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In this paper, a novel metal-free compound, [H2(bpyp)][ClO4]2 (1) (bpyp = 1,3-bis(4-pyridyl)propane), has been successfully synthesized. It undergoes a reversible phase transition at around Tc = 256.19 K (Tc is the Curie temperature). Compound 1 shows a moderate ferroelectric polarization (Ps) of about 0.13 μC cm−2 and a coercive field (Ec) as small as 0.65 kV cm−1. The phase transition behavior of compound 1 is well characterized by differential scanning calorimetry (DSC) and variable temperature single crystal diffraction measurements. The displacement and rotational reorientation motion of H2(bpyp)2+ cations and ClO4− anions induce the phase transition of compound 1 from the non-polar space group P21212 (No. 18) to the polar space group P21 (No. 4). The significant second harmonic generation (SHG) switching response further demonstrates the symmetry breaking from P21212 to P21. In particular, a dielectric study exhibits that the dielectric anomaly of compound 1 increases by 3–6 times at the phase transition temperature, which indicates its potential applications in switchable dielectric elements. Meanwhile, compound 1 shows semiconducting properties with a wide optical bandgap of ∼4.47 eV. This finding suggests that metal-free compounds can be used in environmentally-friendly phase transition materials, contributing to the exploration of ferroelectric–dielectric and nonlinear optical (NLO) switching materials. [ABSTRACT FROM AUTHOR]

For the hybrid organic–inorganic perovskites with the general formula of A2MIIX4 (A = methylammonium; MII = Mn, Cu and Co; X = Cl), the arrangement of metal ions and organic ligands leads to a delicate balance of space, spin and charge, which results in diverse properties. In this paper, we reported a group of hybrid organic–inorganic perovskite single crystals of (CH3NH3)2MnCl4, (CH3NH3)2CuCl4 and (CH3NH3)2CoCl4 grown by a simple solution evaporation method. Magnetic measurements show that all the single crystals display magnetic ordering at low temperature. Our results reveal a novel group of hybrid organic–inorganic magnetic perovskites. [ABSTRACT FROM AUTHOR]

In recent years, metal–organic frameworks (MOFs) have been widely used in various fields, especially in the field of electrochemical energy storage and conversion, because of their excellent properties. It is reported that Co-MOFs usually play the role of templates with other active components to improve the overall properties of materials. Pristine Co-MOFs have been widely used for battery applications because of their excellent performance as well as the simple fabrication process, which can eliminate concerns regarding poorly controlled pyrolysis. Herein, for a further specific summary of particular applications of Co-MOFs, we will mainly review the relative applications of Co-MOFs in lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, lithium–sulfur batteries and metal–air batteries. In this paper, the applications of pristine Co-based MOFs are reviewed in detail, which can provide a reference for future work. [ABSTRACT FROM AUTHOR]

Triazine derivatives, a class of electron-deficient π-conjugated molecules with high photochemical activity and excellent luminescent characteristics, have been utilized as a kind of electron-acceptor for the construction of molecular cages, luminescent and photochromic materials. In this paper, a novel and highly stable MOF with cubane-like clusters, [Co4(SO4)3(F)3(tpt)2(tatb)] (1) (tpt = 2,4,6-tris-(4-pyridyl)-1,3,5-triazine, H3tatb = 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzoic acid), has been successfully synthesized based on a triazine derivative, and possesses unprecedented sulfate- and fluoride-bridged cubane-type tetranuclear cobalt clusters and a 3D + 3D → 3D open framework. Compound 1 shows a rather high BET surface area and exhibits excellent thermal stability and high chemical stability in common solvents and even in acidic or basic solutions (in a pH range from 4 to 12). Moreover, catalytic measurements show that compound 1 is an excellent heterogeneous catalyst for the selective oxidation of aryl alkenes to aldehydes or ketones with conversions of 97%. [ABSTRACT FROM AUTHOR]

Co-crystallization of the antibacterial agent proflavine (PF) with the inorganic salt ZnCl2 by mechanochemical and solution methods results in the formation of novel compounds ZnCl3(HPF) (1) and [HPF]2[ZnCl4]·H2O (2), both containing the proflavinium cation (HPF)+. Both compounds show a 50–125% enhanced antimicrobial activity with respect to a reference standard of AgNO3, and a 25–50% enhancement to the behaviour of the separate components against pathogen indicator strains of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. In terms of crystal structure, both compounds ZnCl3(HPF) and [HPF]2[ZnCl4]·H2O are characterized by extensive π-stacking interactions between the proflavine moieties. The same interaction is predominant in the previously unknown crystal structures of neutral proflavine (PF), as well as in that of its dihydrated monochloride salt, [HPF]Cl·2H2O, which are also described in this paper. [ABSTRACT FROM AUTHOR]

In this paper, palygorskite (Pal) and spherical zinc sulfide (ZnS) nanopowders were successfully synthesized by using a simple hydrothermal method. The ZnS nanoparticles were supported on the framework of Pal without agglomeration, thereby increasing the specific surface area of Pal/ZnS nanocomposites (from 36.33 m2 g−1 to 83.85 m2 g−1). The acquired nanocomposites exhibited a significant enhancement in photoactivity for the degradation of rhodamine B under simulated sunlight irradiation. Specifically, when the content of Pal was 40%, the nanocomposite showed optimal photocatalytic activity, with a degradation rate of rhodamine B of 100% in 150 min. The improved photocatalytic performance of the nanocomposites may be attributed to the fact that the incorporation of Pal not only strengthened the adsorption of rhodamine B, but also reduced the band gap energy of the nanocomposites and the recombination rate of electrons and holes. Such inexpensive high-performance Pal/ZnS nanocomposites could find potential applications for the degradation of organic dyes. [ABSTRACT FROM AUTHOR]

In this paper, a series of Eu3+/Tb3+ doped La3Ga5SiO14 (LGS:Eu3+, Tb3+) phosphors with excellent performance have been synthesized by high-temperature solid-phase method. The effects of Eu3+ and Tb3+ doping in LGS on the host lattice were analyzed by X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) proved that the Eu3+ and Tb3+ ions were successfully doped into the LGS host. The doped Eu3+/Tb3+ ions only occupy the eight-coordinated La3+ sites. The concentration quenching points of LGS:Eu3+ and LGS:Tb3+ phosphors were determined to be 0.16 and 0.18, respectively. The luminescence performance and fluorescence lifetime of LGS:Eu3+, Tb3+ were studied. LGS:Eu3+, Tb3+ phosphors successfully realized Tb3+ → Eu3+ energy transfer to enhance Eu3+ luminescence. The energy transfer mechanism is speculated on using the experimental results. The energy transfer efficiency from Tb3+ to Eu3+ is about 66.83% in La2.46Tb0.18Eu0.36Ga5SiO14. The LGS:Eu3+, Tb3+ phosphors can achieve tunable luminescence by controlling the doping concentrations of Eu3+ and Tb3+. The ΔE is calculated to be 0.2567 eV for the La2.70Eu0.12Tb0.18Ga5SiO14 phosphor. [ABSTRACT FROM AUTHOR]

