Crystal Growth & Design最新文献

Thiocyanates are materials that constitute the thiocyanate anion, ([SCN])⁻. The linear shape of SCN^– raises the chemical flexibility of the thiocyanates. More importantly, the thiocyanate crystals can be obtained in water under mild conditions. In this work, a thiocyanate system of ABi(SCN)₄ (A = Rb, Cs) was studied as potential nonlinear optical (NLO) materials. CsBi(SCN)₄ was grown as large millimeter-sized crystals in water at room temperature. The crystal structure of CsBi(SCN)₄ was determined by single-crystal X-ray diffraction. CsBi(SCN)₄ crystallizes in the orthorhombic space group P2₁2₁2 (No. 18) with unit cell parameters of a = 11.1943(4) Å, b= 7.8431(3) Å, and c = 6.5510(2) Å. CsBi(SCN)₄ is isostructural to previously reported RbBi(SCN)₄. CsBi(SCN)₄ features a three-dimensional (3D) framework, which consists of [Bi(SCN)₄] units and [Cs(SCN)₄] units. The UV–Vis measurement found that CsBi(SCN)₄ exhibits a moderate band gap of 2.6(1) eV, which was verified by density functional theory (DFT) calculations, indicating an indirect band gap of 2.85 eV. Theoretical studies indicated that RbBi(SCN)₄ and CsBi(SCN)₄ possess large birefringence of 0.48@1064 and 0.66@546 nm, respectively. Theoretical studies verified that the Bi atoms and SCN^– anions significantly contributed to the optical properties of CsBi(SCN)₄. CsBi(SCN)₄ exhibited excellent chemical stability, which remained unchanged in air for 180 days and was verified by powder X-ray diffraction. Type-I phase-matching behavior, moderate SHG response, large birefringence, easy growth of large crystals, and high chemical stability make CsBi(SCN)₄ attractive as a nonlinear optical material.

Benzo[c]tetrazolo[2,3-a]cinnolinium-2-olate, a Class 5 mesoionic species, was synthesized and cocrystallized with various small molecules, including water, methanol, formic acid, acetic acid, propionic acid, and trifluoroacetic acid. The nature of the hydrogen bonding interactions was elucidated through single-crystal X-ray diffraction, quantum-chemical calculations, thermogravimetric and differential thermal analyses, and examination of the relationship between aromaticity and hydrogen bonding. In addition, graph-set and geometric analyses were performed to evaluate other noncovalent interactions present within these crystalline assemblies.

Protein crystallization has emerging potential as an efficient and scalable purification approach in biopharmaceutical manufacturing. However, quantitative modeling of crystallization kinetics remains challenging due to limited experimental data quality, difficulty in detecting and characterizing crystals from noisy images, and lack of robustness in parameter estimation across diverse conditions. This study presents an end-to-end system for estimating crystallization kinetics by integrating deep learning-based image analysis with droplet-based crystallization experiments. Synthetic crystal images with realistic noise and morphological variations are employed to train robust models for crystal detection and dimension prediction. These predictions are then coupled with experimental time-series data to extract nucleation and growth data through single experiment-level preprocessing and batch-level optimization. The proposed system accurately identifies multiple crystals within individual droplets, predicts characteristic dimensions under noisy conditions, and constructs generalized kinetic models applicable across varying experimental conditions. This integrated and scalable approach provides a foundation for automated, real-time crystallization monitoring and offers a pathway to real-time kinetic modeling and process optimization in biopharmaceutical applications.

A droplet-based evaporative crystallization platform coupled with deep learning−enabled microscopy provides quantitative analysis of protein crystallization kinetics. Robust multicrystal detection and characteristic dimension prediction are achieved using models trained on synthetic crystal images that capture realistic optical and morphological variability. Time-resolved crystal size trajectories within individual droplets are transformed into nucleation and growth datasets, enabling automated estimation of kinetic parameters across diverse experimental conditions.

A biphenyl-hinged Schiff base compound exhibited three polymorphs with contrasting photophysical properties, i.e., yellow-emissive Form I, red-emissive Form II, and nonemissive yet photochromic Form III. Every two of the polymorphs interconverted only irreversibly under a single stimulus: heating drove the monotropic transition of I → III, supercooling-cold crystallization afforded conversion of III → II, and mechanical grinding induced the II → I change. Linking these one-way steps under distinct external stimuli achieved a closed polymorphic loop, which we tentatively name it as “kyklotropic” transformation, enabling pseudoreversible multistate switching among all three forms.

