1. Electronic Materials Research Laboratory Key Laboratory of the Ministry of Education & International Center for Dielectric Research School of Electronic Science and Engineering Xi'an Jiaotong University Xi'an China
2. State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University Xi'an China
3. Micro‐optoelectronic Systems Laboratories Xi'an Technological University Xi'an China
4. Department of Materials Science and Engineering University of Sheffield Sheffield UK
5. International Research Centre for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China
6. National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei China