On the theory of charge transport and entropic effects in solvated molecular junctions
Abstract
Experimental studies on single-molecule junctions are typically in need of a simple theoretical approach that can reproduce or be fitted to experimentally measured transport data. In this context, the single-level variant of the Landauer approach is most commonly used, but methods based on Marcus theory are also gaining popularity. Recently, a generalized theory unifying these two approaches has also been developed. In the present work, we extend this theory so that it includes entropic effects (which can be important when polar solvents are involved but are likely minor for solid-state systems). We investigate the temperature-dependence of the electric current and compare it to the behavior predicted by the Landauer and the conventional Marcus theory. We argue that this generalized theory provides a simple yet effective framework for understanding charge transport through molecular junctions. Furthermore, we explore the role of the entropic effects in different transport regimes and suggest experimental criteria for detecting them in solvated molecular junctions. Finally, in order to account for nuclear tunneling effects, we also demonstrate how lifetime broadening can be introduced into the Marcus–Levich–Dogonadze–Jortner-type description of electron transport.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 21, 2021
- Source ID
- 10.1063/5.0034782
Entities
People
- Jakub K Sowa
- Rudolph A. Marcus
Organizations
- Army Research Office
- California Institute of Technology
- Hertford College
- Office of Naval Research
- University of Oxford