1. C.H.O.S.E. (Centre for Hybrid and Organic
Solar Energy), Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
2. Department of Physics,
Research Center in Physics of Matter and Radiation (PMR), LISE Laboratory, Université de Namur ASBL, Rue de Bruxelles 61, 5000 Namur, Belgium