PhD defence: Jeppe Fock

Title:"Molecular Electronics - from bulk to single-molecule".

Abstract

Single-molecule electronics is by definition interdisciplinary. Molecules synthesised and characterised in bulk solution by chemist are built into devices and characterised by physicists. The gap between these disciplines is sought bridged in this work. Physiochemical characterization and electrical measurements of single molecule device are presented for two model systems, namely fullerene and end-capped molecules and cruciform molecules.

Fullerence end-capped molecules are used to examinie fullerene as anchoring groups to gold electrodes in mechanically controlled break junctions. Intramolecular excited state charge transfer is seen in solution. In molecular devices the orientation of the molecule is examined using vibrational spectroscopy.

Curciform molecules are OPE-based molecule with redox active side-arms. Electric control of exchange-coupled spins is demonstrated experimentally in a modified by gate-controlled addition/removal of a third spin. The results show that it is possible to controllable and reversible switch a molecule between different polyradical states, using gate-induced redox reactions.