378987 Assembling Quasi-Quaternary Nanocrystal Superlattices for Enhanced Energy Transfer

Wednesday, November 19, 2014: 1:40 PM
International 8 (Marriott Marquis Atlanta)
Matteo Cargnello1, Benjamin T. Diroll1, E. Ashley Gaulding2 and Christopher B. Murray1,2, (1)Chemistry, University of Pennsylvania, Philadelphia, PA, (2)Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA

Multifunctional materials are of great interest for their potential in a variety of fields such as sensing, catalysis, solar cell technology, and drug delivery. Binary nanocrystal superlattices (BNSLs) combine nanocrystals (NCs) with distinct physical properties by self-assembly of monodisperse components. The periodic ordering in BNSLs specifies stoichiometry and interparticle spacing with precision that are not achievable in glassy films or random mixtures and allows engineering of the interactions between the building blocks. Given the wide spectrum of crystalline and quasi-crystalline structures that have been obtained, the opportunities for exploration of these interactions in BNSLs are numerous. In such materials, external stimulation (e.g., light, magnetic fields) of a single component while examining interaction with another can be studied. To increase functionality, ternary NLSs and quasi-ternary NSLs have been demonstrated, but photoluminescent, plasmonic and magnetic components have not been combined in a single assembly.

In this contribution, we show the self-assembly of quasi-quaternary AB13- and AB2-type NSLs using exclusively core-shell particles as building blocks. The NSLs are made of Au/Fe3O4 nanostructures and CdSe/ZnS, CdSe/ZnS/CdS or PbSe/CdSe quantum dots (QDs). We investigated energy-transfer processes in the assemblies by measuring the photoluminescence (PL) of QDs in the final quasi-quaternary NSLs. We demonstrate that energy transfer is enhanced in the assemblies compared to random mixtures due to the maximized number of interactions between the components as a result of the ordering and the higher density of ordered phases.

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