The Materials Science beamline upgrade at the Swiss Light Source
01 Sep 2013-Journal of Synchrotron Radiation (International Union of Crystallography)-Vol. 20, Iss: 5, pp 667-682
TL;DR: The wiggler X-ray source of the Materials Science beamline at the Swiss Light Source has been replaced with a 14 mm-period cryogenically cooled in-vacuum undulator to best exploit the increased brilliance of this new source.
Abstract: The Materials Science beamline at the Swiss Light Source has been operational since 2001 In late 2010, the original wiggler source was replaced with a novel insertion device, which allows unprecedented access to high photon energies from an undulator installed in a medium-energy storage ring In order to best exploit the increased brilliance of this new source, the entire front-end and optics had to be redesigned In this work, the upgrade of the beamline is described in detail The tone is didactic, from which it is hoped the reader can adapt the concepts and ideas to his or her needs
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TL;DR: This work reports a facile colloidal synthesis method for obtaining FAPbI3 and FA-doped CsPbI 3 NCs that are uniform in size and nearly cubic in shape and exhibit drastically higher robustness than their MA- or Cs-only cousins with similar sizes and morphologies.
Abstract: Colloidal nanocrystals (NCs) of APbX3-type lead halide perovskites [A = Cs+, CH3NH3+ (methylammonium or MA+) or CH(NH2)2+ (formamidinium or FA+); X = Cl–, Br–, I–] have recently emerged as highly versatile photonic sources for applications ranging from simple photoluminescence down-conversion (e.g., for display backlighting) to light-emitting diodes. From the perspective of spectral coverage, a formidable challenge facing the use of these materials is how to obtain stable emissions in the red and infrared spectral regions covered by the iodide-based compositions. So far, red-emissive CsPbI3 NCs have been shown to suffer from a delayed phase transformation into a nonluminescent, wide-band-gap 1D polymorph, and MAPbI3 exhibits very limited chemical durability. In this work, we report a facile colloidal synthesis method for obtaining FAPbI3 and FA-doped CsPbI3 NCs that are uniform in size (10–15 nm) and nearly cubic in shape and exhibit drastically higher robustness than their MA- or Cs-only cousins with sim...
368 citations
TL;DR: In this paper, very small superparamagnetic iron oxide nanoparticles were characterized by innovative synchrotron X-ray total scattering methods and Debye function analysis, using the information from both Bragg and diffuse scattering, size-dependent core-shell magnetite-maghemite compositions and full size distributions were derived within a coherent approach.
Abstract: Very small superparamagnetic iron oxide nanoparticles were characterized by innovative synchrotron X-ray total scattering methods and Debye function analysis. Using the information from both Bragg and diffuse scattering, size-dependent core–shell magnetite–maghemite compositions and full size (number- and mass-based) distributions were derived within a coherent approach. The magnetite core radii in 10 nm sized NPs well match the magnetic domain sizes and show a clear correlation to the saturation magnetization values, while the oxidized shells seem to be magnetically silent. Very broad superstructure peaks likely produced by the polycrystalline nature of the surface layers were experimentally detected in room temperature oxidized samples. Effective magnetic anisotropy constants, derived by taking the knowledge of the full size-distributions into account, show an inverse dependence on the NPs size, witnessing a major surface contribution. Finally, an additional amorphous component was uncovered within the ...
146 citations
TL;DR: Droplet-based microfluidics can successfully tackle the problem of solving the practical utility and rational synthesis of multinary colloidal NCs in both a time- and cost-efficient manner, and demonstrates the excellent transference of reaction parameters from microfluidity to a conventional flask-based environment, thereby enabling up-scaling and further implementation in optoelectronic devices.
Abstract: Hybrid organic–inorganic and fully inorganic lead halide perovskite nanocrystals (NCs) have recently emerged as versatile solution-processable light-emitting and light-harvesting optoelectronic materials. A particularly difficult challenge lies in warranting the practical utility of such semiconductor NCs in the red and infrared spectral regions. In this context, all three archetypal A-site monocationic perovskites—CH3NH3PbI3, CH(NH2)2PbI3, and CsPbI3—suffer from either chemical or thermodynamic instabilities in their bulk form. A promising approach toward the mitigation of these challenges lies in the formation of multinary compositions (mixed cation and mixed anion). In the case of multinary colloidal NCs, such as quinary CsxFA1–xPb(Br1–yIy)3 NCs, the outcome of the synthesis is defined by a complex interplay between the bulk thermodynamics of the solid solutions, crystal surface energies, energetics, dynamics of capping ligands, and the multiple effects of the reagents in solution. Accordingly, the rat...
125 citations
TL;DR: A non-beam approach to additive manufacturing of high-entropy alloys is developed based on 3D extrusion of inks containing a blend of oxide nanopowders, hydrogen reduction, and sintering to form face-centered-cubic equiatomic CoCrFeNi alloy.
Abstract: Additive manufacturing of high-entropy alloys combines the mechanical properties of this novel family of alloys with the geometrical freedom and complexity required by modern designs. Here, a non-beam approach to additive manufacturing of high-entropy alloys is developed based on 3D extrusion of inks containing a blend of oxide nanopowders (Co3O4 + Cr2O3 + Fe2O3 + NiO), followed by co-reduction to metals, inter-diffusion and sintering to near-full density CoCrFeNi in H2. A complex phase evolution path is observed by in-situ X-ray diffraction in extruded filaments when the oxide phases undergo reduction and the resulting metals inter-diffuse, ultimately forming face-centered-cubic equiatomic CoCrFeNi alloy. Linked to the phase evolution is a complex structural evolution, from loosely packed oxide particles in the green body to fully-annealed, metallic CoCrFeNi with 99.6 ± 0.1% relative density. CoCrFeNi micro-lattices are created with strut diameters as low as 100 μm and excellent mechanical properties at ambient and cryogenic temperatures. Additive manufacturing of high entropy alloys is still an emerging field that usually relies on expensive pre-alloyed powders. Here, the authors develop a method to 3D ink-print a CoCrFeNi high entropy alloy using inexpensive blended oxide nanopowders, hydrogen reduction, and sintering.