The novel single component molecular ferroelectric single crystal of 1,3,5-trimethylnitrobenzene (TMNB) has been investigated in terms of its temperature dependent polar properties. Three phases have been found in the solid state of TMNB: phase I above 161 K, phase II (incommensurate) between 161 and 152 K and phase III below 152 K. The TMNB crystal structures were determined at 100 K (phase III, sp. gr. Pca21) and at 250 K (phase I, sp. gr. Pnma). Ferroelectricity of phase III along the c-axis has been confirmed by the pyroelectric measurements and observations of the hysteresis loops, revealing spontaneous polarization as small as ∼2 × 10−6 C m−2. The crystal is the first example of an origin of spontaneous polarization related to flexibility of the C–H⋯π hydrogen bonds (molecular joints). The TMNB molecules in the dimer can change the mutual orientation of the dipole moments without breaking the C–H⋯π bonds. In this paper, the mechanism of the phase transitions will be discussed, which is governed by the dynamics of the NO2 groups and the flexibility of the C–H⋯π dimer. [ABSTRACT FROM AUTHOR]

In this paper, the growth of semi-polar GaN thick films was investigated on an m-plane sapphire by hydride vapor phase epitaxy (HVPE). By optimizing parameters of the HVPE process, both (11−22) and (10−13) semi-polar GaN films have been successfully obtained with a mirror surface and excellent crystal quality on different GaN templates grown by metal organic chemical vapor deposition (MOCVD), respectively. The influence of MO-GaN templates on the HVPE growth was further studied. The results revealed that the same plane of a semi-polar HVPE-GaN thick layer was grown on a single-phase template, such as GaN (11−22)HVPE on (11−22)MO-template and GaN (10−13)HVPE on (10−13)MO-template. However, on mixed-phase MO-templates, a single-phase (11−22) GaN thick layer was found to grow even if the original templates contain both (11−22) and (10−13) plane components. Meanwhile, in contrast with the difficult growth of GaN (10−13) with a smooth surface, it is easier to acquire GaN (11−22) thick layers by a HVPE method. A wider window for the growth of the (11−22) plane could partly explain the reason why the pure GaN (11−22) plane could be grown on mixed-phase ((11−22) & (10−13)) MO-templates. In order to explain this phenomenon, both formation energy (Ef) and migration barrier (Em) of these semi-polar faces were calculated. Our results indicated that the Ef of GaN (10−13) (−0.56 eV) is higher than that of (11−22) (−10.73 eV), and the Em of (10−13) (0.30 eV) is lower than that of (11−22) (1.89 eV). So the (11−22)-plane growth was more likely to be prevalent in competition between two phases. [ABSTRACT FROM AUTHOR]

Over the past several decades, halogen bonding has become a standard 'tool' in supramolecular chemistry and particularly in crystal engineering. Traditionally, the study of halogen bonding has primarily been focused on organic materials, but lately there has been a constant increase in interest for halogen-bonded metal–organic materials. Numerous reports and reviews dealing with halogen bonding in single-component metal–organic solids and metallate salts have been published to date. In contrast, the design of multi-component crystals involving neutral metal–organic complexes and/or neutral halogen bond donors as building blocks has been much less explored. The purpose of this paper is to give an overview of the current advances in the preparation of halogen-bonded metal–organic multi-component solids, including salts, cocrystals comprising neutral constituents as well as cocrystals comprising ionic constituents. In doing so, we shall outline the general design strategies which can be employed in the design of such materials, and suggest possible directions for further research in this fascinating field. [ABSTRACT FROM AUTHOR]

This paper examines the influence of temperature and oxygen on the growth of large-scale silicon carbide nanowires by using a combination of sol–gel impregnation and carbothermal reduction methods. To investigate the growth process of SiC nanowires, the microstructural changes of nanowires at different temperatures from 1050 °C to 1550 °C were observed using SEM. In addition, XRD, TEM and FTIR were also used to analyze the nucleation, crystal structure and chemical phase of the SiC nanowires. XPS revealed the chemical reactions that occur during the growth of SiC nanowires. In this paper, we also evaluated the impacts of temperature and oxygen from SiOC (an intermediate) on the growth of SiC nanowires. The results show that a proper temperature was necessary for the nucleation and growth of SiC nanowires. The findings also indicate that the presence of O2 could contribute to the growth of longer SiC nanowires. [ABSTRACT FROM AUTHOR]

Nickel sulfide (Ni3S2) has been widely known in the energy storage field, owing to the high theoretical capacitance, low cost, and environmental friendliness. We reported simple, low-cost hydrothermal synthesis of Ni3S2 nanoparticles as a remarkable electrode material for symmetric supercapacitor (SSC) in this paper. The structural characterization confirms the successful formation of the sample with a nanoparticle-like morphology with good crystallinity. The unique structure is composed of plenty of ion mobilization channels that exhibits superb electrochemical performance. When employed as an electrode material for supercapacitors, the fabricated Ni3S2 nanoparticles displayed the typical features of battery-type faradic electrodes showing an ultra-high specific capacitance of 2495 F g−1 at 1 A g−1 and excellent cycling stability (92.2% capacitance retention after 5000 consecutive CV cycles) within the potential frame of −0.2 to 0.6 V in a three-electrode system, which surpasses many previous literature reports. In the end, a SSC device was assembled exhibiting an optimized and stable potential window of 1.8 V with a high specific capacitance of 116.6 F g−1 at 5 A g−1. Moreover, the Ragone plot shows a high energy density of 52.4 W h kg−1 and an ultra-high power density of 13 500.0 W kg−1, indicating excellent cycling stability (95% retention after 7000 cycles). Additionally, we demonstrated a coin-type SSC that provides sufficient energy to turn on the red LED, which emits light over a certain period to open up possible realistic applications. These results show the great potential of Ni3S2 nanoparticles in the development of high-performance electrode materials for energy storage and conversion systems. [ABSTRACT FROM AUTHOR]

Studying the influence of oxygen on the growth and properties of diamond has research significance. In this paper, we created an oxygen-rich environment by adding Ni2O3 to the Fe–Ni–C system. Large single crystals of oxygen-containing diamond were successfully synthesized using the temperature gradient method (TGM) in a China-type large volume cubic high-pressure apparatus (CHPA) at 5.5–6.0 GPa and 1360–1600 °C. The results show that with the increase of the Ni2O3 content in the Fe–Ni–C system, the rate of diamond growth decreased while the conditions for diamond growth were enhanced. The morphology of the diamonds changed from {111}, {110} and {113} mixed faces to {111} dominant face. The IR results show that the presence of Ni2O3 increased the nitrogen content in diamonds from 237 ppm to 543 ppm. When 3.5 wt% Ni2O3 was added, A-centre nitrogen began to appear in the diamonds. The XPS results confirmed that oxygen successfully entered the diamond lattice in the form of C–O, C＝O, O–C＝O and N–O with a high concentration of Ni2O3 additives. Meanwhile, there were no obvious impurity inclusions and cracks in the diamond crystals. In addition, the Raman peak position of the diamond appeared to red shift, and the FWHM increased from 4.93 cm−1 to 5.52 cm−1. [ABSTRACT FROM AUTHOR]

