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Authors: M. Kruszynska, B. Kempken, H. Borchert, J. Parisi, and
J. Kolny-Olesiak
Design of self-assembled and well-ordered one- (1D), two- (2D) or three-dimensional (3D) systems of highly uniform semiconductor nanocrystals has been recently a rapid developing research field. Controlled arrangement of nanocrystals exhibits properties different from that of isolated nanocrystals. This makes them interesting candidates for a variety of applications. In this work, we present a colloidal synthesis of copper (I) sulfide nanocrystals and their assembly into ordered superlattices. Briefly, nanocrystals were obtained by a reaction between tert-dodecanethiol (t-DDT) and copper acetate (CuAc) dissolved together with trioctylphosphine oxide (TOPO) in an organic solvent [1]. Depending on the reaction conditions, copper sulfide can form hexagonal plates or nanorods. Elongated shape can be achieved by a high reactivity of the starting materials (in a non-coordinating solvent) and the length of the nanorods can be tailored from 20 nm to 100 nm by the adjustment of the nucleation temperature. Disc-shaped particles are formed, if we reduce the activity of the copper ions by exchanging the non-coordinating solvent with oleylamine. During the synthesis copper sulfide nanorods form aggregates which leads to changes in their absorption spectrum. Moreover, TEM analysis shows, that both kinds of nanocrystals have a tendency to form ordered superstructures: 1D chains of nanodiscs and ordered 2D layers of nanorods. [1] M. Kruszynska et al. Size- and shape control of colloidal copper (I) sulfide nanorods. Submitted. |
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