1. Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
2. Theiss Research, Inc., La Jolla, California 92037, United States
3. Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States
4. Department of Chemistry, Ajou University, Suwon 16499, Korea
5. Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States