1 Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China.
2 Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China. Electronic address: yuejiang@m.scnu.edu.cn.
3 Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.
4 Department of Physics, Boston College, Chestnut Hill MA 02467, USA.
5 Center for Excellence in Nanoscience (CAS), Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS), National Center for Nanoscience and Technology, Beijing 100190, China; Guangdong Provincial Engineering Technology Research Center for Transparent Conductive Materials, Guangzhou 510006, China. Electronic address: ding@nanoctr.cn.
6 Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; Guangdong Provincial Engineering Technology Research Center for Transparent Conductive Materials, Guangzhou 510006, China. Electronic address: gaojinwei@m.scnu.edu.cn.