Fluorine-rich carbon dots via liquid-phase pulsed laser for synergistic enhancement of flexible organohydrogel electromagnetic wave absorber

Fluorine-rich carbon dots (CDs) were prepared via a one-step liquid-phase pulsed laser ablation method using fluorinated graphite as the precursor, and subsequently incorporated into an organohydrogel matrix composed of glycerol/water, polyvinyl alcohol and acrylamide monomers to fabricate a novel flexible electromagnetic wave absorber. By tuning the single-pulse laser energy, the graphitization degree and surface functional groups of the CDs were precisely regulated. Fluorine atoms are present not only within the surface active moieties but are also doped into the graphitized carbon cores, where they introduce structural defects and enhancing the dipole polarization capability. The uniform dispersion of the CDs throughout the three-dimensional porous organohydrogel network markedly improves the dielectric loss characteristics and impedance matching. At a thickness of 2.8 mm, the as-prepared CDs-2 hydrogel achieves an optimal reflection loss (RL_min) of −54.1 dB at 11.098 GHz and an absorption bandwidth (EAB) of 3.36 GHz, while maintaining favorable tensile properties and mechanical flexibility. The efficient electromagnetic absorption within the X-band can be ascribed to the synergistic effects of multiple reflections, polarization loss, and conductive loss. This work offers a new strategy for the development of high-performance flexible electromagnetic wave absorber.