All-inorganic materials, mixed halide perovskite (MHP) nanocrystals (NCs), have attracted considerable attention recently because of their excellent luminescence efficiencies and extraordinary physical properties, making them a promising material for next-generation lighting and full-color display. On the other hand, an essential development of blue-emitting devices rather than other color emitters has been hindered by their defect tolerance and quantum efficiency which are relatively lower than those of green-emitting NCs. Moreover, few studies have examined the synthesis and properties of blue-emitting MHP NCs or their applications to light-emitting diodes (LEDs). To solve these problems, this paper reports a facile and controllable way of producing emission wavelength tunable CsPb(Br1−xClx)3 NCs using a fast and straightforward chemical treatment with the trimethylsilyl chloride (TMSC) additive. Structural and chemical analysis showed that the Cl content in the CsPb(Br1−xClx)3 NCs could be modulated by TMSC addition without changing the morphologies. The photoluminescence emission peak wavelength of the CsPb(Br1−xClx)3 NCs could be modulated from 515 to 416 nm by increasing the TMSC content. To this end, blue and green LEDs were successfully demonstrated by using the TMSC-treated CsPb(Br1−xClx)3 NCs as an emissive layer, showing a controllable emission wavelength from 473 to 511 nm. [ABSTRACT FROM AUTHOR]

The demand for proteins with high purity, high activity and high stability is increasing, especially in the biopharmaceutical industry. Traditional industrial protein production technologies include chromatography, which is expensive, and salting out and traditional crystallization methods, which require large amounts of salt and have an adverse effect on the environment. In recent years, a new method—solvent freeze-out (SFO) technology for protein crystallization—has been developed. Compared with traditional methods, SFO requires less salt, and can be carried out at low temperatures, resulting in more stable and active proteins. In addition, SFO can control the nucleation and crystal growth process under different supersaturation levels by setting appropriate operating temperatures, which can ensure industrial application of this technology. This paper reviews important advances in SFO technology for the crystallization of proteins. [ABSTRACT FROM AUTHOR]

A careful selection of organic and inorganic components enables the production of unusual structure types with promising practical properties by facile syntheses. In this paper, we describe novel supramolecular architectures comprising organic adamantane-like divalent building blocks and iodide or polyiodide anions. Highly acidic conditions facilitated the formation of a doubly protonated organic ligand out of 5,7-dimethyl-1,3-diazaadamantane that generates three different crystal structures with inorganic counterions. In these structures, cationic substructures are constructed by transforming neutral organic ligands into [(C10N2H20)I]+ or [(C10N2H20)(H2O)]2+ cations, which crystallize with charge-compensating iodine-based anions of different complexities. All three crystal structures are characterized by various noncovalent forces, ranging from strong (N)H⋯I, (O)H⋯I, and (N)H⋯O hydrogen bonds to secondary and weak I⋯I interactions. Raman and diffuse reflectance spectroscopy as well as DFT calculations were employed to describe the electronic structures and optical properties of new supramolecular architectures, with particular attention to the role of non-covalent interactions. [ABSTRACT FROM AUTHOR]

A new benzothiadiazole-based MOF {[Zn(BIBT)(oba)]·DMA}n (JXUST-3, BIBT = 4,7-bi(1H-imidazol-1-yl)benzo-[2,1,3]thiadiazole and H2oba = 4,4′-oxybisbenzoate) has been solvothermally synthesized and characterized by single crystal X-ray diffraction, IR spectroscopy and TGA. The fluorescence studies suggest that JXUST-3 could simultaneously selectively sense trivalent metal ions including Al3+, Cr3+ and Fe3+ by a turn-off effect, and the detection limits are 0.055, 0.049 and 0.056 μM, respectively. Moreover, JXUST-3 exhibits relatively good thermal and chemical stabilities and reusability. The fluorescent test paper also displayed an obvious turn-off effect, indicating that JXUST-3 can be used as a potential multi-response fluorescent probe. The possible quenching mechanisms of JXUST-3 for Al3+ and Fe3+ were competitive energy absorption, and for Cr3+ ions, they were competitive energy absorption and weak interactions between Cr3+ and the framework. Therefore, JXUST-3 could be viewed as a transition metal MOF fluorescence sensor for Al3+, Cr3+ and Fe3+ by the turn-off effect, simultaneously. [ABSTRACT FROM AUTHOR]

Recently, π-conjugated polymers (CPs) applied to graphitic carbon nitride (g-C3N4) with high crystallinity have received great attention for removing organic pollutants. Herein, we propose that doping oxygen atoms into the g-C3N4 skeleton can improve photodegradation efficiency due to excellent carrier separation through enhanced polarization promoted by π-conjugated system expansion and high crystallinity. In detail, the higher electronegativity and larger size of oxygen atoms can enhance the crystallinity and conjugated plane of g-C3N4 leading to an increase in electrical conductivity and electron delocalization of O-doped g-C3N4, which extremely enhances the polarization degree. Therefore, the mechanism of the improved photocatalytic performance for diclofenac sodium, bisphenol A, and phenol can be attributed to the rapid photodegradation caused by fast charge separation. We believe that this paper can offer a novel perspective on the relationship between crystallinity, conjugation degree, and polarization in photocatalysts for environmental purification. [ABSTRACT FROM AUTHOR]

Emulsions are typically formed in a mixture of immiscible liquids. However, emulsion particles are also found upon mixing miscible liquids. In this paper, we suggest that emulsion particles are formed by ethanol mixed into toluene, as detected via dynamic light-scattering and small-angle X-ray scattering spectroscopy measurements. Furthermore, the addition of ethanol into a homogeneous fullerene solution (C70/toluene) also forms emulsion particles. The emulsion particles could provide a space in which crystallization of C70 occurs via anti-solvent crystallization (ASC). The size change of the emulsion particles through coalescence and shrinkage processes, which depend on the amount of ethanol, explains the change of crystallization environment until a supersaturation state is reached. It is believed to be the previously undiscovered key indicator of the ASC mechanism prior to nucleation. [ABSTRACT FROM AUTHOR]

