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In this work, we investigated the synthesis temperature effect on the crystal growth of Eu-doped ceria nanostructures synthesized via the microwave-assisted hydrothermal method and how it influences their red-light emission. Sphere-like nanoparticles, nanorods, nanorods/nanocubes, and nanocubes were obtained by gradually increasing the synthesis temperature. The structural analysis revealed that the nanocubes displayed higher crystallinity and lower structural disorder in comparison to the other morphologies. X-ray photoelectron spectroscopy (XPS) spectroscopy showed that oxygen vacancies were the predominant defect. The intensity of the photoluminescence emissions of the nanocubes was 60 times higher than that of the sphere-like nanoparticles and nanorods, indicating that the structural symmetry in this morphology is suitable for doping with Eu3+, displaying greater photoluminescence efficiency. The nanocubes also displayed excellent red-light emission, with coordinates (0.63,0.37) close to the red RGB primary at (0.64, 0.32). The lifetime values increased with higher synthesis temperatures. This trend suggests a structural correlation of different morphologies, defects, and homogeneity of the Eu3+ distribution in the crystal lattice and the photoluminescence emission and quenching. Therefore, we showed that controlling the morphology of Eu-doped CeO2 nanostructures is a powerful tool to improve its photoluminescence properties, which is valuable for applications as a red phosphor. [ABSTRACT FROM AUTHOR]

Conductive carbon networks and multicomponent interfaces have been constructed in Fe3O4/TiO2/C or Fe2TiO4/FeTiO3/C composites by pyrolyzing core–shell structured Fe-bdc@TiO2 nanorods at different temperatures. When the temperature rises to 700 °C, the growth of internal Fe3O4 nanoparticles, the gradual damage of TiO2 shells, and the maintenance of a one-dimensional structure promote the formation of continuous conductive carbon networks in paraffin, thereby increasing complex permittivity and dielectric loss. With a further increase in temperature, phase conversion from ferromagnetic Fe3O4 to antiferromagnetic Fe2TiO4 and FeTiO3 would result in the depletion of TiO2 and C, generation of multiple interfaces, and collapse of the one-dimensional structure, causing a slight reduction in complex permittivity and dielectric loss. S-700 has a wide effective absorption bandwidth (EAB) of 6.84 GHz at 2.2 mm (covering the entire Ku band), and S-800 has a large EAB of 4.16 GHz at 2.8 mm, covering the entire X band. We can deduce that conductive carbon networks mainly composed of surface carbon and multiple interfaces between carbon and titanates with defects contribute significantly to conduction loss, dipole polarization, and interfacial polarization, both of which shape RL curves under the influence of interference cancellation. This work provides a feasible strategy based on the construction of conductive networks and multicomponent interfaces in metal–organic framework-derived carbon composites for broadened microwave absorption bandwidth. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) hybrid perovskites have been garnering increasing attention across various fields due to their rich optical, electrical, optoelectronic, and magnetic properties. Current growth techniques only offer millimeter-scale or polycrystalline perovskites, which present a major barrier to the practical large-scale applications of these materials. In this study, we successfully prepared a series of BA2CuCl4–xBrx perovskite single-crystalline nanosheets with centimeter size using a controlled cooling growth method. Characterization results suggest that the obtained single-crystalline nanosheets are of high quality and that Br is uniformly doped. Moreover, these single-crystalline nanosheets exhibit ferromagnetic ordering at low temperatures, with the Curie–Weiss temperature increasing from 14.2 to 16.5 K as Br-doping concentration increases. Our approach provides a potential solution for the scalable synthesis and application of hybrid perovskites. At the same time, this family of 2D magnetic perovskites with tunable optical properties holds great potential for future spintronics applications. [ABSTRACT FROM AUTHOR]

Facile syntheses of branched hematite (α-Fe2O3) crystals with fine-tuning of their nanoscale subunit morphologies were reported. Starting from Prussian red and bisolvent systems with controlled temperature as the crucial parameters, fine-tuning of the nanoscale subunit morphologies in the context of controlling the anisotropic growth of branched α-Fe2O3 crystals was demonstrated. The systematic and optimized studies significantly improved the controlled synthesis of the hierarchical growth of nanoscale subunits, leading to the formation of branched dendritic leaflike (secD3D, tertD2D, and tertD3D) and hyperbranched (secS2D and hypB2D) α-Fe2O3 particles for their size-reduced variants used in photocatalysis. The kinetics of the photo-Fenton degradation of three azo dyes (chlorazol black, direct blue, and methyl orange) with five types of branched dendritic α-Fe2O3 particles were compared systematically. [ABSTRACT FROM AUTHOR]

LiGaTe 2 is a promising nonlinear optical crystal with a large figure of merit ( d 36 2 / n 3 ), but it is difficult to grow the LiGaTe 2 single crystal due to its extreme instability. In this work, we used Ag to replace Li and successfully grew a Li 0.5 Ag 0.5 GaTe 2 crystal by the modified Bridgman method for the first time. We found it has thermal stability below 200 °C in an atmospheric environment, and the thermal expansion coefficient is positive. This is different from LiGaTe 2 and AgGaTe 2 which have a negative thermal expansion coefficient along the c -axis. When the temperature exceeds 200 °C, Li 0.5 Ag 0.5 GaTe 2 is easily decomposed and oxidized. Under closed vacuum conditions, the melting and solidifying points of Li 0.5 Ag 0.5 GaTe 2 are measured to be 719 and 694 °C. XPS spectra show that the binding energies of Li, Ga, and Te are higher than LiGaTe 2 , and the surface is easily oxidized. The A1 vibration modes are found at 117.72 and 135.44 cm -1 by the Raman spectrum which is related to the Te and Ga-Te bond in [GaTe 4 ] 5- tetrahedra. Li 0.5 Ag 0.5 GaTe 2 has a wide transmittance range from 0.94 to 20 μm, and there was two-photon absorption near 16 μm. The phonon spectrum and PDOS were simulated by the DFT calculation to study the phonon vibration modes in the lattice, which shows that the density of the Raman vibration is higher than those of AgGaTe 2 and LiGaTe 2 . The SHG test results showed that the SHG response intensity of Li 0.5 Ag 0.5 GaTe 2 is 1.5 times that of AgGaS 2 , which shows its excellent nonlinear optical properties for mid-IR applications.

