Molecules deposition on highly reactive surfaces: The case study of porphyrins on Fe(001)

The choice of low-interacting substrates to support a molecular layer is extremely relevant for the realization of working devices, especially when molecules with an open structure, such as metal tetraphenylporphyrins (MTPP), are used. Conversely, in the present work, I employ a prototypical highly reactive substrate (such as Fe(001)) to weight its influence on the structural and electronic properties of deposited molecules. To this goal, I have exploited photoemission spectroscopy (XPS and UPS, porphyrin core and valence states properties), Near-Edge X-ray Absorption Fine Structure spectroscopy (NEXAFS, molecule orientation with respect to the buried substrate) and scanning tunneling microscopy (STM, MTPP assembling properties) on three different MTPP molecules (namely, ZnTPP, CoTPP and VOTPP). While Zn- and CoTPP shows basically a planar configuration, VOTPP has the oxygen atom placed outside the main tetra-pyrrole ring, which can influence the molecules assembling on clean substrates.