Stacking of Hexagonal Nanocrystal Layers during Langmuir–Blodgett Deposition

Smilgies, Detlef‐M.; Heitsch, Andrew T.; Korgel, Brian A.

doi:10.1021/jp3015436

Cited by 41 publications

(59 citation statements)

References 45 publications

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“…The spot indexing (open circles) of the GISAXS patterns corresponds to a (110) oriented bcc superlattice with a lattice constant, a bcc , of (a) 3.72 nm, (b) 6.80 nm, and (c) 11.2 nm. The solid white dots indicate the direct and reflected X-ray beam positions and the horizontal lines indicate the sample horizon (white) and the Yoneda peak for the film (red) 41. …”

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confidence: 99%

The Role of Ligand Packing Frustration in Body-Centered Cubic (bcc) Superlattices of Colloidal Nanocrystals

Goodfellow

Bosoy

et al. 2015

J. Phys. Chem. Lett.

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129

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This paper addresses the assembly of body centered-cubic (bcc) superlattices of organic ligand-coated nanocrystals. First, examples of bcc superlattices of dodecanethiol-capped Au nanocrystals and oleic acid-capped PbS and PbSe nanocrystals are presented and examined by transmission electron microscopy (TEM) and grazing incidence small-angle X-ray scattering (GISAXS). These superlattices tend to orient on their densest (110) superlattice planes and exhibit a significant amount of {112} twinning. The same nanocrystals deposit as monolayers with hexagonal packing, and these thin films can coexist with thicker bcc superlattice layers, even though there is no hexagonal plane in a bcc lattice. Both the preference of bcc in bulk films over the denser face-centered cubic (fcc) superlattice structure and the transition to hexagonal monolayers can be rationalized in terms of packing frustration of the ligands. A model is presented to calculate the difference in entropy associated with capping ligand packing frustration in bcc and fcc superlattices.

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confidence: 99%

The Role of Ligand Packing Frustration in Body-Centered Cubic (bcc) Superlattices of Colloidal Nanocrystals

Goodfellow

Bosoy

et al. 2015

J. Phys. Chem. Lett.

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129

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“…Alternatively, it has been shown that the most ordered and large area arrays of MNPs 3 can be assembled on water surface [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] . The process involves deposition of evaporative solution of MNPs on a water surface where it spreads out to form a colloidal solution film.…”

Section: Introductionmentioning

confidence: 99%

“…Providing sufficient resolution for study nano-objects they, in addition, probe large area sample surfaces due to a large beam spread resulting from a very shallow angle of incidence. Assemblies of MNPs on solid substrates were intensively studied by means of grazing incidence X-ray reflectivity (XRR) and small-angle X-ray scattering (GISAXS) 12,13,16,17,27,31,35,37,38 , neutron reflectivity (NR) and grazing incidence small-angle neutron scattering (GISANS) 17 In the present study, for the first time, to our knowledge, a unique combination of in-situ GISAXS and XRR techniques, accompanied by the pressure-area isotherm analysis, BAM and ex-situ SEM were applied for investigation of super-lattices of magnetic nano-particles as they form directly on water surface in a Langmuir trough. Size and value of the magnetic 5 …”

Section: Introductionmentioning

confidence: 99%

Substantial Difference in Ordering of 10, 15, and 20 nm Iron Oxide Nanoparticles on a Water Surface: In Situ Characterization by the Grazing Incidence X-ray Scattering

et al. 2015

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In the present study, for the first time, a unique combination of in situ grazing incidence small-angle X-ray scattering and X-ray reflectivity, accompanied by the pressure-area isotherm analysis, Brewster angle microscopy, and ex situ scanning electron microscopy, was applied for investigation of two-dimensional superlattices of magnetic nanoparticles as they form on a water surface in a Langmuir trough. Iron oxide particles of different sizes stabilized with a single layer of oleic acid were used. It is demonstrated that monodisperse 10 nm particles on a water surface reproducibly form identical highly ordered monolayers in a wide range of experimental conditions, while monodisperse 20 nm particles always form compact three-dimensional clusters and never the monolayers. Monodisperse particles of an intermediate size, 15 nm in diameter, build a metastable monolayer, which shows a tendency for spontaneous transformation to bi-, tri-, and multilayer islands. The importance to use both grazing incidence small-angle X-ray scattering and X-ray reflectivity together with the complementary techniques, to avoid misinterpretation of separate experimental data sets, is underlined.

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“…The 3D nanoparticle structures prepared by the layer‐by‐layer deposition (i.e. by repeatedly applied LB or LS technique) are characterized by a relatively high quality of the lateral order , however, their vertical correlation between the neighboring layers is rather poor . To improve it, some authors tried to fabricate the nanoparticle multilayers in the LB trough in one compression cycle by increasing the surface pressure.…”

Section: Introductionmentioning

confidence: 99%

Application of the paracrystal model to GISAXS analysis of the 3D self-assembled nanoparticle crystals

Végsö

Šiffalovič

Jergel

et al. 2014

Phys. Status Solidi B

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An original diffraction model for the evaluation of the grazing‐incidence small‐angle X‐ray scattering (GISAXS) of the three‐dimensional (3D) supported self‐assembled nanoparticle crystals is presented. The model utilizes the formalism of traditional crystallography that is applied to nanoparticles as scattering entities. The infinite paracrystal concept was adopted in order to include cumulative disorder that is typical for the self‐assembled nanoparticle structures. Azimuthal averaging around a chosen crystallographic direction allows incorporation of texture effects. A transformation of the SAXS paracrystal equations to comply with the GISAXS geometry was employed to describe the scattering process in the limit of the kinematical approximation which facilitates calculations. The model was developed for the face‐centered cubic (FCC) symmetry, however, its extension to any other cubic symmetry is straightforward. The model was tested on a 3D nanoparticle assembly formed on silicon from a dried drop‐cast colloidal solution of monodisperse silver nanoparticles of 5.8 ± 0.6 nm diameter. Presence of the FCC nanoparticle crystal with the [111] texture along the substrate normal was evidenced from evaluation of the synchrotron GISAXS data. The degree of paracrystal disorder is 2.5% and 3.6% parallel and perpendicular to the substrate, respectively, suggesting the anisotropic character of the self‐assembling process. A SAXS measurement of the nanoparticle crystal formed from the same solution in a capillary revealed a randomly oriented FCC structure with a slightly larger paracrystal disorder of 4%. Obviously, different conditions of the nanoparticle crystal formation affect its azimuthal and translational disorder.

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Stacking of Hexagonal Nanocrystal Layers during Langmuir–Blodgett Deposition

Cited by 41 publications

References 45 publications

The Role of Ligand Packing Frustration in Body-Centered Cubic (bcc) Superlattices of Colloidal Nanocrystals

The Role of Ligand Packing Frustration in Body-Centered Cubic (bcc) Superlattices of Colloidal Nanocrystals

Substantial Difference in Ordering of 10, 15, and 20 nm Iron Oxide Nanoparticles on a Water Surface: In Situ Characterization by the Grazing Incidence X-ray Scattering

Application of the paracrystal model to GISAXS analysis of the 3D self-assembled nanoparticle crystals

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