Phase structure-induced amplification of interfacial polarization loss for excellent electromagnetic wave absorption

The development of multicomponent dielectric composites has emerged as a predominant approach to achieving exceptional electromagnetic (EM) wave absorbers. However, elucidating the intrinsic characteristics and absorption mechanism for EM wave absorbers poses significant challenges due to the intertwined discussion of electromagnetic loss with dipole polarization loss, defects/interfacial polarization, and conductive loss, among others. To address this issue, manganese selenide (MnSe) nanocrystals with different phase structures are synthesized successfully by the thermal injection decomposition method, including star-shaped α-MnSe nanocrystals and tetrapod-shaped γ-MnSe nanocrystals, which were combined with rGO layers to form α-MnSe/rGO composites and γ-MnSe/rGO composites. Through controllable phase structure, tune the interfacial charge transfer and establish the link between interfacial polarization and EM wave absorption. Owing to the boosted interfacial polarization loss provided by the star-shaped α-MnSe nanocrystals and rGO layers, α-MnSe/rGO composites harvest an RLmin of −62.4 dB (2.7 mm) and a broad bandwidth of 7.52 GHz at 2.9 mm. This study successfully breaks through the limitations of conventional component design, establishing a robust correlation between phase structure/interfacial polarization and electromagnetic wave dissipation capability. These findings provide valuable insights for developing advanced materials with enhanced electromagnetic wave absorption properties.