Iodine-Induced Structural Transformations of Co-Phthalocyanine on Au(111)

Iodine doping in organic films has been well studied in polymer chemistry, while the role of iodine doping in regulating self-assembled molecular structures on surfaces under ultrahigh vacuum conditions has been little discussed. Herein, we choose iodine (I-2) and cobalt-phthalocyanine (CoPc) molecules as a model system that presents stepwise structural transformation of CoPc self-assembled structures induced by I-2 doping at different dosages. It is found that iodine atoms prefer to occupy the face-centered cubic regions of the Au(111) herringbone reconstruction at the first step, and the herringbone reconstruction is completely lifted when dosing more and more I-2 until the system reaches a full-monolayer coverage. By regulating the 12 dosages step by step on a CoPc precovered surface, various I-CoPc structures are obtained. Furthermore, thermal treatment results in the formation of more homogeneous long-range ordered I-CoPc structures.