Developing dual-state fluorescence materials with high emission efficiency both in solution and solid states is still a challenge. Herein, a functionalized pyrazoline derivative (NF) was designed and synthesized. NF exhibited high blue emission efficiency in both THF solution and solid states with the absolute fluorescence quantum yields of 58% and 43%, respectively. The mechanism of this unique fluorescence behavior was systematically studied with the help of single-crystal structure analysis. The results showed that a close-knit molecular structure existed due to intramolecular C–H⋯π interactions, which can impair the intramolecular rotation to accelerate the radiative transition in the mono-molecule state (in dilute solution). Moreover, the steric hindrance and intermolecular hydrogen-bond interactions of the substituent groups can restrict the close packing and prompt the formation of J-aggregates in the aggregation state, which resulted in high emission performance in the solid state. Meanwhile, the dual-state blue emission property of NF was utilized for the picric acid (PA) detection in the solution state and on a test paper by the synergistic effects of photo-induced electron transfer (PET) and Förster resonance energy transfer (FRET) processes. The limit of detection as low as 6.80 × 10−7 M achieved in the THF–H2O mixture. This work provided a new scope for the design of high dual-state blue emission materials. [ABSTRACT FROM AUTHOR]

A bibliographic and literature-based analysis of the impact of the Cambridge Structural Database (CSD) and the papers associated with crystal structures in the CSD has been undertaken. The analysis shows the broad impact of the CSD in the chemical sciences and also highlights how areas where the CSD has impact have changed over time. In addition, we note the changing nature of crystallography as a science, observing how crystal structures are now impactful. A brief illustration of some more unusual contributions to the CSD and publications using the CSD is also presented. [ABSTRACT FROM AUTHOR]

This paper analyzes the trends in atomic size, coordination number, and relative abundance of metal–oxygen bonds throughout the 6th row of the periodic table, as deduced from the structural data in the CSD. Special emphasis is given to the transition from Ba to the lanthanide series, and from these to the 5d metals. All the data indicate that Lu is closer than La to the behaviour shown by the 5d metals. Besides, a Lu-containing group 3 gives trends down the group that are similar to those of neighboring transition metal groups. [ABSTRACT FROM AUTHOR]

Recently, interest in organic ferroelectrics or antiferroelectrics representing a metal-free perovskite-type has increased significantly. This interest results from the properties of organic systems. First of all, they do not have toxic metals in their structure. Therefore they are environmentally friendly. Also, the method of preparation, simple syntheses, and low-temperature processability increase their attractiveness in terms of application. In this paper, the above properties are associated with the proton dynamics in organic donor–acceptor systems. We present the comparison of the physicochemical properties of four molecular complexes containing the proton acceptor molecule, 6,6′-dimethyl-2,2′-bipyridyl (66DMBP), and one of three organic acid molecules belonging to the benzoquinone group. As proton donor molecules the organic acids: chloranilic, bromanilic and iodanilic acids have been chosen. We present the results of experiments concerning the determination of crystal structures, 1H NMR, inelastic neutron scattering (INS) and UV/vis spectra. In the theoretical part, we attempt to explain the influence of the crystallization method (a type of solvent) on transoid or cisoid arrangement of 66DMBP. In the theoretical approach, we focus on two forms of the complex with chloranilic acid, α-66DMBP·CLA and β-66DMBP·CLA, which undergo solid-to-solid phase transitions, at 380 and 317 K, respectively. We have chosen these examples because the α analogue possesses ferroelectric properties in a wide range of temperatures. [ABSTRACT FROM AUTHOR]

Controllable synthesis of perovskite structured oxides with well-defined facets is a challenging but important route for crystal shape and facet dependent applications. In this paper, we report a urea-modified hydrothermal method for shape tuneable growth of perovskite structured rare-earth chromite (RECrO3) crystals. By adjusting the concentration of urea, continuous shape evolution processes of LaCrO3, PrCrO3 and NdCrO3 were found, such as transformation of LaCrO3 from cubic to truncated cubic and spherical crystals, PrCrO3 from pseudo-cubic to truncated parallelepiped plate twin crystals, and NdCrO3 from parallelepiped plates to their truncated analogues. The shape formation mechanism of each RECrO3 has been generally discussed by considering their structures and the interactions between the crystal facets and shape directing agents. The crystal facet formation mechanism of RECrO3 crystals follows the Bravais–Friedel–Donnay–Harker theory. This paper provides a general shape controllable growth technique for RECrO3 crystals, which is important for further study and application of their anisotropic properties. [ABSTRACT FROM AUTHOR]

Novel hierarchical SiC–SiO2 heterostructures were synthesized on a graphite paper substrate via a catalyst free method. The morphology, microstructure and composition were characterized by SEM, HR-TEM, EDS and XRD. Results revealed that the hierarchy of SiC–SiO2 heterostructures consisted of nanochain structures and nanoweb structures located in different layers of the graphite paper substrate. The nanochain structures were SiC–SiO2 nanochains coated by an exterior SiO2 shell, in which the SiO2 beads were chained to the SiC nanostructure. The nanoweb structures showed that many intersecting SiC nanostructures were encapsulated in irregular SiO2 agglomerates. The formation of hierarchical SiC–SiO2 heterostructures was dependent on the synthesis temperature. The VS process followed by a modulation process was proposed to elucidate the formation mechanism of such hierarchical SiC–SiO2 heterostructures. [ABSTRACT FROM AUTHOR]

Perovskite-structured ABX3 halides are one of the most promising families of materials with many potential applications. However, the controllable growth methods of their crystal facets and the corresponding synthetic chemistry have not yet been resolved. In this paper, we report a ligand substitution strategy for the facet-tunable growth of perovskite structure KMF3 (M = Mg, Mn, Co, Ni and Zn) fluorides under mild hydrothermal conditions. The competition of the strong ligand of NH3 and weak ligand of F− in the octahedral crystal fields of M2+ results in different facet evolution routes for KMF3 samples with the M-site of empty-, partially- or fully-filled 3d orbitals. Although X-ray diffraction results indicated that all five KMF3 compounds are crystalized into the same space group (Pm3m, no. 221), the crystal shape of KMF3 with M = Mg, Mn, Co and Ni evolved from cubic shape to edge-truncated chamfer box shape, while KZnF3 evolved from cubic shape to corner-truncated cubic shape under the same set of synthetic conditions. The cubic shape habitat morphology of KMF3 crystals is enclosed by {100} facets, chamfer box {100} and {110} facets, and corner-truncated cube {100} and {111} facets. The crystal shape formation mechanism was analysed based on ligand field theory and the Bravais–Friedel–Donnay–Harker (BFDH) theory. We expect that the shape controllable synthetic method can benefit the growth of other halide material crystals, and the shape tunable crystals can find more important applications. [ABSTRACT FROM AUTHOR]

In this paper, the fundamental information on interactions in systems concerning nanocrystalline gold disperses on the shaped (octahedron-like or cube-like) Ce1−xYbxO2−x/2 (x = 0 or 0.1) support has been discussed. Four types of Au/Ce1−xYbxO2−x/2 systems with different morphology and defect level of support have been investigated. It was observed that the microstructure and structural features of the support crystals play a key role in the reaction of CO oxidation catalysed by Au/Ce1−xYbxO2−x/2 materials. The divergent influence of Yb3+ dopant on the CO reaction as a function of exposing planes of the support was observed for Ce1−xYbxO2−x/2 and Au/Ce1−xYbxO2−x/2 systems. For the undecorated oxides, the presence of Yb3+ ions in the ceria matrix increased the activity of the octahedron-like oxides, but decreased it for the cube-like ones. On the other hand, the positive effect of the Yb-dopant on the reactivity of Au/Ce1−xYbxO2−x/2 systems was observed for both morphologies. [ABSTRACT FROM AUTHOR]

In this paper, the effect of the hierarchical arrangement of nanocrystallites on CO oxidation and soot combustion activity has been investigated. Hierarchically structured star-shaped particles (HS stars) were compared with microemulsion-derived, loosely arranged nanoparticles (NPs). Star-like Ce0.9REE0.1O1.95 mixed oxides were synthesized by oxidative thermolysis of Ce0.9REE0.1(HCOO)3 mixed formates. The study of the synthesis, structure and catalytic activity of the porous, star-like ceria-based mixed oxides was presented for the first time. It was shown that each level of the hierarchical structure of the star-like mixed oxides has its own functionality and it is vulnerable to modifications. In-depth characterization of as-synthesized ceria allowed determination of the relationship between the hierarchically structured nature of the material and its catalytic activity in CO oxidation and soot combustion. It was concluded that the presence of the 3D structure composed of ceria nanocrystals significantly improves the stability and catalytic activity of the star-like material in comparison to the nanopowder. Moreover, introduction of the trivalent RE ion into the ceria structure led to further improvement of the CO oxidation performance. Finally, the key–lock catalysis concept was applied to explain the enhanced activity of the hierarchically structured star-shaped ceria particles as a catalyst in the soot combustion process in comparison to nanocrystalline CeO2. [ABSTRACT FROM AUTHOR]

This paper demonstrates the utility of joint applications of X-ray diffraction, solid state (ss) NMR, density functional theory (DFT) and molecular mechanics (MM) calculations for the determination of the stereochemistry of paramagnetic bis(aminoacidato)copper(II) compounds. Solution-based and mechanochemical syntheses of trans-bis(leucinato)copper(II) [Cu(Leu)2] with L - and DL -leucine using different solvents always resulted in the same two-dimensional coordination polymers of the LL (previously reported in the literature) and DL diastereomers. The X-ray crystal and molecular structure of trans-catena-[(μ- D -leucinato)(μ- L -leucinato)copper(II)] (space group C2) has symmetry unrelated D - and L -leucine side-chain conformations. An asymmetrical copper(II) DL -amino acid complex has not been observed so far in a non-centrosymmetric space group. Both LL and DL trans-[Cu(Leu)2] crystals have similar intermolecular bonding. The X-ray powder diffraction and magic-angle spinning (MAS) ssNMR information available from the polycrystalline bulk phase of the two compounds agree with their single-crystal results. Besides, the 2H MAS ssNMR spectrum of the polycrystalline sample synthesized using DL -leucine showed weak signals which were ascribed to a small amount of the LL (DD) stereoisomers. DFT calculations of the Fermi-contact contributions aided the 13C and 2H NMR spectral assignments. DFT conformational analyses of the LL and DL isomers revealed two Leu side-chain conformations as the energetically favorable ones in the gas phase and aqueous solution. These are exactly the conformations whose combinations occur in the observed crystal structures. Similar MM potential energies of LL and DL trans-[Cu(Leu)2] in the crystal lattices suggest that crystallization of DL over LL (DD) diastereomers should be attributed to kinetic rather than thermodynamic effects. [ABSTRACT FROM AUTHOR]

In this paper, we report on the effect of sulfur additives (as FeS2 in the Fe90Ni10–C system) on the growth processes, morphology, and defect-and-impurity content of diamond crystals at 6 GPa and 1400 °C. It has been established that the sulfide component plays an inhibitory role in diamond crystallization processes. As the concentration of the sulfur additive (XS) in the system increases from 0 to 20 wt%, the degree of graphite-to-diamond transformation decreases from 100% to zero and the solubility of carbon in the melt decreases from 6.6 to 0.4 wt%. Addition of sulfur to the growth system leads to the appearance of metastable graphite and its amount increases with increasing sulfur content. It is found that the concentration of nitrogen impurities in the synthesized diamonds decreases from 50–100 ppm at XS = 0 to 5–10 ppm at XS = 10–15 wt%. Sulfide additives lead to the transformation of flat-faced octahedral diamond crystals to specific crystals with the elements of antiskeletal growth and fragmentation of their vertices. It is suggested that the main reason for the change in the morphology of diamond crystals is the selective adsorption of sulfide clusters on planar defects located mainly near the vertices of the octahedron. Inhibition of the propagation of growth layers on the {111} faces of diamond crystals leads to the formation of faceted macrosteps, the fragmentation of the crystal vertices and the polycentric structure of the faces. [ABSTRACT FROM AUTHOR]

The synthesis, crystallisation and detailed description of the crystal structure of the THF solvates of four halogen (F, Cl, Br and I) derivatives of dianthranilide (5H,11H-dibenzo[b,f][1,5]diazocine-6,12-dione) have been reported. The influence of the halogen size on the conformation of the halogen derivative, the overall supramolecular architecture including the existing scheme of intermolecular interactions and the selected energy issues have been discussed in detail. The solvates which are described in this paper exhibit an interesting arrangement of molecules in their crystals resembling a "honeycomb". The variety of interactions between the respective molecules, including hydrogen bonds, halogen-mediated noncovalent interactions and π–π contacts, makes them an attractive target for crystallographic studies. The results of our analysis may lead to a better understanding of the role of a halogen functional group in the rational design of specific multicomponent crystalline networks based on compounds consisting of two substituted phenyl rings separated by a fused heterocyclic moiety. [ABSTRACT FROM AUTHOR]

The interaction between carbon monoxide and metal-based catalysts is important in several reactions such as CO hydrogenation, CO oxidation, and CO2 reduction. Consequently, CO adsorption on metal surfaces and nanoparticles largely has been investigated. Current understanding of the microscopic mechanism that governs the metal–CO binding has been enhanced by gas phase studies of well-defined small metal cluster model systems as a function of their size, charge state, and composition. In this highlight paper, key experimental and computational studies dealing with the interaction between CO and transition and coinage metal clusters are discussed, with particular emphasis on the influence of dopant atoms. [ABSTRACT FROM AUTHOR]

Indications of desirable polar order in ethylammonium C2H5NH3(EtA) metal formate [EtA][Na0.5Cr0.5(HCOO)3] and the lack of it in [EtA][K0.5Cr0.5(HCOO)3] raised important questions on the origin of structural phase transition and dipolar dynamics in these kinds of compounds. In this paper we provide results of experimental studies performed on the mixed frameworks, which may give more insight into understanding these phenomena. We report the synthesis of four heterometallic metal–organic frameworks [CH3CH2NH3][KxNa0.5−xCr0.5(HCOO)3] with various compositions (x = 0, 0.04, 0.22, and 0.5). Broadband dielectric spectroscopy assisted by vibrational spectroscopy allows us to determine the role of EtA+ motions in the structural phase transition in the investigated compounds. We clearly demonstrate that the increase of the K/Na ratio results in freer translational movements of the EtA+ cations. [ABSTRACT FROM AUTHOR]

A Cu-based bimetallic hollow structure can be effectively used to enhance the selective oxidation and electrocatalytic activity of a catalyst and to reduce its cost. In this paper, we developed a facile and scalable method for the construction of CuAu bimetallic hollow particles from Cu2O nanoparticle aggregates (NPAs). The synthetic process includes Au growth on the Cu2O NPA surface and silica encapsulation, which is followed by polyol reduction of Cu2O, calcination in air and etching of the SiO2 layer. The obtained hollow CuAu NPs (average diameter of 540 nm and wall thickness of 60 nm) outperform hollow Cu NPs in terms of catalytic activity in the reduction of 4-nitrophenol by NaBH4 in aqueous solution. The activity factors (K = 354 and 255 s−1 g−1) are 2.4 and 1.7 times larger than that of the hollow Cu catalyst, depending on the Au content in the CuAu particles. In addition, the prepared catalyst was stable in the reaction system and can be recycled via centrifugation without a significant loss of catalytic activity. [ABSTRACT FROM AUTHOR]

As a representative of III–V semiconductor materials, InP/ZnS quantum dots are regarded as the star material in the field of light-emitting devices due to their low toxicity and suitable luminescence range. However, there are still some major problems in the preparation process of InP/ZnS QDs, such as phosphine precursors are expensive and difficult to preserve, the nucleation time of short wavelength InP/ZnS QDs is too short and the size distribution is too large. In this paper, we'll replace the traditional tris(trimethylsilyl)phosphine with tris(diethylamino)phosphine as a cheaper phosphine precursor and propose a novel and convenient method for adjusting the luminescence wavelength of InP/ZnS QDs. Different from the traditional method to adjust the emission wavelength by changing the nucleation time, the emission wavelength of InP/ZnS QDs was regulated by changing the number of initially formed cores. Zeolites provide a nucleation site for the InP cores. InP/ZnS QDs that emit between 522 nm and 589 nm were obtained. Moreover, the obtained InP/ZnS QDs have good monochromaticity, and the minimum half-width (half-full width) is up to 48 nm. This method provides a new way to adjust the size of quantum dots with good performance. [ABSTRACT FROM AUTHOR]

For investigating how different 3d ions influence the magnetic relaxation behaviors of 3d–4f systems, six isomorphic tetranuclear 3d–4f compounds of [LnFe(CN)6(H2L)(H2O)(DMF)]2·5H2O (Ln = Dy(1), Tb(2), Ho(3), (H2L = 2,6-diylbis(ethan-1-yl-1-ylidene)-di(isonicotinohydrazide))) and [LnCo(CN)6(H2L)(H2O)(DMF)]2·5H2O (Ln = Dy(4), Tb(5), Ho(6)) were obtained from [M(CN)6]3− bridging LnIII-Schiff-base units. The six isostructural compounds are all centrosymmetric with two nine-coordinated LnIII ions in a muffin configuration and Cs symmetry. Magnetic analyses revealed that complex 1DyFe with a weak antiferromagnetic Dy–Fe interaction does not show a slow magnetic relaxation behavior above 2 K, while diamagnetic CoIII ions in complex 4DyCo enlarge the intermolecular Dy⋯Dy distance and induce ferromagnetic Dy–Dy interactions to suppress the quantum tunneling of the magnetization (QTM) and lead to the single-molecule magnet (SMM) behavior with an energy barrier of Ueff = 11.17 K in 1 KOe dc field. This paper gives another example of inducing paramagnetic 3d ions with weak 3d–4f coupling could not quench QTM effectively, while diamagnetic 3d ions could perform better. [ABSTRACT FROM AUTHOR]

In this paper, three isostructural 1D lanthanide complexes, [Ln(dppc)(H2O)4]n·2nH2O (Ln = Eu, Tb and Eu0.501Tb0.499, named 1-Eu, 2-Tb and Eu0.501Tb0.499), based on 3-(2,4-dicarboxylate phenyl)-2-pyridinecarboxylic acid (H3dppc) have been synthesized and characterized by elemental analysis, IR, PXRD, TG and X-ray crystallography. The complexes exhibit a 1D chain structure, which is further linked into a 3D supramolecular framework by hydrogen bonds. Tuneable emission colour of Eu0.501Tb0.499 is realized by adjusting the excitation wavelength. The sensing properties of 1-Eu and 2-Tb towards Fe3+ and aniline indicate that the two complexes have almost the same superior sensitivity and low detection limit for Fe3+ in aqueous solution, while they have different detection abilities for aniline in DMF solvent. The different detection abilities were discussed by means of PXRD, UV-vis, luminescence lifetimes and molecular surface calculations (Hirshfeld surface analysis and 2D fingerprint plots). [ABSTRACT FROM AUTHOR]

MoS2-based nanomaterials are considered promising effective electrocatalysts to replace precious metal catalysts for hydrogen evolution reaction. However, understanding the effect of MoO2 in MoS2-based catalysts for hydrogen evolution reaction is ambiguous. In this paper, MoS2 nanoflowers of 210–430 nm in diameter were hydrothermally synthesized by the reduction of α-MoO3 particles with KSCN in a hydrochloric acid medium. Similarly, MoO2–MoS2-B nanoflowers and MoO2–MoS2-R nanoflowers were fabricated using α-MoO3 nanobelts and h-MoO3 microrods as Mo sources, respectively. Systematic studies on synthetic parameters verified that the formation of MoS2 nanoflowers is favored with high acidity, low MoO3/KSCN ratio and high temperature. The resultant nanoflowers served as electrocatalysts to drive hydrogen evolution in acidic solution. The MoS2 nanoflowers showed a relatively higher activity with a potential of 256 mV at 10 mA cm−2 compared to MoO2–MoS2-B nanoflowers (283 mV) and MoO2–MoS2-R nanoflowers (305 mV). Furthermore, MoS2 nanoflower catalysts maintained high stability after 1000 cycles and long-term durability for 5 h. The high catalytic activity could be ascribed to the large exposure of the Mo–S species and small amounts of Mo–O species on the MoS2-based catalyst surface. [ABSTRACT FROM AUTHOR]

