1. Key Lab for Special Functional Materials; Ministry of Education; National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting Technology; School of Materials Science and Engineering; and Collaborative Innovation Center of Nano Functional Materials and Applications; Henan University; Kaifeng 475004 China
2. School of Materials Science and Engineering; Georgia Institute of Technology; Atlanta GA 30318 USA
3. Department of Mechanical and Automation Engineering; The Chinese University of Hong Kong; Shatin, N.T. Hong Kong SAR China
4. Beijing Institute of Nanoenergy and Nanosystems; Chinese Academy of Sciences; Beijing 100083 China