title: Resolving the growth of 3D colloidal nanoparticle superlattices by real-time small-angle X-ray scattering.
abstract: The kinetics and intricate interactions governing the growth of 3D single nanoparticle (NP) superlattices (SLs, SNSLs) and binary NP SLs (BNSLs) in solution are understood by combining controlled solvent evaporation and in situ, real-time small-angle X-ray scattering (SAXS). For the iron oxide (magnetite) NP SLs studied here, the larger the NP, the farther apart are the NPs when the SNSLs begin to precipitate and the closer they are after ordering. This is explained by a model of NP assembly using van der Waals interactions between magnetite cores in hydrocarbons with a ∼21 zJ Hamaker constant. When forming BNSLs of two different sized NPs, the NPs that are in excess of that needed to achieve the final BNSL stoichiometry are expelled during the BNSL formation, and these expelled NPs can form SNSLs. The long-range ordering of these SNSLs and the BNSLs can occur faster than the NP expulsion.
authors.affiliation: Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States. CL2551@columbia.edu
authors.forename: Chenguang
authors.initials: C
authors.lastname: Lu
authors.forename: Austin J
authors.initials: AJ
authors.lastname: Akey
authors.forename: Clayton J
authors.initials: CJ
authors.lastname: Dahlman
authors.forename: Datong
authors.initials: D
authors.lastname: Zhang
authors.forename: Irving P
authors.initials: IP
authors.lastname: Herman
mesh_terms: D003102:Colloids / Q000737:chemistry; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D019301:Oleic Acid / Q000737:chemistry*; D010316:Particle Size; D053838:Scattering, Small Angle; D013499:Surface Properties; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D003102:Colloids; D019301:Oleic Acid; D052203:Ferrosoferric Oxide