The slow photon effect can significantly increase the effective optical path length of light and thereby enhance the interaction of light with matter, which would be realized by light propagating at the edges of the photonic band gap (PBG) in photonic crystals (PCs). In this paper, a novel anodic oxidation method with effective voltage-pulse compensation was developed to prepare one-dimensional titania nanotube photonic crystals (1D TiO2 NT PCs) with a high quality of PBG, which could be continuously adjusted and precisely tailored just by modulating the anodization parameters. With the increase of low voltage (Lv) duration, the precise blue shift of the PBG of 1D TiO2 NT PCs was recorded. Through the precise tailoring of PBG in bandgap engineering, the edges of the PBG could be designed and purposely tuned to overlap with the electronic band gap range of the TiO2 material, and the as-prepared 1D TiO2 NT PCs were used as a photocatalyst to degrade methyl orange (MO) molecules due to the enhanced slow photon effect and scattering effect in their highly ordered channel structures. Meanwhile, strategies to enhance the slow photon effect at the edge of the PBG were discussed and evaluated in detail according to our experimental and simulated results. This study would provide a new guide to taking advantage of the slow photon effect to enhance the photocatalytic activities, photoluminescence, and performances of other optoelectronic devices. [ABSTRACT FROM AUTHOR]

Transition metal oxides as electrode materials for LIBs are constrained by tremendous volume changes, self-aggregation and poor conductivity. Therefore, it is extremely imperative and necessary to develop a new electrode material with high capacity and long-term cycles. In this paper, yolk–shell Co-V2O3-24 nanospheres assembled with nanosheets were designed and synthesized through a one-step solvothermal treatment and calcination process. The results show that the anion plays a significant role in morphology induction during the solvothermal reactions. As an anode material, Co-V2O3-24 displayed an outstanding reversible specific capacity of 986.2 mA h g−1 at 0.5 A g−1 after 630 cycles with a high capacity retention rate. Even when tested at 5 A g−1 after 2200 cycles, the specific capacity of 457.6 mA h g−1 can be retained, which indicates that Co-V2O3-24 has excellent rate performance and cycle stability. The outstanding lithium storage properties mainly benefit from the novel 3D hierarchical structure, Co doping and abundant electrochemical active sites. [ABSTRACT FROM AUTHOR]

Electrode materials are important components of supercapacitors and have a significant influence on the electrochemical properties. Herein, a hierarchical core–shell structure of ZnO nanorods (NRs) wrapped with feather-like ultrathin Ni–Co layered double hydroxide composite nanosheet arrays (ZnO NR@Ni–Co LDH CNSAs) was directly fabricated and established on a soft carbon cloth substrate through two facile hydrothermal processes. ZnO NR@Ni–Co LDH CNSAs, which were used as the positive electrode material, exhibited extremely high specific capacitance. The electrode materials integrating the good conductivity of ZnO NRs and the high coulombic efficiency of the ultrathin Ni–Co LDH nanosheets exhibited an excellent supercapacitive performance. The specific capacitance could reach 2683.8 F g−1 when the current density was 1 A g−1. Even at 10 A g−1, the specific capacitance could reach 1986 F g−1. In particular, ZnO NRs were employed as the conductive materials to take advantage of their beneficial electron transport. Furthermore, the interface between Ni–Co LDH CNSAs increased the diffusion rate of the ions due to its buffering function. ZnO NR@Ni–Co LDH CNSAs as the positive electrode material and commercial activated carbon as the negative electrode material established an asymmetric supercapacitor, which demonstrated excellent cycling stability and retained 91.7% of the specific capacitance after 5000 cycles. Moreover, the ASC device exhibited a maximum energy density of 40.04 W h kg−1 at a power density of 1118 W kg−1. The electrode material designed in this paper can be considered as a candidate for positive electrode materials in order to obtain a high-performance storage device with high energy density and high power density. [ABSTRACT FROM AUTHOR]

Improving proton conductivity is of great importance for the further application of metal–organic frameworks (MOFs) or metal–organic coordination polymers (MOCPs) in proton exchange membrane fuel cells. In this paper, we proposed a new approach to increase proton conductivities in MOCPs coming from organic ligands, e.g. coordination inducement and MOCP–cocrystal composite formation strategies, which is based on the potential function of organic ligands. By employing the approach, we have successfully synthesized and characterized three crystalline compounds, PPA (1), [Cu(PPA)I] (2) and [Co(PPA)2(BDC)(H2O)2·(PPA)2(H2BDC)2(H2O)] (3) (PPA = 4-(3-pyridinyl)-2-amino pyrimidine, H2BDC = 1,4-benzenedicarboxylic acid). These compounds show high water stabilities and different proton conducting behaviours, especially compound 3 with a proton conductivity of 2.29 × 10−4 S cm−1 at 325 K and ∼97% RH, which is higher than or comparable to those of some reported compounds. More importantly, a persistent increase in proton conductivity is observed from 1 to 3, which is about one order of magnitude. Furthermore, single crystal analyses show that coordination and hydrogen-bonding interactions play a crucial role in improving proton-conductive properties for these compounds. The study reveals that it is practical to boost the proton conductivity of crystal materials by means of their intrinsic merits and the strategy of molecular design. [ABSTRACT FROM AUTHOR]

Amongst the most popular methods for the production of metal oxide nanostructures is hydrothermal synthesis. For producing ZnO nanostructures, a nitrate-based precursor reaction with equimolar amounts of hexamethylenetetramine (HMTA) is commonly used. In these reactions, zinc nitrate provides the source of Zn2+ ions, and HMTA produces the desired amount of OH− ions. The growth process occurs due to a dissolution-secondary precipitation mechanism. ZnO nanostructures are characterized by anisotropic growth with different growth rates of the individual faces, where (v(0001) > v(101¯0) > v(101¯1¯) > v(101¯1) > v(0001¯)). Therefore, considering the principle of energy minimization, the most favorable is vertical growth perpendicular to the (0001) plane, which ensures the formation of characteristic rod-like nanostruchtures of ZnO. The mentioned process takes place when chemical reactions are in equilibrium. Shifting from the equilibrium conditions by varying the parameters of reaction, or using capping agents, makes it possible to change the growth rate of individual crystallographic planes and, as result, affect the morphology of the obtained nanostructure. In this paper the influence of concentration and composition of the reagents, growth time and temperature, pH of the solution, and the presence of different capping agents on the growth process of nanostructured ZnO were investigated. Optimal synthesis parameters for obtaining nine independent ZnO morphologies have been determined. The distinctive feature of these experiments is the fact that the samples were obtained as durable, homogeneous, epitaxial coatings on hard surfaces. This can be especially interesting for the development of sensors and other fields where surface area is crucial, and it opens up more possibilities than use of the nanostructured ZnO powders. [ABSTRACT FROM AUTHOR]

