1. Institut de Chimie de Rennes, CNRS UMR 6509, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France, Department of Electrical Engineering, Graduate Institute of Electrooptical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan 106, and Institute of Chemistry, Academia Sinica, Taipei, Taiwan 115