Constructing carbon nanotube (CNT) based heterostructures has proven to be an effective way of improving the microwave absorption (MA) capability of these materials, regardless of whether the heterostructures are located on the inner or outer walls of the CNTs. However, the potential of the two sides of CNTs for constructing efficient MA heterostructures has not been compared, and the underlying mechanism behind this difference has not been determined. Therefore, CNT based heterostructures with Fe₂O₃ nanoparticles inside (Fe₂O₃-in-CNTs) and outside (Fe₂O₃-out-CNTs) of the CNTs were synthesized and characterized. The minimum reflection loss and maximum effective bandwidth of the Fe₂O₃-in-CNTs are −34.1 dB at 3.0 mm and 5.1 GHz at 2.6 mm, much better than those of the Fe₂O₃-out-CNTs. Stronger interfacial polarization at the inner surface of the CNTs than at the outer surface was confirmed using off-axis electron holography, which is regarded as the key factor that determines the excellent MA performance of the heterointerface constructed by the inner surface of the CNTs. The attractive potential of the inner surface of CNTs for constructing highly efficient MA heterostructures has, to our knowledge, not been proposed before, the findings of which can shed the light on the approach of developing CNT composited MA materials that have outstanding MA properties.

中文翻译：

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CNT基异质结构中位置选择性介电极化增强，可实现高效微波吸收

事实证明，构建基于碳纳米管（CNT）的异质结构是提高这些材料的微波吸收（MA）能力的有效方法，而不论异质结构是位于CNT的内壁还是外壁上。但是，尚未对CNT两侧构建高效MA异质结构的潜力进行比较，并且尚未确定这种差异背后的潜在机制。因此，合成并表征了具有CNT内部（Fe ₂ O ₃ -in-CNT）和外部（Fe ₂ O ₃ -out-CNT）的Fe ₂ O ₃纳米颗粒的基于CNT的异质结构。Fe的最小反射损耗和最大有效带宽₂ O ₃ in-CNTs在3.0 mm处为-34.1 dB，在2.6 mm处为5.1 GHz，比Fe ₂ O ₃ out-CNTs更好。使用离轴电子全息图确认了CNT内表面的界面极化强度比外表面强，这被认为是决定由CNT内表面构成的异质界面优异MA性能的关键因素。就我们所知，以前尚未提出过用于构建高效MA异质结构的CNT内表面的诱人潜力，其发现可为开发具有出色MA性能的CNT复合MA材料提供方法。