Graphene Materials With Anomalous Infrared Emissivity Yet Superb Chemical Stability

Low infrared emissivity materials (i.e., metallic materials) are of significance for thermal radiation regulation. However, the easy-corrosion susceptibility and poor chemical stability are common bottleneck issues that affect their applications. We report a versatile electronic structure modulation strategy for low infrared (IR) emissivity graphene by engineering the surface chemistry of precursor graphene oxide and the followed reduction/doping process. The fabrication protocols minimize the irreparable disruption of the intrinsic graphitic structure and enable controllable assembly of nanosheets by suppressing formation of carboxyl groups. More significantly, the convenient reduction and halogen doping effects synergistically minimize electron scattering and enhance interfacial charge transport. The low-defective graphitic structure and the ordered multiscale architecture, as well as halogen doping effect, afford exceptional carrier mobility (∼27.1 cm² V^-1s^-1), carrier density (5.73 × 10²⁰ cm^-3), and electrical conductivity comparable to highly oriented pyrolytic graphite. Surprisingly, the anomalous metallic response gives the lowest IR emissivity (0.15, 8-14 µm) for carbon materials, comparable to MXene and traditional metallic materials. The large-scale processability and outstanding long-term stability under chemical conditions offer new insights for the potential infrared applications of graphene materials.