Power discontinuity and shift of the energy onset of a molecular de-bromination reaction induced by hot-electron tunneling

Ana Barragán, Roberto Robles, Nicolás Lorente, Lucia Vitali

Research output: Contribution to journalArticlepeer-review


Understanding the mechanism of molecular dissociation under applied bias is a fundamental requirement to progress in (electro)-catalysis as well as in (opto)-electronics. The working conditions of a molecular-based device and the stability of chemical bonds can be addressed in metal-organic junctions by injecting electrons in tunneling conditions. Here, we have correlated the energy of de-bromination of an aryl group with its density of states in a self-assembled dimeric structure of 4'-bromo-4-mercaptobiphenyl adsorbed on a Au(111) surface. We have observed that the electron-energy range where the molecule is chemically stable can be extended, shifting the bias threshold for the rupture of the -C-Br bond continuously from about 2.4 to 4.4 V by changing the electron current. Correspondingly, the power needed for the dissociation drops sharply at 3.6 V, identifying different reaction regimes and the contribution of different molecular resonance states.

Original languageEnglish (US)
Pages (from-to)15215-15219
Number of pages5
Issue number36
StatePublished - Sep 23 2021

Cite this