Abstract: Using₄ mercaptopyridine(4-MPy) self-assembled on gold substrate as coupling agents, monolayer of cobalt(Ⅱ)-5,10,15,20-tetrakisphenyl-porphyrin (CoTPP) was fabricated on the pyridinyl-ter minated surface. Further deposition of Au nanoparticles enables the detection of CoTPPmolecules in monolayer to be possible by Surface Enhanced Raman Spectroscopy. The red-shift of "structure sensitive" peaks of porphyrin ring indicates the existence of chemicaLInteraction between CoTPPmolecules and the pyridine terminals, which was believed as the coordination between the nitrogen atom of pyridine ring and the cobalt atom in CoTPP. From the orientation of 4-mercaptopyridine SAMs, it can be deduced that the CoTPPmolecules are approximately parallel to Au substrate in the above structure.

Key words: Cobalt(Ⅱ) 5,10,15,20-tetrakisphenyl porphyrin, 4-Mercaptopyridine, Self assembled monolayer(SAM), Surface enhanced Raman spectroscopy(SERS)