Self-assembled gold nanoparticle-molecular electronic networks.

Electronic transport through self-assembled networks consisting of colloidal gold particles interconnected with thiolated alkane molecules is studied using a combination of broad area and scanning probe microscope-based measurements. The molecule-gold nanoparticle ratio and/or type of molecules is used to alter electronic transport paths through the network and allow the resistance to be controllably tuned by several orders of magnitude (∼105-1011 ohms for the structures studied). Local probing and imaging of the colloidal gold networks via atomic force microscopy is able to detect the presence of molecular connections and also indicates that the number of molecules is important for achieving good network packing with a minimum ratio of molecules to particles between 1:1 and 5:1 found to be needed in order to form well-connected molecular electronic circuits. Circuit simulations used to model the electrical behavior of the self-assembled nanoscale networks based on different morphologies and dimensions show good agreement with experiment and provide a guide for engineering network properties using superstructures of different molecules. These results demonstrate directed self-assembly as a potential avenue for the creation of molecular integrated circuits. [ABSTRACT FROM AUTHOR]