Shen Hao, Wang Zhen, Wang Chun, Zou Pengfei, Hou Zhaoyang, Xu Chunlong, Wu Hongjing
Department of Applied Physics, School of Science, Chang'an University, Xi'an 710064, China.
School of Science, Xi'an Shiyou University, Xi'an 710064, China.
Nanomaterials (Basel). 2022 Aug 20;12(16):2871. doi: 10.3390/nano12162871.
Controlling defects and interfaces in composite absorbers can effectively regulate electromagnetic (EM) parameters and enhance the electromagnetic wave (EMW) absorption ability, but the mechanism still needs to be further elucidated. In this study, ZnFeO/ZnO/C composite was synthesized via the hydrothermal method followed by post-annealing in different atmospheres. Defects and interfaces were characterized by Raman, PL spectroscopy, XPS and TEM, and their relationship with dielectric loss and EMW absorption performance was discussed in detail. Results show that the N-annealed ZnFeO/ZnO/C composite with abundant defects and interfaces as well as an optimized composition exhibits excellent EMW dissipation ability, with a value of -17.4 dB and an of 3.85 GHz at a thickness of 2.28 mm. The excellent EMW absorption performance originates from suitable impedance matching, significant conduction loss and strong dielectric loss (interfacial polarization, diploe polarization and defect polarization) dominated by lattice defects and interfaces. This study provides a view into the relationship between defects, interfaces, EM parameters and EMW absorption ability, and also suggests an effective way to promote EMW dissipation ability of the absorbers by controlling defects and interfaces.
控制复合吸收体中的缺陷和界面可以有效地调节电磁（EM）参数并增强电磁波（EMW）吸收能力，但其机理仍需进一步阐明。在本研究中，通过水热法合成了ZnFeO/ZnO/C复合材料，随后在不同气氛中进行后退火处理。通过拉曼光谱、光致发光光谱、X射线光电子能谱和透射电子显微镜对缺陷和界面进行了表征，并详细讨论了它们与介电损耗和EMW吸收性能的关系。结果表明，经N退火处理的ZnFeO/ZnO/C复合材料具有丰富的缺陷和界面以及优化的成分，表现出优异的EMW耗散能力，在2.28 mm厚度下，反射损耗值为-17.4 dB，有效吸收带宽为3.85 GHz。优异的EMW吸收性能源于合适的阻抗匹配、显著的传导损耗以及由晶格缺陷和界面主导的强介电损耗（界面极化、偶极极化和缺陷极化）。本研究揭示了缺陷、界面、EM参数和EMW吸收能力之间的关系，也提出了一种通过控制缺陷和界面来提高吸收体EMW耗散能力的有效方法。
