Liquid-phase Growth Research Articles

Advancing the development of supersonic natural gas liquefaction through understanding heavy hydrocarbon crystallization mechanism

During supersonic natural gas liquefaction, the solidification of heavy hydrocarbon molecules can be used to improve the efficiency of the liquefaction. This study investigates the supersonic crystallization of n-hexane using an experimental system designed by ourself for precise measurement of liquid heavy hydrocarbon vaporization. The results demonstrate that n-hexane gas condenses rapidly 1.5 cm downstream of the nozzle throat, releasing significant latent heat. The subsequent crystallization of these droplets transitions the substance fully from liquid to solid, and the latent heat released during crystallization is much lower than that during condensation. Under different conditions, we found that higher partial pressures intensify n-hexane crystallization, accelerating liquid phase growth despite slower solid phase mass increase. Furthermore, larger nozzle expansion ratios shorten the time and space distribution of the liquid phase mass fraction. Molecular dynamics simulations reveal n-hexane’s melting and surface crystallization temperatures to be approximately 160 ± 1 K and 158 ± 1 K, respectively, with a supercooling degree of 2 K, explaining the observed crystallization behavior in supercooled droplets.

CFs-supported La-BiOIO3/Bi2O3 heterostructures via in situ growth strategies for efficiently removing diclofenac: Fermi level modulation, intermediates identification and radical mechanism

The charge transfer efficiency and the recyclability were still the potential factors limiting the widespread application of photocatalysts for pollutant removal. Herein, a novel design perspective for BiOIO3-based S-scheme heterojunction (La-BiOIO3/Bi2O3) with modulated Fermi level and enhanced internal electric field was proposed by in situ liquid-phase growth strategy. Meanwhile, the CFs@La-BiOIO3/Bi2O3 catalysts with high stability and easy recyclability were assembled based on industrial carbon fiber cloths, which can achieve efficiently photocatalytic removal of diclofenac (DCF, 95.5 %, 20 min) and bisphenol A (BPA, 100 %, 30 min) under simulated sunlight irradiation. The photocatalytic degradation rates of DCF were 52.8 and 12.4 times that of pure BiOIO3 and Bi2O3, respectively. The high specific surface area (39.74 m2·g−1) and suitable bandgap structure (2.74 eV) also demonstrated the excellence of the CFs@La-BiOIO3/Bi2O3 degradation system. Verification of heteroatom-driven electron rearrangement and charge migration route in heterostructure was performed through XPS analysis and Mott-Schottky experiments. Gaussian calculations, LC-MS, and toxicity assessments demonstrated that reactive oxygen species (ROS) such as ·O2− and ·OH selectively attacked the electronic groups of DCF and its intermediates, which combined with holes (h+) retained in the valence bands of Bi2O3 to synergistically achieve efficient degradation and detoxification of DCF. Finally, the charge migration mechanism for the photocatalytic elimination of DCF over CFs@La-BiOIO3/Bi2O3 photocatalyst was proposed. Similar studies can be extended to other structures capable of achieving rational Fermi level modulation and synchronous carrier introduction for the remediation of polluted waters, providing novel perspectives for improving photocatalytic driving capacity.

High-detectivity photodetectors based on CsPbCl3/Au heterostructures

Photodetector based on all-inorganic CsPbCl3 perovskite is drawing increasing interest owing to its stable chemical properties, suitable band gap and superior inherent optoelectronic properties. However, most of the perovskite detectors are fabricated from polycrystalline films with a number of grain boundaries and defects which would decline the device performance. At the same time, the performance of the device is sacrificed by the presence of a large amount of gaps between the metal electrodes and the material. Here, a high detective photodetector is demonstrated based on CsPbCl3 crystals by liquid-phase growth on pre-patterned Au electrodes. Heterojunctions fabricated by liquid-phase self-assembly synthesis form an embedded structure between metal electrodes and the material, which greatly enhances the contact area and reduces the dark current. The device serves as photodetectors with a responsivity of 62.5 μA/W and detectivity up to 1.79 × 1011 Jones. Furthermore, these devices exhibit outstanding performance of field-effect transistors with a remarkable on/off ratio of 107. These results offer novel insights for the exploration of high-performance photodetectors based on all-inorganic perovskite materials.

