1. Department of Chemistry and the Materials Research Center Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
2. Key Laboratory of Green Chemistry and Technology (Ministry of Education) College of Chemistry Sichuan University Chengdu 610064 P. R. China
3. Department of Materials Science and Engineering Northwestern University Evanston IL 60208 USA
4. Applied Physics Program and the Materials Research Center Northwestern University 2220 Campus Drive Evanston IL 60208 USA
5. Department of Materials Science and Engineering and the Argonne Northwestern Solar Energy Research Center (ANSER) Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
6. Flexterra Inc. 8025 Lamon Avenue Skokie IL 60077 USA