Two-Step Electrodeposited 3D Ni Nanocone Supported Au Nanoball Arrays as SERS Substrate

Until now, the fabrication of convenient and high-efficient surface enhanced Raman scattering (SERS) substrate has remained challenging. Inspired of the rose petal effect in nature, we develop an effective and facile strategy to localize the trace amount of probe molecules onto SERS-active hot spots using the hydrophobic Ni nanocone supported hydropholic Au nanoball (denoted as Au NB@Ni NC) substrate. The two-step electrodeposited Au NB@Ni NC shows a hierarchical structure with the closely arranged Au nanoballs on the Ni nanocone pinpoints. This unique structure can not only endow the hot spots between the Au nanoballs in SERS, but also contribute to special wettability after natural storage. The results verify that the high contact angle of the probe drops on the Au NB@Ni NC substrate helps concentrate the probe molecules in the hot spots area, leading to an increased SERS intensity. To be specific, this Au NB@Ni NC substrate could test tiny crystal violet droplet of 5 μl volume at 10−13 M. In practice, we realize the high-sensitive and diverse-analyses SERS detection by simultaneous multiple-spots tests, dispensing with flushing repeatedly. Therefore, this 3D Ni nanocone supported strategy is a promising method for designing applicable SERS substrates.