Power discontinuity and shift of the energy onset of a molecular de-bromination reaction induced by hot-electron tunneling. Issue 36 (8th September 2021)

• Record Type: Journal Article
• Authors: Barragán, Ana; Robles, Roberto; Lorente, Nicolás; Vitali, Lucia
• Is Part Of: Nanoscale. Volume 13:Issue 36(2021)
• Page Start: 15215
• Page End: 15219
• Publication Date: 2021-09-08
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d1nr04229g
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : We describe the electron-induced dissociation of Br atoms in the Au(Br-MBP)2 complex, showing that the reaction onset can be shifted from 2.4 to 4.4 V while the required power drops sharply to 20% when a second molecular resonance is involved. Abstract : 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.