Self-Assembly of CdSe Nanoplatelets into Giant Micrometer-Scale Needles Emitting Polarized Light

• Published in: Nano letters 2014-02, Vol.14 (2), p.710-715
• Main Authors: Abécassis, Benjamin, Tessier, Mickael D, Davidson, Patrick, Dubertret, Benoit
• Format: Article
• Language: English
• Subjects: Anisotropy; Cadmium selenides; Colloids; Condensed Matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Dispersions; Exact sciences and technology; Fullerenes and related materials; Intermetallics; Materials science; Methods of nanofabrication; Micrometers; Nanostructure; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics; Self assembly; Structure of solids and liquids; crystallography; Visible and ultraviolet spectra; X-ray diffraction and scattering; X-ray scattering (including small-angle scattering)
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl4039746

We report on the self-assembly of colloidal CdSe nanoplatelets into micrometers long anisotropic needle-like superparticles (SPs), which are formed in solution upon addition of an antisolvent to a stable colloidal dispersion. Optical fluorescence microscopy, transmission electron microscopy, and small-angle X-ray scattering provide detailed structural characterization and show that each particle is composed of 106 nanoplatelets organized in highly aligned columns. Within the SPs, the nanoplatelets are stacked on each other to maximize the contact surface between the ligands. When deposited on a substrate, the planes of the platelets are oriented perpendicularly to its surface and the SPs exhibit polarized emission properties.