Synthesis of vertically conformal ZnO/CuO core-shell nanowire arrays by electrophoresis-assisted electroless deposition

Vertically conformal ZnO/CuO core-shell nanowire (NW) arrays with high aspect ratios were synthesized by electrophoresis-assisted electroless deposition (EAELD) of CuO onto preformed ZnO NWs. Using this method, conformal CuO seeds were successfully formed on long ZnO NWs by the electrostatic attachment of colloidal Cu₂O NPs under the solution and subsequent thermal oxidation. Using the CuO seeds, conformal CuO shell to core ZnO NWs were successfully fabricated by kinetic-limited deposition in the solution, which overcame the inherent diffusion limitations of conventional electroless deposition. This experimental evidence and thermodynamic modeling results are presented to validate the proposed EAELD mechanism. The vertically conformal hetero-nanostructure arrays developed in this work are a promising platform for applications such as solar cells and catalysts because of the maximized junction areas and active sites.