Morphology control of SERS-active 2D gold nanosnowflakes†
Two-dimensional (2D) gold-branched nanomaterials such as nano-snowflakes or nano-dendrites have previously been demonstrated as promising candidates for surface-enhanced Raman scattering (SERS) substrates and catalysis. Herein, we present a rapid and effective synthesis method for preparing 2D gold nanosnowflakes (Au NSFs) where pre-existing seeds in the growth solution act as nucleation centers and avoid new nucleus formation. Methods to fine-tune the morphology and size of the 2D Au NSFs by adjusting the synthesis conditions are also explained, along with the discussion of a proposed formation mechanism to explain the experimental data on morphology formation. In addition, the optical properties of various controlled morphologies of 2D Au NSFs are explored and the SERS performance is investigated to study the relationship between the substrate local environment and SERS enhancement. This work not only involves the preparation of SERS active 2D Au NSFs with controlled morphology, but also provides a deeper understanding of dendritic formation.