Incorporation of pollutants, e.g., heavy metals, or critical elements, e.g., lithium, as impurities in mineral phases can significantly affect their mobility or sequestration in the environment. Even when present at low concentrations, impurities can alter the solubility and reactivity of the host mineral. In this study, we investigate the incorporation of trace amounts of iron (Fe 3+ ) and chromium (Cr 3+ ) during the crystal growth of the aluminum (Al 3+ ) hydroxide, gibbsite, a major component of bauxite ores, an important soil mineral, and a dominant mineral phase in stored radioactive wastes. Using a comprehensive suite of analytical techniques, we show that both Cr 3+ and Fe 3+ can be incorporated into the gibbsite lattice during coprecipitation by replacing Al 3+ in octahedral sites. These small amounts are consistent with limited to no structural isomorphism shared between Al 3+ and Cr 3+ /Fe 3+ hydroxide precipitates, nor room temperature miscibility of their isostructural M 2 O 3 oxide forms, in contrast with oxyhydroxide forms where Al 3+ and Fe 3+ share similar structural topologies. Despite the limited uptake of Cr 3+ /Fe 3+ , we show that these impurities have significant implications for gibbsite dissolution behavior. The limited uptake of Cr 3+ /Fe 3+ (e.g. 0.43% Cr 3+ and 0.4% Fe 3+ ), we show that these impurities have significant implications for gibbsite dissolution behavior and subsequent reactivity in complex environments.

As the effects of climate change become more severe and widespread, maintaining personal thermal homeostasis becomes necessary for survival. In principle, advanced textiles and garments have the ability to leverage light absorption, transmission and/or reflection, in addition to straightforward convection, to heat or cool bodies in extreme temperature conditions. For cooling, in particular, surfaces adept at selectively reflecting or refracting high-energy incident light (200 nm-2.5 mm) from the sun while transmitting or emitting infrared light (8-13 mm) from radiant body heat boast the ability to maintain cooler body temperatures, even when exposed to direct sunlight and the open sky. Here, we present a strategy to transform common clothing into implements for passive personal cooling. As confirmed by Mie scattering calculations, cheap and biocompatible calcium carbonate and barium sulfate micro/nanoparticles are found to serve as suitable reflectors for radiative cooling. Finite-difference time domain simulations reveal, surprisingly, that higher reflectance is achieved with surface coatings containing these materials, as compared to extruded metamaterial fibers containing CaCO 3 and BaSO 4 particles embedded within a polymer matrix. A stepwise process involving photoinitiated chemical vapor deposition and ion-exchange driven crystal growth is used to create a lamellar composite coating comprised of alternating CaCO 3 and BaSO 4 nano/microparticle layers directly on the surface of common fabrics. A polyester poplin fabric coated in this manner shows a cooling ability of up to 8 °C compared to an uncoated sample, achieving a maximum cooling of 6 °C below ambient temperature. Wash and durability testing of the lamellar coating reveal no mechanical degradation and no evident attenuation in the material's performance, affirming its resilience and long-term effectiveness as a functional textile coating for personal cooling. We also assess the performance of our coated fabrics in multiple outdoor environments to conclude that we can achieve up to 3.4 °C of sub-ambient cooling in optically complex built environments.

Demystifying the molecular mechanism of growth is vital for the rational design, synthesis, and optimization of functional nanomaterials. Despite the promising perspectives and extensive efforts, the growth mechanism of atomically thin TiO 2 (B) nanosheets remains unclear, hence it is difficult to tune their band and surface structures. Herein, we report an oriented attachment-based crystallization mechanism of TiO 2 (B) nanosheets from a 1D titanium glycolate coordination polymer through hydrolysis and condensation. With time-tracking experiments, this 1D coordination polymer is found to be an intermediate in the synthesis of TiO 2 (B) nanosheets by using Ti alkoxides and chlorides as precursors, suggesting the universality of the 1D-to-2D growth mechanism. Such a side-to-side attachment pathway bridges the classical and nonclassical interpretations of crystallization, and meanwhile hints at the possibility of other 1D complexes as potential precursors for 2D materials.

The growth process of metal–organic framework (MOF) nanocrystals defines their properties and functions. However, defects may be prevalent during the crystallization of even seemingly perfect MOFs, such as zeolitic imidazolate framework-8 (ZIF-8), and yet direct probing of such structural defects has been challenging because of the lack of nanoscale techniques to locally examine individual nanocrystals. Here, we directly study local defects, such as missing linkers or metal vacancies, in ZIF-8 nano- and microcrystals with near-field IR nanospectroscopy combined with density functional theory calculations. We track the chemical changes during crystallization and show that structural defects like zinc cations that are bound to molecules of the reactant gradually disappear with ripening of the crystals, while dangling and missing linker defects prevail. The resulting defect-terminating groups or open-metal sites produce mechanical anisotropy and reduce the Young's modulus, as measured via tip force microscopy with nanoscale resolution and supported by theoretical modeling. However, these structural defects also open the door for defect engineering to tune the performance of ZIF-8 by offering additional adsorption sites for targeted catalytic reactions, chemical sensing, or gas capture. [ABSTRACT FROM AUTHOR]

Vacuum deposition of perovskites is a promising method for scale-up fabrication and uniform film growth. However, improvements in the photovoltaic performance of perovskites are limited by the fabrication of perovskite films, which are not optimized for high device efficiency in the vacuum evaporation process. Herein, we fabricate CsPbI 2 Br perovskite with high crystallinity and larger grain size by controlling the deposition sequence between PbI 2 and CsBr. The nucleation barrier for perovskite formation is significantly lowered by first evaporating CsBr and then PbI 2 (CsBr-PbI 2 ), followed by the sequential evaporation of multiple layers. The results show that the reduced Gibbs free energy of CsBr-PbI 2 , compared with that of PbI 2 -CsBr, accelerates perovskite formation, resulting in larger grain size and reduced defect density. Furthermore, surface-modified homojunction perovskites are fabricated to efficiently extract charge carriers and enhance the efficiency of perovskite solar cells (PeSCs) by modulating the final PbI 2 thickness before thermal annealing. Using these strategies, the best PeSC exhibits a power conversion efficiency of 13.41% for a small area (0.135 cm 2 ), the highest value among sequential thermal deposition inorganic PeSCs, and 11.10% for a large area PeSC (1 cm 2 ). This study presents an effective way to understand the crystal growth of thermally deposited perovskites and improve their performance in optoelectronic devices.

Coamorphous and cocrystal drug delivery systems provide attractive crystal engineering strategies for improving the solubilities, dissolution rates, and oral bioavailabilities of poorly water-soluble drugs. Polymeric additives have often been used to inhibit the unwanted crystallization of amorphous drugs. However, the transformation of a coamorphous phase to a cocrystal phase in the presence of polymers has not been fully elucidated. Herein, we investigated the effects of low concentrations of the polymeric excipients poly(ethylene oxide) (PEO) and poly(vinylpyrrolidone) (PVP) on the growth of carbamazepine-celecoxib (CBZ-CEL) cocrystals from the corresponding coamorphous phase. PEO accelerated the growth rate of the cocrystals by increasing the molecular mobility of the coamorphous system, while PVP had the opposite effect. The coamorphous CBZ-CEL system exhibited two anomalously fast crystal growth modes: glass-to-crystal (GC) growth in the bulk and accelerated crystal growth at the free surface. These two fast growth modes both disappeared after doping with PEO (1-3% w/w) but were retained in the presence of PVP, indicating a potential correlation between the two fast crystal growth modes. We propose that the different effects of PEO and PVP on the crystal growth modes arose from weaker effects of the polymers on cocrystallization at the surface than in the bulk. This work provides a deep understanding of the mechanisms by which polymers influence the cocrystallization kinetics of a multicomponent amorphous phase and highlights the importance of polymer selection in stabilizing coamorphous systems or preparing cocrystals via solid-based methods.

