Making Contacts to Single Molecules: Are We There Yet?

The problem of connecting two wires to a single molecule has several practical solutions, varying from break junctions, to gaps formed by controlled evaporation and self-assembled structures. Here, we focus on gold nanoparticle self-assembled junctions, and break junctions, two techniques that allow the number of molecules in the gap to be determined. We show that the nanoparticle junctions are affected by the electronic properties of the nanoparticles, and that corrections for these effects tend to bring the data into closer agreement with both break-junction measurements and ab initio calculations.