Zhang Yajun, Pan Long, Zhang Peigen, Sun ZhengMing
Key Laboratory of Advanced Metallic Materials of Jiangsu Province School of Materials Science and Engineering Southeast University Nanjing 211189 P. R. China.
Small Sci. 2022 May 21;2(7):2200018. doi: 10.1002/smsc.202200018. eCollection 2022 Jul.
High-performance electromagnetic (EM) absorbing materials are in urgent need due to severe EM pollution caused by fast development of communication technology and electronic devices. Gradient structure benefits EM absorbing performance. However, the relevant study is very limited, and the relationship between component layers and overall performance is unclear. Herein, a gradient structure containing impedance matching layer, lossy layer, and reflective layer is built via repeated casting-drying method using TiCT MXene and polyvinyl alcohol. With optimized gradient structure, the minimum reflection loss (RL) reaches -74.8 dB with effective absorbing bandwidth (EAB) covering the whole X-band. The good absorbing performance is ascribed to the good impedance matching, which is derived from the stepwisely increased permittivity of each layer. Moreover, it is found that RL reaches the lowest value when lossy layer permittivity is close to the average permittivity of impedance matching layer and reflective layer. In addition, the decrease of lossy layer permittivity causes the decrease of total thickness of the gradient structure. This work demonstrates the effectiveness of gradient structure toward strong and broadband microwave absorption and provides rules for designing proper gradient structures to satisfy different requirements.
由于通信技术和电子设备的快速发展导致严重的电磁污染，高性能电磁吸收材料亟待开发。梯度结构有利于电磁吸收性能。然而，相关研究非常有限，各组成层与整体性能之间的关系尚不清楚。在此，通过使用TiCT MXene和聚乙烯醇的重复浇铸干燥法构建了包含阻抗匹配层、损耗层和反射层的梯度结构。通过优化梯度结构，最小反射损耗（RL）达到-74.8dB，有效吸收带宽（EAB）覆盖整个X波段。良好的吸收性能归因于良好的阻抗匹配，这源于各层介电常数的逐步增加。此外，发现当损耗层介电常数接近阻抗匹配层和反射层的平均介电常数时，RL达到最低值。此外，损耗层介电常数的降低导致梯度结构总厚度的减小。这项工作证明了梯度结构对强宽带微波吸收的有效性，并为设计合适的梯度结构以满足不同要求提供了规则。
