Topology selectivity of a conformationally flexible precursor through selenium doping

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Conformational arrangements in nanostructures dictate material properties.
• On-surface synthesis often yields disordered structures due to conformational diversity.
• Controlling molecular conformation is key to achieving desired nanoarchitectures.

Purpose of the Study:

• To explore controlling conformational arrangements of flexible precursors during on-surface synthesis.
• To achieve selective C3h conformer formation and improve nanopore structural homogeneity.
• To develop ordered two-dimensional metal-organic nanostructures using selenium doping.

Main Methods:

• Deposition of 2,4,6-tris(3-bromophenyl)-1,3,5-triazine precursor on Cu(111).
• Low-coverage selenium doping at varying temperatures.
• High-resolution scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM).
• Density functional theory (DFT) calculations.

Main Results:

• A random phase of C3h and Cs conformers was initially obtained.
• Selenium doping at 0.01 ML achieved C3h conformer selectivity and improved nanopore homogeneity.
• Ordered 2D metal-organic nanostructures were formed via selenium doping from room temperature to 365 K.
• Energy diagrams were regulated by the presence or absence of Se atoms.

Conclusions:

• Selenium doping is an effective strategy to control molecular conformation in on-surface synthesis.
• This approach enables the formation of ordered nanostructures with improved homogeneity.
• The findings expand the toolbox for on-surface synthesis of conformationally flexible precursors for advanced nanomaterials.