title: Evaporation-induced assembly of quantum dots into nanorings.
abstract: Herein, we demonstrate the controlled formation of two-dimensional periodic arrays of ring-shaped nanostructures assembled from CdSe semiconductor quantum dots (QDs). The patterns were fabricated by using an evaporative templating method. This involves the introduction of an aqueous solution containing both quantum dots and polystyrene microspheres onto the surface of a planar hydrophilic glass substrate. The quantum dots became confined to the meniscus of the microspheres during evaporation, which drove ring assembly via capillary forces at the polystyrene sphere/glass substrate interface. The geometric parameters for nanoring formation could be controlled by tuning the size of the microspheres and the concentration of the QDs employed. This allowed hexagonal arrays of nanorings to be formed with thicknesses ranging from single dot necklaces to thick multilayer structures over surface areas of many square millimeters. Moreover, the diameter of the ring structures could be simultaneously controlled. A simple model was employed to explain the forces involved in the formation of nanoparticle nanorings.
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: Jixin
authors.initials: J
authors.lastname: Chen
authors.forename: Wei-Ssu
authors.initials: WS
authors.lastname: Liao
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Tinglu
authors.initials: T
authors.lastname: Yang
authors.forename: Stacey E
authors.initials: SE
authors.lastname: Wark
authors.forename: Dong Hee
authors.initials: DH
authors.lastname: Son
authors.forename: James D
authors.initials: JD
authors.lastname: Batteas
authors.forename: Paul S
authors.initials: PS
authors.lastname: Cremer
mesh_terms: D005898:Glass; D006860:Hydrogen Bonding; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence / Q000379:methods; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D016877:Oxidants / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry; D045663:Quantum Dots; D013056:Spectrophotometry, Ultraviolet
chemical_list: D016877:Oxidants; D011137:Polystyrenes