Chinese Academy of Sciences, China
Tie Wang has completed his PhD at the age of 28 years from Changchun Institute of Applied Chemistry Chinese Academy of Sciences and postdoctoral studies from Florida University. He is a professor of Institute of Chemistry Chinese Academy of Sciences. He has published more than 33 papers in reputed journals including Scinence, JACS, Angew Chem, PANS et al, and has been serving as an editorial board member of Journal of Analytical & Molecular Techniques.
Self-assembly, driven by non-covalent interactions, is the fundamental mechanism behind the formation of cellular machineries that perform essential functions of life. To date, anisotropic nanoparticles have been used in the design of directional bonding interactions on the nanometer scale through crystal-face-specific functionalization of these particles with recognition groups and/or through shape-induced anisotropic interactions.1 Recently, we have reported that anisotropy-driven self-assembly of CdSe/CdS semiconductor core/shell nanorods can yield needle-like superparticles with a single supercrystalline domain through a kinetic process.2 However, in this process, the formation of needle-like superparticles is sensitively dependent on the level of octylamine ligands on the surface of CdSe/CdS nanorods, which requires a surface treatment for incubating CdSe/CdS nanorods in a very dilute octylamine chloroform (0.1%, v/v) solution for 6 to 7 days.2 This requirement makes it very inconvenient to use this kinetic approach for making needle-like superparticles. To overcome this difficulty, here we report a new synthesis for making needle-like CdSe/CdS supercrystals, which is based on the preparation of CdSe/CdS nanorods exhibiting a static structure with hydrophobic anisotropy through surface functionalization with 1,12 dodecanediamine. Because 1,12-dodecanediamine ligands are primarily functionalized onto the side faces of CdSe/CdS nanorods, their bottom and top faces exhibit more hydrophobicity than their side faces due to the hydrophilicity of amine groups. Therefore, the hydrophobic anisotropy of the resultant nanorods leads to the formation of needle-like superparticles through a process of self-assembly of these nanorods. Significantly, the surface treatment of 1,12-dodecanediamine requires only 10 min, and the quality of the resulting needle-like superparticles is comparable to that of those made using octylamine treatment for 6 to 7 days. These superparticles are important in their applications as energy-down conversion LEDs, which is important for their use as energy down-conversion phosphors in manufacturing polarized light-emitting diodes.