Ropakova I. Exciton dynamics in J-aggregates and its interaction with exciton traps in aqueous solutions and polymer films

The thesis is devoted to the study of the optical properties and exciton dynamics in molecular nanocrystals (J-aggregates) of mono- and trimethine dyes in aqueous solutions and polymer films. It was found that the following factors significantly affect the morphology and, consequently, the spectral properties of J-aggregates: in aqueous solutions, the agglomeration of individual aggregates into associates, as well as the structure of the molecules forming the aggregate; in solid-state samples, in particular polymeric films, is the method of sample preparation. It is shown that the luminescent properties of J-aggregates in polymer films are significantly determined by the exciton self-trapping. A theoretical model of the interaction of a linear molecular aggregate with an impurity (nanoparticle, organic molecule, etc.) is constructed. It is demonstrated that exciton resonances in J-aggregates of monomethine dyes can enhance the luminescence of dyes (excitonic traps). It was found that at a distance of about 10 nm from the PIC, amphi-PIC and TC J-aggregates, the luminescence of the DiD and Rh6G dyes is 5 times enhanced. Key words: J-aggregate, luminescence, exciton, cyanine dyes, polymer film.