1. School of Photovoltaic and Renewable Energy (SPREE), University of New South Wales (UNSW), Sydney 2052, Australia
2. Research Centre for Functional Materials (RCFM), National Institute for Materials Science (NIMS), Tsukuba 305-0047, Japan
3. Electron Microscope Unit (EMU), University of New South Wales (UNSW), Sydney 2052, Australia
4. School of Mechanical and Manufacturing Engineering, University of New South Wales (UNSW), Sydney 2052, Australia
5. School of Engineering, Macquarie University, Sydney 2109, Australia