Using a combination of experiment and simulation, we study how two-dimensional (2D) crystals of colloidal nanoparticles grow on cylindrical substrates. The cylindrical geometry allows us to examine growth in the absence of Gaussian curvature but in the presence of a closure constraintthe requirement that a crystal loops back onto itself. In some cases, this constraint results in structures that have been observed previously in theory and nonequilibrium packing experiments: chiral crystals and crystals with linear defects known as "line slips". More generally, though, the structures we see differ from those that have been observed: the line slips are kinked and contain partial vacancies. We show that these structures arise because the cylinder changes how the crystal grows. After a crystal wraps around the cylinder and touches itself, it must grow preferentially along the cylinder axis. As a result, crystals with a chiral line slip tend to trap partial vacancies. Indeed, we find that line slips that are less aligned with the cylinder axis incorporate more partial vacancies on average than the ones that are more aligned. These results show that crystal growth on a cylinder is frustrated by the closure requirement, a finding that may shed some light on the assembly of biological nanosystems such as tobacco mosaic virus and might inform ways to fabricate chiral optical nanomaterials. [ABSTRACT FROM AUTHOR]

Engineering nanostructures for semiconductor materials is recognized as an important strategy for achieving excellent photocatalytic activity. Although multiple nanostructures of bismuth oxychloride (BiOCl) were reported, their synthesis procedures were still complicated and thus limited scalable and practical photocatalytic decomposition. Here, we propose a highly efficient route to achieve BiOCl nanowires through simply stirring the precursor of Bi2O3 powder in the saturated NaCl solution at room temperature. The concentration of NaCl plays a crucial role in growing BiOCl nanowires under the mechanism of oriented attachment, uncovered by continuous observations of product morphologies at different reaction stages. Compared to conventional BiOCl powder, BiOCl nanowires exhibited favorable energy band structures with narrow band gaps, which are predominated by the unique structure with a high aspect ratio and exposed active {001} facets. A superior visible-light photocatalytic activity for degrading Rhodamine B dye was found in the case of the prepared BiOCl, which is faster than that for BiOCl nanoparticles and TiO2. [ABSTRACT FROM AUTHOR]

Complex crystal structures are composed of multiple local environments, and how this type of order emerges spontaneously during crystal growth has yet to be fully understood. We study crystal growth across various structures and along different crystallization pathways, using self-assembly simulations of identical particles that interact via multiwell isotropic pair potentials. We apply an unsupervised machine learning method to features from bond-orientational order metrics to identify different local motifs present during a given structure's crystallization process. In this manner, we distinguish different crystallographic sites in highly complex structures. Tailoring this order parameter to structures of varying complexity and coordination number, we study the emergence of local order along a multistep crystal growth pathway─from a low-density fluid to a high-density, supercooled amorphous liquid droplet and to a bulk crystal. We find a consistent under-coordination of the liquid relative to the average coordination number in the bulk crystal. We use our order parameter to analyze the geometrically frustrated growth of a Frank-Kasper phase and discover how structural defects compete with the formation of crystallographic sites that are more high-coordinated than the liquid environments. The method presented here for classifying order on a particle-by-particle level has broad applicability to future studies of structural self-assembly and crystal growth, and they can aid in the design of building blocks and for targeting pathways of formation of soft-matter structures.

Fluorinated polyimides (PIs) are among the most promising candidates for gate dielectric materials in organic electronic devices because of their solution processability and outstanding chemical, mechanical, and thermal stabilities. Additionally, fluorine (F) substitution improves the electrical properties of PI thin films, such as enhanced dielectric properties and reduced surface trap densities. However, the relationship between the fluorination density of PIs and crystal growth modes of vacuum-deposited conjugated molecules on PI thin films, which is directly related to the lateral charge transport along the PI-organic semiconductor interface, has not been systematically studied. Herein, five different soluble PIs with different F densities were synthesized, and the correlation between fluorination and thin-film properties was systematically investigated. Not only were their dielectric properties modulated, but the growth modes of the organic molecules deposited on the PI thin films also changed with increasing surface F density. This phenomenon was observed by both surface and crystallographic analyses, which resulted in extremely high operational stability of field-effect transistors and the successful fabrication of organic complementary circuits. We believe that the correlation between PI backbone fluorination and its thin-film properties will provide practical insights into the material design based on controlled molecular directed surface assembly on fluorinated polymer dielectrics.

The high photoelectric conversion efficiency and low cost of perovskite solar cells (PSCs) have further inspired people's determination to push this technology toward industrialization. The high-quality perovskite films and high-efficiency and stable PSCs are the crucial factors. Ionic liquids have been proven to be an effective strategy for regulating high-quality perovskite films and high-performance PSCs. However, the regulation mechanism between ionic liquids and perovskites still needs further clarification. In this study, a novel sulfonic acid-functionalized ionic liquid, 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BSO 3 HMImOTf), was used as an effective additive to regulate high-quality perovskite films and high-performance devices. Microscopic mechanism studies revealed strong interactions between BSO 3 HMImOTf and Pb 2+ ions as well as halogens in the perovskite. The perovskite film is effectively passivated with the controlled crystal growth, suppressed ion migration, facilitating to the greatly improved photovoltaic performance, and superior long-term stability. This article reveals the regulatory mechanism of sulfonic acid type ionic liquids through testing characterization and mechanism analysis, providing a new approach for the preparation of high-quality perovskite devices.

Halide perovskites have emerged as highly promising materials for ionizing radiation detection due to their exceptional characteristics, including a large mobility-lifetime product, strong stopping power, tunable band gap, and cost-effective crystal growth via solution processes. Semiconductor-type X-ray detectors employing various micro/nano perovskite materials have shown impressive progress in achieving heightened sensitivity and lower detection limits. Here, we present a comprehensive review of the applications of micro/nano perovskite materials for direct type X-ray detection, with a focus on the requirements for micro/nano crystal assembly and device properties in advanced X-ray detectors. We explore diverse processing techniques and optoelectronic considerations applied to perovskite X-ray detectors. Additionally, this review highlights the challenges and promising opportunities for perovskite X-ray detector arrays in real-world applications, potentially necessitating further research efforts.

The relentless growth of metal-organic framework (MOF) chemistry is paralleled by the persistent urge to control the MOFs physical and chemical properties. While this control is mostly achieved by solvothermal syntheses, room temperature procedures stand out as more convenient and sustainable pathways for the production of MOF materials. Herein, a novel approach to control the crystal size and defect numbers of a dihydroxy-functionalized zirconium-based metal-organic framework (UiO-66(OH) 2 ) at room temperature is reported. Through a reaction-diffusion method in a 1D system, zirconium salt was diffused into an agar gel matrix containing the organic linker to form nanocrystals of UiO-66(OH) 2 with tailored structural features that include crystal size distribution, surface area, and defect number. By variation of the synthesis parameters of the system, hierarchical MOF nanocrystals with an average size ranging from 30 nm up to 270 nm and surface areas between 201 and 500 m 2 g -1 were obtained in a one-pot synthetic route. To stress the importance of crystal size, morphology, and structural defects on the adsorption properties of UiO-66(OH) 2 , the adsorption capacity of the MOF toward methylene blue dye was tested with the largest and most defected crystals achieving the best performance of 202 mg/g. The distinctive structural characteristics including the hierarchical micromesoporous frameworks, the nanosized particles, and the highly defective crystals obtained by our synthesis procedure are deemed challenging through the conventional synthesis methods. This work paves the way for engineering MOF crystals with tunable physical and chemical properties, using a green synthesis procedure, for their advantageous use in many desirable applications.

Comprehensive understanding and precise manipulation of the crystallization process for organic-inorganic hybrid perovskite materials are crucial for advancing perovskite single-crystal optoelectronic technology. In this study, we theoretically and experimentally investigated the influence of interface tension on the synthesis of perovskite single crystals. On the basis of the understanding of the nucleation and growth mechanisms, we developed a polydimethylsiloxane-assisted temperature-gradient growth technique to prepare high-quality MAPbBr 3 single crystals. Using this technique, we harvested some high-quality MAPbBr 3 single crystals, with the narrowest reported full width at half-maximum (0.00806°) of X-ray diffraction rocking curve, the longest carrier lifetime of 1002 ns, and an ultralow trap-state density of 4.25 × 10 9 cm -3 . Furthermore, the X-ray detector fabricated using our MAPbBr 3 single crystal exhibited a high sensitivity of 7275 μC Gy 1- cm 2 and a low minimum detection limit of 0.67 μGy s -1 . This paper presents a novel method to control the crystallization and growth processes of high-quality perovskite single crystals.

Development of biodegradable plastic materials is of primary importance in view of acute environmental and health problems associated with the accumulation of plastic waste. We fabricated a biodegradable composite material based on hydroxyethyl cellulose polymer and tyrosine nanocrystals, which demonstrates enhanced strength and ductility (typically mutually excluding properties), superior to most biodegradable plastics. This emergent behavior results from an assembly pattern that leads to a uniform nanoscale morphology and strong interactions between the components. Water-resistant biodegradable composites encapsulated with hydrophobic polycaprolactone as a protection layer were also fabricated. Self-assembly of robust sustainable plastics with emergent properties by using readily available building blocks provides a valuable toolbox for creating sustainable materials.

Laser crystals with multiwavelength emission characteristics are potential light sources for terahertz radiation. Herein, the pure and Nd-doped Bi 2 Ti 2 O 7 (BTO) laser crystals with sizes up to 16 × 13 × 5 mm 3 were successfully grown using the flux method in the KF-B 2 O 3 -CaBi 4 Ti 4 O 15 growth system. The crystal structure, ideal morphology, chemical, mechanical, and thermal properties, optical transmission and Raman spectra, refractive index, absorption, and fluorescence spectra, as well as fluorescence lifetimes, were systematically studied. Besides, the spectral parameters of Nd 3+ ions in the BTO crystal were systematically calculated based on the Judd-Ofelt theory. The Nd:BTO crystal has a wide transmittance range (0.44-7.30 μm), a small coefficient of thermal expansion (5.80 × 10 -6 K -1 ), and a large absorption full width at half-maximum (fwhm) (31.2 nm) at around ∼804 nm, making it more potential for use in high-power laser systems. Moreover, fluorescence spectra show four emission peaks at 1054, 1062, 1104, and 1112 nm. The strong multiwavelength emission property makes Nd:BTO a promising laser crystal, serving as a potential light source for terahertz radiation.

A Si1–xGex (x ∼ 0.5) crystal measuring 10 mm in diameter was grown by the traveling liquidus zone method using the Gradient Heating Furnace aboard the International Space Station. We quantitatively investigated the composition and shape of the crystal/melt interface during growth by analyzing the grown crystal. The growth interface shapes were obtained by tracing the striations that varied as a result of modulation of the interface near the Si seed to a smooth convex shape as the SiGe crystal growth proceeded. We also successfully measured the Ge concentrations on the interface using an electron-probe microanalyzer. Several growth interfaces showed a highly uniform Ge composition within mole fraction ±0.0005. Detailed measurements of the shapes and the Ge concentrations on those interfaces revealed that millimeter-scale Ge concentration gradient fluctuations existed for more than 16 h in a nonsteady and unsaturated SiGe melt in front of a crystal growth interface grown under microgravity conditions. [ABSTRACT FROM AUTHOR]

The aluminum oxyhydroxide boehmite is an important crystalline phase in nature and industry. We report development of a flexible additive-free hydrothermal synthesis method to prepare high quality boehmite nanoplates with sizes ranging from under 20 nm to 5 μm via using hydrated alumina gels and aluminum hydroxide amorphous powders as precursors. The size and morphology of the boehmite nanoplates was systematically varied between hexagonal and rhombic by adjusting precursor concentrations, pH, and the synthesis temperature, due to face-specific effects. The transformation mechanism is consistent with dissolution and reprecipitation, and involves transitory initial appearance of metastable gibbsite that is later consumed upon nucleation of boehmite. Detailed X-ray pair distribution characterization of the solids over time showed similarities in short-range order that suggest linkages in local chemistry and bonding topology between the precursors and product boehmite, yet also that precursor-specific differences in long-range order appear to manifest subtle changes in resulting boehmite characteristics, suggesting that the rate and extent of water release or differences in the resulting solubilized aluminate speciation lead to slightly different polymerization and condensation pathways. The findings suggest that, during dissolution of the precursor, precursor-specific dehydration or solution speciation could be important aspects of the transformation impacting the molecular-level details of boehmite nucleation and growth. [ABSTRACT FROM AUTHOR]

The effect of a weakly interacting dilute complexing agent on the nucleation rates of a small-molecule solute was explored using the model system of 3-nitrophenol as the inhibited molecule in a toluene solution with a 3-aminobenzoic acid inhibitor. Induction times were measured experimentally using the probability distribution of the solute crystals nucleation events as a function of time. Experimental results demonstrated that a small concentration of inhibitor (0.25% molar with respect to solute) led to a 230% increase in induction times with respect to noninhibited controls at identical supersaturation. Product crystal growth rates, polymorphism, and purity were found to be unaffected by the complexing agent, confirming that the change in nucleation rate was only due to nucleation inhibition. The nucleation rate kinetics of the solute were studied as a function of supersaturation, with and without the inhibitor. Data indicated that upon the addition of the inhibitor, there is a sharp decrease in the pre-exponential factor for the nucleation rate correlation, while there is minimal change on the activation energy. The experimental data were rationalized using a nucleation kinetics model based on the two-step nucleation theory. Analysis of the parameters defined in the nucleation rate equation for the two-step model indicated that the change in rates came from suppression of the ordering kinetic constant for the transition from a prenucleation cluster to a nucleus. A mechanism for the inhibition was proposed in which the formation of intermolecular complexes between solute and additive disrupts the ordering step by hindering the rearrangement of molecules within clusters. [ABSTRACT FROM AUTHOR]

RbEuFe4As4 exhibits both superconducting order in the FeAs layers and ferromagnetic order in the Eu layers, providing a good platform to study the interaction and microscopic coexistence of these two traditionally incompatible orders. Growing high-quality RbEuFe4As4 single crystals is essential to investigate these phenomena at a deeper level. Here we report the successful growth of the RbEuFe4As4 single crystals with millimeter-size dimensions using a RbAs flux. The high-quality crystals were characterized via resistivity, magnetization, and heat capacity measurements. Single crystal X-ray diffraction data refinements reveal almost regular FeAs4 tetrahedra (As1–Fe–As1 = 108.60(7)°, As2–Fe–As2 = 109.01(8)°, and As1–Fe–As2 = 109.81(2)°) in RbEuFe4As4, providing structural support for the highest superconducting transition temperature (Tc = 36.8 K) among all known AAeFe4As4 (A = K, Rb, Cs; Ae = Ca, Sr, Eu) compounds. Our flux method using RbAs can also be employed to grow other desired transition metal compounds targeting the same crystal structure. [ABSTRACT FROM AUTHOR]

The semiconductor Tl6SeI4 was previously identified as a promising semiconductor for room temperature nuclear radiation detection. As the detection performance and carrier transport strongly depend on the concentration of impurity energy levels acting as scattering centers and carrier trapping, material purification is a crucial prerequisite step to obtain spectroscopic-grade detector performance. In this contribution, we present a highly efficient purification method using a bent ampule for evaporating Se, Tl2Se, and TlI precursors for Tl6SeI4. On the basis of impurity analysis performed by glow discharge mass spectroscopy, the main impurities in Tl2Se were identified to be Pb, Bi, and Al, while in TlI the main impurities are Al and Sn. The bent-ampule method successfully reduces or removes the Cl, Pb, and Te impurities from the Se precursor, the Pb, Bi, and Al impurities from the Tl2Se precursor, and removes Sn from TlI. Informed by the analysis results, density functional theory calculations were performed to study the identified impurities and related defects. The calculation results show that Bi and Al act as deep defect levels, which can be detrimental to the detector performance of Tl6SeI4. If the growth condition of Tl6SeI4 is Tl-rich/Se-poor, impurity of Si can introduce deep donors. However, it becomes electrically benign if growth conditions are Tl-poor/Se-rich, while Sn and Pb impurities are shallow donors. Centimeter-size Tl6SeI4 crystals were grown by the two-zone vertical Bridgman method using the purified precursors. The detector made of Tl6SeI4 crystal maintains the high resistivity on the order of 1011 Ω·cm after purification, ideal for suppressing leakage current. The detector exhibits both full-energy and Tl escape photopeaks upon 122 keV γ-ray from 57Co radiation source. The electron mobility-lifetime product μeτe for Tl6SeI4 detector is 8.1 × 10–5 cm2·V–1. On the basis of the carrier rise time measured from output pulses induced by 5.5 MeV α-particles from 241Am, the electron and hole mobilities were estimated to be 112 ± 22 and 81 ± 16 cm2·V–1·s–1, respectively, comparable to those of the leading detector materials HgI2 and TlBr. These results validate the potential of this compound for hard radiation detection, and the impurity analysis presented here allows future efforts to focus on reducing the concentration of the identified impurities. [ABSTRACT FROM AUTHOR]

Acentric compounds with a layered structure are of current interest owing to their advanced functional properties for technical applications. However, the growth of bulk single crystals of acentric materials with a quasi-two-dimensional structure is challenging, which severely hinders the intrinsic properties investigation and optoelectronic applications of these materials. Herein, we report the controlled growth of bulk CdTeMoO6 single crystals with a layered structure and the investigation of their linear and nonlinear optical properties. High quality CdTeMoO6 single crystals with dimensions of ∼26 × 10 × 9 mm3 were successfully grown through the modified top-seeded solution growth method using TeO2-MoO3 as a flux. The transparent range of CdTeMoO6 single crystals is in the range of 0.345–5.40 μm, and with large birefringence (Δn = no – ne = 0.2868–0.2219 from 514 nm to 1.5467 μm). In addition, the nonlinear optical (NLO) coefficient d36 of CdTeMoO6 single crystals was measured to be 8.5 pm/V using Maker Fringe techniques. We also found CdTeMoO6 is type-I phase-matchable based on the calculated phase-matching curves. Our results indicated that CdTeMoO6 single crystal is an excellent birefringent material combined with a promising NLO material for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Thorough process understanding is a prerequisite for implementing quality by design during development of a pharmaceutical crystallization process. Identification of the critical process parameters and raw material attributes and creation of mechanistic models that can correlate these to the product quality attributes are the first steps in this approach. In this paper, a mechanistic model of antisolvent crystallization has been proposed. The model considers dependence of crystal growth rate on crystal mean size. A risk assessment was performed using Failure Mode and Effects Analysis to identify critical process parameters for designing experimentation. Crystal morphological data required for development of this model have been obtained using focused beam reflectance measurement. MATLAB has been used to identify optimal growth and nucleation parameters. The proposed model compares favorably to other similar models with respect to the accuracy of prediction of crystal size, surface area, and volume, even at varying feedrate profiles of antisolvent during crystallization. The average residual value obtained in given model is of the order of 1/10th of the previous models. The superlative performance likely originates from the fact that most models ignore the size dependence of crystal growth rate. We expect the proposed model to be a useful tool in the arsenal of those involved in development of pharmaceutical crystallization. [ABSTRACT FROM AUTHOR]

A crystal growth technique, interfacial cocrystallization, is demonstrated to be a simple and effective method for preparing multicomponent crystal forms. The technique is based on the generation of a liquid–liquid interface between two immiscible solutions of cocrystal-forming compounds, and its utility is demonstrated through the preparation of polymorphs and hydrates of caffeine cocrystals, involving three different hydroxy-2-naphthoic acids, including the formation of some with unexpected compositions. [ABSTRACT FROM AUTHOR]

The influence of a series of cationic surfactants composed of cetyltrimethylammonium cations with different counterions (Br-, Cl-, OH-, C7H8O3S-, [CeCl3Br]-, and NO3-) on the aging process of gold nanoclusters (Au NCs) was studied. The finely different points of Au NCs treated by different surfactants were demonstrated by UV-vis and fluorescence spectra, transmission electron microscopy images, etc. Because of the difference of counterions, these surfactants have diverse physicochemical properties in surface activity, specific conductivity, pH, and viscosity, which may account for the difference of Au NCs in the aging process. In addition, the affinity of the counterions in surfactants to the surface of Au has also been demonstrated completely. This affinity may further guide the difference of the synthesized Au nanomaterials. [ABSTRACT FROM AUTHOR]

Semiconductor nanowires are commonly described as being defect-free due to their ability to expel mobile defects with long-range strain fields. Here, we describe previously undiscovered topologically protected line defects with null Burgers vector that, unlike dislocations, are stable in nanoscale crystals. We analyze the defects present in semiconductor nanowires in regions of imperfect crystal growth, i.e., at the nanowire tip formed during consumption of the droplet in self-catalyzed vapor–liquid–solid growth and subsequent vapor–solid shell growth. We use a form of the Burgers circuit method that can be applied to multiply twinned material without difficulty. Our observations show that the nanowire microstructure is very different from bulk material, with line defects either (a) trapped by locks or other defects, (b) arranged as dipoles or groups with a zero total Burgers vector, or (c) have a zero Burgers vector. We find two new line defects with a null Burgers vector, formed from the combination of partial dislocations in twinned material. The most common defect is the three-monolayer high twin facet with a zero Burgers vector. Studies of individual nanowires using cathodoluminescence show that optical emission is quenched in defective regions, showing that they act as strong nonradiative recombination centers. [ABSTRACT FROM AUTHOR]

III–V solar cells in the nanowire geometry might hold significant synthesis-cost and device-design advantages as compared to thin films and have shown impressive performance improvements in recent years. To continue this development there is a need for characterization techniques giving quick and reliable feedback for growth development. Further, characterization techniques which can improve understanding of the link between nanowire growth conditions, subsequent processing, and solar cell performance are desired. Here, we present the use of a nanoprobe system inside a scanning electron microscope to efficiently contact single nanowires and characterize them in terms of key parameters for solar cell performance. Specifically, we study single as-grown InP nanowires and use electron beam induced current characterization to understand the charge carrier collection properties, and dark current–voltage characteristics to understand the diode recombination characteristics. By correlating the single nanowire measurements to performance of fully processed nanowire array solar cells, we identify how the performance limiting parameters are related to growth and/or processing conditions. We use this understanding to achieve a more than 7-fold improvement in efficiency of our InP nanowire solar cells, grown from a different seed particle pattern than previously reported from our group. The best cell shows a certified efficiency of 15.0%; the highest reported value for a bottom-up synthesized InP nanowire solar cell. We believe the presented approach have significant potential to speed-up the development of nanowire solar cells, as well as other nanowire-based electronic/optoelectronic devices. [ABSTRACT FROM AUTHOR]

We present a detailed study on the static magnetic properties of individual permalloy nanotubes (NTs) with hexagonal cross-sections. Anisotropic magnetoresistance (AMR) measurements and scanning transmission X-ray microscopy (STXM) are used to investigate their magnetic ground states and its stability. We find that the magnetization in zero applied magnetic field is in a very stable vortex state. Its origin is attributed to a strong growth-induced anisotropy with easy axis perpendicular to the long axis of the tubes. AMR measurements of individual NTs in combination with micromagnetic simulations allow the determination of the magnitude of the growth-induced anisotropy for different types of NT coatings. We show that the strength of the anisotropy can be controlled by introducing a buffer layer underneath the magnetic layer. The magnetic ground states depend on the external magnetic field history and are directly imaged using STXM. Stable vortex domains can be introduced by external magnetic fields and can be erased by radio-frequency magnetic fields applied at the center of the tubes via a strip line antenna. [ABSTRACT FROM AUTHOR]

Atomically thin two-dimensional (2D) materials exhibit superlative properties dictated by their intralayer atomic structure, which is typically derived from a limited number of thermodynamically stable bulk layered crystals (e.g., graphene from graphite). The growth of entirely synthetic 2D crystals, those with no corresponding bulk allotrope, would circumvent this dependence upon bulk thermodynamics and substantially expand the phase space available for structure–property engineering of 2D materials. However, it remains unclear if synthetic 2D materials can exist as structurally and chemically distinct layers anchored by van der Waals (vdW) forces, as opposed to strongly bound adlayers. Here, we show that atomically thin sheets of boron (i.e., borophene) grown on the Ag(111) surface exhibit a vdW-like structure without a corresponding bulk allotrope. Using X-ray standing wave-excited X-ray photoelectron spectroscopy, the positions of boron in multiple chemical states are resolved with sub-angström spatial resolution, revealing that the borophene forms a single planar layer that is 2.4 Å above the unreconstructed Ag surface. Moreover, our results reveal that multiple borophene phases exhibit these characteristics, denoting a unique form of polymorphism consistent with recent predictions. This observation of synthetic borophene as chemically discrete from the growth substrate suggests that it is possible to engineer a much wider variety of 2D materials than those accessible through bulk layered crystal structures. [ABSTRACT FROM AUTHOR]

Glasses of the mol composition 2 BaO·TiO2·2 SiO2 + x SiO2 (with x = 0.0, 0.1, 0.2, 0.5, 0.75, 1.5, 2.0, and 3.0 mol) were prepared, polished, and crystallized at 810 °C for 5 h or more. All glasses showed the sole crystallization of Ba-fresnoite (Ba2TiSi2O8). The crystal orientations at the immediate surfaces were analyzed by EBSD and showed that all glasses exhibit a nonrandom orientation distribution, i.e., oriented nucleation at the surface. While the glasses with x = 0.0, 0.1, and 0.2 show rather broad orientation preferences in the form of c-axes tilted from the surface by roughly 10-50°, the glasses with x = 1.5 or higher show discrete textures where specific crystal orientations are significantly preferred with orientation spreads of less than ±15°. While the glasses with x = 0 and 0.1 show polygon crystals at the surface and in the bulk, dendritic crystals are observed in the bulk of all other analyzed compositions. Phase separation solely occurred in the glass with x = 1.5 during the applied heat treatments. [ABSTRACT FROM AUTHOR]

We develop a thermal-elastic stress model using the finite element method to predict three-dimensional anisotropic stress in AlN single crystals homoepitaxially grown by the physical vapor transport process; we also perform numerical experiments for a 1-in. AlN crystal surrounded by different cone-tube designs and grown along various orientations. The influences of the cone-tube shape and the growth orientation on the stresses inside the AlN crystal are investigated in detail. The simulation results show that the von Mises stress exceeds 1.11 GPa under all specified growth conditions, while the anisotropy is negligible. The resolved shear stresses are strongly dependent on the thermal gradient inside the growing crystal and the growth orientation. Strong anisotropy of the resolved shear stress is observed upon tilting of the growth orientation. The resolved shear stress along {0001}⟨1120⟩ primary slip system reveals that the c-axis growing crystal is under tensile stress along all three primary slip directions. Nevertheless, an inversion of the resolved shear stress from tensile to compressive along the -a3 slip direction is observed when changing the growth orientation. The total resolved shear stress shows 6-fold symmetry, reflection symmetry and 2-fold symmetry along [001], [10√3], and [100] growth orientations, respectively. [ABSTRACT FROM AUTHOR]

Nucleation and growth of two-dimensional (2D) islands on a terrace are the dominant growth mechanisms of colloidal crystals whose particle interaction is attractive. The step velocity, vstep, of the 2D islands at various area fractions, ϕarea, and polymer concentrations, Cp, has been investigated. At low Cp (weak attractive interaction between particles), there is a nearly linear relationship between vstep and ϕarea, whereas it is parabolic for high Cp (strong attraction). Depending on the Cp, two manners of kink generation at a step are observed: 1D nucleation under strong attraction and association of mound formation under weak attraction. As a result of mound formation, abundant kinks are created at steps, resulting in a linear relationship between vstep and ϕarea, whereas the relationship is parabolic for step propagation associated with 1D nucleation. Though the kink site is the most favored site for particles to be incorporated into crystals, weak attractive interaction makes the step front site an incorporation site as well, and this latter process is the main mechanism for mound formation. This study is the first to elucidate the relationship between step kinetics and the kink generation mechanism of colloidal crystals, and these new findings significantly contribute to better control of the growth of colloidal crystals. [ABSTRACT FROM AUTHOR]

The Plateau-Rayleigh (P-R) crystal growth was recently proposed and dramatically extended the one-dimensional nanomaterials synthesis due to its tunable morphological features. Previously reported P-R growth is mainly focused on the relative low-temperature reactions (<1273 K, which is less than the melting point of reaction products or intermediate products), while high-temperature P-R growth with a molten state is rarely studied. To extend P-R growth to high temperature and reveal the underlying mechanism, herein we take the synthesis of SiC/SiO2 heterostructures as the prototype. With optimized growth temperature, we reported a novel high-temperature P-R growth of the beaded SiC/SiO2 nanochain heterostructures through a vapor-phase synthesis. The as-obtained SiC/SiO2 nanochain heterostructures involved the single-crystalline 3C-SiC core with diameters of ~20 nm, the amorphous SiO2 shell with thicknesses of 200-300 nm, and many uniform periodic amorphous SiO2 beads with diameters of 800-1000 nm. Further experiments and thermodynamics analysis reveal that the saturated vapor pressure and viscosity of the intermediate product SiO play a key role in this growth. This study not only provides a novel extension of P-R growth with the synthesis of SiC/SiO2 heterostructures but also reveals the significance of the saturated vapor pressure and viscosity of the intermediate product in the high-temperature P-R growth. It is expected that such findings will facilitate the applications of one-dimensional nanomaterials synthesis. [ABSTRACT FROM AUTHOR]

Molybdenum ditelluride (MoTe2), which is stabilized in both semiconducting hexagonal (2H) and metallic distorted octahedral (1T') phases, has attracted increasing attention owing to their attractive properties for promising wide applications. Exploring the full potential of this emerging material requires a reliable synthesis approach to precisely control its phase structure. Here, we report on the growth of high crystallinity MoTe2 nanosheets with a controlled phase via the tellurization of chemical vapor deposition-grown MoO2 nanosheets. The single crystal MoO2 nanosheets with rhombus shape were converted into MoTe2 single crystal nanosheets with morphology maintained well through the tellurization process. The phase structure of as-grown MoTe2 is determined by the synergetic effect of thermodynamics and kinetics in the crystal growth process, which is based on the difference in the thermodynamic stability and the lattice strain between 2H and 1T' phases. Low growth temperature combined with a slow tellurization rate (low Te content) is favorable for growing 2H-MoTe2, while high growth temperature together with a fast tellurization rate (high Te content) is beneficial to grow 1T'-MoTe2. A phase diagram based on the thermodynamics and kinetics of MoTe2 growth was drawn, which provides significant guidance for future synthesizing of two-dimensional materials with a controlled phase structure. [ABSTRACT FROM AUTHOR]

Crystallization of an organic compound, namely, resorcinol, has been studied in a thermal gradient over a substrate where samples are, in addition, mechanically displaced at a constant rate. In such an experiment, nucleation and growth occur in well-defined dissipative conditions. The results show the capability of this method to produce thin films in the resorcinol ß-form. Further, the alignment of the crystals within these films is along a preferred orientation. Employing polarized optical microscopy and X-ray diffraction measurements in terms of specular diffraction and pole figures shows that the crystals alignment follows the thermal gradient. Variation of the displacement rate, i.e., the sample velocity in the gradient field, shows additionally strong variation of the crystal orientations, showing that the kinetic of the crystal formation is crucial for the alignment in the thermal gradient. [ABSTRACT FROM AUTHOR]

The microcrystalline film of an open-ring isomer (1o) of diarylethene 1 was prepared on an Al plasmonic chip with a grating structure. Photoisomerization from 1o to the closed-ring isomer (1c) and growth of needle-shaped crystals in 1c were observed in situ under an upright-inverted microscope. In the center part of the film, crystal growth of needle-shaped-crystal of 1c was observed upon UV irradiation from the top side, but not upon UV irradiation from the bottom side. However, crystallization occurred at the edge of the film upon UV irradiation from the bottom side. It was suggested that crystal growth of 1c required a high mobility of 1c near the film surface. Furthermore, the existence of 1o platform is also found to be required for alignment of 1c molecules by the results under the irradiation from the bottom and top sides. With the Al plasmonic chip, the conversion rate from 1o to 1c was larger inside the grating by the plasmonic enhanced field. Therefore, when the attenuated UV light was irradiated to the film edge with high mobility of 1c from the bottom side, the conversion rate was more than 60%, and the needle-shaped crystals of 1c were observed only inside the grating area. Crystal growth was controlled by the conversion rate of 1c promoted inside the grating. From the above, the larger conversion rate of 1c more than 60%, a high mobility of 1c near the film surface or edge, and the existence of the 1o platform for alignment of 1c molecules, are considered to be required for crystal growth in 1c. [ABSTRACT FROM AUTHOR]