93 citations
References
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01 Jan 2003
3,254 citations
"The Materials Science beamline upgr..." refers methods in this paper
...Bending mirror 2 was achieved using the flexural hinge system described by Rossetti et al. (2002)....
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TL;DR: The thermal expansion of AlN, cubic BN, and BP has been measured from 77 to 1300 K by x−ray techniques as mentioned in this paper, and the derived thermal expansion coefficients are compared with those of diamond, Si, Ge, SiC, GaP, and BeO using the Debye temperature as a scaling parameter.
Abstract: The thermal expansion of AlN, cubic BN, and BP has been measured from 77 to 1300 K by x−ray techniques The derived thermal expansion coefficients are compared with those of diamond, Si, Ge, SiC, GaP, and BeO using the Debye temperature as a scaling parameter It is apparent that the thermal expansion of Si is the smallest, SiC is intermediate, and all of the others are larger The thermal expansion of Mo and W is also reviewed in order to determine how well these metals match the thermal expansion of the adamantine or diamondlike crystals
648 citations
"The Materials Science beamline upgr..." refers background in this paper
...20, 667–682 P. R. Willmott et al. MS beamline upgrade at the SLS 673 The thermal expansion coefficient of silicon changes almost linearly between 77 and 300 K (Slack & Bartram, 1975) such that l=l ¼ 2:55 10 4 ð11Þ as one cools from 300 to 77 K....
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TL;DR: The method of measuring and inverting diffraction patterns from nanocrystals represents a vital step towards the ultimate goal of atomic resolution single-molecule imaging that is a prominent justification for development of X-ray free-electron lasers.
Abstract: Synchrotron X-ray radiation, produced by electron accelerators at central facilities, can now be produced in extremely narrow coherent beams. When these X-rays illuminate a crystal of nanometre dimensions a diffraction pattern emerges that is highly resolved. This provides a powerful new tool for structural analysis, as the fine features of the diffraction pattern can be interpreted in terms of sub-atomic distortions within the crystal attributable to its contact with an external support. Coherent X-ray diffraction patterns derived from third-generation synchrotron radiation sources can lead to quantitative three-dimensional imaging of lattice strain on the nanometre scale. Coherent X-ray diffraction imaging is a rapidly advancing form of microscopy: diffraction patterns, measured using the latest third-generation synchrotron radiation sources, can be inverted to obtain full three-dimensional images of the interior density within nanocrystals1,2,3. Diffraction from an ideal crystal lattice results in an identical copy of this continuous diffraction pattern at every Bragg peak. This symmetry is broken by the presence of strain fields, which arise from the epitaxial contact forces that are inevitable whenever nanocrystals are prepared on a substrate4. When strain is present, the diffraction copies at different Bragg peaks are no longer identical and contain additional information, appearing as broken local inversion symmetry about each Bragg point. Here we show that one such pattern can nevertheless be inverted to obtain a ‘complex’ crystal density, whose phase encodes a projection of the lattice deformation. A lead nanocrystal was crystallized in ultrahigh vacuum from a droplet on a silica substrate and equilibrated close to its melting point. A three-dimensional image of the density, obtained by inversion of the coherent X-ray diffraction, shows the expected facetted morphology, but in addition reveals a real-space phase that is consistent with the three-dimensional evolution of a deformation field arising from interfacial contact forces. Quantitative three-dimensional imaging of lattice strain on the nanometre scale will have profound consequences for our fundamental understanding of grain interactions and defects in crystalline materials4. Our method of measuring and inverting diffraction patterns from nanocrystals represents a vital step towards the ultimate goal of atomic resolution single-molecule imaging that is a prominent justification for development of X-ray free-electron lasers5,6,7.
616 citations
"The Materials Science beamline upgr..." refers background in this paper
...Phase retrieval and inversion of the oversampled intensity distribution around a Bragg peak (Sayre, 1952) allows one to obtain the electron density and relative displacements (i.e. strain fields) with subångström resolution of the atoms from their ideal bulk-like positions (Pfeifer et al., 2006)....
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TL;DR: New X-ray diffraction techniques, which take advantage of the latest synchrotron radiation sources, can be used to obtain quantitative three-dimensional images of strain, leading to new knowledge of how nanomaterials behave within active devices and on unprecedented timescales.
Abstract: The understanding and management of strain is of fundamental importance in the design and implementation of materials. The strain properties of nanocrystalline materials are different from those of the bulk because of the strong influence of their surfaces and interfaces, which can be used to augment their function and introduce desirable characteristics. Here we explain how new X-ray diffraction techniques, which take advantage of the latest synchrotron radiation sources, can be used to obtain quantitative three-dimensional images of strain. These methods will lead, in the near future, to new knowledge of how nanomaterials behave within active devices and on unprecedented timescales.
563 citations
"The Materials Science beamline upgr..." refers methods in this paper
...Coherent X-ray diffraction imaging (CXDI) in the Bragg geometry is an emerging quantitative technique for imaging the internal defect structure of nano- and micro-crystalline objects and materials (Robinson & Harder, 2009) and extended samples (Robinson et al., 2005; Le Bolloc’h et al., 2005)....
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