TY - JOUR A1 - Kapernaum, Nadia A1 - Lange, Alyna A1 - Ebert, Max A1 - Grunwald, Marco A. A1 - Häge, Christian A1 - Marino, Sebastian A1 - Zens, Anna A1 - Taubert, Andreas A1 - Gießelmann, Frank A1 - Laschat, Sabine T1 - Current topics in ionic liquid crystals JF - ChemPlusChem N2 - Ionic liquid crystals (ILCs), that is, ionic liquids exhibiting mesomorphism, liquid crystalline phases, and anisotropic properties, have received intense attention in the past years. Among others, this is due to their special properties arising from the combination of properties stemming from ionic liquids and from liquid crystalline arrangements. Besides interesting fundamental aspects, ILCs have been claimed to have tremendous application potential that again arises from the combination of properties and architectures that are not accessible otherwise, or at least not accessible easily by other strategies. The current review highlights recent developments in ILC research, starting with some key fundamental aspects. Further subjects covered include the synthesis and variations of modern ILCs, including the specific tuning of their mesomorphic behavior. The review concludes with reflections on some applications that may be within reach for ILCs and finally highlights a few key challenges that must be overcome prior and during true commercialization of ILCs. KW - electrochemistry KW - ionic liquid crystals KW - mesogen mesophases KW - self-assembly KW - X-ray diffraction Y1 - 2021 U6 - https://doi.org/10.1002/cplu.202100397 SN - 2192-6506 VL - 87 IS - 1 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Uchida, Ryusuke A1 - Binet, Silvia A1 - Arora, Neha A1 - Jacopin, Gwenole A1 - Alotaibi, Mohammad Hayal A1 - Taubert, Andreas A1 - Zakeeruddin, Shaik Mohammed A1 - Dar, M. Ibrahim A1 - Graetzel, Michael T1 - Insights about the Absence of Rb Cation from the 3D Perovskite Lattice BT - Effect on the Structural, Morphological, and Photophysical Properties and Photovoltaic Performance JF - Small N2 - Efficiencies >20% are obtained from the perovskite solar cells (PSCs) employing Cs+ and Rb+ based perovskite compositions; therefore, it is important to understand the effect of these inorganic cations specifically Rb+ on the properties of perovskite structures. Here the influence of Cs+ and Rb+ is elucidated on the structural, morphological, and photophysical properties of perovskite structures and the photovoltaic performances of resulting PSCs. Structural, photoluminescence (PL), and external quantum efficiency studies establish the incorporation of Cs+ (x < 10%) but amply rule out the possibility of Rb-incorporation into the MAPbI(3) (MA = CH3NH3+) lattice. Moreover, morphological studies and time-resolved PL show that both Cs+ and Rb+ detrimentally affect the surface coverage of MAPbI(3) layers and charge-carrier dynamics, respectively, by influencing nucleation density and by inducing nonradiative recombination. In addition, differential scanning calorimetry shows that the transition from orthorhombic to tetragonal phase occurring around 160 K requires more thermal energy for the Cs-containing MAPbI(3) systems compared to the pristine MAPbI(3). Investigation including mixed halide (I/Br) and mixed cation A-cation based compositions further confirms the absence of Rb+ from the 3D-perovskite lattice. The fundamental insights gained through this work will be of great significance to further understand highly promising perovskite compositions. KW - cation miscibility KW - cesium cation KW - perovskite solar cells KW - rubidium cation KW - X-ray diffraction Y1 - 2018 U6 - https://doi.org/10.1002/smll.201802033 SN - 1613-6810 SN - 1613-6829 VL - 14 IS - 36 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Burek, Katja A1 - Dengler, Joachim A1 - Emmerling, Franziska A1 - Feldmann, Ines A1 - Kumke, Michael Uwe A1 - Stroh, Julia T1 - Lanthanide Luminescence Revealing the Phase Composition in Hydrating Cementitious Systems JF - ChemistryOpen N2 - The hydration process of Portland cement in a cementitious system is crucial for development of the high‐quality cement‐based construction material. Complementary experiments of X‐ray diffraction analysis (XRD), scanning electron microscopy (SEM) and time‐resolved laser fluorescence spectroscopy (TRLFS) using europium (Eu(III)) as an optical probe are used to analyse the hydration