Induced Conductance in Single-Molecule Junctions

The goal of molecular electronics is the realization of integrated molecular circuits. For this purpose reliable contacts to single molecules have to be built and the characteristics of those junctions need to be investigated. We have demonstrated that the mechanically controllable break junction (MCBJ) technique is a suitable tool to study the electrical transport through molecular junctions and to analyze the electronic structure of the molecules. Furthermore, based on the use of complex molecules, we are able to control the conductance of single molecular junctions. On the one hand, molecular switches are transformed in-situ from a non-conductive “off”- to a conductive ”on”-state via light-irradiation of a well-defined wavelength. On the other hand molecule-metal complexes are turned from an isolating to a conductive state by introducing metal centers into the molecular structures. The findings provide a significant contribution to the development of functional molecular junctions.