Abstract: N-doped carbon materials are promising electromagnetic wave (EMW) absorbers, yet the distinct roles of N configurations (Graphitic-N, Pyridinic-N, and Pyrrolic-N) in dielectric loss remain unclear. This work introduces a ligand-centered molecular design strategy using 2-methylimidazole and 4-dimethylaminopyridine to precisely modulate N configurations. Systematic characterization reveals that 4-dimethylaminopyridine stabilizes Pyrrolic-N, increasing its content to 42.95% while reducing Graphitic-N to 9.57%, which introduces defects and enhanced polarization centers. Combining Debye relaxation theory and first-principles calculations, we quantitatively decouple dielectric contributions: Graphitic-N enhances conduction loss via improved carrier mobility, whereas Pyrrolic-N governs polarization loss. As a result, the Graphitic-N rich NC-M sample achieves a minimum reflection loss (RL) of -70.82 dB at 1.97 mm, while the Pyrrolic-N-rich NC-D sample extends the effective absorption bandwidth (EAB) to 5.9 GHz. This work establishes a clear structure-activity relationship, offering a rational pathway for designing configuration-controlled EMW absorbers.

Key words: N-doped, Electromagnetic wave absorption, Polarization loss, Dielectric properties