Enhanced dispersion of CdSe/MEH-CN-PPV hybrid nanocomposites by in situ polymerization using AEM as photopolymerizable precursor


Colloidal quantum dots (CQDs) can easily become aggregated when blended in a polymer matrix. Although several techniques have been reported to prepare dispersed CQDs in a polymer matrix, the novel approach of this work is to obtain well-dispersed CQD-polymer nanocomposites through the in situ photopolymerization of a third source, thereby broadening the material selection available for such nanocomposites. Therefore, dispersed CQD-polymer nanocomposites were prepared by the photopolymerization of 2-aminoethyl methacrylate hydrochloride (AEM) precursor in a blend of trioctyl phosphine oxidecapped CdSe CQDs and poly(2-methoxy-5-(2'-ethylhexyloxy)- α,α'dicyano-p-xylylidene-alt-2,5-dihexyoxy-p-xylylidene) (MEH-CN-PPV). The photopolymerization of AEM was developed for this work in order to prevent possible decomposition of CQDs induced by introducing metallic catalysts or heat and to eliminate the need for further functionalization of CQDs or polymers. The morphology of the photopolymerized CdSe CQD/MEH-CN-PPV/AEM was corroborated by direct observation of the quantum dot dispersion in the resultant sphere-shaped structures via transmission electron microscopy. Photoluminescence quenching and shorter photoluminescence decay lifetime of the MEHCN- PPV in the photopolymerized nanocomposite were observed, indicating that the photopolymerized CdSe CQD/ MEH-CN-PPV/AEM nanocomposite has an enhanced energy transfer efficiency in comparison to typical aggregated CdSe quantum dot/MEH-CN-PPV nanocomposites as a result of better dispersion. © Springer-Verlag 2012.