Supramolecular Structure Enabled Photo-Responsive Charge Transport in Porphyrin-Based Junctions

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Organic Electronics

Background:

• Supramolecular electronics enables functional devices with tunable charge transport (CT) via non-covalent structures.
• Modulating supramolecular CT with external stimuli is challenging due to a lack of rigid, predictably responsive systems.

Purpose of the Study:

• To investigate porphyrin-based supramolecular structures for light-responsive charge transport.
• To develop a more effective photo-responsive CT mechanism in supramolecular systems.

Main Methods:

• Fabrication of porphyrin-contained cages using rigid ligands to control porphyrin-porphyrin distance.
• Characterization of charge transport properties in solid-state junctions under light illumination.
• Theoretical calculations to elucidate the mechanism of conductivity reduction.

Main Results:

• Porphyrin cages showed higher electron-hole pair separation efficiency than monomers in the solid state.
• Illumination reduced current in cage junctions, indicating photo-responsive charge transport.
• Conductivity reduction is attributed to an increased molecule-electrode energy offset under light.
• Photo-responsive CT was tunable by altering the porphyrin's metal ion and cage-electrode distance.

Conclusions:

• Porphyrin-based supramolecular cages exhibit effective photo-responsive charge transport.
• The study provides a new strategy for developing tunable supramolecular optoelectronic devices.