Assembly of colloidal semiconductor nanorods in solution by depletion attraction

Summary, in English

Arranging anisotropic nanoparticles into ordered assemblies remains a challenging quest requiring innovative and Ingenuous approaches. The variety of interactions present in colloidal solutions of nonspherical inorganic nanocrystals can be exploited for this purpose. By tuning depletion attraction forces between hydrophobic colloidal nanorods of semiconductors, dispersed in an organic solvent, these could be assembled into 2D monolayers of close-packed hexagonally ordered arrays directly in solution. Once formed, these layers could be fished onto a substrate, and sheets of vertically standing rods were fabricated, with no additional external bias applied. Alternatively, the assemblies could be isolated and redispersed in polar solvents, yielding suspensions of micrometer-sized sheets which could be chemically treated directly in solution. Depletion attraction forces were also effective in the shape-selective separation of nanorods from binary mixtures of rods and spheres. The reported procedures have the potential to enable powerful and cost-effective fabrication approaches to materials and devices based on self-organized anisotropic nanoparticles.

• Author: Dmitry Baranov; Angela Fiore; Marijn Van Huis; Cinzia Giannini; Andrea Falqui; Ugo Lafont; Henny Zandbergen; Marco Zanella; Roberto Cingolani; Liberato Manna
• Publishing year: 2010-02-10
• Language: English
• Pages: 743-749
• Publication/Series: Nano Letters
• Volume: 10
• Issue: 2
• Links: http://dx.doi.org/10.1021/nl903946n
• Document type: Journal article
• Publisher: The American Chemical Society (ACS)
• Keywords: Depletion forces; Nanocrystals; Nanorods; Self-assembly
• Status: Published
• ISBN/ISSN/Other: ISSN: 1530-6984