1. Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
2. Department
of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
3. Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
4. Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025, United States