1. School of Flexible Electronics (Future Technologies) & Institute of Advanced Materials, Key Laboratory of Flexible Electronics, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing, China
2. National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
3. Department of Physics, University of Arkansas, Fayetteville, AR, USA