1. Department of Chemistry and the Argonne−Northwestern Solar Energy Research Center, Northwestern University, Evanston, Illinois 60208-3113, Photovoltaic and Optoelectronic Devices Group, Departament de Física, Universitat Jaume I, 12071 Castelló, Spain, and Departamento de Físico-Química, Instituto de Química de Araraquara, Universidade Estadual Paulista, R. Prof. Francisco Degni s/n, 14800-900 Araraquara SP, Brazil