Molecular-scale thermoelectricity: as simple as 'ABC'.

Area of Science:

• Molecular electronics
• Thermoelectric materials
• Nanoscale transport phenomena

Background:

• Measuring the Seebeck coefficient of single molecules and self-assembled monolayers (SAMs) is experimentally challenging.
• Predicting thermoelectric properties from electrical characteristics could streamline material discovery.
• Conductance-voltage (G-V) measurements are more accessible than direct Seebeck coefficient measurements.

Purpose of the Study:

• To present a novel strategy for predicting an upper bound to the Seebeck coefficient of single molecules and SAMs.
• To utilize conductance-voltage (G-V) characteristics for this prediction, avoiding complex thermoelectric setups.
• To establish a screening method for identifying promising thermoelectric materials at the molecular level.

Main Methods:

• Fitting measured G-V curves of single molecules/SAMs using three parameters (a, b, c) within the 'ABC' theory.
• Developing a theoretical framework to predict the maximum Seebeck coefficient magnitude from these G-V fits.
• Comparing histograms of predicted Seebeck coefficients with experimentally measured values for various SAMs.

Main Results:

• The 'ABC' theory successfully predicts an upper bound for the Seebeck coefficient based on G-V measurements.
• Excellent agreement was observed between predicted and measured Seebeck coefficients for six different anthracene-based SAMs.
• The method provides a reliable way to assess material potential for thermoelectric applications.

Conclusions:

• The developed strategy offers a simplified approach to estimate the Seebeck coefficient of molecular systems.
• This prediction method can effectively guide experimental efforts, saving resources by identifying promising candidates early.
• The findings demonstrate the utility of G-V characteristics in predicting thermoelectric performance of single molecules and SAMs.