Gold Nanorods: A Journey Towards Successful Synthesis

A.N.D. Kolb, J.H. Johnston
Victoria University of Wellington/MacDiarmid Institute for Advanced Materials and Nanotechnology, NZ

Keywords: gold nanorods, synthesis protocols, reproducibility, challenges, successes

Summary:

Gold nanorods (AuNRs) are attracting substantial research interest due to their remarkable size- and shape-related optical properties. AuNRs in solution are brightly coloured but not golden whereby the precise colours of AuNRs depend on accurately engineered 2D structures with defined aspect ratio. We found that the reproducibility of peer-reviewed seed-mediated synthesis protocols of AuNRs with defined aspect ratio is very low in our facility. Our research indentifies the challenges of seeded growth AuNR syntheses, explores practical solutions to improve the reproducibility of AuNRs with defined aspect ratio and discusses these approaches. Our particular challenges arise from laboratory temperatures cooler than 25 °C, the source and form of chemicals as well as the sometimes very difficult removal of excess surfactant. UV/Vis absorption spectroscopy and transmission electron microscopy document the progresses made by exploring practical solutions to overcome our challenges and relates the colours of water-soluble AuNRs to their sizes and shapes. This talk provides enhanced knowledge for applied scientists who are less familiar with AuNR syntheses or who are having issues in their own facilities. The shared insights improve significantly the reproducibility of published protocols as well as the accessibility of AuNRs for inexperienced researchers of this particular study field.