Structure and electronic configuration of tetracyanoquinodimethane layers on a Au(111) surface

The organic molecule tetracyanoquinodimethane (TCNQ) is a strong charge acceptor with a large tendency to form metal-organic charge transfer compounds. Using a low temperature scanning tunneling microscope we characterize the self-organization of TCNQ in ultra-thin films on a Au(1 1 1) surface and its electronic structure. We find that the molecules are weakly adsorbed on the metal, forming extended networks stabilized by hydrogen bonds. Despite its strong acceptor character, we find a negligible charge transfer from the metal surface. (C) 2008 Elsevier B.V. All rights reserved.