Impact of dendritic interface modifiers on phase behavior of polyvinylcarbazol-CdSe/ZnS nanocomposite films

The phase behavior of mixtures of poly(9-vinylcarbazol) (PVK) and CdSe/ZnS quantum dots (QDs) were studied depending on the nature of the surfactant used as QDs shell, namely, native surfactant (NS) originated from the QDs synthesis, and specially designed two-component interface modifiers comprising of dendritic phosphonic acids possessing alkyl- or cyano-terminal groups and hexyl phosphonic acid as a cosurfactant. It is shown, that the nature of interface modifier dramatically influence on distribution of QDs in the nanocomposite film. Thus, both the native surfactant and alkyl-containing dendritic interface modifiers favors to phase segregation of QDs in the resulting nanocomposites where two-dimensional aggregates are localized near-surface layer of the PVK film. In contrast, the cyano-containing dendritic interface modifier provides the homogeneous QDs distribution through the film thickness. We determined that the concentration quenching of QDs photoluminescence is observed for PVK/ QD(NS) film. For PVK films containing QDs grafted with dendritic surfactants, the luminescent intensities increase vs QD concentration up to 80-85 wt%.