Researching self-assembly and reaction of organic molecules on metal or metal oxide surface through Synchrotron radiation photoemission spectroscopy

Researches proved that the efficiency of organic photo-electronic depend strongly on the degree of order and orientations of the organic molecule film. In order to obtain ordered organic nanostructures on surfaces, Prof. Zhu Junfa’s group studied the Ullmann reaction, diffusion and self-assembly behaviors of 4,4’’-dibromo-m-terphenyl (DMTP) molecules on Cu(111) surface with scanning tunneling microscope (STM) and X-ray photoemission spectroscopy (XPS). In addition, they successfully synthesized the object ordered organic nanostructures. The study proposed a method for fabrication of organometallic oligomers and polymers based on C-M-C bonds, various macro-cyclic species are observed. The results are published at ACS Nano, 2014, 8, 709.

Self-assembly of DMTP molecules into organometallic polymer chains and cyclic oligomers on Cu(111) surface.

Moreover, they have studied the Ullmann reaction of 3, 5, 3″, 5″-tetrabromo-para-terphenylmolecules (TBrTP) on Cu(111) surface. Different nanomesh structures based on covalent, organometallic and halogen bonds are obtained depend on the different temperature of Cu(111) surface. The degree of order of these nanomesh structures decreased with their bonding strength increasing. The related results are published at J. Phys. Chem. C, 2014, 118, 13018. 

Ullmann reaction of TBrTP molecules into nanomesh structures based on different bonding type on Cu(111) surface.

In addition, they have studied the metalation of 2HTPP (tetraphenylporphyrin) with Ni atoms on TiO2(110) surface. 2HTPP molecules adsorbed on TiO2(110) surface with an “saddle” configuration, however after metalation with single Ni atoms into NiTPP (Ni-tetraphenylporphyrin), its adsorption configuration turns into a “four-lobe one” with ~45 degree rotation. The results are published in Chem. Commun., 2014, 50, 8291. 

N 1s XP spectra and STM images of 2HTPP and NiTPP on TiO2(110)-1*1 surface.