Selective adsorption of copper phthalocyanine atop functionalized organic monolayers

We report the observation of site-selective adsorption of copper phthalocyanine (CuPc) atop organic surfaces. The organic surfaces consist of monolayers of various alkane derivatives (stearic acid, 1-octadecano,1 and 1-iodooctadecane) adsorbed on the surface of highly oriented pyrolytic graphite (HOPG). Our scanning tunneling microscopy (STM) studies show that the alkane derivatives form templates, which can provide different adsorption sites for the CuPc. The observed selective adsorption behavior is attributed to a dominating preference of the CuPc for adsorption on the hydrocarbon-chain portions of the supporting layers. We also discuss the results of molecular mechanics simulations, which support the STM observations.