Cyclodextrin mediated phase transfer in water of organic capped CdS nanocrystals

In this work the phase transfer of blue emitting CdS nanocrystals (NCs) from organic solvent to water is reported. Oleic acid capped CdS NCs were synthesized in non-coordinating solvents and effectively transferred from organic phase, i.e. hexane, in aqueous solution. The transfer was mediated by the formation of an inclusion complex between NC surfactant and α-cyclodextrin (αCD). Effect of αCD concentration and NC size on the phase transfer process was evaluated. No NC aggregation in the phase transfer and long stability in time were observed. The spectroscopic properties of the resulting solution were investigated. Finally a supramolecular hierarchical multilayer system with high level of structural complexity was fabricated by using a layer-by-layer assembling procedure of CdS-NC/αCD inclusion complex in multilayered films.