In situ patterning of hierarchical nanoporous gold structures by in-plane dealloying

• We report a novel in-plane dealloying method that generates NPG structures.
• In-plane patterning allows the dealloying rate to be directly quantified by SEM.
• Microscale patterns were also generated with our method.
• This method can produce NPG dot arrays that are effective for SERS and MEF.

We report a novel in situ patterning method that generates hierarchical nanoporous gold (NPG) structures such as sub-micron NPG disks and microscale NPG patterns during dealloying for the first time. Our patterning method also enables the quantification of dealloying rate by scanning electron microscopy (SEM) without the need for depth-resolving imaging modalities. As potential applications, we demonstrate that the hierarchical NPG dot arrays are effective for surface-enhanced Raman scattering (SERS) and metal-enhanced fluorescence (MEF), both are highly sensitive molecular sensing techniques.