Tuning intermolecular π-π stacking by isomeric engineering in single-molecule junctions

Area of Science:

• Materials Science
• Organic Electronics
• Supramolecular Chemistry

Background:

• Intermolecular π-π stacking is crucial for organic semiconductor and optoelectronic device performance.
• Tailoring molecular structures is essential for controlling material properties.

Purpose of the Study:

• To investigate the relationship between molecular structure and intermolecular π-π stacking effects.
• To explore charge transport properties influenced by stacking in engineered molecular wires.
• To establish a foundation for designing advanced materials with tunable intermolecular interactions.

Main Methods:

• Engineering molecular wires with pyridine, thiazole, and thiophene units.
• Utilizing single-molecule scanning tunnelling microscopy-break junction (STM-BJ) technique.
• Conducting single-molecule conductance measurements, flicker noise analysis, and current-voltage (I-V) studies.
• Integrating theoretical analyses to elucidate stacking mechanisms.

Main Results:

• Demonstrated a direct correlation between intramolecular charge polarization and stacking capability.
• Elucidated the mechanism for manipulating intermolecular π-π stacking at the microscale.
• Established a structure-property relationship between charge polarization and stacking-driven charge transport.

Conclusions:

• Intramolecular charge polarization is a key factor governing intermolecular π-π stacking.
• The findings provide a pathway for designing organic materials with enhanced charge transport properties.
• This research advances the understanding of molecular interactions for novel electronic and optoelectronic applications.