1 Departments of Chemistry and Physics, University of California, Berkeley, Berkeley, CA, USA. nsginsberg@berkeley.edu.
2 Materials Science Division and Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. nsginsberg@berkeley.edu.
3 Kavli Energy NanoSciences Institute at Berkeley, Berkeley, CA, USA. nsginsberg@berkeley.edu.
4 Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. tisdale@mit.edu.