* Corresponding authors

^a Department of Chemistry, University of Liverpool, Crown Street, Liverpool, UK

^b Institute for Tropical Technology (ITT), Vietnam Academy of Science and Technology (VAST), Vietnam

^c Department of Physics, University of Liverpool, Crown Street, Liverpool, UK

^d Iota NanoSolutions Ltd, Crown Street, Liverpool, UK

^e School of Biological Sciences, University of Liverpool, Crown Street, Liverpool, UK

^f Liverpool Institute for Nanoscale Science Engineering and Technology (LINSET), University of Liverpool, Crown Street, Liverpool, UK

^g The Davy-Faraday Research Laboratory, The Royal Institution of Great Britain, 21 Albemarle Street, London, UK
E-mail: ntk.thanh@ucl.ac.uk

^h Department of Physics & Astronomy, University College London, Crown Street, London, UK