Laser‐Induced Covalent Defunctionalization of Graphene — Precise Patterning and Site‐Selective Removal of Functional Groups

Abstract In this study, for the first time, site‐selective defunctionalization concepts for structuring and reusing covalently patterned monolayer graphene are reported. Using a laser‐activated precursor deposition approach with dibenzoyl peroxide (DBPO), phenyl moieties are covalently grafted onto graphene with high spatial precision. Temperature‐dependent Raman spectroscopy reveals that functionalization is fully reversible, with lattice‐scale defunctionalization occurring at 225 °C, independent of the initial functionalization degree. By applying high‐power laser irradiation ( λ _{exc .} = 532 nm) the covalent addends can be selectively removed with high local control, as confirmed by Raman mapping and Kelvin probe force microscopy (KPFM). This photothermal process enables a lateral defunctionalization resolution of ≈0.5 µm. Importantly, it is demonstrated that “erased” regions can be successfully refunctionalized using a second laser “writing” sequence, achieving highly reproducible functionalization levels. The ability to iteratively “write,” “erase,” and “rewrite” covalent functionalities with a precise control of the grafting pattern establishes graphene as a promising platform for chemically tunable, high‐resolution 2D data storage.