1. Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
2. Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
3. School of Physics, Complex Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4, Ireland
4. Centre for Disruptive Photonic Technologies, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
5. Optoelectronics Research Centre, University of Southampton, Southampton SO17 183, United Kingdom
6. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
7. NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
8. Division of Materials Technology, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore