1. Institute for Advanced Study Shenzhen University Shenzhen 518060 P. R. China
2. Centre for Advanced Optoelectronic Functional Materials Research Key Laboratory for UV Light-Emitting Materials and Technology Northeast Normal University Changchun 130000 P. R. China
3. Harrow International School Hong Kong 38 Tsing Ying Road, Tuen Mun New Territories Hong Kong P. R. China
4. Institute of Microscale Optoelectronics Shenzhen University Shenzhen 518060 P. R. China