Area-selective monolayer deposition of iron(II) α-octabutoxyphthalocyanine complex on nano-patterned TiO2 thin films on a glass substrate

Abstract

Iron(II) 1,4,8,11,15,18,22,25-octabutoxyphthalocyanine complex (Fe(OBu)8Pc) was synthesized and deposited on nano-cratered titanium dioxide thin films on a glass substrate. The TiO2 thin films had been selectively modified with bifunctional 2-aminoethyl dihydrogen phosphate, which binds to the nano-cratered TiO2 surface from its phosphate group, but leaves the glass substrate unmodified, creating hence a nano-patterned amino-functionalized surface. n-Butyl amine was used as a model ligand to examine the ability of Fe(OBu)8Pc to bind with amino groups in a solution state. According to 1H nuclear magnetic resonance and UV–Vis measurements, two separate amino groups can bind to the axial sites of Fe(OBu)8Pc using coordination bonds. Fe(OBu)8Pc complex molecules form a monolayer on an amino-functionalized TiO2 thin films when using THF as a solvent in the deposition step. The X-ray photoelectron spectroscopy and scanning electron microscopy analysis results indicate that a monolayer of Fe(OBu)8Pc complexes lie parallel to the carrier surface replicating the nanostructure while having free coordination sites for sensing applications and leaving the glass substrate on the floors of the craters available for further functionalization.