Viable synthetic route for a luminescent porphyrin monolayer covalently assembled on a molecularly engineered Si(100) surface

A three-step strategy to covalently anchor 5,10,15,20-tetrakis(hydroxyphenyl)porphyrin molecules on Si(100) substrates was developed. It consists of the functionalization of the Si(100) surface by the grafting of 10-undecylenic acid methyl ester on the H-terminated silicon surface, followed by the ester hydrolysis and, finally, by the covalent assembly of the tetrakis(hydroxyphenyl)porphyrin. The obtained system was characterized by monochromated angle-resolved X-ray photoelectron spectra and atomic force microscopy measurements. Results indicated the covalent linkage of the porphyrin molecules to the functionalized substrate surface. Moreover, both XPS and AFM measurements suggest that the porphyrins bind the surface in a vertical fashion. The monolayer optical behavior was studied by photoluminescence measurements at room temperature.