1. DST Unit of Nanoscience and Thematic Unit of Excellence, Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
2. Faculty of Engineering and Natural Sciences, Tampere University, FI-33101 Tampere, Finland
3. Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
4. Institute of Photonics, University of Eastern Finland, FI-80101 Joensuu, Finland
5. Department of Bioproducts and Biosystems, Aalto University, FI-00076 Aalto, Finland