Affiliation of Author(s):材料科学与技术学院

Journal:ADVANCED FUNCTIONAL MATERIALS

Key Words:complex permittivity conduction loss dielectric materials point defect polarization

Abstract:Dielectric materials are greatly desired for electromagnetic absorption applications. Lots of research shows that conduction loss and polarization are two of the most important factors determining complex permittivity. However, the detailed dissipation mechanisms for the improved microwave absorption performance are often based on semiempirical rules, lacking practical data relationships between conduction loss/polarization and dielectric behaviors. Here, a strategy of introducing point defects is used to understand such underlying relationships, where polarizability and conductivity are adjustable by manipulating oxygen deficiency or heteroatoms. Based on first principles calculations and the applied oxygen-deficient strategy, dielectric polarization is shown to be dominant in determining the permittivity behaviors in semiconductors. Meanwhile, the presented nitrogen doping strategy shows that conduction loss is dominant in determining the permittivity behavior in graphitized carbon materials. The validity of the methods for using point defects to explore the underlying relations between conduction loss/polarization and dielectric behaviors in semiconductor and graphitized carbon are demonstrated for the first time, which are of great importance in optimizing the microwave absorption performance by defect engineering and electronic structure tailoring.

ISSN No.:1616-301X

Translation or Not:no

Date of Publication:2019-07-01

Co-author:Quan, Bin,Shi, Wenhao,Ong, Samuel Jun Hoong,Lu, Xiaochi,Wang, Paul Luyuan,Guo Yufeng,Zheng, Lirong,Xu, Zhichuan J.

Correspondence Author:姬广斌,郭宇锋,Xu, Zhichuan J.,jiguangbin