1. Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland, Departament de Ciències Experimentals, Universitat Jaume I, 12071 Castelló, Spain, and Environmental Material Laboratory, Material Science of Engineering, Graduate School of Engineering, Shibaura Institute of Technology 3-9-14, Shibaura, Minatoku, Tokyo, Japan 108-8548