The authors gratefully acknowledge the financial support from the EU Graphene Flagship project (no. 881603). This work was partly supported the Agence Nationale de la Recherche (ANR) through the LabEx project Chemistry of Complex Systems (ANR-10-LABX-0026_CSC). We wish to acknowledge the Centre National de la Recherche Scientifique (CNRS) and the International Center for Frontier Research in Chemistry (icFRC). S.P. is indebted to the Chinese Scholarship Council for supporting her Ph.D. internship as a visiting Ph.D. student. A.F.A. wish to thanks the EUR CSC Graduate School (Strasbourg, France) for supporting his Master studies.