1. Department of Electronic Science and Engineering and Tianjin Key Laboratory of Process Control and Green Technology for Pharmaceutical Industry Nankai University Tianjin 300350 P. R. China
2. School of Mechanics and Photoelectric Physics Anhui University of Science and Technology Huainan 232001 P. R. China
3. School of Science Shandong Jianzhu University Jinan 250101 P. R. China
4. Research Group of Quantum‐Dot Materials & Devices Institute of New‐Energy Materials Tianjin University Tianjin 300350 P. R. China
5. School of Material Science and Engineering Hebei University of Technology Tianjin 300130 P. R. China
6. School of Physics The University of Sydney New South Wales 2006 Australia