* Corresponding authors

^a Department of Chemistry, University of California, One Shields Avenue, Davis, CA, USA
E-mail: albalch@ucdavis.edu, mmolmstead@ucdavis.edu
Fax: +1 (1)530 752 8995
Tel: +1 (1)530 752 0941

^b Department of Chemistry, Clemson University, Clemson, SC, USA
E-mail: luis@clemson.edu
Fax: +1 (1)864 656 6613
Tel: +1 (1)864 656 0778

^c Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
E-mail: hdorn@vt.edu
Fax: +1 (1)540 231 3255
Tel: +1 (1) 540 231 5953

^d Luna Innovations, Inc., (nanoWorks division), 521 Bridge Street, Danville, VA, USA