Open AccessArticle
Synthesis, Characterization and Catalytic Performance of Well-Ordered Crystalline Heteroatom Mesoporous MCM-41
Crystals 2017, 7(4), 89; doi:10.3390/cryst7040089 -
Abstract
Mesoporous heteroatom molecular sieve MCM-41 bulk crystals with the crystalline phase were synthesized via a one-step hydrothermal method using an ionic complex as template. The ionic complex template was formed by interaction between cetyltrimethylammonium ions and metal complex ion [M(EDTA)]2− (M =
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Mesoporous heteroatom molecular sieve MCM-41 bulk crystals with the crystalline phase were synthesized via a one-step hydrothermal method using an ionic complex as template. The ionic complex template was formed by interaction between cetyltrimethylammonium ions and metal complex ion [M(EDTA)]2− (M = Co or Ni)]. The materials were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, N2 adsorption-desorption isotherms, and X-ray absorption fine structure spectroscopy. The results showed that the materials possess a highly-ordered mesoporous structure with a crystalline phase and possess highly uniform ordered arrangement channels. The structure is in the vertical cross directions with a crystalline size of about 12 µm and high specific surface areas. The metal atoms were incorporated into the zeolite frameworks in the form of octahedral coordinate and have a uniform distribution in the materials. The amount of metal complexes formed by metal ion and EDTA is an essential factor for the formation of the vertical cross structure. Compared to Si-MCM-41, the samples exhibited better conversion and higher selectivity for cumene cracking. Full article
Open AccessArticle
Two Organic Cation Salts Containing Tetra(isothiocyanate)cobaltate(II): Synthesis, Crystal Structures, Spectroscopic, Optical and Magnetic Properties
Crystals 2017, 7(3), 92; doi:10.3390/cryst7030092 -
Abstract
Single crystals of two hybrid organic-inorganic molecular solids, benzyl pyridinium tetra(isothiocyanate)cobalt ([BzPy]2[Co(NCS)4]) (1) and benzyl quinolinium tetra(isothiocyanate)cobalt ([BzQl]2[Co(NCS)4]) (2), were grown using a slow evaporation growth technique at room temperature and
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Single crystals of two hybrid organic-inorganic molecular solids, benzyl pyridinium tetra(isothiocyanate)cobalt ([BzPy]2[Co(NCS)4]) (1) and benzyl quinolinium tetra(isothiocyanate)cobalt ([BzQl]2[Co(NCS)4]) (2), were grown using a slow evaporation growth technique at room temperature and their IR, UV-Vis, X-ray crystal structures, luminescence, and magnetism were reported. The crystal structural analysis revealed that two molecular solids crystallize in the monoclinic space group P21/c of 1 and P21/n of 2. The cations form a dimer through weak C–H···π/π···π interactions in 1 and 2, and the adjacent cation (containing N(6) atom) in 2 forms a columnar structure through π···π weak interactions between the quinoline and benzene rings, while the anions in 1 form a layer structure via short S···Co interactions. The anions (A) and cations (C) are arranged alternatively into a column in the sequence of ···A–CC–A–CC–A··· for 1, while the two anions and cationic dimer in 2 form an alliance by the C–H···π, C–H···S and C–H···N hydrogen bonds. A weak S···π interaction was found in 1 and 2. The two molecular solids show a broad fluorescence emission around 400 nm in the solid state at room temperature, and weak antiferromagnetic coupling behavior when the temperature is lowered. Full article
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Open AccessReview
Borates—Crystal Structures of Prospective Nonlinear Optical Materials: High Anisotropy of the Thermal Expansion Caused by Anharmonic Atomic Vibrations
Crystals 2017, 7(3), 93; doi:10.3390/cryst7030093 -
Abstract
In the present study the thermal structure evolution is reviewed for known nonlinear optical borates such as β-BaB2O4, LiB3O5, CsLiB6O10, Li2B4O7, K2Al
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In the present study the thermal structure evolution is reviewed for known nonlinear optical borates such as β-BaB2O4, LiB3O5, CsLiB6O10, Li2B4O7, K2Al2B2O7, and α-BiB3O6, based on single-crystal and powder X-ray diffraction data collected over wide temperature ranges. Temperature-dependent measurements of further borates are presented for the first time: α-BaB2O4 (295–673 K), β-BaB2O4 (98–693 K), LiB3O5 (98–650 K) and K2Al2B2O7 (98–348 K). In addition to the established criteria for nonlinear optical (NLO) properties of crystals, here the role of the anisotropy and anharmonicity of the thermal vibrations of atoms is analysed as well as changes in their coordination spheres and the anisotropy of the thermal expansion of the crystal structure. Non-centrosymmetric borates, especially those that have NLO properties, often show distinct anisotropies for each cation in comparison to centrosymmetric borates. All considered NLO borates contain BO3 triangles, which are the principal cause of the strong anisotropy of the thermal expansion. Full article
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Open AccessArticle
The Influence of Conductive Nanodomain Walls on the Photovoltaic Effect of BiFeO3 Thin Films
Crystals 2017, 7(3), 81; doi:10.3390/cryst7030081 -
Abstract
Two Planar Pt electrodes with an inter-electrode distance of about 100 nm were fabricated at the surface of BiFeO3 thin films, which allow the manipulation of ferroelectric domain switching at nanoscale. This electrode configuration was pursued to study conductive domain-wall influence on
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Two Planar Pt electrodes with an inter-electrode distance of about 100 nm were fabricated at the surface of BiFeO3 thin films, which allow the manipulation of ferroelectric domain switching at nanoscale. This electrode configuration was pursued to study conductive domain-wall influence on the photovoltaic current in BiFeO3 thin films. Modulations of short-circuit photovoltaic current and hysteretic conductive switching behaviors were found in the above nanodevices, accompanied by the generation of the conductive domain walls connecting two gapped electrodes. Our technique provides a new method to configure ferroelectric domains, where the influence of the conductive domain walls on the photovoltaic effect is preeminent. Full article
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Open AccessArticle
Growth and Physical Properties of SrxCa1−xCrO3 Single Crystals
Crystals 2017, 7(3), 91; doi:10.3390/cryst7030091 -
Abstract
Perovskites SrxCa1−xCrO3 attract much attention due to the controversy on the anomalous electronic state. In this study, we synthesized a series of SrxCa1−xCrO3 (0 ≤ x ≤ 1) single crystals under high pressure
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Perovskites SrxCa1−xCrO3 attract much attention due to the controversy on the anomalous electronic state. In this study, we synthesized a series of SrxCa1−xCrO3 (0 ≤ x ≤ 1) single crystals under high pressure and high temperature conditions with self-oxidization. The crystal structure was determined using X-ray diffraction (XRD). With the increase of x, the structure transformed from orthorhombic to tetragonal to cubic. Antiferromagnetism was observed except for SrCrO3, and the TN decreased with increased x. All samples demonstrated semiconductive behavior by electrical resistivity measurement. Full article
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Open AccessArticle
X-ray Structures of Succinimidyl Halobenzoates
Crystals 2017, 7(3), 90; doi:10.3390/cryst7030090 -
Abstract
The crystal and molecular structures of five succinimidyl halobenzoates are reported. Corresponding derivatives with the respective halo-radionuclide (18F, 76Br, 123I/124I/125I/131I) were prepared and used for the radiolabeling of biologically active (macro-)molecules (peptides, proteins,
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The crystal and molecular structures of five succinimidyl halobenzoates are reported. Corresponding derivatives with the respective halo-radionuclide (18F, 76Br, 123I/124I/125I/131I) were prepared and used for the radiolabeling of biologically active (macro-)molecules (peptides, proteins, antibodies) under mild labeling conditions. All compounds were crystalized from petroleum ether/ethyl acetate mixtures. Full article
Open AccessArticle
Crystal Growth and Glass-Like Thermal Conductivity of Ca3RE2(BO3)4 (RE = Y, Gd, Nd) Single Crystals
Crystals 2017, 7(3), 88; doi:10.3390/cryst7030088 -
Abstract
Crystal growth and thermal properties of binary borates, Ca3RE2(BO3)4 (RE = Y, Gd, Nd), are considered promising crystals for laser applications. These single crystals were grown by the Czochralski method. The crystal and defect structure were
