An XPS study of the interaction between tin(II) phthalocyanine and polycrystalline iron

The interaction between tin phthalocyanine (SnPc) and polycrystalline iron has been studied with XPS and synchrotron radiation excited XPS. After incremental annealing of a thin film of SnPc on a polycrystalline iron substrate, a low binding energy component of the Sn 3d core level became increasingly abundant. This component is attributed to metallic tin, and thus, it is suggested that a substitution reaction has occurred. Quantitative analysis of the carbon and nitrogen core level intensities is consistent with such a substitution. The reaction is observable at room temperature, but is enhanced at elevated temperatures. It is also shown that after thermal desorbtion of the SnPc adlayer, the residual carbon component is significantly reduced relative to a thermally cleaned polycrystalline surface.