[1] Univ Kentucky, Dept Chem, Lexington, KY 40506 USA
[2] Univ London Imperial Coll Sci Technol & Med, Dept Chem, London SW7 2AZ, England
[3] Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA
[4] Georgia Inst Technol, Ctr Organ Photon & Elect, Atlanta, GA 30332 USA
[5] Chinese Acad Sci, Inst Chem, Beijing Natl Lab Mol Sci, Beijing 100190, Peoples R China
[6] Polyera Corp, Skokie, IL 60077 USA