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Crystal growth and thermal properties of binary borates, Ca3RE2(BO3)4 (RE = Y, Gd, Nd), are considered promising crystals for laser applications. These single crystals were grown by the Czochralski method. The crystal and defect structure were characterized. Volumetric chemical methods without prior separation of the components were developed and applied for the determination of the dependence of chemical compositions of the crystals on the growth conditions. The thermal conductivity was investigated in the 50–300 K range. The character of the temperature dependence of thermal conductivity was found to be similar to that of glass. The possible reasons of the observed features of the thermal conductivity were analyzed. Full article
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Open AccessArticle
Application of the Improved Inclusion Core Model of the Indentation Process for the Determination of Mechanical Properties of Materials
Crystals 2017, 7(3), 87; doi:10.3390/cryst7030087 -
Abstract
The improved Johnson inclusion core model of indentation by conical and pyramidal indenters in which indenter is elastically deformed and a specimen is elastoplastically deformed under von Mises yield condition, was used for determination of mechanical properties of materials with different types of
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The improved Johnson inclusion core model of indentation by conical and pyramidal indenters in which indenter is elastically deformed and a specimen is elastoplastically deformed under von Mises yield condition, was used for determination of mechanical properties of materials with different types of interatomic bond and different crystalline structures. This model enables us to determine approximately the Tabor parameter С = НМ/YS (where НМ is the Meyer hardness and YS is the yield stress of the specimen), size of the elastoplastic zone in the specimen, effective apex angle of the indenter under load, and effective angle of the indent after unloading. It was shown that the Tabor parameter and the size of elastoplastic deformation zone increase monotonically with the increase of the plasticity characteristic indentation test results significantly more informative. Full article
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Open AccessArticle
Strength of Alkane–Fluid Attraction Determines the Interfacial Orientation of Liquid Alkanes and Their Crystallization through Heterogeneous or Homogeneous Mechanisms
Crystals 2017, 7(3), 86; doi:10.3390/cryst7030086 -
Abstract
Alkanes are important building blocks of organics, polymers and biomolecules. The conditions that lead to ordering of alkanes at interfaces, and whether interfacial ordering of the molecules leads to heterogeneous crystal nucleation of alkanes or surface freezing, have not yet been elucidated. Here
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Alkanes are important building blocks of organics, polymers and biomolecules. The conditions that lead to ordering of alkanes at interfaces, and whether interfacial ordering of the molecules leads to heterogeneous crystal nucleation of alkanes or surface freezing, have not yet been elucidated. Here we use molecular simulations with the united-atom OPLS and PYS alkane models and the mW water model to determine what properties of the surface control the interfacial orientation of alkane molecules, and under which conditions interfacial ordering results in homogeneous or heterogeneous nucleation of alkane crystals, or surface freezing above the melting point. We find that liquid alkanes present a preference towards being perpendicular to the alkane–vapor interface and more parallel to the alkane–water interface. The orientational order in the liquid is short-ranged, decaying over ~1 nm of the surface, and can be reversed by tuning the strength of the attractions between alkane and the molecules in the other fluid. We show that the strength of the alkane–fluid interaction also controls the mechanism of crystallization and the face of the alkane crystal exposed to the fluid: fluids that interact weakly with alkanes promote heterogeneous crystallization and result in crystals in which the alkane molecules orient perpendicular to the interface, while crystallization of alkanes in the presence of fluids, such as water, that interact more strongly with alkanes is homogeneous and results in crystals with the molecules oriented parallel to the interface. We conclude that the orientation of the alkanes at the crystal interfaces mirrors that in the liquid, albeit more pronounced and long-ranged. We show that the sign of the binding free energy of the alkane crystal to the surface, ΔGbind, determines whether