Space‐Confined Low‐Power Laser‐Induced Fabrication of Nanoscale‐Cu‐Integrated Flexible Carbon Electrodes for Electrochemical Sensing

ABSTRACT Conventional laser irradiation of polyimide (PI) films for flexible electrode fabrication is limited by uncontrolled ablation, compromising structural precision and functional integration. Here, a spatially confined, low‐energy laser‐induced direct‐write strategy is reported that enables precise control over carbonization and nanomaterial integration in flexible carbon‐based electrodes. In the proposed sandwich configuration, a PI film is confined between two glass substrates during nanosecond (ns) laser irradiation, governing localized heat absorption and diffusion to achieve controlled graphitization with minimal structural damage. The confinement architecture further facilitates the laser‐induced reduction of a copper (Cu) metal–organic framework (Cu‐MOF) precursor, thereby enabling selective in situ incorporation of electroactive Cu nanoparticles directly into the carbon matrix. Optimization of the confinement geometry and laser parameters yields electrodes comprising highly graphitized, sheet‐like carbon structures with uniformly dispersed spherical Cu nanoparticles, improving both electrical conductivity and surface catalytic activity. The fabricated flexible electrodes are used as nonenzymatic glucose sensors, achieving a wide linear detection range (from 0.25 µ m to 10 m m ), a sensitivity of 2586.1 µA m m −1 cm −2 (0–1 m m ), and a detection limit of 2.72 µ m . Stable electrochemical performance is retained for the fabricated electrodes under repeated mechanical deformation, validating the robustness of this laser‐processing strategy for sensing applications.