| AVS 59th Annual International Symposium and Exhibition | |
| Graphene and Related Materials Focus Topic | Monday Sessions |
| Session GR+EM+ET+NS+TF-MoA |
| Session: | Electronic Properties and Charge Transport |
| Presenter: | L. Kong, Univ. of Nebraska-Lincoln |
| Authors: | L. Kong, Univ. of Nebraska-Lincoln G.J. Perez Medina, Univ. of Nebraska-Lincoln, Univ. of Puerto Rico J. Colón Santana, Univ. of Nebraska-Lincoln L. Rosa, Univ. of Nebraska-Lincoln, Univ. of Puerto Rico L. Routaboul, Maître de conférences de l'Université de Strasbourg, France P. Braunstein, Maître de conférences de l'Université de Strasbourg, France B. Doudin, Institut de Physique et Chimie des Matériaux de Strasbourg, France C.-M. Lee, Kyung Hee Univ., Korea J. Choi, Kyung Hee Univ., Korea P.A. Dowben, Univ. of Nebraska-Lincoln |
| Correspondent: | Click to Email |
Both gold and graphene are excellent conductors, and one might expect that both conductors would fully screen the photoemission and inverse photoemission final states of a molecular adsorbate, but in fact this is not the case. The comparison of the electronic structure of p-quinonoid zwitterionic type molecules with a large intrinsic dipole of 10 Debyes adsorbed on both gold and graphene on copper substrates, shows that the interaction between the adsorbate molecules and graphene is very weak, confirming that graphene is chemically inert. We find that the photoemission and inverse photoemission final states are well screened for p-quinonoid zwitterionic dipolar molecules on gold. This is not observed in the case of this quinonoid zwitterion adsorbed on graphene on copper. This weaker screening is evident in a larger highest occupied molecular orbital to lowest unoccupied molecular orbital gap for the molecules on graphene. The larger highest occupied molecular orbital to lowest unoccupied molecular orbital gap for the molecules on graphene indicates that a much weaker screening on the photoemission and inverse photoemission final states for these dipolar molecules on graphene than that on gold. This work is reviewed in the context of other studies of molecular adsorption on graphene.