1. Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
2. National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
3. Division of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510006, P. R. China
4. Institute of Pulmonary Diseases, Sun Yat-sen University, Guangzhou 510006, P. R. China
5. Department of Mechanical & Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
6. Department of Electronic & Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong