Switching the on-surface orientation of oxygen-functionalized helicene
Jan Voigt1, Mohammed Hasan2, Christian Wäckerlin1,3,4
1Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.
Chirality
|February 22, 2024
Summary
Researchers explored modifying surfaces with functionalized helicenes for advanced organic electronics. Depositing a novel heterohelicene on copper revealed molecular self-assembly and reorientation upon heating, paving the way for new device applications.
Area of Science:
- Surface Science
- Organic Electronics
- Chiral Materials
Background:
- Helicenes are chiral organic molecules with significant optoelectronic potential.
- Surface functionalization with helicenes is crucial for developing novel organic material devices.
- Understanding molecular behavior on surfaces is key to controlling material properties.
Purpose of the Study:
- To investigate the adsorption and modification of a specific heterohelicene on a copper(111) surface.
- To explore the impact of temperature and coverage on helicene molecular orientation and bonding.
- To lay the groundwork for designing advanced organic electronic devices using functionalized helicenes.
Main Methods:
- Deposition of a heterohelicene (containing furano and hydroxyl groups) onto a copper(111) surface under ultrahigh vacuum conditions.
- Analysis of adsorbate modifications at varying temperatures and coverages.
- Observation of molecular self-assembly and changes in adsorption modes (lying vs. standing).
Main Results:
- At low temperatures and coverages, helicene molecules preferentially lie flat to maximize substrate contact.
- Thermal treatment induces deprotonation of hydroxyl groups.
- Heating also causes a partial reorientation of molecules from a lying to a standing adsorption mode.
Conclusions:
- The study demonstrates controllable surface modification of helicenes on copper(111).
- Thermal-induced deprotonation and reorientation offer pathways for tuning molecular assembly.
- These findings are vital for the rational design of helicene-based organic electronic devices.
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