Crystal morphology plays a pivotal role in all applications because it affects the performance and processing behaviors of crystals. Foreign compounds are often employed to control the crystal morphology; conversely, morphology variations are sometimes attributed to uncontrolled impurities present in the crystallizing solution. Here, we explore the impact of modifiers on the crystallization and morphology of mefenamic acid (MFA), a nonsteroidal anti-inflammatory drug. We focus on the roles of benzoic acid, 2-chlorobenzoic acid, and 2,3-dimethylaniline, compounds that may be retained as minor components after MFA synthesis. We explored the effects of these compounds at varying MFA supersaturation levels. Whereas the additives did not alter the polymorphic form of MFA, they significantly modified crystal morphology, leading to elongated and blade-like crystals. In contrast to numerous published cases, these compounds do not affect the growth rates of the dominant crystal faces. Instead, we show that the observed morphology changes are due to modifier-driven crystal twinning that may be initiated by disruptions of the crystal nucleation. These findings highlight the importance of considering nonclassical nucleation , wherein impurities and modifiers may influence crystallization through pathways beyond direct surface adsorption such as cluster formation and lattice disruption. This study provides critical insights into the role of foreign compounds in crystal engineering, emphasizing the need for an integrated outlook on their effects on crystal nucleation and growth to optimize crystallization strategies and enhance drug performance.

The uniformity of phosphorus doping during the growth of large-size monocrystalline silicon directly determines the resistivity distribution of wafers,thus influencing the conversion efficiency and yield of downstream solar cells. This has become one of the core challenges in photovoltaic material preparation. The introduction of a cusp magnetic field (CUSP) can effectively regulate the melt flow pattern and temperature distribution, suppress detrimental convection, and promote phosphorus homogenization, representing a mainstream approach for the future enlargement of monocrystalline silicon wafers (≥G12).In this study, multiphysics coupling simulations of the Czochralski growth process of 300 mm n-type monocrystalline silicon (G12) were conducted using the CG-Sim software, combined with experimental validation. The regulatory effects of different zero-magnetic-surface (ZMS) positions and magnetic field intensities on phosphorus distribution and resistivity uniformity were systematically investigated. The the results demonstrate that the application of a CUSP significantly modifies the melt flow field structure and thermal field, thus optimizing phosphorus transport pathways and doping uniformity. When the ZMS is located at 1/2 of the melt depth below the solid–liquid interface, and the magnetic field intensity is 0.3 T, a stable and symmetric composite vortex structure forms within the melt, turbulent viscosity is moderately suppressed, and both radial and axial phosphorus uniformities are improved. Experimental resistivity measurements showed good agreement with the simulation results.This work elucidates the physical mechanism by which a cusp magnetic field improves doping uniformity but also offers theoretical guidance and data support for the industrial growth of large-size, high-uniformity silicon materials.

Particle growth within micrometer-sized porous solids was revealed through nondestructive synchrotron radiation (SR) analysis. In this study, the precipitation of platy particles of layered double hydroxide (LDH) was conducted in the presence of glass porous solids containing interconnected pores formed by fusion of glass beads at the onset of sintering. During the hydrothermal reaction of magnesium–aluminum-type LDH (MgAl-LDH) in the presence of the disk-shaped glass porous solids, the disk shape was preserved while white precipitates formed. Vertically aligned platy particles first precipitated at the necks between glass beads and subsequently covered the glass-bead surfaces from the exterior toward the interior regions, as revealed by complementary analyses including X-ray diffraction, scanning electron microscopy, elemental analyses, and SR multiscale X-ray computed tomography. The SR analysis, a nondestructive technique, successfully visualized LDH platy layers covering the interior surfaces of the porous solid without manual or mechanical processing to obtain disk cross sections, which could otherwise damage the layers. These analyses also revealed that MgCO₃ particles precipitated through the rapid consumption of Al³⁺ (Mg/Al molar ratio of the starting solution = 4) during or after LDH formation. This behavior is supported by the growth of smaller LDH particles vertically aligned on larger ones on both the glass surfaces and the resulting powders, consistent with the general interpretation of the preferential incorporation of Al³⁺ into LDH layers compared with Mg²⁺. Notably, such particles were not generated without the addition of the glass porous solid. Therefore, the results in this study elucidate the precipitation mechanisms of LDH platy particles in bulk porous solids with micrometer-sized interconnected pores, which show potential for treatment of large amounts of water treatment. Thus, this study paves the way for preparing easily handled and bulk inorganic materials composed of naturally abundant elements with increased surface area.

