1. Institut de Ciència de Materials de Barcelona (CSIC) and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Campus Universitari de Bellaterra, Cerdanyola E-08193, Barcelona, Spain
2. Laboratory for Organic Matter Physics, University of Nova Gorica, Vipavska 13, SI-5000 Nova Gorica, Slovenia
3. Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, B-7000 Mons, Belgium
4. Department of Eng. Electronica and CrNE, Universitat Politecnica Catalunya, E-08034 Barcelona, Spain
5. Serveis Tecnics de Recerca, Universitat de Girona, Edifici Jaume Casademont (porta E), Pic de Peguera, 15 La Creueta, E-17003 Girona, Spain