1. Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark, http://www.ku.dk/english/
2. Sino‐Danish Center for Education and Research (SDC), Shuangqing Road 18, Haidian District, Beijing 100085, People's Republic of China
3. Nano‐Science Center, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
4. Center for Electron Nanoscopy, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
5. Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark