Ultra‐Low‐Threshold Laser Patterning of Graphene With a Modular Sulfonium Library for Programmable Work‐Function Engineering

Abstract

ABSTRACT Achieving spatially resolved chemical functionalization on graphene lattices is essential for fabricating advanced two‐dimensional (2D) architectures. However, current covalent patterning strategies struggle to simultaneously minimize energy input for lattice preservation and offer the chemical versatility required for fine‐tuning the local doping state of the 2D lattice. Here, a modular diaryl‐sulfonium platform is developed for the ultra‐low‐threshold covalent patterning of monolayer graphene, further enabling substituent‐encoded pattern of local work‐function. Driven by a highly efficient, graphene‐mediated hot‐electron single‐electron transfer (SET) mechanism, this approach lowers activation barriers, enabling non‐destructive patterning with laser powers as low as 0.10 mW and irradiation time of a few seconds—orders of magnitude lower than conventional photon‐driven processes—thereby ensuring high pattern fidelity without thermal degradation. By incorporating a library of six chemically distinct σ‐bound substituents (including phenyl, fluorophenyl, trifluoroethyl, vinyl, phenylthiophenyl, and bromoethyl) onto a unified sulfonium scaffold, precise control over local work‐function can be achieved. Kelvin Probe Force Microscopy (KPFM) reveals a continuous, chemically tunable spectrum of surface potential shifts (ΔCPD from ∼30 to ∼300 mV). Combined with exceptional ambient stability and thermal erasability, this work offers a robust, energy‐efficient paradigm for chemically encoding reconfigurable 2D electronic landscapes.