1201171-05-2Relevant academic research and scientific papers
Mono-, bis- and tetrahydroxy phthalocyanines as building blocks for monomolecular layer assemblies
Sariola, Essi,Kotiaho, Anne,Tkachenko, Nikolai V.,Lemmetyinen, Helge,Efimov, Alexander
experimental part, p. 397 - 411 (2010/11/17)
We have developed three basic phthalocyanine structures, containing one, two, or four hydroxy groups, which are simple to synthesize and purify, as well as can be characterized well by NMR and MS. These building blocks can easily be further modified to have anchor groups, which make the molecules suitable for attachment to solid substrates. We have used thioacetate and pentafluorophenyl ester moieties, giving target phthalocyanines the ability to self-assemble on gold, metal oxides, and glass. Bonding densities calculated from the absorbances of the layers suggest mean molecular area to be in the range of 13 nm 2, which can be partially controlled by side substituents and the number of linkers.
Photoinduced vectorial electron transfer in multilayered Langmuir-Blodgett films of porphyrin and phtalocyanine derivatives
Alekseev,Tkachenko,Efimov,Lemmetyinen
experimental part, p. 1230 - 1241 (2011/01/05)
A series of new phtalocyanines and phtalocyanine-fullerene dyads was synthesized. The dyads were transferred to solid substrates in the form of the Langmuir-Blodgett films. Poly(hexylthiophene) (PHT) and/or phtalocyanine (B6PH) were used as secondary electron donors in the multilayered structures, together with molecules of phtalocyanine-fullerene (B6PF) or porphyrin-fullerene (DHD6ee) dyads in a matrix of octadecylamine (ODA) molecules in a ratio of 1: 9. Directed photoinduced electron transfer in films was studied by means of the time-resolved Maxwell displacement charge method. It was established that the addition of a monolayer of molecules of the secondary B6PH donor to a monolayer of molecules of the DHD6ee/ODA (1: 9) dyad resulted in a thirty-fold increase in the sample's photovoltaic response; it did not, however, change the recombination rate of the charges as compared to a single monolayer of the dyad molecules. In the case of bilayer samples consisting of B6PF/ODA (1: 9) and PHT/ODA (3: 2) monolayers, both quantities increased. The absorption of visible light over a wide spectral range was achieved via the use of three-component (PHT, B6PH and DHD6ee) multilayered structures. The relative sensitivities of the samples to excitation radiation were assessed and the efficiencies of their transformation of light energy to electric potential were compared. The largest sensitivity values were obtained for three-component samples prepared from PHT, B6PH, and DHD6ee monolayers in which the sensitivity value was 500 times larger than that for a separate monolayer of DHD6ee dyad molecules.
