1. Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore
2. Departments of Chemistry and Chemical & Biomolecular Engineering, National University of Singapore, Singapore 119077, Singapore
3. Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 639798, Singapore
4. Department of Radiation Science and Technology, Delft University of Technology, Delft 2629 JB, The Netherlands