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Novel monoisomeric perylene imide derivatives with terpyridinyl and pyrrolidinyl substituents were synthesized and deposited onto solid substrates, such as a thin film of Al2 O3 and mesoporous TiO2 nanoparticle layer, by using a simple dip-by-dip method. Arrays of up to 33 layers were built on Al2 O3 . In the case of mesoporous TiO2 , the interstitial volume between the particles was filled up with dye assemblies. Deposition could produce either layers of microcrystals or molecular layers if an appropriate washing procedure was used. The resultant arrays were studied by means of scanning electron microscopy, X-ray photoelectron spectroscopy measurements, and UV/Vis absorption.

Formation of self-assembled monolayers (SAMs) of three porphyrin and one phthalocyanine derivatives on thin ZnO film was studied by monitoring absorption spectra of the samples. The compounds were equipped with carboxylic or phosphate groups to bind to the surface. The SAM formation was found to be fast. The layer was formed in less than 15 min for all studied porphyrins, and 30 min was sufficient to form phthalocyanine layer. For porphyrins with different anchor groups the SAM formation was too fast to see any difference between the anchoring groups. The stability of SAMs was tested then by immersing the samples into neat solvents. Upon immersion the SAMs were gradually losing the absorbance for all the compounds with degradation trends being in line with p[Formula: see text] values of the binding groups of the same type. However, even for the weakest binding group the SAM was relatively stable after a few tens of minutes of washing, which was sufficient to remove physisorbed compounds but the SAM was essentially not destroyed. Comparison of SAMs on thin films with SAMs on ZnO nanorods and TiO2 nanoparticle films indicated the same fast layer formation but relatively weaker SAMs stability, showing 20–40% faster absorption losses during the washing.

The photoinduced electron transfer processes were studied for hybrid systems consisting of self-assembled monolayer of zinc phthalocyanine (ZnPc) assembled on ZnO nanorods and a film of organic hole transporting material (HTM) atop. Polythiophene (P3HT) or Spiro-OMeTAD were used as HTM. The study was carried out by ultrafast transient absorption spectroscopy technique with selective excitation of ZnPc at 680 nm or P3HT at 500 nm. Data analysis revealed that photoexcitation of ZnPc in the structure ZnO|ZnPc|P3HT results in a fast (1.8 ps) electron transfer from ZnPc to ZnO, which is followed by a hole transfer from the ZnPc cation to P3HT roughly in 30 ps. However, in the case of ZnO|ZnPc|Spiro-OMeTAD structure, the primary reaction upon excitation of ZnPc is a fast (0.5 ps) hole transfer from ZnPc to Spiro-OMeTAD, and the second step is electron injection from the ZnPc anion to ZnO in roughly 120 ps. Thus, we demonstrate two structurally very similar hybrid architectures that implement two different mecha...

We have synthesized a set of porphyrin and phthalocyanine compounds with two different silane anchors. Syntheses of the anchor-substituted chromophores have been carried out via hydrosilylation of alkene derivatives, catalyzed by platinum complexes. The reduction side-process was suppressed using specific anchor/catalyst pairs, and the silane-containing compounds were successfully isolated from hydrogenated by-products in pure form with good yields. The target porphyrinoids having stable reactive silane anchors possess the ability to self-assemble on metal oxides and quartz surfaces and optical fibers. Covalent attachment is done in one-step, which makes the bonding process fast and easy. Immobilized chromophores were further converted by on-surface reactions into Zn(II) and Mg(II) metal complexes. The metallation time was found to be as fast as 1 min for Zn ion. Bonding densities calculated from the absorbances of the deposited layers give rough estimations for packing of the molecules on various substrates and evidence for monomolecular layers formation.