Deeply understanding the physical and chemical properties of a melt requires an accurate description of its structure. In this paper, we investigated the structures of Li4GeO4 and Li6Ge2O7 melts which are of interest for growing germanate functional crystals. The structural changes of polycrystalline Li4GeO4 and Li6Ge2O7 from room temperature to their melting temperatures were monitored by Raman spectroscopy and analyzed by density functional theory (DFT) and factor group theory (FGT) calculations. A striking spectral change was observed for polycrystalline Li4GeO4, which is due to the orthorhombic-to-monoclinic phase transition and the Li+ disorder induced by the phase transition. Spectral similarity between monoclinic Li4GeO4 and its corresponding melt indicates that the anion motif of the Li4GeO4 melt is the GeO44− tetrahedron. The Li6Ge2O7 crystal has 180 lattice phonons (45Ag + 45Au + 45Bg + 45Bu) at the centre of the Brillouin zone, including 90 Raman-active phonons (45Ag + 45Bg). All the Raman-active bands were assigned by DFT calculations. The Raman spectrum of polycrystalline Li6Ge2O7 varies smoothly and continuously in the heating/melting process, indicating that the Ge2O76− anion groups in the crystal are preserved in the melt. The disproportionation reaction that often occurs in silicate melts was not found in the Li6Ge2O7 melt. A nucleophilic substitution reaction is proposed to explain the composition-induced structural transformation present in the Li+-rich germanate melts. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate a low-temperature aqueous solution process, based on a continuous flow reactor design, for the long-duration continuous growth of ZnO epitaxial layers at a constant growth rate without interruption. Using a strategy of site-controlled epitaxial growth of ZnO, we grew patterned ZnO mesas having hexagonal honeycomb structures on top of lattice-matched patterned ZnAl2O4 buffer layers. Subsequently, we applied the continuous flow reactor for long-duration lateral epitaxial overgrowth (LEO) of ZnO layers on the honeycomb-patterned ZnO mesas. Dislocation etch pit analysis suggested a dislocation density for the coalesced LEO-grown ZnO layer of approximately 108 cm−2. X-ray diffraction revealed that the combination of LEO and a hexagonal honeycomb geometry is a promising approach for preparing wing-tilt-free thick ZnO layers displaying substantial strain relief. The micro-photoluminescence spectra of the overgrown wings featured a more intense band edge emission, confirming the significant improvement in crystalline quality in the wing regions. [ABSTRACT FROM AUTHOR]

A specific number of structures described in this paper with adamantane and memantine fragments have been synthesised and characterised. Their single crystals have been grown and their crystal structures have been determined. XPac analysis has shown that there are four sets of isostructural crystals based on adamantane/memantine-specific hydrogen bond patterns and packing of bulky substituents. The use of packing density analysis, QTAIMC and Hirshfeld surface analyses has allowed the elucidation of the influence of the nature and position of functional groups and molecular arrangement on the strength of non-covalent interactions in crystals and overall packing efficiency. The nature and size of a fragment in the para-position of the phenyl ring have been found to have the highest influence on the packing architecture. [ABSTRACT FROM AUTHOR]

Antimony selenide (Sb2Se3) is a low-toxic, element-abundant, narrow bandgap (Eg = ∼1.1–1.3 eV) semiconductor that shows potential for UV-Visible-Near-infrared optoelectronic applications. This paper reports the use of potassium selenocyanate (KSeCN) as a novel molecular selenium source to synthesize Sb2Se3 uniform nanorods. The resulting nanorods have been carefully characterized and are found to exhibit decent photoconductivity as well as broad-spectrum optical absorption with an Eg value of ∼1.35 eV. A molecular reaction mechanism is rationally proposed and evidenced for forming Sb2Se3, which is related to the thermal decomposition of selenocyanate (SeCN−) anions through the cleaving of Se–CN bonds to elemental Se(0), followed by its reduction to Se2− anions. Our work using KSeCN offers an alternative method for the synthesis of metal selenides with desirable nanostructures and properties. [ABSTRACT FROM AUTHOR]

Monodisperse nanoparticle aggregates (NPAs) have great potential for applications in biomedical detection, light harvesting, and photocatalysis, but the synthesis of these materials using a one-pot method remains challenging due to the difficulty of the separation of the nucleation and growth processes. In this paper, monodisperse spherical Cu2O NPAs were synthesized using a simple one-pot strategy. The size of the Cu2O NPAs was controlled from 294 nm to 443 nm, and the size distribution was as narrow as δ = 8.1% and 5.6%. The key to the formation of NPAs with a narrow size distribution can be attributed to the in situ generated CuCl acting as seeds to control the aggregation process of the primary Cu2O NPs. This method is extremely simple and scalable, and the reaction was conducted in air and aqueous solution at room temperature. [ABSTRACT FROM AUTHOR]

In this paper, an Sb/Cl-incorporated nickel foam (NF) electrode material was grown on acid-pretreated NF by one-step chemical vapor deposition using SbCl3 as the Sb source. The synthetic conditions can be optimized by adjusting the dosage of SbCl3. The sample exhibits excellent electrochemical properties due to its unique morphology of porous nanosheet clusters, with a high specific capacity of 1248 C g−1 at 1 A g−1 and excellent rate performance (capacity retention of 70.5% at 10 A g−1). An asymmetric supercapacitor fabricated with Sb/Cl-incorporated NF and activated carbon exhibits a high energy density of 57.6 W h kg−1 at a power density of 1202 W kg−1 with good cycling stability. The capacity retention after 10 000 cycles is 83.3%. Given these characteristics, this work provides a simple and scalable strategy for designing an electrode and a device with superior electrochemical performance in next-generation energy storage applications. [ABSTRACT FROM AUTHOR]

It is difficult to control the stability of the 4H polytype in the growth of SiC single crystals by the PVT method. When the crucible was immovable, it was found that the temperature and the temperature gradient of the growth interface gradually increased and were almost unchanged with the crystal growth by the simulation. This resulted in the segregation of the gas composition and a variable Si/C ratio of the growth interface, due to which polytype inclusions and defects were easily formed. In this paper, we proposed a new method for stabilizing the 4H polytype of the SiC crystals by controlling the temperature field of the growth interface and gradually moving up the graphite crucible during crystal growth. The simulation results showed that the method could simultaneously reduce the range of the temperature rise and drop the temperature gradient at the growth interface. Thus, the gas phase composition was stable during the growth process, which will be useful for the stability of the 4H polytype. Finally, 4 inch SiC single crystals with 4H polytype stability and low defects were successfully obtained though this new method. Also, the quality of the as-grown SiC crystals was characterized by X-ray diffraction, Raman spectroscopy and Candela optical surface analysis. The results show that the method of slowly moving up the crucible during crystal growth is very effective in controlling the 4H polytype and improving the quality of SiC single crystals. [ABSTRACT FROM AUTHOR]