Redox-controlled conductance of polyoxometalate molecular junctions

Area of Science:

• Molecular electronics
• Nanotechnology
• Materials science

Background:

• Polyoxometalates, such as phosphomolybdates, exhibit tunable redox properties.
• Molecular junctions are crucial for understanding electron transport at the nanoscale.

Purpose of the Study:

• To demonstrate the reversible *in situ* photoreduction of phosphomolybdate molecular junctions.
• To investigate the electronic transport mechanisms before and after photoreduction.

Main Methods:

• Fabrication of molecular junctions using phosphomolybdate monolayers on gold electrodes.
• Conductive atomic force microscopy for electrical measurements.
• Analysis of current-voltage data using machine learning and clustering algorithms.

Main Results:

• Photoreduction increased junction conductance by approximately 10-fold, creating a stable open-shell state.
• Pristine junctions showed symmetric current-voltage curves dominated by the LUMO.
• Photoreduced junctions exhibited asymmetric curves attributed to SOMO and SUMO mediation.

Conclusions:

• Reversible switching of electronic states in phosphomolybdate junctions is achievable via photoreduction.
• Understanding electron transport mechanisms is key for developing switchable polyoxometalate-based nanoelectronic devices.