Assembling thiolated gold nanoparticles in compact patterns: a transmission electron microscopy and scanning probe microscopy investigation

We present results from a study of the deposition of synthesized dodecanethiol capped gold clusters onto solid substrates investigated using Transmission Electron Microscopy (TEM) and Scanning Probe Microscopy (SPM). TEM imaging of films prepared onto carbon coated grids using the drop cast method from cluster solutions that have undergone an increasing number of selective size separation steps show the efficacy of the vapor transfer technique in narrowing down the particle size distribution. In order to assemble the gold clusters in compact patterns and investigate their organization using SPM, we have prepared 1,4-benzenedimethanethiol self-assembled films onto heteroepitaxial gold on mica to be used as a substrate. A comparison of results obtained on this substrate using gold cluster films prepared with the drop cast method and the Langmuir-Blodgett (LB) technique is made. In the case of LB films made from size-selected nanoparticles, we present room temperature scanning tunneling images of clusters arranged in compact patterns.