Fluorescence quenching in PVK:ZnSe nanocomposite structure

The role of the inclusion of ZnSe nanoparticles (NPs) into conducting poly (9-vinylcarbazole) (PVK) on the fluorescence emission has been investigated. The optical properties such as emission and absorption of PVK:[ZnSe] nanocomposites were found to be strongly dependent on the concentration of ZnSe NPs embedded in the PVK matrix. The study was carried out on the PVK:[ZnSe] nanocomposite both in solution and in solid thin film states. The fluorescence spectra are found to be strongly altered upon the embedding of ZnSe nanoparticles into the PVK host matrix. In the solution form, the fluorescence spectra of the nanocomposite with different concentration of NPs undergo dramatic changes both in shape and in intensity. Itʹs found that the adjunction of small fraction of ZnSe nanoparticles quenches considerably the PVK fluorescence at the expense of an exhalation of the NPs fluorescence especially for low concentrations. This trend is described within the Förster formalism which involves non-radiative energy transfer from the donor (PVK) to the acceptor (ZnSe NPs). In the thin film form the fluorescence and absorption spectroscopy characterizations show the formation of complexes between ZnSe NPs and PVK. The modified Stern–Volmer model is used to interpret the fluorescence quenching in PVK:[ZnSe] nanocomposites thin films.