Mask-Assisted Seeded Growth of Segmented Metallic Heteronanostructures

Controlling the deposition of exotic metals in the seeded growth of multimetal nanostructures is challenging. This work describes a seeded growth method assisted by a mask for synthesis of segmented binary or ternary metal nanostructures. Silica is used as a mask to partially block the surface of a seed and a second metal is subsequently deposited on the exposed area, forming a bimetallic heterodimer. The initial demonstration was carried out on a Au seed, followed by deposition of Pd or Pt on the seed. It was found that Pd tended to spread out laterally on the seed while Pt inclined to grow vertically into branched topology on Au. Without removal of the SiO2 mask, Pt could be further deposited on the unblocked Pd of the Pd-Au dimer to form a Pt-Pd-Au trimer. Mask-assisted seeded growth provides a general strategy to construct segmented metallic nanoarchitectures.