1. Electronic Materials Research Laboratory Key Laboratory of the Ministry of Education & International Center for Dielectric Research School of Electronic and Information Engineering Xi'an Jiaotong University Xi'an 710049 P. R. China
2. Micro‐optoelectronic Systems Laboratories Xi'an Technological University Xi'an 710032 P. R. China
3. State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University Xi'an 710049 P. R. China
4. International Research Centre for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 P. R. China
5. State Key Laboratory for Mechanical Behaviour of Materials Xi'an Jiaotong University Xi'an 710049 P. R. China
6. School of Material Science and Energy Engineering Foshan University Foshan Guangdong 528000 P. R. China