Interfacial Screening in Ultrafast Voltammetry: A Theoretical Study of Redox-Active Monolayers

Area of Science:

• Electrochemistry
• Physical Chemistry
• Surface Science

Background:

• Electron transfer (ET) at ultrashort timescales is crucial for electrochemical devices.
• Interfacial screening significantly influences ET kinetics and experimental characterization.
• Ultrafast electrochemical methods require understanding charging current dynamics.

Purpose of the Study:

• To theoretically investigate the impact of interfacial screening on electron transfer (ET) at ultrashort time scales.
• To analyze the role of charging current decay in determining reorganization energy (λ) and electronic coupling (|M|).
• To identify suitable conditions for ultrafast characterization of ET in redox active monolayers.

Main Methods:

• Theoretical investigation using linear sweep voltammetry (LSV).
• Analysis of time-dependent charging current decay.
• Examination of scan rate effects on ultrafast characterization.

Main Results:

• Charging current decay mitigates its impact on faradaic processes but limits applicable scan rates.
• Effective interfacial screening for weakly coupled systems can be achieved within the charging time constant.
• Screening levels vary with monolayer coverage and supporting ion saturation, affecting time constants.

Conclusions:

• Nanoscale charging time constants are suitable for ultrafast ET investigation in weakly coupled systems.
• Electrode surface coverage and supporting ion saturation influence interfacial screening.
• Findings aid in designing electrochemical systems with high faradaic efficiency at ultrafast limits.