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Synthesis of porphyrin nanotubes by ionic self-assembly and properties characterization.
|Valentinas Snitka 1, Vida Mizariene 1, Gediminas Seniunas 1, Ingrida Bruzaite 2, Mindaugas Rackaitis 3
1. Kaunas University of Technology, Research Center for Microsystems and Nanotechnology (RCMN KTU), Studentu 65 - 203, Kaunas 3031, Lithuania
In this work the porphyrin nanotubes were built by ionic self-assembly in aqueous solutions of two oppositely charged porphyrins- anionic Meso-tetra(4-sulfonatophenyl)porphine dihydrochloride (TPPS4) and cationic Meso-tetra(4-pyridyl)porphine (T4MPyP). The electrostatic forces between these porphyrin blocks contribute to the formation of porphyrin aggregates in the form of nanotubes, enhance the structural stability of these nanostructures. The porphyrin nanotubes obtained are hollow structures with the length of 300 nm and diameter 50 nm. Photocatalytic porphyrins are used to reduce metal complexes from aqueous solution and to control the deposition of Au from AuHCl4 onto porphyrin nanotubes. Porphyrin nanotubes are shown to reduce metal complexes and deposit gold selectively onto the outer surface of the tubes. The colloidal solution of gold nanoparticles lead to gold strip inside nanotube composite structures. Solution and monolayer spectra for the UV–vis experiments were obtained on an Ocean Optics diode array spectrophotometer to confirm the J-aggregates and nanotubes formation. The porphyrin nanotubes structure was investigated by Hitachi S-4800 electron microscope in STEM mode and by AFM imaging. The electrical properties of porphyrin nanotubes and nanotubes functionalized by gold were investigated by conductivity imaging using Scanning Probe Microscopy. It was demonstrated the possibility to build porphyrin nanotubes from the anionic Meso-tetra(4-sulfonatophenyl)porphine dihydrochloride and cationic HematoporphyrinIX dihydrochloride porphyrins and to deposit gold on the nanotubes from gold salt solution and inside the porphyrin tubes from gold nanoparticles (3-15 nm) colloidal suspensions. The results obtained in the work open a possibilities to build a new kind of nanodevices for photovoltaics, nanophotonics ant sensing.
Presentation: Oral at E-MRS Fall Meeting 2007, Symposium B, by Valentinas Snitka
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-12 20:52 Revised: 2009-06-07 00:44