Stability of functionalized platform molecules on Au(111)

Area of Science:

• Surface science
• Materials chemistry
• Organic electronics

Background:

• Trioxatriangulenium (TOTA) molecules are promising platforms for advanced materials.
• Understanding their surface interactions is crucial for device applications.

Purpose of the Study:

• To investigate the stability and decomposition of functionalized TOTA molecules on Au(111) surfaces.
• To correlate surface behavior with gas-phase stability and theoretical calculations.

Main Methods:

• Sublimation of functionalized TOTA molecules (methyl, ethyl, ethynyl, propynyl, hydrogen) onto Au(111).
• Low-temperature scanning tunneling microscopy (LT-STM) for surface analysis.
• Density functional theory (DFT) calculations for binding energies and stability.

Main Results:

• Ethyl-TOTA and methyl-TOTA exhibit high stability (>99%) on Au(111).
• H-TOTA shows partial decomposition (60%), while ethynyl-TOTA and propynyl-TOTA decompose extensively (>99%).
• Surface-induced decomposition is driven by strong binding energies of decomposition products to Au(111), contradicting gas-phase stability trends.

Conclusions:

• The stability of functionalized TOTA molecules on Au(111) is highly dependent on the specific functional groups.
• Decomposition on Au(111) is governed by surface interactions and binding energies, not solely by intrinsic molecular stability.
• Van der Waals forces play a significant role in the initial adsorption of TOTA molecules.