# Spatially Resolved 2D Laser Writing on Graphene Using Diazonium Salts

## TL;DR

This paper introduces a laser-based method to precisely pattern, erase, and rewrite functional groups on graphene with high precision.

## Contribution

The work introduces a novel laser-induced defunctionalization pathway and demonstrates a 'write-erase-rewrite' cycle on graphene.

## Key findings

- Laser-guided functionalization of graphene achieves levels comparable to solution-based methods.
- High laser power enables precise erasure of functional groups on graphene.
- Erased areas can be refunctionalized, enabling a complete 'write-erase-rewrite' cycle.

## Abstract

We present the first investigation of precise laser‐guided patterning, functionalization, defunctionalization, and refunctionalization of single‐layer graphene (SLG) with three different aryl diazonium salts. Using scanning Raman microscopy (SRM) we confirmed the spatially resolved nature of the functionalization. We systematically investigated the influence of key laser parameters (power, irradiation time, and wavelength) and the electronic effects of the substituents on both the functionalization efficiency and integrity of graphene. Our solid‐phase approach unequivocally demonstrates that laser‐triggered covalent attachment can achieve high functionalization levels comparable to solution‐based methods. We also unveil a novel laser‐induced defunctionalization pathway at high laser powers and prolonged irradiation times, which allows for the precise, patterned functional group “erasure” – a significant advantage over nonselective thermal annealing. Furthermore, we successfully demonstrate the successful readdressing and refunctionalization of these laser “erased” areas, enabling a complete “write‐erase‐rewrite” cycle. This work establishes a robust and highly adaptable platform for creating complex, mixed‐functionalized graphene architectures with micrometer precision.

A comprehensive investigation of laser‐induced covalent patterning, defunctionalization, and refunctionalization of single‐layer graphene with aryl diazonium salts is reported. Scanning Raman microscopy verifies spatial control, while systematic variation of laser parameters and substituent effects highlights the versatility of the method. The demonstrated “write‐erase‐rewrite” capability establishes a robust platform for micrometer‐scale fabrication of complex, functionalized graphene architectures.