1. National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronic, South China Normal University, Guangzhou 510006, China
2. International Academy of Optoelectronics at Zhaoqing, South China Normal University, Zhaoqing 526238, China
3. Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
4. Department of Chemical Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada