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We reported a novel donor–acceptor complex with near-infrared emission of 735 nm. During the hierarchical self-assembly process, the supramolecular system twisted into a micro-helix with red emission, depending on both crystal thickness and used solvent, despite the nonpolar structure. It is revealed that the uniform alignment of cyano groups along the stacking columns and the solvent effect induces the twisting. This research provides an innovative approach for designing helical organic micro/nanostructures and near-infrared emission materials. [ABSTRACT FROM AUTHOR]

This year marks the 50th anniversary of a significant milestone in organic optoelectronics, i.e., the first account of metallic-like conductivity in an entirely organic material, tetrathiafulvalene–tetracyanoquinodimethane (TTF–TCNQ). Since the discovery of this prototypical TTF–TCNQ charge-transfer (CT) pair, countless studies, ranging from various aspects, have been done on this fascinating TTF–TCNQ and related CT complexes. More recently, the CT complex-based approach has emerged as an elegant way of designing various next-generation functional organic materials, viz. room temperature phosphorescent (RTP), thermally activated delayed fluorescent (TADF), near infra infrared (NIR) emissive, organic spin-systems, etc. This highlight discusses how the synergy between computational screening and crystal engineering principles can be used to obtain the desired functional output and modulate the CT complex's bulk optical and electronic features. Emphasis is given to some of the recent non-covalent CT complex-based approaches to designing functional optical materials like RTP, TADF, NIR-emissive, chiral CT complex, etc. [ABSTRACT FROM AUTHOR]

Single crystals of Ce-doped gadolinium scandium aluminum garnet (Gd3Sc2Al3O12; GSAG) with Ca2+, Mg2+ and Li+ co-dopants were grown by the Bridgman method. Regardless of melt composition, crystals tend to grow close to the congruent composition. Introduction of Ca2+ or Mg2+, as in other Ce-doped garnets, leads to an increase of absorption below 350 nm, which may indicate formation of Ce4+ states, while no effect is seen with Li+ co-doping. High Ce concentration and co-doping accelerate the scintillation rise and decay times; the codopants strongly significantly reduce the afterglow. [ABSTRACT FROM AUTHOR]

Photoresponsive molecular crystals have sparked interest owing to their potential application prospects. In this study, we achieved dual mechanical responses of a cyanostilbene-based crystal BN. The crystal exhibited both stress-induced mechanical flexibility and light-induced photomechanical bending. Two distinct mechanical responses are related to different underlying phenomena and were not interlinked. While elasticity is attributed to criss-cross packing arrangement in the isotropic structure, photomechanical bending is attributed to the formation of heterogeneous phase distribution due to monomer to dimer cycloaddition product formation. The crystal did not demonstrate photoswitching activity. However, it exhibited thermal reversibility, highlighting reversible dimer to monomer conversion. [ABSTRACT FROM AUTHOR]

A facile and in situ successive linker replacement through single-crystal-to-single-crystal (SC--SC) transformation process in cadmium coordination networks (CNs) based on 3,6-bis(pyridin-3-yl)-1,2,4,5-tetrazine (3,3'-pytz) and 4,4'-bipyridine (4,4'-bipy) in chloroform/methanol solution is reported. In this work, we synthesized a 2D square-grid homo-linker (4,4'-bipy) coordination network of {[Cd(4,4'-bipy)2(ClO4)2] (CHCl3)4}n (1) after 24 h at room temperature. Compound 1 undergoes facile and in situ SC--SC transformation at room temperature to a 2D rectangular-grid mixed-linker (4,4'-bipy and 3,3'-pytz) coordination network of {[Cd(4,4'-bipy)(3,3'-pytz)(ClO4)2](CHCl3)(MeOH)}n (2) after two weeks through a core@shell crystal. Further, by keeping compound 2 in the mother liquor, the second SC--SC structural transformation to the 2D rhombic-grid homo-linker (3,3'-pytz) of {[Cd(3,3'-pytz)2(H2O)1.4(MeOH)0.6](3,3'-pytz)(MeOH)1.4(ClO4)2}n (3) occurs within two months. In these stepwise SC--SC transformations, we report for the first time the facile and in situ fabrication of 2D coordination networks by the replacement of linkers via the core--shell pathway. Unlike compound 3, which was stable in air, single crystals of 1 and 2 were unstable outside the mother solution, and due to the absorption of water from air, they were transformed into microcrystalline materials of {[Cd(4,4'-bipy)(H2O)2(ClO4)2](4,4'-bipy)}n (1T) and {[Cd(3,3'-pytz)(H2-O)2(ClO4)2](4,4'-bipy)}n=1 or ∞ (2T), respectively. [ABSTRACT FROM AUTHOR]

The article introduces a novel roasting technique under a dynamic magnetic field (RDMF) that enables the rapid synthesis of MnB crystals, producing bulk and powder forms within seconds.

CsPbBr3 crystals exhibit high photoelectric absorption, large carrier mobility, long carrier lifetimes, and notable stability at room temperature. With an intermediate bandgap of 2.3 eV, they allow the fabrication of stable photonic devices and show good application prospects in the field of nuclear radiation detection. Through the adjustment of the polycrystalline raw material synthesis, crucible shape design, and multiple growths, a high-quality CsPbBr3 crystal of Φ 50 mm x 80 mm with uniform and crack-free appearance was successfully grown by the vertical Bridgman method. The FWHM of the different crystalline planes was characterized by XRD rocking curves, which showed that the (010) plane has a narrower half peak width and higher crystallinity. Detectors with an Au/CsPbBr3/Au structure were fabricated by magnetron sputtering with Au electrodes of 2 mm in diameter, and the resistivity of the (100) crystal plane and (010) crystal plane was 2.5 x 109 Ω cm and 7.8 x 109 Ω cm, respectively. Under a 5 V bias, UV lamp bands and X-ray irradiation tests revealed that devices with the (010) plane had higher switching ratios and sensitivity, resulting in higher signal-to-noise ratios at lower X-ray doses. [ABSTRACT FROM AUTHOR]

Photoelastic effect was applied to analyze the relationship between fringe spacing in wide-angle conoscopic interference and structural stress of KDP crystals. Based on this analysis, the influence of supersaturation on the shear stress of rapidly growing KDP crystals was investigated experimentally. The results revealed a positive correlation between overall structural strain and growth supersaturation of KDP crystals. Additionally, the shear strain of each crystal concentrates at the boundaries of growth sectors. [ABSTRACT FROM AUTHOR]

This work explores the synthesis and DFT study of five tetranuclear Pb(II) complexes and the role of tetrel bonding in their crystal engineering. Three synthesised Pb(II) complexes and two theoretical tetrameric Pb(II) complexes with halogenated thiophene carboxylate and 1,10-phenanthroline ligands are reported here. Their structural configurations, which feature chair-like repeating units connected via oxygen bridges, without Pb–Pb bonds, show two types of packing arrangements. Each Pb atoms form hemidirectional coordination creating space for the formation of tetrel bonds. The close packed arrangements are stabilised and guided by tetrel bonds. The Pb⋯Br tetrel bonds were found to contribute −4.38 kcal mol−1 and Pb⋯Cl −3.37 kcal mol−1 for the stability of the complexes. These tetrel bonds direct the packing arrangements within the crystal lattice. Additionally, open packed arrangements are stabilised by hydrogen bonds. These findings offer new insights into the design of lead-based metal organic frameworks and highlights the critical role of tetrel bonds in the crystal architecture. [ABSTRACT FROM AUTHOR]

An exceptional example of multiple C–H⋯π(alkyne) contacts has been discovered in the crystal packing of the syn-diastereomeric conformer of 1,2-di(7′-methoxynaphth-1′-yl)-3,6-di(4′′-n-propylphenylethynyl)benzene (syn-1). In contrast, the chiral crystal of anti-1, derived from a racemic mixture via spontaneous resolution, predominantly features conventional C–H⋯π(arene) contacts. The comprehensive analysis of the C–H⋯π contacts in the crystal packing of 1 was conducted using Hirshfeld surface, van der Waals crust, and quantum theory of atoms-in-molecules (QTAIM) methods. The electron density at the bond critical points (σBCP) along the bond path in the C–H⋯π contacts exhibits a moderate correlation with the dimensionless penetration index (pCH). This finding unveils the essentially identical characteristics of the C–H⋯π interactions, irrespective of the sp- and sp2-carbons. The C–H⋯π(alkyne) contacts are almost statistically populated within the range of pure van der Waals interactions, whereas the C–H⋯π(arene) contact exhibits a slight deviation from the criteria. The crystal structure of syn-1 exemplifies an exceptional formation of multiple C–H⋯π(alkyne) contacts, contrasting with the generally rare occurrence of C–H⋯π(alkyne) interactions. [ABSTRACT FROM AUTHOR]

Hybrid chiral perovskites with promising optoelectronic and spintronic applications have attracted great attention. However, reports on hybrid chiral antiperovskites have been rare. In this work, we have successfully designed and synthesized a pair of new homochiral hybrid X3AB-type hexagonal antiperovskite crystals [R- and S-3-chloroquinuclidinium]3(CdCl3)(CdCl4) (R-1 and S-1) by a homochiral strategy. Accordingly, the racemic crystal [3-chloroquinuclidinium]CdCl3 has experienced a significant transformation from an ordinary one-dimensional chain-like hybrid framework to an infrequent hybrid hexagonal antiperovskite structural stacking in homochiral crystals. The enantiomeric relationship between R-1 and S-1 verified by circular dichroism spectra and their active nonlinear optical intensity indicates the delivery of chirality from organic cations to the entire molecular level. In addition, the representative R-1 exhibits an evident thermal anomaly and step-like dielectric response around 406 K, pointing to a possible isomorphic phase transition in R-1 and S-1. To our knowledge, this is the first report on homochiral hybrid hexagonal antiperovskite crystals. This finding would inspire the design of a novel chiral antiperovskite family by a homochiral strategy. [ABSTRACT FROM AUTHOR]

Hybrid chiral perovskites with promising optoelectronic and spintronic applications have attracted great attention. However, reports on hybrid chiral antiperovskites have been rare. In this work, we have successfully designed and synthesized a pair of new homochiral hybrid X3AB-type hexagonal antiperovskite crystals [R- and S-3-chloroquinuclidinium]3(CdCl3)(CdCl4) (R-1 and S-1) by a homochiral strategy. Accordingly, the racemic crystal [3-chloroquinuclidinium]CdCl3 has experienced a significant transformation from an ordinary one-dimensional chain-like hybrid framework to an infrequent hybrid hexagonal antiperovskite structural stacking in homochiral crystals. The enantiomeric relationship between R-1 and S-1 verified by circular dichroism spectra and their active nonlinear optical intensity indicates the delivery of chirality from organic cations to the entire molecular level. In addition, the representative R-1 exhibits an evident thermal anomaly and step-like dielectric response around 406 K, pointing to a possible isomorphic phase transition in R-1 and S-1. To our knowledge, this is the first report on homochiral hybrid hexagonal antiperovskite crystals. This finding would inspire the design of a novel chiral antiperovskite family by a homochiral strategy. [ABSTRACT FROM AUTHOR]

A highly transparent Tb1−xTmxVO4 (TTV) single crystal with a size of Ø 30 × 35mm3 has been successfully grown employing the Czochralski method. X-ray powder diffraction measurement was carried out, confirming that TTV crystallizes in the tetragonal system. The full width at half maximum of the rocking curve for the TTV crystal is 14 arcsec, revealing that TTV has excellent crystallinity. The TTV crystal exhibits high transparency over a wide wavelength range. The measured Verdet constants of the TTV crystal at 532, 633, and 1064 nm are 282, 214, and 139 rad m−1 T−1, respectively, which are remarkably larger than those of the commercially available TGG crystal. The extinction ratio of TTV at 1064 nm reaches 43 dB, which exceeds the largest value of TGG. The laser-induced damage threshold and thermal conductivity of TTV have also been studied to assess its practical application in high-power laser system. Above presented results demonstrate that TTV has high potential as a magneto-optical material in the VIS–NIR region. [ABSTRACT FROM AUTHOR]

3-Nitro-1,2,4-triazole-5-one (NTO) has received wide attention and has applications owing to its excellent detonation performance and low sensitivity. A new crystal form of NTO was prepared via the solvent evaporation method and named γ-NTO. Its crystal properties were studied through single-crystal X-ray diffraction, and the results indicated that the unit cell of γ-NTO belongs to the monoclinic space group Pc, with eight molecules in the single unit cell. The density of this crystal is calculated to be 1.907 g cm−3, which is higher than that of β-NTO and similar to that of α-NTO. The crystal morphology was calculated to be a polygonal shape with a symmetrical growth pattern using the reactive force field. Based on the analysis of reactive molecular dynamics, the thermal decomposition mechanism of different crystal forms of NTO was elucidated, and the results showed that γ-NTO demonstrates higher gas production, providing a successful way to enhance detonation performance. The results of IR and differential thermal analysis (DTA) support the above conclusions. [ABSTRACT FROM AUTHOR]

The distribution of impurities within aggregates is crucial for managing overall impurity levels and enhancing product quality. However, current detection methods often fall short to provide accurate information. This paper presents a novel fluorescence-staining method for effective solvent tagging within crystals, which can enhance impurity management. [ABSTRACT FROM AUTHOR]

In this paper, we propose an approach based on parameter β, which equals the free volume in a unit cell normalized to the van der Waals volume of the molecules. The analysis was carried out within a cluster including two-component crystals [CF1 + CF2], in which one of the components remains constant (CF1) and the other varies (CF2). Linear correlation equations, such as β(CC) = C + D·β(CF2), linking the β(CC) parameter of the two-component crystals with the similar parameter β(CF2) of the single-component crystal for the strictly fixed temperatures were derived on the basis of the crystallographic experimental data. The coefficients of the correlation equations for different clusters were analyzed. A relationship was discovered between the correlation coefficient D and the HYBOT descriptor describing the donor and acceptor interactions with the other molecules. A graphic method was developed for analyzing the β(CC) parameter for the cocrystals belonging to the same cluster relative to the β parameter values of the individual compounds β(CF1) and β(CF2). The correlation equations derived in the study give an opportunity to evaluate the unit cell volume of a hypothetical cocrystal knowing only the crystal structure of a single-component crystal of one of the cocrystal components. [ABSTRACT FROM AUTHOR]

The rapid development of kilowatt-level lasers is in urgent need of excellent magneto-optical materials for Faraday isolators. In this work, a new component Tb3Al2Ga3O12 crystal was designed to meet applications in high-power lasers. A high-quality single crystal has been successfully obtained by the Czochralski technique. The Tb3Al2Ga3O12 crystal is verified to have high crystallinity with a small full width at half maximum (FWHM) of 43.2′′ and exhibits excellent uniformity, especially enhanced magneto-optical properties, exceeding ∼7–15% that of the traditional TGG crystal. These excellent attributes suggest that the Tb3Al2Ga3O12 crystal can be a promising candidate for Faraday isolators. [ABSTRACT FROM AUTHOR]

Owing to its wide band gap, extreme mechanical hardness and high thermal conductivity, GaN has found widespread applications in optoelectronic devices and high-power/-frequency devices. However, the growth of high-quality and large-size GaN crystal substrates is still a great challenge, which hinders the development of power and radio frequency (RF) devices. The Na-flux method can emerge as an effective strategy to address these challenges. Nevertheless, the growth quality of GaN crystals is influenced by several factors during the growth process. This study focused on investigating the growth rate and quality of GaN in relation to the growth temperature and pressure. It also explains the difference in the solubility between N3− and GaN as a function of temperature in liquid phase melts. The intricacy of the Na-flux method and the opacity of the growth process present significant obstacles to the growth of GaN crystals. In order to accurately determine and optimise the growth conditions, the temperature distribution and material transport during the growth process are predicted by simulation. A series of validation experiments were conducted to investigate the influence of temperature and pressure on GaN crystallisation. Under optimised growth conditions, high-quality GaN crystals with a full width at half maximum of 433 arcsec (002) were obtained. This work provides an effective strategy for the liquid-phase growth of high-quality GaN crystals, facilitating the development of high-performance blue-green lasers, RF and power devices. [ABSTRACT FROM AUTHOR]

By adopting CVD-SiC recycled blocks as a SiC source, SiC crystals were successfully grown with a high growth rate of 1.46 mm h−1via the PVT method. The micropipe density and the dislocation density of the grown crystal suggested good crystal quality despite its high growth rate. [ABSTRACT FROM AUTHOR]

To the best of our knowledge, the spectroscopic and highly efficient tunable multi-wavelength laser properties of Er3+,Yb3+,Pr3+ triple-doped BaLaGa3O7 crystals are demonstrated for the first time in this study. The maximum output power of 0.81 W at ∼2.7 μm was obtained under the absorbed pump power of 3.53 W with an optical-to-optical conversion efficiency of 22.9%. The slope efficiency is 27.0%. The results demonstrate that the triple-doped crystals with the sensitizer Yb3+ and deactivator Pr3+ can not only enhance the pump efficiency effectively but also suppress the self-terminating "bottleneck" effect of Er3+ so that the laser threshold is reduced and the laser efficiency is improved. The Er3+,Yb3+,Pr3+ triple-doped BaLaGa3O7 crystal is a promising candidate for high-efficiency mid-infrared laser devices. [ABSTRACT FROM AUTHOR]

We demonstrate the structure, spectroscopy, and laser performance of an Er3+ and Pr3+ co-doped LuYSGG crystal grown by the Cz method. The XRD result shows that it belongs to the cubic system with the space group Ia3¯d. A refractive index curve in the range of 320–3000 nm is obtained by fitting the Sellmeier equation. The lifetimes of the 4I13/2 and 4I11/2 levels are 0.871 and 0.728 ms, and the ratio is reduced obviously from 3.4 to 1.2 due to the doping of deactivator Pr3+. In CW mode, a maximum output power of 1059 mW is achieved with a slope efficiency of 17.58% and laser center wavelength of ∼2.8 μm. Beam quality factors of 1.40/1.34 are achieved. The results suggest that the Er,Pr:LuYSGG crystal is a potential candidate for generating a high-power mid-infrared laser and can be applied in irradiation environments. [ABSTRACT FROM AUTHOR]

Er3+/Yb3+ codoped glass ceramics containing BaF2 crystals were obtained through a melt quenching process; the precipitation of BaF2 nanocrystals was confirmed by structural characterization. The effects of crystal quantity and size on the transmittance and upconversion fluorescence of the samples were analyzed. The precipitation of nanocrystals leads to a significant increase in upconversion luminescence intensity. The fluorescence spectra at different pump powers were measured. Er3+ and Yb3+ energy level diagrams and possible energy transfer routes during upconversion luminescence were explored. Furthermore, the functional relationship between temperature and the upconversion fluorescence intensity ratio of the samples was analyzed. When the temperature is 293 K, the relative sensitivity reaches the maximum of 1.38% K−1. [ABSTRACT FROM AUTHOR]

Isostructural crystals are crucial for the development of high-performance functional materials and precise control over physicochemical properties, whereas the design of isostructural crystals is extremely challenging. In this work single-component isostructural crystals were obtained with the substitution of side-chain groups. High-quality single crystals of isostructural crystals methyl 2-amino-5-methylbenzoate (MAMB) and methyl 2-amino-5-methoxybenzoate (MAMOB) were harvested through sublimation crystallization. Their crystal structures were determined by single-crystal X-ray diffraction (SCXRD). Similar intermolecular interactions and packing modes suggested that MAMB and MAMOB are 3D isostructural, and the quantitative similarity parameters were calculated via the XPac program. Furthermore, these two obtained isostructural crystals exhibited similar blue light emission behaviors and solvation effects. [ABSTRACT FROM AUTHOR]

Molecular crystals that exhibit photomechanical responses show great promise as photoactuators and other smart materials in various fields. Herein, we synthesized two new barbituric acid derivative crystals (crystals 1 and 2), which exhibit distinct photomechanical responses towards a laser irradiation of 532 nm and UV LED photoirradiation of 365 nm, respectively. Crystal 1 demonstrated photomechanical bending upon exposure to 532 nm laser, whereas crystal 2 exhibited dramatic bursting, followed by jumping of its fragments upon UV irradiation. The photomechanical responses of both crystals are attributed to the [2 + 2] photocycloaddition reaction. However, their different kinematic responses are related to different amounts of accumulated strain energy owing to photocycloaddition and its subsequent release in the crystal lattice. The accumulation of strain energy depended on various factors such as the structural arrangement of the crystals, packing modes and overall directionality of non-covalent interactions. Furthermore, the position of the olefinic bond and peripheral substituents played a key role in determining the development of strain energy. [ABSTRACT FROM AUTHOR]

In modern laser science, nonlinear optical crystals play a crucial role as indispensable functional materials. Overcoming the inherent defects of traditional materials such as two-photon absorption and low laser damage thresholds, the search for high-performance nonlinear optical crystals remains an urgent and unresolved challenge. In this study, we extensively utilized deep learning techniques to construct a lightweight convolutional neural network. This network is built on the basis of information about the nuclear charge of elements and the number of atoms in compounds, creating carefully designed feature maps for accurately predicting the formation energy of nonlinear optical crystals. Our model demonstrates outstanding performance, with predictive metrics showing R2 = 0.985, RMSE = 0.128, and MAE = 0.083. This remarkable predictive capability enables our network to efficiently predict the formation energy of crystals and reliably assess their stability. Our approach is poised to play a crucial role in high-throughput screening, significantly reducing computational burdens and accelerating the discovery process of novel crystals. This significant achievement provides an efficient and reliable tool for crystal material research, opening up new possibilities for future materials science investigations. [ABSTRACT FROM AUTHOR]

