Paul Mulvaney, Susanne Seibt and Heyou Zhang
ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, VIC., 3010, Australia
Nanotechnology is about using single nanoscale objects in devices and applications. Yet there are still few ways to reliably manipulate and position single nanocrystals with nanometre spatial resolution. In this talk, I will discuss the positioning of single nanocrystals into arrays using several different assembly methods. A key question is whether one can assemble
nanocrystals using chemical forces or whether it is better to use applied fields to drive assembly. We show that electrophoresis (see Figure 1), the movement of particles in an applied DC electric field, is a valuable tool for single nanocrystal manipulation. We demonstrate oriented deposition of gold rods as well as deposition of semiconductor nanocrystals.
Figure 1. Vertical gold nanorod assembly via EPD (a) A schematic of the geometry of the vertically assembled gold nanorod array. (b) Atomic force microscopy image of part of a gold nanorod array showing 9 × 9 vertically oriented gold nanorods (scale bar: 10 μm). (c) 3D coloured map of the height profile extracted from the atomic force microscopy image. (Colour bar: Height).
The unusual aspect dependent optical properties of gold rods has been a key driver for a lot of molecular plasmonics. Yet we still do not understand the mechanism of rod growth. In the second part of this talk, I will present recent SAXS data on the growth of gold rods studied at the Australian synchrotron.
. Heyou Zhang, Calum Kinnear, and Paul Mulvaney. “Fabrication of single-nanocrystal arrays”, Advanced Materials, Art. 1904551, (2019).
. Heyou Zhang, Jasper Cadusch, Calum Kinnear, Timothy James, Ann Roberts, and Paul Mulvaney. “Direct assembly of large area nanoparticle arrays”, ACS Nano, 12, 7529–7537, (2018).
Acknowledgements: This work was supported by ARC Grant CE170100026.