Liu Pengfei, Li Da, Zhao Xiaoguang, Huang Yanqi, Ma Jingyun, Lian Jiangfang, Qiu Shijie, Shen Zhisen, Li Zhuan, Ma Zhenhui, Ma Song
The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, P. R. China.
Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, SAR, 999077, P. R. China.
Adv Sci (Weinh). 2025 Jul 16:e10198. doi: 10.1002/advs.202510198.
Nitrogen-doped carbon (NC) nanosheets with tunable electronic features have been considered as effective dielectric materials to tackle the severe electromagnetic pollution. However, it is still a critical issue to reconcile the contradiction between the skin effect originates from the intrinsic high conductivity of NC and the optimal dielectric loss capability. Herein, we prepared NC nanosheets consisting of numerous microdomain to simultaneously achieve good impedance matching and dielectric dissipation performance. The NC surfaces are separated by defect regions into numerous 50-100 nm dielectric isolated islands, while loading ≈40 nm Ni-based alloy nanoparticles (NPs) as tunable electron donating sources. The electron cloud density of the loaded NPs can be tuned by altering the alloy species including NiCo, NiFe and NiMn. NiFe and NiMn NPs with stronger electron donating ability can provide more mobile charges in the isolated islands than that of Ni and NiCo NPs, thereby facilitating the enhancement of electron migration and in-plane interfacial polarization. Consequently, NiFe@NC with better dielectric-magnetic synergy presented a maximum absorption intensity of -101.6 dB with a broadened absorption bandwidth of 10.7 GHz. This work proposes for the first time to effectively tailor the electron cloud density for absorbers utilizing alloying treatment and offers profound insights into dielectric loss mechanisms.
具有可调电子特性的氮掺杂碳（NC）纳米片被认为是解决严重电磁污染的有效介电材料。然而，如何协调源于NC固有高电导率的趋肤效应与最佳介电损耗能力之间的矛盾仍是一个关键问题。在此，我们制备了由大量微区组成的NC纳米片，以同时实现良好的阻抗匹配和介电耗散性能。NC表面被缺陷区域分隔成许多50-100纳米的介电隔离岛，同时负载约40纳米的镍基合金纳米颗粒（NPs）作为可调电子供体源。通过改变合金种类（包括NiCo、NiFe和NiMn）可以调节负载NPs的电子云密度。与Ni和NiCo NPs相比，具有更强电子供体能力的NiFe和NiMn NPs可以在隔离岛中提供更多的移动电荷，从而促进电子迁移和面内界面极化的增强。因此，具有更好介电-磁协同效应的NiFe@NC呈现出-101.6 dB的最大吸收强度和10.7 GHz的拓宽吸收带宽。这项工作首次提出利用合金化处理有效地调整吸收体的电子云密度，并为介电损耗机制提供了深刻的见解。