Ambient pressure crystalline phases of decalins and perfluorodecalins are described. The fluorinated analogues of decalins are compounds of special interest due to their excellent gas-solubility properties regardless of the isomer. The aim of this work was to obtain crystals of the compounds and analyze the packing of the molecules to check if some voids are present in the phases of perfluorodecalins, as in, e.g. gas hydrate clathrates, thus preserving the properties of the liquid phase with dissolved gases. All the single crystals were prepared using an IR laser-assisted process directly on the goniometer of a single-crystal diffractometer. In addition, powder diagrams for flash-cooled samples were recorded. Raman spectroscopy supported the experiments for the crystalline and liquid phases. [ABSTRACT FROM AUTHOR]

Traditional chemical solution deposition (CSD) methods for growing Ga2O3 films face two main issues: limited thickness per deposition, necessitating multiple coating-annealing cycles for adequate film thickness, and a decline in crystal quality with increased thickness. This study introduces an innovative CSD technique for fabricating (GaAl)2O3 films, achieving both high thickness and superior crystal quality, where the aluminum content results from the diffusion of aluminum from sapphire substrates during annealing. The technique uses a precursor solution with high viscosity and cation concentration, allowing single-layer thicknesses of up to 180 nm. Additionally, the incorporation of silver nitrate for silver doping enhances nucleation, growth, and epitaxial quality, inducing a unique twelve-fold symmetry in the (−201) oriented (GaAl)2O3 films. Notably, silver serves as a catalyst and largely evaporates at high temperatures, thus preserving the film's final composition and performance. This study highlights the effectiveness of this CSD approach in simultaneously improving crystal quality and achieving desired film thickness, making it a promising method for mass production of high-quality (GaAl)2O3 films. [ABSTRACT FROM AUTHOR]

Zn1−xMgxTe crystal is expected to be less harmful, more efficient, and economical as a blue-green LED material. In this study, Zn1−xMgxTe and P:Zn1−xMgxTe crystals with different x (0.06 ≤ x ≤ 0.25) values were prepared by the travelling Te solution method. The required polycrystalline materials for crystal growth were successfully synthesized by an element direct reaction method. The XPS results demonstrate that the Mg element is present in Zn1−xMgxTe polycrystalline as Mg2+. The lattice constants of zinc-blende Zn1−xMgxTe are approximately linearly dependent fitted as α(x) = 6.107 + 0.18x (Å). The Mg content dynamic equilibrium between the source materials, Te solution and crystal was anticipated to be progressively achieved throughout the crystal growth and then the segregation of the Mg in the as-grown crystal is reduced. The ranges of fluctuations in the Mg contents for Zn0.90Mg0.10Te and Zn0.75Mg0.25Te were 0.092–0.104 and 0.212–0.227, respectively, along the radial direction. When compared to the calculated values found in the literature, there is less axial segregation of the Mg component during the crystal growth. The Mg content along the axial direction of the crystal of Zn0.82Mg0.18Te increases at a rate of around 0.0047 cm−1, which is significantly less than that of Zn0.80Mg0.20Te crystal grown by the melting method (0.028 cm−1). As-grown Zn0.90Mg0.10Te and Zn0.75Mg0.25Te crystals have infrared and UV-vis-NIR transmittance values close to 60%, and their bandgaps are between 2.2 eV and 2.4 eV, respectively. The resistivity of intrinsic Zn0.75Mg0.25Te crystals is as high as 1.62 × 108 Ω cm. The lowest resistivity of P:Zn0.92Mg0.08Te crystals with p-type conduction is 28.6 Ω cm, and the greatest hole concentration is 8.02 × 1016 cm−3, according to the results of the Hall test. [ABSTRACT FROM AUTHOR]

The end-of-life recycling of crystalline silicon photovoltaic (PV) modules and the utilisation of waste is of fundamental importance to future circular-economy societies. In the present work, the wet-chemistry synthesis route – a low-temperature dissolution–precipitation process – was explored to produce aluminosilicate minerals from waste c-Si solar cells. Nanostructured crystals were produced in an alkaline medium by increasing the reaction temperature from room temperature to 75 °C. The morphology of the produced crystals varied from nanolayered aggregates to rod-shaped crystals and was found to be dependent on the temperature of the reaction medium. Chemical and phase composition studies revealed that the synthesised compounds consisted of structurally different phases of aluminosilicate minerals. The purity and elemental composition of produced crystals were evaluated by energy dispersive spectroscopy (EDS) and micro X-ray fluorescence (μXRF) analysis, confirming the presence of Al, O, and Si elements. These results give new insights into the processing of aluminosilicate minerals with sustainable attributes and provide a possible route to reducing waste and strengthening the circular economy. [ABSTRACT FROM AUTHOR]

