Marcus Theory of Thermoelectricity in Molecular Junctions

Abstract

Thermoelectric energy conversion is perhaps the most promising of the potential applications of molecular electronics. Ultimately, it is desirable for this technology to operate at around room temperature, and it is therefore important to consider the role of dissipative effects in these conditions. Here, we develop a theory of thermoelectricity which accounts for the vibrational coupling within the framework of Marcus theory. We demonstrate that the inclusion of lifetime broadening is necessary in the theoretical description of this phenomenon. We further show that the Seebeck coefficient and the power factor decrease with increasing reorganisation energy, and identify the optimal operating conditions in the case of non-zero reorganisation energy. Finally, with the aid of DFT calculations, we consider a prototypical fullerene-based molecular junction. We estimate the maximum power factor that can be obtained in this system, and confirm that C${}_{60}$ is an excellent candidate for thermoelectric heat-to-energy conversion. This work provides general guidance that should be followed in order to achieve high-efficiency molecular thermoelectric materials.

arXiv commentSupporting Information available at https://doi.org/10.1021/acs.jpcc.8b12163

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Cited by in corpus (10)

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• A thermodynamic approach to measuring entropy in a few-electron nanodevice
• On the theory of charge transport and entropic effects in solvated molecular junctions
• Electronic measurements of entropy in meso- and nanoscale systems
• Efficient heating of single-molecule junctions for thermoelectric studies at cryogenic temperatures
• The role of metallic leads and electronic degeneracies in thermoelectric power generation in quantum dots
• Energy Transfer and Thermoelectricity in Molecular Junctions in Non-Equilibrated Solvents
• Electron hopping heat transport in molecules
• Noise and Thermodynamic Uncertainty Relation in "Underwater" Molecular Junctions
• Potential barriers are nearly-ideal quantum thermoelectrics at finite power output