The performance of dry powder inhalers (DPIs) is governed by a complex interplay of deagglomeration, attachment, detachment, and dispersion. Here, we show that crystal morphology serves as a master variable that elucidates and redefines the mechanistic roles of process parameters in DPI systems. Through the deliberate engineering of four distinct crystal morphologies of fluticasone propionate (FP), we systematically decoupled the effects of blending time (15–120 min) and flow rate (40–80 L/min) on aerosolization. Analysis of the fine particle fraction (FPF) and particle deposition patterns allowed us to isolate the contributions of each parameter to the underlying aerosolization mechanisms. Our results reveal a sophisticated, morphology-dependent interplay. We found that for specific crystal habits, the role of blending time is not confined to modulating deagglomeration and attachment but extends to critically impacting detachment. Similarly, the influence of flow rate is not limited to detachment; for certain morphologies, it becomes a significant factor in driving deagglomeration. Ultimately, this work demonstrates that crystal morphology does not merely affect dispersion; it dictates the extent to which blending and flow rate control the entire cascade of aerosolization events. These findings establish a robust design principle for the rational engineering of inhalable crystals to achieve predictable and optimized therapeutic performance.

The widespread use of synthetic azo dyes in various industries has caused large amounts of polluted wastewater to be released into the environment. These dyes, such as Congo Red (CR), are toxic, mutagenic, and carcinogenic, and their high chemical stability and resistance to light and oxidation make their removal from aquatic systems particularly challenging. In this study, we investigated the catalytic performance of a newly synthesized hydroxo-bridged Cu(II)-based metal–organic framework (Cu-MOF) for the degradation of CR in the presence of hydrogen peroxide (H₂O₂), under both dark and illuminated (white-LED-light) conditions. The catalytic degradation of a 100 ppm CR solution under the dark condition reached 95.4% conversion within 70 min, with a kinetic rate constant (k) of 0.0335 min^–1, turnover number (TON) of 645.4, and turnover frequency (TOF) of 9.22, surpassing the performance reported for several other Cu-MOF examples. Under white-LED-light irradiation, the catalytic activity was further enhanced compared to that under dark conditions. This enhancement can be attributed to light-induced charge separation within the MOF structure, where photogenerated positive holes (h⁺) play a key role in the degradation process. These findings suggest that hydroxo-bridged Cu-MOF is a promising heterogeneous catalyst for the efficient degradation of persistent organic dyes in wastewater treatment applications.

In the field of semiconductor display technology, GaN epitaxial growth has long been constrained by the performance bottlenecks of substrates and buffer layers. Current homogeneous substrates are costly and size-constrained, while heterogeneous substrates, such as sapphire and SiC, suffer from significant lattice mismatch with GaN, limiting large-area device fabrication. This study used a wafer-level polycrystalline Mo substrate, attributed to its excellent electrical conductivity, thermal conductivity, high melting point, chemical stability, and moderate thermal expansion coefficient─properties that render it a favorable substrate for growing high-quality GaN functional layers. Additionally, incorporating an AlN buffer layer between Mo and GaN further alleviated the lattice mismatch. Notably, highly c-axis-oriented AlN thin films are a prerequisite for fabricating high-quality and uniform GaN layers. Through precise control of magnetron sputtering parameters, the highly c-axis-oriented AlN textured thin films were successfully achieved on polycrystalline Mo substrates, achieving epitaxial growth with exclusive (002) plane orientation. This effectively alleviates lattice mismatch and stress between the substrate and GaN functional layer, thereby enhancing the crystalline quality. Further studies revealed that the chamber environment postglow discharge exerts a critical impact on the orientation and crystalline quality of AlN films. By precisely optimizing the process, the intensity of the AlN (002) diffraction peak was enhanced by 108% and surface roughness was reduced by 75%. The study demonstrates high uniformity on 4 in. Mo substrates, which was a key technology for low-cost, large-area Micro-LED epitaxy growth, and provides a new path for the industrialization of GaN-based devices.