Described are two experimental findings: (1) selective CO2 uptake by dipeptide-based molecular crystals of Boc- L -methionyl- L -alanine methyl ester 1 with seemingly nonporous crystal architecture and (2) its CO2 sorption state successfully visualized at the atomic level by means of in situ X-ray crystallographic analysis. More important was the latter, from which intermolecular interactions between CO2 and the surrounding molecules of 1 in the crystal were analyzed by ab initio calculations, indicating that attraction between them was mainly composed of a dispersion force. In addition, a comparison study of the crystal structure of 1 with those of analogous dipeptide crystals (isomorphous with 1) demonstrated that the thermal fluctuations of the dipeptide molecules in the solid state triggered CO2 permeation into the isolated voids present in the crystal lattice of 1. [ABSTRACT FROM AUTHOR]

Basal plane dislocations (BPDs) in 4H-SiC are the main reason for the degradation of bipolar devices. In the experiment, the distribution of 4-fold symmetry BPDs is observed in the etch pit density of the 4H-SiC wafer, which is inconsistent with the phenomenon of the distribution of 6-fold symmetry BPDs because of the hexagonal structure of 4H-SiC. To explain the distribution of 4-fold symmetry BPDs in the grown crystal, 3D modeling of BPDs in 4H-SiC crystals grown by the PVT method has been performed. The results show that the adoption of 4-degree off-axis seed crystals that are widely used in the industry caused the distribution of 4-fold symmetry BPDs. Moreover, the distribution of BPDs is 6-fold symmetry in on-axis grown 4H-SiC single crystals; with the increase of the off-angle, the distribution of BPDs gradually changes from 6-fold to 4-fold symmetry, and the maximum value of the BPD density is at the periphery. In the end, the strategy of growing 4H-SiC crystals with large-size seed crystals has been proposed to reduce the BPD density in the wafer and improve the quality of the substrate. The calculation results shows that the use of 220 mm seed crystals can reduce the BPD density by 15% compared with 200 mm seed crystals. [ABSTRACT FROM AUTHOR]

An incisive analysis of C-H...O and O-H...O hydrogen-bonded patterns and their three-dimensional crystal packing networks in some polyoxygenated decalins, encountered during our quest for recently conceptualised and synthetically accessed polycyclitols, has revealed several distinctive motifs in their supramolecular architectures. The observed supramolecular packing motifs displayed significant variabilities, ranging from simple ribbon-like designs to fittingly organized columnar architectures, depending on the spatial disposition of oxyfunctionalisation patterns. The crucial role of the surrogate carbonate protecting group present in some of the intermediates has been studied by comparing the crystal packing in substrates with and without this functionality. [ABSTRACT FROM AUTHOR]

Self-assembly of short peptides stands as a pivotal avenue in the development of functional materials. Herein we report a flexible transformation during humidity-induced actuation of triglycine crystals with a sheet conformation, which originates from the strengthening of water hydrogen bonding to form hydrated triglycine crystals exhibiting a polyproline II conformation. [ABSTRACT FROM AUTHOR]

Elastically flexible photo-actuating organic molecular crystals can serve as potential candidates in regard to the design of multi-performance sensors or actuators. Here, we are reporting an acylhydrazone derivative whose elastically flexible crystals demonstrate photosalient effect, which is preceded by photomechanical bending. Results drawn from the kinematic analysis indicate that the two photomechanical effects can be controllably induced by the selection of a suitable power density of UV light. [ABSTRACT FROM AUTHOR]

High-temperature piezoelectric materials with good temperature stability are essential for various sensors fabrication. The monoclinic piezoelectric crystals α-BiB3O6 (BIBO) not only possess high resistivity, but also strong piezoelectric behaviors, and are promising for high-temperature sensing application. In this study, the temperature stability of electro-elastic coefficients of BIBO crystals was studied by using an impedance method. Results reveal that the piezoelectric coefficients d21 and d22 exhibited excellent temperature stability over the tested temperature range of 20–650 °C, and the variations were found to be <±5%. In addition, the optimal sensitive cuts relevant to the longitudinal extensional vibration mode (LE), face shear vibration mode (FS) and thickness shear vibration mode (TS) were designed, and the maximum piezoelectric coefficients values for the LE, FS and TS modes were 40.0, −20.6 and 37.8 pC N−1, respectively. Furthermore, the fatigue behaviors of the BIBO crystal cuts annealed at high-temperature of 650 °C and low-pressure of 5 × 10−3 Pa for 10–20 h were investigated, where the dielectric and piezoelectric properties were showing a slight decrease, relating to the formation of oxygen vacancies, as confirmed by the electron paramagnetic resonance (EPR) spectra. In total, the BIBO crystals obtained show stable piezoelectric behaviors with neglegible attenuation (<5%) after annealing treatment, indicating its merits for piezoelectric sensing over a wide temperature range under low-pressure environments. [ABSTRACT FROM AUTHOR]

