Unexpected Electronic Properties of Micrometer-Thick Supracrystals of Au Nanocrystals

We investigated the electronic properties of highly ordered three-dimensional colloidal crystals of gold nanocrystals (7 ± 0.4 nm), called supracrystals. Two kinds of Au supracrystals with typical thicknesses of 300 nm and 5 μm, respectively, are probed for the first time with scanning tunneling microscopy/spectroscopy at 5 K revealing similar power law behavior and showing homogeneous conductance with the fingerprint of isolated nanocrystal. Potential applications evading the size-related risks of nanocrystals could be then considered