Halide based perovskite materials have attracted attention as a promising candidate for the optoelectronic applications, predominantly in photovoltaic device, due to their superior potential properties such as high absorption coefficient, direct bandgap, long carrier lifetime, high balanced hole and electron mobility, low cost, facile deposition techniques, etc. Despite of this, the fundamental understanding of their physicochemical properties is still debatable in the scientific community. In this review article, we provide the deep insight into the development of perovskite single crystals using different techniques, their potential properties, and their practical applications in the various optoelectronic applications. In addition, we have compared all the reported protocols available for crystal growth and highlighted the best technique to achieve high quality crystals with better size, shape, and possession of potential key quantities to be more useful in optoelectronics. At last, we emphasized difficulties in view of chemical uses and suggested a new direction for the further research and development in the area of the halide based perovskite materials. [ABSTRACT FROM AUTHOR]

The quality of stored frozen products such as foods and biomaterials generally degrades in time due to the growth of large ice crystals by recrystallization. While there is ample experimental evidence that recrystallization within such products (or model systems thereof) is often dominated by diffusion-limited Ostwald ripening, the application of Ostwald-ripening theories to predict measured recrystallization rates has only met with limited success. For a model system of polycrystalline ice within an aqueous solution of sugars, we here show recrystallization rates can be predicted on the basis of Ostwald ripening theory, provided (1) the theory accounts for the fact the solution can be nonideal, nondilute and of different density than the crystals, (2) the effect of ice-phase volume fraction on the diffusional flux of water between crystals is accurately described, and (3) all relevant material properties (involving binary Fick diffusion coefficients, the thermodynamic factor of the solution, and the surface energy of ice) are carefully estimated. To enable calculation of material properties, we derive an alternative formulation of Ostwald ripening in terms of the Maxwell-Stefan instead of the Fick approach to diffusion. First, this leads to a cancellation of the thermodynamic factor (a measure for the nonideality of a solution), which is a notoriously difficult property to obtain. Second, we show that Maxwell-Stefan diffusion coefficients can to a reasonable approximation be related to self-diffusion coefficients, which are relatively easy to measure or predict in comparison to Fick diffusion coefficients. Our approach is validated for a binary system of water and sucrose, for which we show predicted recrystallization rates of ice compare well to experimental results, with relative deviations of at most a factor of 2. [ABSTRACT FROM AUTHOR]

InN crystals with hexagonal shapes were grown from InCl3 and KNH2 in supercritical ammonia at around 280 MPa. For a successful crystal growth a molar ratio of the chloride to the amide of 1:3 was applied, thus providing an essentially ammononeutral milieu. The obtained InN crystals vary in size and aspect ratio depending on the applied furnace temperature: at 663 K hexagonal platelets up to 2 μm in diameter, as well as rods with lengths of 4 μm and diameters of 1 μm were obtained; at 773 K rods grew up to 2.5 μm in length. By combining both temperature programs, with a 10 h annealing step at both temperatures, we were able to increase the crystal size up to 5.2 μm in length and 0.4 μm in diameter. [ABSTRACT FROM AUTHOR]

In the current work, successful growth of an In-doped CdZnTe (InCZT) ingot with a bulk size of ~8 cm long and 2.5 cm diameter was achieved through gradient freeze process. The whole crystal ingot was cut in six small ingots (1-6), and from these, we have selected pieces 1, 2, 4, and 6, which were again cut into ~2 mm thickness portions (named 1-1, 1-2, 2-1, 2-2, 4-1, and 6-1) and polished for further characterization. The single phase and direction of growth was verified by X-ray diffraction analysis, which confirmed its growth along (111) plane. The excellence of the grown crystal was analyzed through high-resolution X-ray diffraction (HRXRD), which confirms that the grown crystals is quite perfect and may be used in device fabrications. The Vickers microhardness indentation studies and load dependence studies on different parts of 1-1, 1-2, 2-1, 2-2, 4-1, and 6-1 InCZT crystals are carried at different loads from 0.098 to 0.49 N. Examination of these samples reveals RISE behavior and it is explained by several models of Mayer's law, Hays-Kendall's tactic, and proportional resistance model. Also fracture toughness, brittleness index, yield strength, and elastic stiffness values are measured from indentation studies and found very much correlated with HRXRD analysis. [ABSTRACT FROM AUTHOR]

Group-V elemental monolayers were recently predicted to exhibit exotic physical properties such as nontrivial topological properties, or a quantum anomalous Hall effect, which would make them very suitable for applications in next-generation electronic devices. The free-standing group-V monolayer materials usually have a buckled honeycomb form, in contrast with the flat graphene monolayer. Here, we report epitaxial growth of atomically thin flat honeycomb monolayer of group-V element antimony on a Ag(111) substrate. Combined study of experiments and theoretical calculations verify the formation of a uniform and single-crystalline antimonene monolayer without atomic wrinkles, as a new honeycomb analogue of graphene monolayer. Directional bonding between adjacent Sb atoms and weak antimonene-substrate interaction are confirmed. The realization and investigation of flat antimonene honeycombs extends the scope of two-dimensional atomically-thick structures and provides a promising way to tune topological properties for future technological applications. [ABSTRACT FROM AUTHOR]

Nickel is capable of discharging electric and magnetic shocks in aerospace materials thanks to its conductivity and magnetism. Nickel nanowires are especially desirable for such an application as electronic percolation can be achieved without significantly increasing the weight of the composite material. In this work, single-crystal nickel nanowires possessing a homogeneous magnetic field are produced via a metal–organic precursor decomposition synthesis in solution. The nickel wires are 20 nm in width and 1–2 μm in length. The high anisotropy is attained through a combination of preferential crystal growth in the ⟨100⟩ direction and surfactant templating using hexadecylamine and stearic acid. The organic template ligands protect the nickel from oxidation, even after months of exposure to ambient conditions. These materials were studied using electron holography to characterize their magnetic properties. These thin nanowires display homogeneous ferromagnetism with a magnetic saturation (517 ± 80 emu cm–3), which is nearly equivalent to that of bulk nickel (557 emu cm–3). Nickel nanowires were incorporated into carbon composite test pieces and were shown to dramatically improve the electric discharge properties of the composite material. [ABSTRACT FROM AUTHOR]

A microfluidic platform combined with a deterministic model accounting for surface ligands reveals precious insights into the nanocrystal formation process. The comparison of on-line kinetic information with model predictions enables the derivation of temperature-dependent kinetic parameters for the CdSe model system. This fully generalizable approach represents a step forward toward a quantitative prediction of the nanocrystal size distribution, enabling the control and optimization of process performance and material properties. [ABSTRACT FROM AUTHOR]