Laser-Induced Covalent Defunctionalization of Graphene - Precise Patterning and Site-Selective Removal of Functional...

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Covalently patterned monolayer graphene offers potential for advanced applications.
• Site-selective functionalization and defunctionalization are crucial for structuring graphene.
• Reversible modification is key for reusable and tunable graphene platforms.

Purpose of the Study:

• To report site-selective defunctionalization concepts for patterned monolayer graphene.
• To demonstrate iterative 'writing,' 'erasing,' and 'rewriting' of covalent functionalities.
• To establish graphene as a platform for high-resolution 2D data storage.

Main Methods:

• Laser-activated precursor deposition using dibenzoyl peroxide (DBPO) for phenyl moiety grafting.
• Temperature-dependent Raman spectroscopy to study functionalization reversibility.
• High-power laser irradiation (532 nm) for selective covalent addend removal.
• Raman mapping and Kelvin probe force microscopy (KPFM) for spatial control confirmation.

Main Results:

• High spatial precision achieved in covalent grafting of phenyl groups onto graphene.
• Fully reversible functionalization demonstrated, with defunctionalization at 225 °C.
• Selective photothermal removal of covalent addends with ≈0.5 µm lateral resolution.
• Successful refunctionalization of 'erased' regions, enabling iterative modification.

Conclusions:

• Site-selective photothermal defunctionalization and refunctionalization enable precise graphene structuring.
• The iterative 'write-erase-rewrite' capability establishes graphene for chemically tunable 2D data storage.
• This work provides a pathway for reusable, patterned graphene materials.