Electrodeposition of nanoflake Pd structures: structure-dependent wettability and SERS activity.

The characteristic properties of metal surfaces, i.e., wettability and surface-enhanced Raman scattering (SERS) activity, have been the subject of intensive research because of their useful applications. In the present work, we report a simple electrodeposition of nanoflake Pd structures onto clean Au surfaces without the use of additives. The fine structure of the nanoflake Pd surfaces was regulated by controlling the deposition charge, and the effect of the structural variations on the wettability and SERS activity was examined. The wettability of nanoflake Pd structures in terms of water contact angle was closely related to the fine structures of Pd deposits and their surface roughness. The SERS activity of the nanoflake Pd surfaces was highly dependent on the presence of sharp edge sites on the Pd structures. Well-defined nanoflake Pd structures prepared using a deposition charge of 0.04 C exhibited superhydrophobic natures and reproducible SERS activity. The effect of the metal surface structures on the wettability and the SERS activity demonstrated in this work provides insight into the fabrication of functional metal nanostructures.