process of two cement systems in the absence and presence of different organic admixtures. We show that different analysed admixtures and the used sulphate carriers in each cement system have a significant influence on the hydration process, namely on the time‐dependence in the formation of different hydrate phases of cement. Moreover, the effect of a particular admixture is related to the type of sulphate carrier used. The quantitative information on the amounts of the crystalline cement paste components is accessible via XRD analysis. Distinctly different morphologies of ettringite and calcium−silicate−hydrates (C−S−H) determined by SEM allow visual conclusions about formation of these phases at particular ageing times. The TRLFS data provides information about the admixture influence on the course of the silicate reaction. The dip in the dependence of the luminescence decay times on the hydration time indicates the change in the structure of C−S−H in the early hydration period. Complementary information from XRD, SEM and TRLFS provides detailed information on distinct periods of the cement hydration process. KW - cement admixtures KW - cement hydration KW - Europium KW - luminescence KW - SEM KW - X-ray diffraction Y1 - 2019 U6 - https://doi.org/10.1002/open.201900249 SN - 2191-1363 VL - 8 IS - 12 SP - 1441 EP - 1452 PB - Wiley-VCH-Verl. CY - Weinheim ER - TY - JOUR A1 - Herzog, Marc A1 - Bojahr, Andre A1 - Goldshteyn, J. A1 - Leitenberger, Wolfram A1 - Vrejoiu, I. A1 - Khakhulin, D. A1 - Wulff, M. A1 - Shayduk, Roman A1 - Gaal, P. A1 - Bargheer, Matias T1 - Detecting optically synthesized quasi-monochromatic sub-terahertz phonon wavepackets by ultrafast x-ray diffraction JF - Applied physics letters N2 - We excite an epitaxial SrRuO3 thin film transducer by a pulse train of ultrashort laser pulses, launching coherent sound waves into the underlying SrTiO3 substrate. Synchrotron-based x-ray diffraction (XRD) data exhibiting separated sidebands to the substrate peak evidence the excitation of a quasi-monochromatic phonon wavepacket with sub-THz central frequency. The frequency and bandwidth of this sound pulse can be controlled by the optical pulse train. We compare the experimental data to combined lattice dynamics and dynamical XRD simulations to verify the coherent phonon dynamics. In addition, we observe a lifetime of 130 ps of such sub-THz phonons in accordance with the theory. KW - acoustic waves KW - epitaxial layers KW - phonon dispersion relations KW - terahertz waves KW - thin film devices KW - X-ray diffraction Y1 - 2012 U6 - https://doi.org/10.1063/1.3688492 SN - 0003-6951 VL - 100 IS - 9 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Schwarze, Thomas A1 - Traeger, Juliane A1 - Kelling, Alexandra A1 - Schilde, Uwe A1 - Holdt, Hans-Jürgen T1 - Macrocyclic dithiomaleonitriles for an efficient PdCl2 coordination JF - Inorganica chimica acta : the international inorganic chemistry journal N2 - We have synthesized a set of new unsaturated macrocyclic dithioethers with an increasing number of flexible methylene units 1-7 (Scheme 2) to investigate the correlation between the ring size of these ligands, the chelation effect and the consequences for an efficient PdCl2 coordination. The dithioethers 1-7 and the complex [PdCl2(4)]center dot CHCl3 were characterized by X-ray diffraction analysis. The crystal structures of 1-7 show that 2-7 are better preorganized chelating ligands for an exocyclic PdCl2 coordination than 1. The chelation effect of 1-7, the orientation of the sulfur atoms and the S center dot center dot center dot S donor distances, are influenced by the flexibility of the methylene units. In this series the unsaturated macrocyclic ligands 5 and 6 are the best chelating ligands for an efficient PdCl2 coordination. Comparative solvent extraction experiments with mn-12S(2)O(2) (mn = maleonitrile) reveal that the low interface activity of the new ligands reduces the extraction rate. However, a comparison with open-chain dithiomaleonitriles shows the impact of the macrocyclic effect of 4 and 5 on the extraction yield. KW - Thioether ligands KW - Palladium KW - Synthesis KW - X-ray diffraction KW - Chelation effect KW - Extraction Y1 - 2013 U6 - https://doi.org/10.1016/j.ica.2013.08.020 SN - 0020-1693 SN - 1873-3255 VL - 408 IS - 2 SP - 53 EP - 58 PB - Elsevier CY - Lausanne ER -