Self-directedly assembled porphyrin thin films with high photoactivity

Abstract

A novel silanized metalloporphyrin cobalt monomer (SMPCM) was prepared by using 5,10,15,20-tetra(4-hydroxyphenyl)porphyrin cobalt (CoTHPP) and γ-isocyanatopropyltriethoxysilane (ICPTES) as the reactants. Followed by the hydrolysis–polymerization of the organosilanes in the axial direction and peripheries of the SMPCM, the ordered porphyrin thin films with uniform morphology were facilely prepared on various substrates by the self-directed assembly of the SMPCM. The thin films formed was characterized by UV-vis spectra, electron microscopies, X-ray diffraction spectra, Fourier transform infrared spectra, fluorescence spectra and X-ray photoelectron spectra. The results demonstrated that the axial assembly between the Co³⁺ ion in the center of porphyrin macrocycle and ICPTES can prevent porphyrin lamellar from curling in horizontal direction, and then enhanced the order and stability of the films. Especially, the thin films possessed high, sensitive and stable photoelectronic response.