing microscale structures are fabricated in a single step via locally confined electrochemical 3D printing using FluidFM - a microchanneled cantilever nanopipette capable to deliver electrolyte through sub-microscale opening. The 3D printed structures are constructed in a layer-by-layer fashion, which allows complex geometrical shapes such as double rings, helices and pyramids. We report the process performance in terms of printing speed (in the range 7 - 40 nm s-1 for silver and 27 - 42 nm s-1 for nickel) and reveal dense inner structure and chemical purity of the printed features.