Engineering polarization surface of hierarchical ZnO microspheres via spray-annealing strategy for wide-frequency electromagnetic wave absorption  

作　　者：Lei Wang Mengqiu Huang Xuefeng Yu Wenbin You Biao Zhao Chongyun Liang Xianhu Liu Xuefeng Zhang Renchao Che 

机构地区：[1]Laboratory of Advanced Materials,Shanghai Key Lab of Molecular Catalysis and Innovative Materials,Department of Materials Science,Fudan University,Shanghai 200438,China [2]Department of Chemistry,Fudan University,Shanghai 200433,China [3]Joint-Research Center for Computational Materials,Zhejiang Laboratory,Hangzhou 311100,China [4]School of Materials Science and Engineering,Shanghai Institute of Technology,Shanghai 201418,China [5]Key Laboratory of Materials Processing and Mold,Zhengzhou University,Ministry of Education,Zhengzhou 450002,China [6]Institute of Advanced Magnetic Materials,College of Materials and Environmental,Engineering,Hangzhou Dianzi University,Hangzhou 310012,China

出　　处：《Journal of Materials Science & Technology》2022年第36期231-239,共9页材料科学技术（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.51725101,11727807,51672050,61790581,22088101);the Ministry of Science and Technology of China(No.2018YFA0209102);the Infrastructure and Facility Construction Project of Zhejiang Laboratory。

摘　　要：Regulating orientation growth plays a dominant role in enhancing dielectric properties for the electromagnetic(EM)functional materials,which faces a huge challenge in the synthesis method.By sprayannealing strategy,hierarchical ZnO microspheres assembled by ZnO nanorods and nanoparticles were successfully fabricated.With confined microsphere space and controlling crystal growth,oriented ZnO nanorods possess rich defects,Zn-polar,O-polar faces,and high permittivity.Meanwhile,temperaturedependency of exposed polarization surfaces is discovered in the semiconductor ZnO nanoparticles with evolved aspect ratios.As pure dielectric EM wave absorption material,the hierarchical ZnO microsphere exhibits adjustable complex permittivity and polarization behaviors.When the thickness is 2.4 mm,the hierarchical ZnO-1 absorber shows the widest efficient absorption(RL≤–10 d B)region from 9.9 to18.0 GHz(8.1 GHz,^50.6%testing frequency).The minimum reflection loss(RL)of ZnO-1 can reach–31.5 d B at only 2.0 mm.Because of the outstanding dielectric loss ability and wide absorption frequency,large-scale hierarchical ZnO microspheres can be a potential EM absorption candidate.

关 键 词：ZnO microspheres Spray drying Electromagnetic wave absorption Orientated polarization Dielectric loss 

分 类 号：TB34[一般工业技术—材料科学与工程]