In Situ Growth of Conductive Metal-Organic Framework onto Cu2O for Highly Selective and Humidity-Independent Hydrogen Sulfide Detection in Food Quality Assessment.

The sensitivity of chemiresistive gas sensors based on metal oxide semiconductors (MOSs) has been inherently affected by ambient humidity because their reactive oxygen species are easily hydroxylated by water molecules, which significantly reduces the accuracy of the gas sensors in food quality assessment. Although conventional metal organic frameworks (MOFs) can serve as coatings for MOSs for humidity-independent gas detection, they have to operate at high working temperatures due to their low or nonconductivity, resulting in high power consumption, significant manufacturing inconvenience, and short-term stability due to the oxidation of MOFs. Here, the conductive and thickness-controlled CuHHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene)-coated Cu2O are developed by combining in situ etching and layer-by-layer liquid-phase growth method, which achieves humidity-independent detection of H2S at room temperature. The response to H2S only decreases by 2.6% below 75% relative humidity (RH), showing a 9.6-fold improvement than the bare Cu2O sensor, which is ascribed to the fact that the CuHHTP layer hinders the adsorption of water molecules. Finally, a portable alarm system is developed to monitor food quality by tracking released H2S. Compared with gas chromatography method, their relative error is within 9.4%, indicating a great potential for food quality assessment.

Control of Liquid–Liquid Phase Separation, Nucleation, and Growth of L‐Menthol Single Crystals from Water–Ethanol Solvent Mixtures

AbstractL‐Menthol is a commonly used material in food production for flavor enhancement and fragrances, as well as in pharmaceuticals. However, during the solution crystallization process of L‐menthol, there is a major issue of oiling out or liquid–liquid phase separation (LLPS) in most organic solvents and their mixtures. The objective of the current work is to prevent the LLPS phenomenon and grow high‐quality single crystals of L‐menthol. A water–ethanol mixed solvent with nine different mixing ratios is used, ranging from 0.99W:0.01E to 0.91W:0.09E, through the conventional slow evaporation process. The findings indicate that the mixing composition of the solvent plays a significant role in the variation of solubility, refractive index, LLPS, nucleation, and crystallization. This is clearly demonstrated in the phase diagram. The occurrence of LLPS phenomenon, nucleation, growth behavior, and morphology of L‐menthol single crystals through optical microscopy is identified. Additionally, the internal structure and thermal stability of the grown polymorphs using PXRD, SCXRD, and DSC analyses are confirmed.

Research Progress in Liquid Phase Growth of GaN Crystals.

As a wide band gap semiconductor, gallium nitride (GaN) has high breakdown voltage, excellent structural stability and mechanical properties, giving it unique advantages in applications such as high frequency, high power, and high temperature. As a result, it has broad application prospects in optoelectronics and microelectronics. However, the lack of high-quality, large-size GaN crystal substrates severely limit the improvement of electronic device performance. To solve this problem, liquid phase growth of GaN has attracted much attention because it can produce higher quality GaN crystals compared to traditional vapor phase growth methods. This review introduces two main methods of liquid phase growth of GaN: the flux method and ammonothermal method, as well as their advantages and challenges. It reviews the research history and recent advances of these two methods, including the effects of different solvents and mineralizers on the growth quality and performance of GaN crystals, as well as various technical improvements. This review aims to outline the principles, characteristics, and development trends of liquid phase growth of GaN, to provide more inspiration for future research on liquid phase growth, and to achieve further breakthroughs in its development and commercial application.

Polymorphism and orientation control of copper-dicarboxylate metal-organic framework thin films through vapour- and liquid-phase growth.

Precise control over the crystalline phase and crystallographic orientation within thin films of metal-organic frameworks (MOFs) is highly desirable. Here, we report a comparison of the liquid- and vapour-phase film deposition of two copper-dicarboxylate MOFs starting from an oriented metal hydroxide precursor. X-ray diffraction revealed that the vapour- or liquid-phase reaction of the linker with this precursor results in different crystalline phases, morphologies, and orientations. Pole figure analysis showed that solution-based growth of the MOFs follows the axial texture of the metal hydroxide precursor, resulting in heteroepitaxy. In contrast, the vapour-phase method results in non-epitaxial growth with uniplanar texture only.

