(Invited) Energy Alignment at the Molecule – Electrode Interface: An Electrochemical-Potential / Hardness View. (20th July 2018)

• Record Type: Journal Article
• Authors: Vilan, Ayelet
• Is Part Of: ECS transactions. Volume 86:Number 3(2018)
• Page Start: 67
• Page End: 78
• Publication Date: 2018-07-20
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/08603.0067ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : Although the importance of energy-alignment at hetero-interface is undeniable, the mechanism dictating it is still debatable. Confusion is even larger for molecular monolayers, because molecules are mostly insulators with no energy-levels in the vicinity of the Fermi-level. This rules out molecular ionization as a means to establish electronic equilibrium. Still, there is a growing evidence for energy alignment between adsorbed molecules and the Fermi-level of their supporting substrate. This can be understood as an equilibrium between the Fermi level of the contact(s) and the chemical potential of the electrons in the molecule, established via polarization of the bound electrons in the immediate vicinity of the interface. The extent of this polarization relates to the notion of 'chemical hardness' and is relevant for both chemical binding and physical contact. This concept is demonstrated for several examples of molecular monolayers on Si and on Au.