To be of use for connecting molecules, MWs need to self-assemble following well-defined routes and form reliable electrical contacts between them. To reproducibly self-assemble a complex circuit based on single molecules. Ideally, they would connect to diverse materials, such as gold metal surfaces (for connections to outside world), biomolecules (for nanosensors, nanoelectrodes, molecular switches) and most importantly, they must allow branching. The connectors should also be available of pre-determined diameter and length. They should also have covalent bonding to ensure reproducible transport and contact properties.
DNA-like molecules have specific molecular-scale recognition and can be used in molecular scaffold fabrication. Complex shapes have been demonstrated, but unfortunately metal coated DNA which is electrically conducting is too thick to connect to individual molecules. Thinner coated DNA lacks electronic connectivity and is unsuited for connecting molecular electronics components.
Some varieties of carbon nanotubes (CNTs) are conducting, and connectivity at their ends can be achieved by attachment of connecting groups. Unfortunately manufacturing CNTs with pre-determined properties is impossible at present, and the functionalized ends are typically not conducting, limiting their usefulness as molecular connectors. Individual CNTs can be soldered in an electron microscope, but the contact is not covalent and cannot be self-assembled.
Possible routes for the construction of larger functional circuits using MoSI MWs have been demonstrated, either via gold nanoparticles as linkers, or by direct connection to thiolated molecules. The two approaches may lead to different possible applications. The use of GNPs offers the possibility of branching and construction of larger circuits.