Galvanic replacement mediated growth of dendritic gold nanostructures with a three-fold symmetry and their applications to SERS

Hierarchical, three-fold symmetrical, single-crystalline gold dendrites are synthesized on different metal substrates including Al, Zn, and Ni in a mixture of ethanol and water with the assistance of an ionic liquid. Structural characterizations suggest that the obtained gold dendrites are grown along the <211> directions. Such <211>-oriented gold dendrites are seldom reported. Both the metal substrate and the volume ratio of ethanol and water have demonstrated a significant effect on the dendrite morphologies. The obtained gold dendrites are found to yield large SERS enhancement factors for rhodamine 6G (R6G) and the morphology of the branches is a key for the enhancement.