Dispersion and aggregation of quantum dots in polymer-inorganic hybrid films

The mechanisms of dispersion of spherical CdSe/ZnS quantum dots (QD) in the polymer-inorganic nanocomposite thin films based on two types of polymers poly(9-vinylcarbazole) (PVK) and poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) have been studied. The radial distribution function (RDF) and the potential of mean force (PMF) in these composite films with QD concentration from 17 to 80 wt.% were determined. Analysis of RDF and PMF of the obtained composites PVK/QD and PFO/QD has revealed the three different states of QD spatial organization as a function of the polymer-QD interaction. Using transmission electron microscopy and X-ray photoelectron spectroscopy, it was shown that the PVK/QD composites tend to phase segregate with the formation of bilayer structures, whereas in the PFO/QD composites uniform distribution of QDs occurs. The results showed that the morphology has a significant impact on the optical properties of nanocomposites. In the PVK/QD nanocomposites a photoluminescence quenching is observed with the increase of QD concentration unlike in the PFO/QD nanocomposites.