Mobility of thiolates on Au(111) surfaces

Area of Science:

• Surface Science
• Materials Chemistry
• Nanotechnology

Background:

• Self-assembled monolayers (SAMs) on gold surfaces are crucial for various applications.
• Thiol binding to gold involves diverse motifs, influenced by surface defects and adatoms.
• Previous studies focused on high surface coverage, with limited understanding of initial binding.

Purpose of the Study:

• To investigate thiol binding motifs in the low-coverage regime of SAM formation.
• To determine the relative stability and mobility of methane thiolate binding motifs on gold.
• To understand the influence of surface defects and adatoms on initial SAM assembly.

Main Methods:

• Theoretical calculations were employed to study methane thiolate binding on gold.
• Analysis focused on the low-coverage regime, simulating the initial stages of SAM formation.
• Relative stability and mobility of different binding motifs were assessed.

Main Results:

• Identified and compared the stability of various thiol binding motifs at low surface coverage.
• Rationalized the mobility of these motifs, considering adsorption, movement, and re-adsorption rates.
• Demonstrated that gold adatoms and surface defects critically affect initial motif formation.

Conclusions:

• The initial binding motif in SAM formation is highly dependent on the availability of gold adatoms and surface defects.
• Understanding low-coverage binding is essential for controlling SAM formation kinetics and structure.
• Theoretical insights provide a foundation for designing and fabricating functionalized gold surfaces.