Growth and chemistry of TCNQ films on nickel (111)

Abstract

The adsorption and temperature stability of the strong electron acceptor, tetracyanoquinodimethane (TCNQ), has been studied on a Ni(111) surface by thermal desorption, Auger, XPS, UPS and Raman spectroscopies. We find strong evidence for formation of negatively charged TCNQ, corresponding to TCNQ −. The onset of dehydrogenation of the adsorbed species varies with absolute coverage, starting at 460 K for submonolayer quantities of TCNQ and moving up to 500 K for the 350 K saturation-coverage film which is found to be 3 monolayers thick. The primary decomposition products are hydrogen cyanide and hydrogen (500–700 K) followed by carbon diffusion into the nickel and desorption of molecular nitrogen at 800 K.