1. Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, No.99 Shangda Road, Baoshan District, Shanghai 200444, P. R. China
2. Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
3. Key Laboratory of Advanced Display and System Applications, Shanghai University, Ministry of Education, No.149 YanChang Road, Jingan District, Shanghai 200072, P. R. China
4. School of Materials Science and Engineering, Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, 1 Jinji Road, Guilin 541004, P. R. China