Multistep and multiscale electron transfer and localization dynamics at a model electrolyte/metal interface

Abstract

The lifetime, coupling, and localization dynamics of electronic states in molecular films near metal electrodes fundamentally determine their propensity to act as precursors or reactants in chemical reactions, crucial for a detailed understanding of charge transport and degradation mechanisms in batteries. In the current study, we investigate the formation dynamics of small polarons and their role as intermediate electronic states in thin films of dimethyl sulfoxide (DMSO) on Cu(111) using time-and angle-resolved two-photon photoemission spectroscopy. Upon photoexcitation, a delocalized DMSO electronic state two monolayers from the Cu surface is initially populated, becoming a small polaron on a 200 fs timescale, consistent with localization due to vibrational dynamics of the DMSO film. The small polaron is a precursor state for an extremely long-lived and weakly-coupled multilayer electronic state, with a lifetime of several seconds, thirteen orders of magnitude longer than the small polaron. Although the small polaron in DMSO has a lifetime of 140 fs, its role as a precursor state for long-lived electronic states could make it an important intermediate in multistep battery reactivity.

Ultrafast generation and decay of a surface metal

“…Electron density and curvature of the metallic band show a two-fold build-up (t1 = 20(20) fs, t2 = 1.20(15) ps), which is followed by a decay on a timescale of hundreds of ps (t3 = 219(13) ps); see Methods for details on the fitting. The effective mass is a measure of the electron localization in real space 32,33 . The rise of 1/meff can be viewed as dynamic delocalization of the photoexcited electrons and the subsequent decrease of 1/meff during the decay as dynamic localization 33 .…”

“…The effective mass is a measure of the electron localization in real space 32,33 . The rise of 1/meff can be viewed as dynamic delocalization of the photoexcited electrons and the subsequent decrease of 1/meff during the decay as dynamic localization 33 . The degree of localization is correlated with the photoexcited electron density.…”

Equilibrium and Dynamical Characteristics of the Solvation Associated with the Li+/Li Redox Couple at the Ethylene Carbonate/Graphene Interface

“…In a much broader context, the basic elements underlying the electron transfer reaction shown in eq 1 are also present in a variety of heterogeneous electron transfer processes such as in the photoinjection of electrons into semiconductors from redox species adsorbed at the electrolyte/semiconductor interfaces in dye-sensitized solar cells 35,36 or in localizations of excess electrons at metal/electrolyte interfaces. 37,38 T h i s c o n t e n t i s Our strategy to tackle the study of the redox equilibrium included three stages: the first one was focused on establishing differences between the solvation structures of reactant and product states in the presence of a planar electrode and those prevailing in bulk phases. We then moved to the examination of the fluctuations of the solvent/solute Coulomb coupling as a means to construct the corresponding Marcus plots.…”

“…In the present paper, we will present results from molecular dynamics simulations of systems which bear some points in common with those previously commented, although the objective here will be aimed at assessing the role of polar solvation as a modulating agent of the following model electron transfer reaction when the oxidized and reduced species remain adsorbed at a planar graphene cathode of an electrochemical cell, in contact with ethylene carbonate (ETC; see Figure ). In a much broader context, the basic elements underlying the electron transfer reaction shown in eq are also present in a variety of heterogeneous electron transfer processes such as in the photoinjection of electrons into semiconductors from redox species adsorbed at the electrolyte/semiconductor interfaces in dye-sensitized solar cells , or in localizations of excess electrons at metal/electrolyte interfaces. , …”

Nonaqueous Solvent Adsorption on Transition Metal Surfaces with Density Functional Theory: Interaction of N,N-Dimethylformamide (DMF), Tetrahydrofuran (THF), and Dimethyl Sulfoxide (DMSO) with Ag, Cu, Pt, Rh, and Re Surfaces

“…To this end, experiments have been carried out to investigate the interactions of these solvents with metal surfaces. Electrochemical studies have indicated that solvents interact with transition metal surfaces, affecting fundamental electrochemical properties and the rates of reactions at these electrodes. − Different solvents, such as DMSO, DMF, and THF, have distinct and electrode-dependent effects on the potential of zero charge (PZC), capacitance, and other fundamental surface electrochemical properties. ,− Differences in PZC and capacitance among different solvents, and metals, originate at least in part from differences in metal–solvent interactions, including possible chemisorption and its effect on interfacial solvent orientation. ,,− Spectroscopic experiments − have also been used to study solvent–metal interactions. For example, spectroscopic evidence indicates a strong chemisorption of DMSO on Pt, and also significant interaction with Au , and Ag, displaying preferential adsorption to step sites .…”