The thesis is devoted to studying the luminescence formation mechanisms and the electronic excitation dynamics for cyanine dyes in monomer and aggregate states in nanostructured materials, such as surfactant micelles and reverse micelles, liposomes, nanoporous SiO2 and АОА matrices, polymer films, using steady-state absorption and luminescence spectroscopy and time-resolved luminescence spectroscopy. It has been shown that formation in nanostructured media strongly influences on spectral properties and structure of cyanine dyes J-aggregates. Particularly, for the excitonic band (J-band) broadening and the shape changing has been observed due to stronger static disorder and the exciton localization effects. Features of J-aggregates formation in highly structured pores of anodic aluminum oxide (AOA) have been studied using spherical BIC J-aggregates and thread-like PIC J-aggregates. Spectroscopic investigations show the presence of both types of the J-aggregates in the AOA pores. It leads to a static disorder increasing in the J-aggregates. Besides, in the case of the thread-like J-aggregates changes in the structure have been supposed also. BIC J-aggregates embed into water pool of AOT reverse micelles as a whole. Changing reverse micelles diameter foremost influences on static disorder in BIC J-aggregates with much less influence on their physical sizes. Contrary, for PIC J-aggregates in reverse micelles strong decreasing the exciton delocalization length was found. Simultaneously, very intense monomer absorption band and the low intense J-band was observed pointing to the hindered aggregation process for PIC J-aggregates in small volume of AOT reverse micelles. The one-dimensional exciton migration was demonstrated for PIC J-aggregates in water solutions and nanovolumes of the direct and reverse micelles. It has been shown that the exciton path length depends on the exciton delocalization length and, hence, is changing in different media: l ~ 80 nm - in water soluyions (Ndel ~ 86), l ~ 35 nm - AOT reverse micelles (Ndel ~ 33) and l ~ 115 nm - CPB molecular shell (Ndel ~ 93). Formation of TC J-aggregating in the layered polymer films results in the both luminescence and absorption bands widening and red-shift. The main reason of this was explained as the static disorder decrease under the local environment influence. PIC J-aggregates formation in a layered polymer films using the LbL assembly method reveal a significant J-band widening and the exciton coherence length decreasing down to 15 monomers due to the local environment influence on the J-aggregates. The J-aggregates luminescence is appeared to be strongly quenched with the luminescence quantum yield ~ 0.005 and the luminescence lifetime ~ 40 ps. The structure of PIC J-aggregates formed in a LbL film (3D islands) differs from that reported for J-aggregated formed in aqueous solutions and some polymeric film (1D fibers). At 80 K the luminescence spectrum consists of two emission bands: a narrow near resonant band and a broad red-shifted on 1200 cm-1 with respect to the J-band one, which are assigned to coexisting free and self-trapped excitons, respectively, which are divided by the self-trapping barrier with the height of about 105 cm-1. The exciton self-trapping is caused by a strong exciton-phonon coupling with the coupling constant g ~ 1.97. The excitoning self-trapping results in the very small luminescence quantum yield of PIC J-aggregates in a LbL film at room temperature. For the first time J-aggregates luminescence varying through the distance controlled interaction with metal nanoparticles has been demonstrated. In water solutions the maximal two-fold plasmon enhancement of the TC J-aggregates luminescence has been found at the distance of about 16 nm between metal nanoparticles surface and J-aggregates which corresponds to the distance of about 41 nm from an NP's center to a J-aggregate. The theoretical model was proposed which gives good correlation with the experimental results and predicts more than 20-fold enhancement of J-aggregates luminescence and strong luminescence enhancement dependence on the exciton coherence length. It was found that maximal 4-fold TC J-aggregate luminescence enhancement in the polymer films could be achieved at 15 nm distance from 50 nm diameter silver nanoparticles. It has been found that maximal 8-fold luminescence enhancement for PIC J-aggregates in the LbL films could be achieved at 16 nm distances between 17 nm diameter gold NPs and the J-aggregates. Exciton-plasmon interaction in studied disordered system leads to further the exciton coherence length decreasing down to 8 monomers with simultaneous the luminescence lifetime growth up to ~ 100 ps. The experimental data have revealed a very effective FRET between the pair of dyes entrapped in structurally heterogeneous media (SDS micelles, PC liposomes, and porous SiO2 matrices). This effect can be explained in part by the forced concentration of the hydrophobic dyes molecules in nanoscale volumes of micelles, liposomes, and in pores of SiO2 matrices. However, the measured relative quantum yields ( ) as a function of effective dye concentration in nanovolume do not agree perfectly with the standard F?rster-type theory for homogeneous solutions with dyes molecules randomly distributed in a three-dimensional volume. Taking into account the apparent fractal nature of the interacting molecules distribution in heterogeneous media we obtain that d ~ 3.0, 2.9, 2.7 for micelles, liposomes, and porous SiO2 matrices, respectively. We conclude that the highly effective FRET between the dyes in studied heterogeneous media is governed by (i) effective concentration of dyes in nano-scale volumes and (ii) in cases of liposome and SiO2 matrix, a non-uniform fractal-like character of the distribution of the dye molecules within nano-volumes. Using different organic dye molecules we have studied the features of their intermolecular interactions in nanoporous silica matrices. The increasing the dye amount loaded to the matrix causes the second red-shifted emission peak appearance and shortening luminescence lifetime, whereas the dyes absorption spectra did not change. Basing on these facts, dyes excimer formation was considered as the origin of the additional luminescence band. The excimer configuration for the both dyes was evaluated using the Kasha of exciton splitting model for oblique dimers. The short distance and large angles between molecules forming the excimers allow us to suggested ground dimers formation with twisted face-to-face configuration. It was considered that the excimer formation is caused by spatial confinement in the nanoscale silica pores. Keywords: luminescence, exciton, J-aggregate, exciton delocalization length, static disorder, nanostructured materials, cyanine dye.
