Tuning the Growth Pattern of Triangular Silver Nanoplates from Lateral to Vertical by Secondary Metal Addition

We are presenting an easy synthetic access to the aqueous synthesis of truncated trigonal silver nanobipyramids with tunable width and height in a facile two step synthesis. We modified a synthesis that employs seed particles with twinning faults on which silver is deposited laterally along the twinning fault, leading to flat particles. The ratio of lateral and vertical growth is adjusted by the co-titration of further noble metal salts at nanomolar concentrations alongside the silver precursor. Thus, besides the edge lengths, the thickness and related aspect ratio of metal bipyramids can be tuned. By tracking the growth of the particles via their localized surface plasmon resonance position during the reaction using optical transmission spectroscopy, we present insights into the modification of the growth mechanism for truncated silver nanobipyramids.