the crystal nucleation is homogeneous (ΔGbind ≥ 0) or heterogeneous (ΔGbind < 0). Our analysis indicates that water does not promote heterogeneous crystallization of the alkanes because water stabilizes more the liquid than the crystal phase of the alkane, resulting in ΔGbind > 0. While ΔGbind < 0 suffices to produce heterogeneous nucleation, the condition for surface freezing is more stringent, ΔGbind < −2 γxl, where γxl is the surface tension of the liquid–crystal interface of alkanes. Surface freezing of alkanes is favored by their small value of γxl. Our findings are of relevance to understanding surface freezing in alkanes and to develop strategies for controlling the assembly of chain-like molecules at fluid interfaces. Full article
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Open AccessArticle
The Syntheses, Crystal Structure and Luminescence Properties of Cone-Like Octadentate Europium (III) Complexes with Four Short Alkoxy Substituents
Crystals 2017, 7(3), 85; doi:10.3390/cryst7030085 -
Abstract
Treatment of 1-(4′-methoxy or ethoxy phenyl)-4,4,4-trifluoro-1,3-butanedione with europium (III) chloride in the presence of piperidine resulted in the halide ligands exchange yielded new piperidinium tetrakis{1-(4′-methoxy or ethoxy phenyl)-4,4,4-trifluoro-1,3-butanedionato} europate (III) complexes 2a and 2b. Complexes 2a and 2b have been characterized by elemental
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Treatment of 1-(4′-methoxy or ethoxy phenyl)-4,4,4-trifluoro-1,3-butanedione with europium (III) chloride in the presence of piperidine resulted in the halide ligands exchange yielded new piperidinium tetrakis{1-(4′-methoxy or ethoxy phenyl)-4,4,4-trifluoro-1,3-butanedionato} europate (III) complexes 2a and 2b. Complexes 2a and 2b have been characterized by elemental analysis, 1H NMR spectroscopy, and FAB-MS, and their absolute structures were determined by single crystal X-ray diffraction analysis. The complexes 2a and 2b have the monoclinic space groups C2/c (No. 15, 4′-substituent = OCH3) and with P − 1 (No. 2, 4′-substituent = OC2H5), respectively. X-ray analysis results showed that eight coordinate structures of the complexes 2a and 2b have conelike structures, like calix[4]arenes, but their structures were slightly different due to the crystal packing and the existence of the solvent molecule. The complexes 2a and 2b exhibited identical, strong photoluminescence emissions in the solution phase. Full article
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Open AccessArticle
A Structural Analysis of Spiropyran and Spirooxazine Compounds and Their Polymorphs
Crystals 2017, 7(3), 84; doi:10.3390/cryst7030084 -
Abstract
In this work, crystal structures of commercially available photochromic compounds, i.e., spiropyrans and spirooxazines, were investigated by single-crystal X-ray diffraction. A total of five new structures were obtained via isothermal evaporation experiments under different conditions, namely 1,3,3-Trimethylindolino-benzopyrylospiran (I), 1,3,3-Trimethylindolinonaphtospirooxaxine (II), 1-(2-Hydroxyethyl)-3,3-dimethylindolino-6′-nitrobenzopyrylospiran (III), and
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In this work, crystal structures of commercially available photochromic compounds, i.e., spiropyrans and spirooxazines, were investigated by single-crystal X-ray diffraction. A total of five new structures were obtained via isothermal evaporation experiments under different conditions, namely 1,3,3-Trimethylindolino-benzopyrylospiran (I), 1,3,3-Trimethylindolinonaphtospirooxaxine (II), 1-(2-Hydroxyethyl)-3,3-dimethylindolino-6′-nitrobenzopyrylospiran (III), and 1,3,3-Trimethylindolino-8′-methoxybenzopyrylospiran (IVa and IVb). Since the basic structure of a spiropyran/-oxazine does not present typical hydrogen bond accepting and donating groups, this study illustrates the importance of additional functional groups connected to this kind of molecules to induce specific intermolecular interactions. Our results show that possible hydrogen bonding interactions are rather weak due to the high steric demand of these compounds. These results are supported by a search of the Cambridge structural database focused on related structures. Full article
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Open AccessArticle
Growth of High Quality Al-Doped CsLiB6O10 Crystals Using Cs2O-Li2O-MoO3 Fluxes
Crystals 2017, 7(3), 83; doi:10.3390/cryst7030083 -
Abstract