Effect of annealing ambient on SiGe layer formation using Al–Ge paste for III–V solar cell application

A mixed paste of aluminum (Al) and germanium (Ge) (7:3) was prepared and screen-printed on silicon (Si) substrates, followed by annealing at a peak temperature of 1000 °C in an IR rapid thermal annealing furnace to investigate the liquid-phase growth of silicon–germanium (SiGe) epitaxial layers. The gas ambient during annealing was changed to investigate the effect on SiGe layer quality and physical properties. The SiGe formed samples were observed by scanning electron microscopy and energy dispersive X-ray spectroscopy. Oxygen-containing atmosphere suppressed the SiGe layer formation by oxidizing the Al particle surface, limiting the reaction of the particle to the Si surface. On the other hand, annealing in an argon atmosphere without oxygen resulted in the formation of SiGe layers with a thickness of over 30 μm.

In-situ X-ray diffraction analysis of SiGe liquid phase growth on Si using Al–Ge paste

We performed in-situ two-dimensional X-ray diffraction measurements during a silicon-germanium (SiGe) layer formation process to analyze the liquid-phase epitaxial growth of a SiGe layer on silicon (Si) substrate by a simple method of aluminum-germanium (Al–Ge) paste screen-printing and annealing. The aluminum (Al) and germanium (Ge) from the Al–Ge paste were found to be in the liquid phase starting around 540 °C for the Al–Ge paste containing Al and Ge powders, while it starts around 430 °C for the one containing Al–Ge alloy powder. During the cooling process from the peak temperature of 900 °C down to 430 °C, a SiGe layer was epitaxially grown in the same orientation as the Si substrate. Around 430 °C, the remaining material in the liquid phase formed during the temperature increase solidified and the reaction was terminated. The XRD results suggest that most of the Al in the liquid phase exists as liquid phase from the peak temperature down to 430 °C. The Al liquid phase mediates the melting of Si and Ge, and the Si substrate functions both as a Si source, and as a seed crystal for the growth of the SiGe layer. Both samples show that the Ge concentration is sharply increased in the SiGe layer to around 13 at% at the interface and retains a uniform concentration distribution up to the Al paste matrix/SiGe interface. The change in crystallinity during the liquid phase growth indicates that the properties of the SiGe layer formed by this method can be controlled by adjusting the composition of the Al–Ge paste and the annealing temperature profile.

Real-time (nanoseconds) determination of liquid phase growth during shock-induced melting

Melting of solids is a fundamental natural phenomenon whose pressure dependence has been of interest for nearly a century. However, the temporal evolution of the molten phase under pressure has eluded measurements because of experimental challenges. By using the shock front as a fiducial, we investigated the time-dependent growth of the molten phase in shock-compressed germanium. In situ x-ray diffraction measurements at different times (1 to 6nanoseconds) behind the shock front quantified the real-time growth of the liquid phase at several peak stresses. These results show that the characteristic time for melting in shock-compressed germanium decreases from ~7.2nanoseconds at 35gigapascals to less than 1nanosecond at 42gigapascals. Our melting kinetics results suggest the need to consider heterogeneous nucleation as a mechanism for shock-induced melting and provide an approach to measuring melting kinetics in shock-compressed solids.

Microwave-anion-exchange route to spinel CuCo2S4 nanosheets as cathode materials for magnesium storage

Exploring high-performance cathode materials is of great significance for development of rechargeable magnesium batteries. Herein, two-dimensional ultrathin spinel CuCo2S4 nanosheets synthesized via microwave-assisted liquid-phase growth and anion-exchange post-sulfuration method. As a magnesium storage material, the electrochemical behavior of the CuCo2S4 nanosheets is investigated in different voltage ranges. After activated for several cycles in 0.1–2.1 V, the CuCo2S4 nanosheet material can show good electrochemical reversibility between 0.1 and 2.0 V with capacity of 191.4 mAh g−1 (50 mA g−1) and 114.5 mAh g−1 (500 mA g−1). The excellent Mg-storage properties are attributed to the fast kinetics of Mg2+ by the 2D morphology and ternary structure. A conversion reaction of the magnesium ion storage mechanism is confirmed by ex situ X-ray diffraction characterization. The excellent performance of spinel CuCo2S4 nanosheets validates the viability of the multinary strategy and sheds light on the application of 2D material design for cathode research.

