Bilayer graphene was prepared by the subsequent deposition of a (13)C single-layer graphene and a (12)C single-layer graphene on top of a SiO(2)/Si substrate. The bilayer graphene thus prepared was studied using Raman spectroscopy and in situ Raman spectroelectrochemistry. The Raman frequencies of the (13)C graphene bands are significantly shifted with respect to those of (12)C graphene, which allows us to investigate the single layer components of bilayer graphene individually. It is shown that the bottom layer of the bilayer graphene is significantly doped from the substrate, while the top layer does not exhibit a signature of the doping from the environment. The electrochemical doping has the same effect on the charge carrier concentration at the top and the bottom layer despite the top layer being the only layer in contact with the electrolyte. This is here demonstrated by essentially the same frequency shifts of the G and G' bands as a function of the electrode potential for both the top and bottom layers. Nevertheless, analysis of the intensity of the Raman modes showed an anomalous bleaching of the Raman intensity of the G mode with increasing electrode potential, which was not observed previously in one-layer graphene.

A planar binuclear phthalocyanine and its dizinc and dicobalt derivatives, in which two phthalocyanine units share a common benzene ring, have been studied by spectroscopy, electrochemistry, and spectroelectrochemistry. Their Langmuir-Blodgett film-forming properties have been examined, and the results of molecular orbital calculations on these and related systems are also presented. The properties are compared with those of the corresponding mononuclear control molecules. UV-visible-near IR absorption and magnetic circular dichroism spectroscopies and cyclic and differential pulse voltammetry indicate that, in these compounds, two relatively independent chromophore units interact and therefore that the two phthalocyanine planes are not completely planar in solution. The electrochemical and spectroelectrochemical measurements show the formations of various mixed-valence oxidation and reduction species in the binuclear compounds. The nonmetalated and dizinc complexes exhibit both Si and S2 emission. The radiative lifetimes (r) of the dizinc complex are smaller than those of the metal-free binuclear derivative for both Si and S2 emission, while the quantum yields ( fa) are larger. Furthermore, for S2 emission, the fa and t values of the binuclear compounds are larger than those of the corresponding mononuclear control molecules. Molecular orbital calculations within the framework of the Pariser-Parr-Pople approximation reproduce the splitting of the Q absorption band and further show that the splitting becomes larger the smaller the size of the shared common aromatic unit. In monolayers spread on water, the metal-free binuclear complex appears to have a slipped-stack conformation, tilted from the airwater interface normal plane. In Langmuir-Blodgett films, it may form a slipped-stack molecular arrangement with the stacking axis parallel to the substrate and/or a flat-lying conformation on the substrate surface.

This work is focused on synthesis, characterization, and determination of main parameters of the multilayer P123 templated TiO 2 films. The mesoporous multilayer thin films consist of TiO 2 nanoparticles on the F-doped SnO 2 (FTO) conductive glass substrates. The films were grown by implementing the protocol of supramolecular templating with the amphiphilic triblock copolymer, Pluronic P123. The templated multilayer films were manufactured by repeated dip coating followed by the thermal treatment at 350 °C for 2 h after deposition of each layer. It was found that the multilayer preparation technique at 350 °C has serious limitations. The structure does not further increase its specific surface area (roughness factor) after deposition of more than 3-5 layers. The new surface area added by deposition of the top layer is compensated by the reduction of the surface area lost due to the sintering of the bottom layers. The careful review of the analytical data suggests that the morphology of the P123 templated TiO 2 structure is likely the tightest arrangement of randomly positioned particles of a certain size on a given pore diameter. The bulk material consists of pores evenly formed in all directions while a denser crust is formed on the surface where the fusion was restricted in one direction at the interface with the air. Subsequent thermal treatments of the multilayer films were applied to improve the anatase crystallinity while keeping the open morphology and small particle size. The morphological changes of the mesoporous structure during the subsequent thermal treatment at 425-540 °C were investigated.

The interaction between self-aggregated porphyrins such as 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) and 5,10,15,20-tetrakis(4-phosphonatophenyl)porphyrin (TPPP), and a generation 5 (G5) PAMAM dendrimer template is governed by minute differences of porphyrin acido-basic properties. While at neutral pH both monomeric TPPS and TPPP form complexes with G5, decreasing pH did not lead to porphyrin ring protonation (pK(a) approximately 5) but rather to the preferential formation of H-aggregates (probably H-dimers), most likely due to protonation of the G5. Upon further acidification of the solution, this face-to-face orientation of the porphyrin units is being converted to edge-to-edge aligned J-aggregates with a tightly defined structure. This process starts by protonation of the porphyrin ring at pH below 2.3 and 2.8 for TPPS and TPPP, respectively. The AFM imaging of porphyrin/G5 nanostructures obtained at pH 0.7 shows the formation of long nanorods of TPPS with partially aggregated G5 and small aggregates of TPPP connected to individual G5 molecules.