Dense arrays of zinc oxide nanorods with high specific surface areas were grown by hydrothermal method and functionalized by self-assembled monolayer (SAM) of porphyrins. The growth process was optimized to obtain dense arrays of nanorods with diameter of 60–80 nm and length up to 1.5 μm. The increase in the effective surface area was monitored by comparing the absorbances of SAM deposited both on the flat and nanorod surfaces of ZnO. To alter further semiconductor-organic SAM interactions, a 2 or 5 nm thick layer of either Al2O3 or TiO2 was deposited on the ZnO nanorods. The present results show that both carboxylic acid and triethoxysilane anchors can be used to form porphyrin SAMs on the studied metal oxide substrates, and the electronic interactions between the metal oxide and porphyrin SAM are strongly modified by a thin layer of Al2O3 or TiO2. These hybrid semiconductor-organic SAM constructions present promising model systems for advanced spectroscopy studies of semiconductor-organic interfaces wit...

Terpyridine-substituted perylenes containing cyclic anhydrides in the peri position were synthesized. The anhydride group served as an anchor for assembly of the terpyridyl-crowned chromophores as monomolecular layers on metal oxide surfaces. Further coordination with Zn(2+) ions allowed for layer-by-layer formation of supramolecular assemblies of perylene imides on the solid substrates. With properly selected anchor and linker molecules it was possible to build high quality structures of greater than ten successive layers by a simple and straightforward procedure. The prepared films were stable and had a broad spectral coverage and high absorbance. To demonstrate their potential use, the synthesized dyes were employed in solid-state dye-sensitized solar cells, and electron injection from the perylene antennas to titanium dioxide was observed.

Large aromatic chromophores, e.g. phthalocyanines or perylene derivatives are widely used in modern photonic applications. For these systems, well-organized films of the chromophores are very important. One of the ways to ensure the order on molecular level is to bind the organic dyes covalently to a solid substrate with a suitable anchor group. Expanding the concept, multilayered supramolecular assemblies can be built on surfaces as well.In the present Thesis various chromophores with a capability to anchor onto a solid surface were prepared. Synthesized molecules were porphyrins, phthalocyanines, and perylene mono- and diimides with different substituents. The anchor-surface pairs were of several types, and the chromophores were attached to a surface by one- or two-step methods.Two of the perylene monoimide derivatives were found to be a perfect basement for construction of multilayered films. Using a metal-ligand interaction it was possible to prepare stable double layers, as well ten molecules thick stable deeply colored multilayer films. The developed approach is versatile and will allow in future to expand the capabilities of molecular film architecture.

Highly ordered thin molecular films, from monolayer to multilayer assemblies, promise considerable development for micro- and nanotechnology. In particular, the application of supramolecular chemistry to the direct assembling of functional layers at surfaces added a new and highly diverse class of materials to modern material science. Multicomponent arrays are attractive materials for applications such as nonlinear optical materials, enzyme sensors, solar energy storage devices, and molecular rectifiers in several fields as optics, biotechnology, photo- and electrochemistry. The talk will describe a recently developed set of perylene and phthalocyanine derivatives from which one can build highly organized multilayered structures on metal oxide surfaces. The essential finding is the use of terpyridyl-crowned perylenemonoimides monoanhydrides as the anchoring substances. Another key point is a proper choice of bis(terpyridyl)perylenediimide or terpyridyl-phthalocyanine linkers. Combination of these two factors allows to assemble highly colored and stable multilayered molecular films by a simple and reproducible procedure. As a proof of concept it has been demonstrated that molecular arrays can be successfully used in solid state DSSC even at ambient conditions. One can expect many other potential uses of the proposed multilayers. The tpy-perylene spacers of a fixed length make possible a localization of specific ions or chromophores at a controlled depth inside the layer. This would allow to create a gradient of redox potentials across the film and to achieve, e.g. upon photoexcitation, a charge shift into a certain distance and direction. High absorbance of the multilayered films might eliminate the need of using porous structures, while the possibility to cover easily large surfaces is a great advantage in practical applications. Figure 1

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Perylene diimides (PDIs) substituted with a terpyridine moiety at the bay-region have been synthesized. These building blocks were used to construct supramolecular complexes in chloroform. A dimer and a trimer were built via the bay-region complexation with zinc. The PDI compounds were further modified to have silane anchors and PDI self-assembled monolayers (SAMs) were prepared on a quartz substrate. Complexation of metal ions was also done on the surface, and this was observed clearly in the absorption spectrum. These studies on the surface show possible progress in the study of supramolecular multilayer structures.