Growth of van der Waals Halide Perovskites within the Interlayer Spacings of Mica

Two-dimensional hybrid organic–inorganic perovskites (2D-HOIPs) have been extensively researched for use in solar cells as well as optoelectronic devices over the past few years. Controllable growth of single-crystalline 2D-HOIP thin films has been regarded as a key component for the development of high-performance end devices. Here, we report a solution-based method for the growth of 2D-HOIPs using muscovite mica as a van der Waals substrate that yields millimeter-scale perovskite flakes. Interestingly, the grown 2D-HOIP flakes lie embedded within the interlayer spacings of muscovite mica. We find that such 2D-HOIP flakes buried in mica demonstrate enhanced photostability in comparison to conventional 2D-HOIP flakes. Such liquid-phase growth in the interlayer spacings of van der Waals substrates opens a new avenue for developing novel material structures for designing optoelectronic devices.

Nonconfinement growth of edge-curved molecular crystals for self-focused microlasers.

Synthesis of single-crystalline micro/nanostructures with curved shapes is essential for developing extraordinary types of optoelectronic devices. Here, we use the strategy of liquid-phase nonconfinement growth to controllably synthesize edge-curved molecular microcrystals on a large scale. By varying the molecular substituents on linear organic conjugated molecules, it is found that the steric hindrance effect could minimize the intrinsic anisotropy of molecular stacking, allowing for the exposure of high-index crystal planes. The growth rate of high-index crystal planes can be further regulated by increasing the molecular supersaturation, which is conducive to the cogrowth of these crystal planes to form continuously curved-shape microcrystals. Assisted by nonrotationally symmetric geometry and optically smooth curvature, edge-curved microcrystals can support low-threshold lasing, and self-focusing directional emission. These results contribute to gaining an insightful understanding of the design and growth of functional molecular crystals and promoting the applications of organic active materials in integrated photonic devices and circuits.

Molecular Encapsulation from the Liquid Phase and Graphene Nanoribbon Growth in Carbon Nanotubes.

Growing graphene nanoribbons from small organic molecules encapsulated in carbon nanotubes can result in products with uniform width and chirality. We propose a method based on encapsulation of 1,2,4-trichlorobenzene from the liquid phase and subsequent annealing. This procedure results in graphene nanoribbons several tens of nanometers long. The presence of nanoribbons was proven by Raman spectra both on macroscopic samples and on the nanoscale by tip-enhanced Raman scattering and high-resolution transmission electron microscopic images.

SiGe Epitaxial Growth on Si Substrate Using Al-Ge Paste

We investigated the liquid-phase growth of silicon-germanium (SiGe) epitaxial layers formed on Si substrates by a simple and rapid process of screen-printing of Al-Ge paste followed by high temperature annealing. Aluminum (Al) and germanium (Ge) (7:3) mixed paste was prepared, screen-printed on a Si substrate and annealed in an infra-red (IR) furnace at peak temperatures between 800°C to 1000°C. After reaching the Al melting point at 660°C, the melted Al dissolves the Si surface and Ge powder in the paste forming a thick liquid phase of melted Al-Ge-Si layer on the dissolved surface of the Si substrate. During the cooling process, a SiGe layer starts to grow epitaxially at the Si interface. The formed SiGe was observed by scanning electron microscope (SEM), and energy dispersive X-ray spectrometry (EDX) and characterized by X-ray diffraction reciprocal space mapping (XRD-RSM). The thickness of the SiGe layer depended on the peak temperature reaching about 25mm at 1000oC. The results suggest the epitaxially grown SiGe is strain-relaxed with a graded Ge concentration.

Rational Design of Zinc/Zeolite Catalyst: Selective Formation of p-Xylene from Methanol to Aromatics Reaction.

The production of p-xylene from the methanol to aromatics (MTA) reaction is challenging. The catalytic stability, which is inversely proportional to the particle size of the zeolite, is not always compatible with p-xylene selectivity, which is inversely proportional to the external acid sites. In this study, based on a nano-sized zeolite, we designed hollow triple-shelled Zn/MFI single crystals using the ultra-dilute liquid-phase growth technique. The obtained composites possessed one ZSM-5 layer (≈30 nm) in the middle and two silicalite-1 layers (≈20 nm) epitaxially grown on two sides of ZSM-5, which exhibited a considerably long lifetime (100 % methanol conversion >40 h) as well as an enhanced shape selectivity of p-xylene (>35 %) with a p-xylene/xylene ratio of ≈90 %. Importantly, using this sandwich-like zeolite structure, we directly imaged the Zn species in the micropores of only the ZSM-5 layer and further determined the specific structure and anchor location of the Zn species.