Abstract: High quality and large size Al-doped CsLiB6O10 (CLBO) single crystals have been successfully grown by top-seeded solution growth (TSSG) technique using Cs2O–Li2O–MoO3 fluxes. The advantages of this newly developed flux system were investigated by
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Abstract: High quality and large size Al-doped CsLiB6O10 (CLBO) single crystals have been successfully grown by top-seeded solution growth (TSSG) technique using Cs2O–Li2O–MoO3 fluxes. The advantages of this newly developed flux system were investigated by viscosity measurements and growth experiments. Al-doped CLBO presents a very high transmittance in the visible region and the weak absorption values at 1064 nm along a and c axes are only 140 and 50 ppm/cm, respectively. The measured LIDT of Al-doped CLBO at λ = 1064 nm and τ = 5.0 ns is 5.10 GW/cm2. Moreover, Al-doped CLBO exhibits an apparent enhancement of the hygroscopic nature in contrast with the undoped crystal as determined by the humidity experiments. Finally, a high fourth harmonic generation (FHG) conversion efficiency of 63% utilizing Al-doped CLBO has been achieved by a picosecond mode-locked Nd:YAG laser, the results also reveal that Al doping has no obvious impact on the FHG conversion efficiency. Full article
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Open AccessArticle
The Effects of ACRT on the Growth of ZnTe Crystal by the Temperature Gradient Solution Growth Technique
Crystals 2017, 7(3), 82; doi:10.3390/cryst7030082 -
Abstract
A finite element method is used here to simulate the temperature field, the thermosolutal convection, the solute segregation, and the non-isothermal phase transformation during the growth of ZnTe crystal via the temperature gradient solution growth technique (TGSG) with an accelerated crucible rotation technique
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A finite element method is used here to simulate the temperature field, the thermosolutal convection, the solute segregation, and the non-isothermal phase transformation during the growth of ZnTe crystal via the temperature gradient solution growth technique (TGSG) with an accelerated crucible rotation technique (ACRT). Three different trapezoid-wave ACRT sequences are proposed, and their effects are examined from the views of the constitutional supercooling and the mixing of the solution. The solution in front of the growth interface can be fully mixed only during the constant rotation stage of the ACRT when there is a clockwise Ekman flow. An inappropriate ACRT can produce excessively strong clockwise and counterclockwise Ekman flows, and this results in constitutional supercooling in front of the central part of the growth interface at the beginning of the stop stage and in front of the peripheral part at the end of the constant rotation stage. By adjusting the acceleration rate of the ampoule rotation, the appropriate Ekman flows can be obtained to well mix the solution and avoid the constitutional supercooling. An appropriate ACRT sequence is provided, which can facilitate the mixing of the solution, avoid constitutional supercooling, and improve the growth interface morphology. Full article
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Open AccessArticle
Synthesis, Crystal Structures, and Properties of Two Coordination Polymers Built from Imidazolyl and Carboxylate Ligands
Crystals 2017, 7(3), 73; doi:10.3390/cryst7030073 -
Abstract
Two new two-dimensional (2D) layer coordination polymers—namely, [Cd(L)2]n (1) and [Co(L)2(H2O)]n (2)—were synthesized by the reaction of corresponding metal salts with 3-(1H-imidazol-4-yl)benzoic acid (HL) incorporating 4-imidazolyl and
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Two new two-dimensional (2D) layer coordination polymers—namely, [Cd(L)2]n (1) and [Co(L)2(H2O)]n (2)—were synthesized by the reaction of corresponding metal salts with 3-(1H-imidazol-4-yl)benzoic acid (HL) incorporating 4-imidazolyl and carboxylate functional groups, and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, and powder X-ray diffraction (PXRD). Complex 1 is a 2D network with (4, 4) topology, while 2 is a typical 63-hcb topology net. Complex 1 exhibits intense light blue emission in the solid state at room temperature. Full article
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Open AccessArticle
Cobalt-Substituted Seven-Layer Aurivillius Bi8Fe4Ti3O24 Ceramics: Enhanced Ferromagnetism and Ferroelectricity
Crystals 2017, 7(3), 76; doi:10.3390/cryst7030076 -
Abstract
