Synthesis and characterization of nanocomposites based on nanoparticles attached to carbon nanotubes
Final Report Abstract
The aim of the project was to understand the attachment of colloidal nanoparticles to carbon nanotubes and the electrical transport through those structures. In the frame of this project we gained a much deeper understanding of the attachment of colloidal nanoparticles to sp2 carbon materials. First, we investigated the attachment of platinum alloy nanoparticles. In this case we deal with only one energy level, namely the Fermi level (work function), which makes the interpretation easier. In contrast, in semiconductor materials we had to deal also with the band levels. By the help of DFT simulations we interpret the results as an electrostatic interaction between the nanoparticles and the carbon nanotubes based on a charge transfer between the two sub-systems due to a difference in workfunction. In the following, we concentrated on the sculpturing (shape transformation) of CdSe semiconductor nanoparticles. We could see that halogenated hydrocarbon can trigger a transformation of the shape to pyramidal structures which we could decorate with gold clusters. Those pyramidal semiconductor nanoparticles were then attached to the sp 2 carbon materials. We found that the used chlorinated hydrocarbons partially decompose and release chloride which is integrated into the surface of the nanoparticles. Those “atomic ligands” help to attach semiconductor materials to carbon surfaces. With another semiconductor material, namely ZnO, we showed that such nanoparticlenanotube composites can be used for efficient photodetectors. The nanoparticles harvest the incoming light and promote charge carriers to the carbon nanotubes, which increases their conductance. The mechanism is discussed as a gating effect. This device works as oxygen or light sensing transistor, but could also be of advantage in solar cells.
Publications
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Growth and reductive transformation of a gold shell around pyramidal cadmium selenide nanocrystals, J. Mater. Chem. 20 (2010) 10602
Michaela Meyns, Neus G. Bastus, Yuxue Cai, Andreas Kornowski, Beatriz H. Juarez, Horst Weller, Christian Klinke
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Reversible attachment of platinum alloy nanoparticles to non-functionalized carbon nanotubes, ACS Nano 4 (2010) 2438
Beate Ritz, Hauke Heller, Anton Myalitsin, Andreas Kornowski, Francisco J. Martin- Martinez, Santiago Melchor, Jose A. Dobado, Beatriz H. Juarez, Horst Weller, Christian Klinke
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Oxygen and light sensitive field-effect transistors based on ZnO nanoparticles attached to individual double-walled carbon nanotubes, Nanoscale 4 (2012) 251
Alina Chanaewa, Beatriz H. Juarez, Horst Weller, Christian Klinke
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Vertically oriented carbon nanostructures and their application potential for polymerbased solar cells, J. Phys. Chem. C 116 (2012) 412
Holger Borchert, Florian Witt, Alina Chanaewa, Fabian Werner, Jan Dorn, Thomas Dufaux, Marta Kruszynska, Anne Jandke, Michael Holtig, Tamara Alfere, Jens Bottcher, Christoph Gimmler, Christian Klinke, Marko Burghard, Alf Mews, Horst Weller, Jurgen Parisi
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Interfacing quantum dots and graphitic surfaces with Cl-based atomic ligands, ACS Nano 7 (2013) 2559
Fabiola Iacono, Cristina Palencia, Leonor de la Cueva, Michaela Meyns, Luigi Terracciano, Antje Vollmer, Maria J. de la Mata, Christian Klinke, Jose M. Gallego, Beatriz H. Juarez, Roberto Otero
