Single-molecule rectification
02/07/15 15:53
Single-molecule rectification lies at the heart of the field of molecular electronics and its experimental realization is quite challenging. In this work, our experimental colleagues at UAM have demostrated large rectification ratios (> 100) in single-molecule junctions based on a metal-oxide cluster (polyoxometalate), using a scanning tunneling microscope (STM) both at ambient conditions and at low temperature. These rectification ratios are the largest ever observed in a single-molecule junction. More importantly, by following the variation of the IV characteristics with the separation between the tip and the molecule, we have been able to unambiguously demostrate that rectification is due to asymmetric coupling to the electrodes of a molecule with an asymmetric level structure. In principle, this mechanism can be implemented in other type of molecular junctions using both organic and inorganic molecules and provides a simple strategy for the rational design of molecular diodes.
