[1] Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Dahlem), Germany
[2] Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan
[3] Department of Applied Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom
[4] KANSAI Advanced Research Centre, Nanotechnology Section, 588-2, Iwaoka, Iwaoka-cho, Nishiku, Kobe 651-24, Japan