In this work, Aurivillius-phase Bi8Fe4-xCoxTi3O24 (7-BFCT, 0 ≤ x ≤ 0.4) powders and ceramics were successfully prepared by the combination of citrate combustion and hot-press methods. X-ray diffraction (XRD) and high-resolution transmission electron
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In this work, Aurivillius-phase Bi8Fe4-xCoxTi3O24 (7-BFCT, 0 ≤ x ≤ 0.4) powders and ceramics were successfully prepared by the combination of citrate combustion and hot-press methods. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) indicate a successful synthesis of the pure phase of the 7-BFCT ceramics, and all the samples showed a good seven-layer structure of the Aurivillius phase. Partial Fe substituted by Co was found to be effective to enhance both ferromagnetic and ferroelectric properties at room temperature, and the largest remnant magnetization (2Mr) of ~0.69 emu/g was revealed at the composition of x = 0.4. Zero field cooling and field cooling (ZFC-FC) magnetization measurement confirmed its magnetic transition occurring at a high temperature of ~750 K. Correspondingly, the enhanced ferroelectric properties of such Co-substituted ceramics were also investigated. Full article
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Open AccessArticle
Synthesis, Crystal Structure, Magnetic Property and Photo-Induced Coloration of a One-Dimensional Chain Complex
Crystals 2017, 7(3), 77; doi:10.3390/cryst7030077 -
Abstract
A novel photoactive complex was constructed from two non-photoactive ligands and cobalt (II) ions. Upon ultra violet (UV) irradiation (365 nm), the color of complex 1 changes from orange to violet. The ESR spectrum indicates that the photoactive phenomenon of complex 1 originates
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A novel photoactive complex was constructed from two non-photoactive ligands and cobalt (II) ions. Upon ultra violet (UV) irradiation (365 nm), the color of complex 1 changes from orange to violet. The ESR spectrum indicates that the photoactive phenomenon of complex 1 originates from an intermolecular energy transfer between the H5DDCPBA ligand and phenanthroline ligand. This photoactive complex shows high thermal stability according to the investigation of thermogravimetric analyses. In addition, the temperature dependence of magnetic susceptibilities for the orange complex 1 was also investigated systematically. Full article
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Open AccessArticle
Interface Crystallization of Ceria in Porous Silica Films for Solar Applications
Crystals 2017, 7(3), 80; doi:10.3390/cryst7030080 -
Abstract
Antireflective (AR) coatings with photocatalytic activity for solar cover glasses are extensively investigated at present, mostly in multilayer systems including titania. In this study, bifunctional single coats from porous silica in combination with up to 33 mol % ceria were prepared by sol–gel
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Antireflective (AR) coatings with photocatalytic activity for solar cover glasses are extensively investigated at present, mostly in multilayer systems including titania. In this study, bifunctional single coats from porous silica in combination with up to 33 mol % ceria were prepared by sol–gel dip-coating on low-iron soda-lime float glass. After heat treatment for one hour at 350 °C, the coated glasses were characterized. Solar transmittance decreased with increasing ceria content, whereas photocatalytic activity increases. Crystallization of cubic ceria was detected by grazing incidence X-ray diffraction. Chemical depth profiling by secondary neutral mass spectrometry revealed the enrichment of cerium at the coating surface as well as at the interface to the glass substrate. Self-assembled ceria crystallization at the interfaces resulted in a three-layered mesostructure of the coating, which was verified by field-emission scanning electron spectroscopy. Cubic ceria crystals at the interface act as a barrier for the sodium diffusion from the substrate, which prevents the poisoning of the photocatalyst, while those crystals at the surface act as an electron donor for photooxidation processes, both enabling adequate photocatalytic activity. The triple-layer architecture with the sequence of high/low/high refractive index materials allows for optical interference sustaining the AR-function. Full article
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Open AccessArticle
The Effect of Trimethylaluminum Flow Rate on the Structure and Optical Properties of AlInGaN Quaternary Epilayers
