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Authors: Xiaoping Jin, Jie Li, Marta Kruszynska, Jürgen Parisi, and Joanna
Kolny-Olesiak
Inorganic nanocrystals have exhibited many interesting, novel size- and shape-dependent properties. Especially nanorods and nanowires draw scientific attention, due to their unique chemical and physical properties, caused by their dimensional anisotropy. Semiconducting nanowires are of particular interest since they may serve as key components of nanoscale electronic and photonic devices. They are also promising absorber materials for photovoltaic applications, because they not only have tunable absorption properties, due to the size quantization effect, but also a better conductivity, compared to 0D, spherical nanoparticles. Here we are going to present our work on the colloidal synthesis of 1D nanostructures of two semiconductor materials, CdTe and CuInS2. Both materials attract interest due to their pronounced quantum size effect and optical activity both in the visible and near-infrared spectral regimes. Our synthetic procedures allow for synthesizing CdTe nanowires1 and CuInS2 nanorods2 and to control their morphology. By varying the reaction conditions, several different shapes of CdTe nanowires could be obtained, like ultrathin, straight, saw-tooth-like and one-sided branched nanowires. Our investigations on the growth mechanism indicate that the formation of nanowires is based on an oriented attachment mechanism. The synthesis of CuInS2 yields nanorods with wurtzite crystallographic structure and different aspect ratio and shape (e.g., pencil-, teardrop- or fish-like). The use of oleylamine as a solvent turned out to be crucial for shape control in both cases (CdTe nanowires and CuInS2 nanorods). Furthermore, the reaction between oleic acid and oleylamine in the presence of metal ions proved to be essential not only to control the activity of the monomers but also to provide reaction conditions facilitating CdTe nanowires and CuInS2 network formation. (1) Jin, X.; Kruszynska, M.; Parisi, J.; Kolny-Olesiak, J. Nano Research 2011, 4, 824-835. (2) Kruszynska, M.; Borchert, H.; Parisi, J.; Kolny-Olesiak, J. Journal of the American Chemical Society 2010, 132, 15976-86. |
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