•  
  •  
 
Nano Research

Article Title

Flexible design of gradient multilayer nanofilms coated on carbon nanofibers by atomic layer deposition for enhanced microwave absorption performance

Authors

Shichao Zhao, State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China University of Chinese Academy of Sciences, Beijing 100039, China
Lili Yan, State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China University of Chinese Academy of Sciences, Beijing 100039, China
Xiaodong Tian, University of Chinese Academy of Sciences, Beijing 100039, China Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Yequn Liu, State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China Analytical Instrumentation Center, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Chaoqiu Chen, State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Yunqin Li, State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China University of Chinese Academy of Sciences, Beijing 100039, China
Jiankang Zhang, State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China University of Chinese Academy of Sciences, Beijing 100039, China
Yan Song, Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Yong Qin, State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China

Keywords

atomic layer deposition, conductive gradient multilayer nanofilms, electrospun carbon nanofiber, microwave absorption, dielectric material

Abstract

ABSTRACT Impedance matching is important for achieving high-efficiency microwave absorbers. The high conductivity of dielectric loss materials such as pure metals and carbon nanomaterials generally results in poor absorption owing to the low impedance matching between the absorbers and air. Carbon nanostructures are very promising candidates for high-efficiency absorption because of their attractive features including low density, high surface area, and good stability. Herein, a new strategy is proposed to improve the impedance matching of dielectric loss materials using electrospun carbon nanofibers as an example. The carbon nanofibers are coated with specifically designed gradient multilayer nanofilms with gradually increasing electroconductibility synthesized by doping ZnO with different Al2O3 content (AZO) by atomic layer deposition. The gradient nanofilms are composed of five layers of dielectric films, namely, pure Al2O3, AZO (5:1, the pulse cycle ratio of ZnO to Al2O3), pure ZnO, AZO (10:1), and AZO (20:1). The versatile gradient films serve as intermediate layers to tune the impedance matching between air and the carbon nanofiber surfaces. Therefore, the carbon nanofibers coated with gradient films of rationally selected thicknesses exhibit remarkably enhanced microwave absorption performance, and the optimal reflection loss reaches −58.5 dB at 16.2 GHz with a thickness of only 1.8 mm. This work can help further understand the contribution of impedance matching to microwave absorption. Our strategy is general and can be applied to improve the absorption properties of other dielectric loss materials and even for applications in other fields.

Graphical Abstract

Publisher

Tsinghua University Press

Share

COinS