Asymmetric dumbbells from selective deposition of metals on seeded semiconductor nanorods.

Sowing the seeds: the growth of Au and Ag(2)S nanoparticles at distinct positions on CdSe-seeded CdS heterostructured nanorods can be precisely controlled by variations in the concentration of the Au and Ag precursors, respectively. The ability to direct growth on the nanorods can lead to "Janus-type" structures where Au is located at the more reactive end of the nanorod, whilst Ag(2)S is located at the other (see picture; CdSe dark blue, CdS light blue, Au yellow, Ag(2)S gray).