1. Institute of Fundamental and Frontier Sciences
2. University of Electronic Science and Technology of China
3. Chengdu 610054
4. China
5. Institute of Solar Energy Materials and Devices
6. College of Materials Science and Engineering
7. Sichuan University
8. Chengdu 610065
9. Department of Electronic and Electrical Engineering
10. University College London
11. London WC1E 7JE
12. UK
13. Centre for Photonic Systems
14. Department of Engineering
15. University of Cambridge
16. Cambridge CB3 0FA