Crystals 2017, 7(3), 69; doi:10.3390/cryst7030069 -
Abstract
In this work, a series of quaternary AlxInyGa1−x−yN thin films have been successfully achieved using metal organic chemical vapor deposition (MOCVD) method with adjustable trimethylaluminum (TMA) flows. Surface morphology and optical properties of AlxIny
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In this work, a series of quaternary AlxInyGa1−x−yN thin films have been successfully achieved using metal organic chemical vapor deposition (MOCVD) method with adjustable trimethylaluminum (TMA) flows. Surface morphology and optical properties of AlxInyGa1−x−yN films have been evaluated. The indium segregation effect on the enhancement of UV luminescence emission in AlxInyGa1-x-yN films with increasing TMA flows was investigated. Our results shed some lights on future optical materials design and LED/LD applications. Full article
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Open AccessArticle
Unexpected Au Alloying in Tailoring In-Doped SnTe Nanostructures with Gold Nanoparticles
Crystals 2017, 7(3), 78; doi:10.3390/cryst7030078 -
Abstract
Materials with strong spin-orbit interaction and superconductivity are candidates for topological superconductors that may host Majorana fermions (MFs) at the edges/surfaces/vortex cores. Bulk-superconducting carrier-doped topological crystalline insulator, indium-doped tin telluride (In-SnTe) is one of the promising materials. Robust superconductivity of In-SnTe nanostructures has
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Materials with strong spin-orbit interaction and superconductivity are candidates for topological superconductors that may host Majorana fermions (MFs) at the edges/surfaces/vortex cores. Bulk-superconducting carrier-doped topological crystalline insulator, indium-doped tin telluride (In-SnTe) is one of the promising materials. Robust superconductivity of In-SnTe nanostructures has been demonstrated recently. Intriguingly, not only 3-dimensional (3D) nanostructures but also ultra-thin quasi-2D and quasi-1D systems can be grown by the vapor transport method. In particular, nanostructures with a controlled dimension will give us a chance to understand the dimensionality and the quantum confinement effects on the superconductivity of the In-SnTe and may help us work on braiding MFs in various dimensional systems for future topological quantum computation technology. With this in mind, we employed gold nanoparticles (GNPs) with well-identified sizes to tailor In-SnTe nanostructures grown by vapor transport. However, we could not see clear evidence that the presence of the GNPs is necessary or sufficient to control the size of the nanostructures. Nevertheless, it should be noted that a weak correlation between the diameter of GNPs and the dimensions of the smallest nanostructures has been found so far. To our surprise, the ones grown under the vapor–liquid–solid mechanism, with the use of the GNPs, contained gold that is widely and inhomogeneously distributed over the whole body. Full article
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Open AccessArticle
Synthesis, Crystal Structure and Catalytic Activity of a 1D Chained Ca(II) Coordination Polymer with 3,5-Bis(4-pyridylmethoxy)benzoate Ligand
Crystals 2017, 7(3), 72; doi:10.3390/cryst7030072 -
Abstract
A new 1D chained Ca(II) coordination polymer—namely, [CaL2(H2O)2]n (HL = 3,5-bis(4-pyridylmethoxy)benzoic acid)—was synthesized though the reaction of Ca(ClO4)2·4H2O, 3,5-bis(4-pyridylmethoxy)benzoic acid and NaOH in H2O/CH3CH2OH
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A new 1D chained Ca(II) coordination polymer—namely, [CaL2(H2O)2]n (HL = 3,5-bis(4-pyridylmethoxy)benzoic acid)—was synthesized though the reaction of Ca(ClO4)2·4H2O, 3,5-bis(4-pyridylmethoxy)benzoic acid and NaOH in H2O/CH3CH2OH (v:v = 1:2) solution. Its structure was determined by elemental analysis, infrared spectrum, and single-crystal XRD. Structural analyses show that each Ca(II) ion is eight-coordinated by six oxygen atoms of four 3,5-bis(4-pyridylmethoxy)benzoate ligands and two oxygen atoms of two coordinated H2O molecules to form a square-antiprismatic CaO8 polyhedron. The Ca(II) complex displays a 1D chained structure constructed by the bridging effect of the bidentate carboxyl group of 3,5-bis(4-pyridylmethoxy)benzoate ligand. The catalytic activity of the Ca-complex was tested for the preparation of propargylamine in the A3 coupling reaction. Full article
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