Controlled synthesis of gold nano bipyramids

Abstract

Gold nano bipyramids (Au NBPs) and nanorods (Au NRs) have been heavily
researched due to their unique properties, but the current growth methods have shown
to be too tedious. They are specialized gold nanoparticles with distinct shapes, and
there are two common types of elongated colloidal plasmonic metal nanocrystals. The
difference is that Au NPBs have narrower shapes and sharper tips than Au NRs. In
this study, we utilizedthe seed-mediated approach to synthesize the Au NBPs sample
and focus on improving the yield of Au NBPs and aim to understand the effect of the
concentration ratio between CTAC/sodium citrate by changing the concentration of
sodium citrate to obtain a high yield of Au NBP. We also tried various CTAB
concentrations within our growth solution during our study. We kept most of our
growth solution formula the same throughout this experiment but with varied
concentrations of CTAB with the same seed solutions. We had to be precise with how
much of each chemical we added to our solution and the order in which we added
them. Preliminary results showed that the growth solution with 40mM of CTAB
combined with the concentration CTAC/CiNa3 21:1 seed solution was better than the
one with 50mM of CTAB. Each sample's characterization was measured using
Transmission Electron Microscopy (TEM) and UV-Vis spectra. As we find ways to
improve the meditated seed growth of Au NBPs, they have a high potential to be
useful for future uses, such as in the photocatalyst and medical fields.