摘要
Heteroatom substitution has been investigated to be a feasible way to optimize microwave absorption properties of core-shell structural nanocapsules at gigahertz.Although dielectric capacity has been increased at specific frequency with substituted absorbents,its broadband absorption performance is still relatively poor ascribed to the low dipole oscillation amplitude of single substituted heteroatom.In this study we demonstrate that sulfur and oxygen co-substituted heterostructure leads to high microwave absorption property of core-shell structural Fe@C nanocapsules at broadened frequency range,comparable to the single sulfur substitutional Fe@C nanocapsules.Experimental characterizations coupled with first-principles calculations reveal that the microwave absorption enhancement is triggered by the sulfur-oxygen co-substitution,which results in the serious symmetry breaking and thus leads to the charge separation at the co-substituted area.In particular,the nanocapsules exhibt the minimum reflection loss capcacity R(d B)of-52 d B at 6.8 GHz and the bandwith for R(d B)<-20 dB is in the frequency range of 3.1-12.7 GHz.The present study not only offers a deep insight into the relationship between heteroatom and microwave absorption property,but also puts forward a mentality for further designing microwave absorbents.
伴随着电子信息行业的迅猛发展,高频段电磁波由于其信息容量大成为了电子通讯领域的重要载体.但是,其所导致的电磁波污染以及电磁干扰问题已经大大影响了人们的生活和相关设备运行.而异质结构由于其空间不对称性,可以诱发形成电偶极子,已经被报道可以有效地提升材料的微波吸收性能.本文通过空气气氛下退火处理,以硫元素掺杂Fe@C纳米胶囊为基础,制备了具有异质硫元素和氧元素共同掺杂的Fe@C纳米胶囊材料.XPS分析发现掺杂结构主要由-C-S-C-、-C=S-、-C-SO-以及-C-SO2-四种结构组成.电磁响应测试结合第一性原理计算模拟发现,C-S-O异质掺杂结构有着所有异质掺杂结构中最高的电偶极子偶极矩,在外部电磁场的作用下,相较于硫元素掺杂异质结构,上述共掺杂异质结构将会产生更加强烈的极化震荡,并在宏观上体现为介电损耗性能的提升和微波吸收性能的增长.
作者
Yixing Li
Xinyu Chen
Qian Wei
Weiwei Liu
Yanhui Zhang
Gaowu Qin
Zhen Shi
Xuefeng Zhang
李逸兴;陈新宇;韦钱;刘伟伟;张艳辉;秦高梧;石振;张雪峰(School of Materials Science and Engineering,Key Laboratory for Anisotropy and Texture of Materials(MOE),Northeastern University,Shenyang 110819,China;Institute of Advanced Magnetic Materials,College of Materials and Environmental Engineering,Hangzhou Dianzi University,Hangzhou 310012,China)
基金
supported by the National Natural Science Foundation of China(U1704253,U1908220)
the Fundamental Research Funds for the Central Universities(N160208001,N180206001)
the Zhejiang Provincial Natural Science Foundation(LR18E010001)
the National 1000-Plan for Young Scholars
the Start-Up Funding Supported from the Northeastern University of China。
