SAXS study of core-shell colloids

Beyer, D.; Lebek, Werner; Hergeth, Wolf‐Dieter; Schmutzler, K.

doi:10.1007/bf01411105

Cited by 27 publications

(14 citation statements)

References 13 publications

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“…Furthermore, a suitable structural model must be formulated to extract information from the SAXS patterns. In the literature, there already exists a number of structural models for nanoparticles and their internal structure such as homogenous spheres and core-shell particles 19 . There has also been formulated general models to describe complex internal structures such as the Teubner-Strey description of microemulsions 20 .…”

Section: Introductionmentioning

confidence: 99%

Structure and crystallinity of water dispersible photoactive nanoparticles for organic solar cells

Pedersen

Simonsen

et al. 2015

J. Mater. Chem. A

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Water based inks would be a strong advantage for large scale production of organic photovoltaics. Formation of water dispersible nanoparticles produced by the Landfester method is a promising route to achieve such inks. We provide new insights into key ink properties for poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) nanoparticles such as internal structure and crystallinity of the dispersed nanoparticles and the previously unreported drastic changes that occur when the ink is cast into a film. We observe through Transmission Electron Microscopy (TEM) and small angle X-ray scattering (SAXS) that the nanoparticles in dispersion are spherical with nano domains of P3HT -partly crystalline. When wet processed and dried into films the nanoparticles lose their spherical shape and become flattened to oblate shapes with a large aspect ratio. Most particles are observed to have a diameter 13 times of the particle height. After casting to a film the crystal domains adopt a preferred orientation with the majority of the nano crystals (68%) with faceon orientation to the substrate. We propose that low substrate surface energy is responsible for particle deformation and texturing. Broader contextPolymer solar cells have demonstrated power conversion efficiencies comparable to what can be achieved with other thin-film technologies, but some issues with respect to environmental impact remain to be addressed. Photoactive nano-particles in aqueous dispersion have been envisioned as an effective way to do away with the use of toxic and environmental harmful solvents in the coating process of polymer solar cells. Preforming the donor/acceptor blend in nanoparticles that are dispersed in water allows for use of only aqueous or alcohol-based inks for coating, while at the same time providing a means of controlling the nano-structure of the heterojunction. We show that the nano-particles are very sensitive to the type of coating method and substrate surface energy, and that an otherwise optimal nano-structure may be compromised during coating by phase separation. Our results indicate that focusing the development effort on other types of stabilizing surfactants may provide the means to control phase separation and thus the formation of optimal nano-structure in roll-to-roll coated, environmental friendly polymer solar cells. Figure 3, Particle deformation and reorientation of crystal domains. A) Schematic of face-on and edge-on orientation of P3HT. B) AFM measurements of individual P3HT:PCBM 1:1 nanoparticles spin cast on a mica substrate.The fitted trend line finds the particle diameter is about 13 times the particle height. C) Azimuthal distribution of P3HT 100 crystallinity normalized to the highest degree of crystallinity. The overall texture (angular distribution of integrated diffraction intensity) does not change as a function of annealing. Before annealing 68% of the crystallinity is aligned edge-on with the substrate (80-100 degrees azimuthal angle. D) P3HT 100 average domain size as funct...

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Section: Introductionmentioning

confidence: 99%

Structure and crystallinity of water dispersible photoactive nanoparticles for organic solar cells

Pedersen

Simonsen

et al. 2015

J. Mater. Chem. A

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“…Contrary to spherical brush synthesis, numerous different morphologies of core-shell particles have been studied and extensively commented [28]. However, most of the characterization experiments concern the radial repartition of comonomers or surface analyses [24,27,[29][30][31][32][33][34][35][36][37]. Surprisingly, the properties in solution of core-corona particles and the nature of the hydrophilic layer have been related in few studies [26,[38][39][40], since polyelectrolyte brushes have been more precisely described in terms of interfacial distribution of monomers and thickness of the brush according to molecular characteristics (grafting density, contour length of the chains, and curvature of the surface) and the nature of the surrounding medium (ionic strength and pH) [13,17,22,[41][42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

Characterizations and properties of hairy latex particles

Borget

Lafuma

Bonnet-Gonnet

2005

Journal of Colloid and Interface Science

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“…For the internal structure of the latexes including interphases within the particles, it is important to have a method which allows one to determine fine structures between 0.01 nm (0.1 Å ) and about 20 nm with high contrast. For instance, X-ray scattering techniques were successfully used to establish the existence of an interfacial region [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Characterization of interphases in core—shell latexes by solid-state NMR

Landfester¹,

Spieß

1998

Acta Polym.

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Concepts for the characterization of composite latex particles by advanced solid‐state NMR methods are discussed. The techniques are based on 1H spin‐diffusion experiments usually applied to detect heterogeneities in polymers and polymer blends. In latexes, they allow one to characterize the morphology, including substructures in the interphase between core and shell. Motional heterogeneities within the phases are also detected. The techniques are used to characterize an extended series of core—shell particles composed of poly(n‐butyl acrylate) (PBuA) and poly(methyl methacrylate) (PMMA) synthesized in semicontinuous two‐step emulsion polymerization processes. The influence of process parameters such as synthesis temperature, crosslinking density in the core, shell content, particle size, and annealing are investigated.

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SAXS study of core-shell colloids

Cited by 27 publications

References 13 publications

Structure and crystallinity of water dispersible photoactive nanoparticles for organic solar cells

Structure and crystallinity of water dispersible photoactive nanoparticles for organic solar cells

Characterizations and properties of hairy latex particles

Characterization of interphases in core—shell latexes by solid-state NMR

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