Characterisation of gold nanoparticles and rods using high angle annular dark field imaging

This study demonstrates use of high angle annular dark field (HAADF) imaging for the characterisation of gold nano-objects. HAADF, which is based on scanning transmission electron microscopy (STEM), has been used to measure gold spherical colloids and 1:6 aspect ratio gold nanorods. It has been demonstrated that this approach offers a realistic way of representing the dimensions (length, width and height) of a statistically relevant number of nano-objects (at least 200) in a realistic period of time. This new approach does not involve tilting the sample and as such, is more time efficient than traditional electron tomography and does not require sophisticated software analysis.