1. Department of Physics University of Central Florida Orlando FL 32816 USA
2. Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
3. Key Laboratory of Medical Physics and Image Processing of Shandong Province School of Physics and Electronics Shandong Normal University Jinan 250358 P. R. China
4. School of Materials and Chemical Engineering Ningbo University of Technology Ningbo 315048 P. R. China
5. Department of Physics Bernal Institute University of Limerick Limerick V94 T9PX Ireland
6. Hybrid Materials for Opto‐Electronics Group Department of Molecules and Materials MESA+ Institute for Nanotechnology Molecules Center and Center for Brain‐Inspired Nano Systems Faculty of Science and Technology University of Twente Enschede 7500 AE Netherlands