New Approach for Large-Area Thermoelectric Junctions with a Liquid Eutectic Gallium-Indium Electrode

Area of Science:

• Materials Science
• Organic Electronics
• Nanotechnology

Background:

• Relating thermoelectric performance to molecular structure is crucial for organic thermoelectrics.
• A need exists for reliable platforms for molecular-level thermoelectric measurements.

Purpose of the Study:

• To introduce an efficient approach for thermoelectric characterization of large areas of molecular monolayers.
• To enable noninvasive, reversible top-contact formation for molecular thermoelectric devices.

Main Methods:

• Utilized liquid eutectic gallium-indium (EGaIn) with a cone-shaped microelectrode.
• Developed a platform for ambient condition measurements with high-yield device fabrication (up to 97%).
• Collected statistically sufficient thermoelectric data sets (approx. 6000 data points per sample in hours).

Main Results:

• Successfully estimated thermopowers of EGaIn (3.4 ± 0.1 μV/K) and Ga2O3 (3.4 ± 0.2 μV/K).
• Validated the platform using well-studied oligophenylenethiolate molecules.
• Demonstrated the platform's capability for large-area molecular junction characterization.

Conclusions:

• The developed EGaIn-based platform offers an efficient and reproducible method for molecular thermoelectric characterization.
• This approach facilitates the study of structure-property relationships in organic thermoelectrics.
• The platform opens new avenues for developing large-area molecular thermoelectric junctions.