Matlab implementation of a novel semi-structured kinetic model for methanotroph-photoautotroph cocultures

This paper presents the matlab implementation details of a novel semi-structured kinetic model for methanotroph-photoautotroph cocultures. This includes the parameterization of the modeling equations, and the initialization of the simulation based on experimental conditions. More importantly, it provides details on how the differential equations governing mass balances in both gas and liquid phases are integrated together to simulate the system dynamics over time. The semi-structured kinetic model for methanotroph-photoautotroph coculture is validated using a wide range of experimental conditions. The model:•Accurately predicts both the coculture growth in liquid phase and the gas composition changes in head space over time.•Explicitly models the exchange of in situ produced O2 and CO2 within the coculture.•Considers the self-shading effect on the growth of photoautotroph.

Liquid-phase catalytic growth of graphene

The liquid-phase catalytic growth of graphene is suitable for mass production with environment-friendliness, high yield, low cost and a wide choice of substrates.

Core-shell Fe3O4@SnO2 nanochains toward the application of radar-infrared-visible compatible stealth

Multiband-compatible stealth materials play an increasingly crucial role in the field of modern military defence because they can enable the targeted objects to dodge advance detection technologies. In this study, chain-like Fe3O4@poly(ethyleneglycol dimethacrylate-co-methacrylic acid) nanocomposites were constructed as precursors through the magnetic field-induced distillation precipitation polymerisation. Then, the liquid-phase seed-mediated growth method, together with subsequent calcination, was applied to introduce SnO2 shells and remove poly(ethyleneglycol dimethacrylate-co-methacrylic acid) shells, which led to the successful preparation of innovative core–shell Fe3O4@SnO2 nanochains. The unique microstructure and appropriate components endowed nanochains with multiple functional applications. The minimum reflection loss value was approximately −39.4 dB (5.67 GHz), exhibiting excellent microwave absorption performance. The possible microwave absorption mechanisms involve interfacial polarisation, space charge polarisation, natural resonance, and multiple reflections and scatterings. The optimal infrared reflectivity reached 0.64, 0.51, and 0.37 in three atmospheric windows, indicating outstanding infrared stealth performance, which was attributed to the intense infrared reflection of SnO2 shells. Furthermore, three nanochains showed different colours (dark green, brick red, and bright orange), revealing selection absorption for visible light. This can be attributed to the combined effect of visible responses of SnO2 shells along with Bragg diffraction from the periodic arrangement of Fe3O4 particles in a single nanochain. Thus, core-shell Fe3O4@SnO2 nanochains can be considered as promising radar-infrared-visible compatible stealth materials. This discovery opens a new means to exploit multiband-compatible stealth materials.

An atomic view on the evolution of spall damage in solid–liquid mixed aluminum at high strain rates through stretching simulations

Using the classical molecular dynamic method, we investigated the evolution of spall damage through a series of stretching simulations for solid–liquid mixed aluminum at several initial temperatures. The results show that a turning point appears before void nucleation when the initial temperature is higher than 940 K in mixed Al at a strain rate of 3 × 108 s−1. The formation mechanism of the turning point is due to the local liquid phase nucleation. The growth of the local liquid phase gradually destroys the consecutive solid phases. The lower tensile strength of liquid Al than solid Al leads to the formation of the turning point. The voids tend to nucleate in the liquid phase in mixed Al at different initial temperatures except at 940 K. The time of void nucleation will be delayed due to the melting process before void nucleation in mixed Al. A nucleation and growth (NAG) model can describe the nucleation and growth of voids very well in mixed Al at 900, 920, 960, and 980 K. By adding the criterion of liquid phase proportion, the NAG model can also well describe the void volume fraction history of mixed Al at 940 K. We clarified the micro-mechanisms of spall damage evolution in mixed Al through tension simulation. The relevant results can provide a reference for future work on spall damage studies in solid–liquid mixed metals.