[1] Ecole Polytech Fed Lausanne, Lab Photomol Sci, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland
[2] Ecole Polytech Fed Lausanne, Lab Photon & Interfaces, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland
[3] Ecole Polytech Fed Lausanne, Grp Mol Engn Funct Mat, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland
[4] Ist Italiano Tecnol, Ctr Nano Sci & Technol Polimi, I-20133 Milan, Italy
[5] Panasonic Corp, Adv Res Div, Kadoma, Osaka 5718501, Japan
[6] Politecn Milan, Dipartimento Fis, I-20133 Milan, Italy