We demonstrate the temperature distribution, optical and laser performances of a YAP/Tm:YAP/YAP composite crystal fabricated by thermal bonding technology. The thermal distribution simulations show that the bonded crystal possesses a higher thermal dissipation efficiency than that of the unbonded one. The wavefront distortion of the bonded YAP/Tm:YAP crystal is close to the unbonded Tm:YAP, indicating a high bonding quality. The optical transmission spectra and absorption loss suggest that the bonding region is a uniform transition and almost without scattering interface. Moreover, compared with the un-bonded Tm:YAP crystal, a maximum average output power of 41.2 W and slope efficiency of 49.5% are achieved on the bonded crystal, which are increased by 28.4% and 21.0%, respectively. Therefore, the 1.94 μm laser performance can be effectively improved by combining pure YAP crystals on the Tm:YAP crystal as end-caps. [ABSTRACT FROM AUTHOR]

A charge-transfer crystalline solid of 3,3′-diindolyl(3-pyridyl)methane with solvated methanol (PMDI·MeOH) was synthesized and structurally characterized. Upon UV irradiation, the colorless PMDI·MeOH crystal became more intense orange, which could be attributed to the intraligand charge-transfer through the unit cell shrinkage caused by the intermolecular contraction between PMDI and methanol molecules, and a crystalline defect, as investigated by X-ray structural analysis, nuclear magnetic resonance, mass spectroscopy, thermal analysis, and computational studies. [ABSTRACT FROM AUTHOR]

A novel benzimidazole-1,2,3-triazole hybrid molecule, 4-(1H-benzo[d]imidazol-2-yl)-1-(2-methoxyphenyl)-1H-1,2,3-triazol-5-amine, was synthesized. Two concomitant polymorphs of the title compound were crystallized from the same solution simultaneously. Various quantum chemical methods were used to explain the formation of these polymorphic structures and predict their stability to external influence. Studying the possibility of changing the conformation by rotating aromatic rings around single bonds using the m06-2x/cc-pVTZ method and analyzing the molecular structure of the compound in the obtained crystal forms showed that the studied polymorphs differ in the conformation of the molecules. Both polymorphic structures have close lattice energies calculated in a plane wave approximation and energetic structures constructed using pairwise interaction energies. Two polymorphic forms can be classified as a columnar-layered packing of the dimeric building units. Quantum chemical modeling of the displacement of layers relative to each other allows us to state that both concomitant polymorphs are resistant to external mechanical influence. Thus, it can be assumed that the studied concomitant polymorphs were formed not due to kinetic and thermodynamic factors affecting the crystallization process, but due to the ability of two conformers with close energies to form crystals very similar in structure. [ABSTRACT FROM AUTHOR]

The grating structure and periodic assembly in D -(−)-poly(3-hydroxybutyrate) (PHB), or simply poly(3-hydroxybutyrate), with diluent-modulated optical regularity are analyzed using microscopy techniques coupled with a unique 3D interior dissection technique. The top-surface valley band is a result of impingement of branching crystals evolving from normal-oriented main lamellar stalks, and the top-surface band is a result of the protruding lamellar stalks. The 3D dissection shows direct experimental proof of discontinuous interfaces between the successive bands, which are created by periodic impingement of neighboring lamellar bundles growing in the normal direction from the substrate. The iridescence phenomenon from the PHB periodic bands can be attributed to the grating-assembly structures with cross-bar pitches tuned to a suitable range by combination of diluents and temperature of growth, whose function resembles those seen in nature's iridescent crystals. [ABSTRACT FROM AUTHOR]

Here we present a solution-based method of growing three-dimensional flower-shaped metal halide perovskite crystals by drop casting solutions of FAxMA1−xPbyI1+2y precursors (FA = formamidinium, MA = methylammonium) on close-packed monolayers of titanium dioxide (TiO2) colloidal particles. The colloidal films directed perovskite crystallization during solvent evaporation, with crystals first nucleating within the confining interstitial sites between colloidal particles and growing perpendicular to the substrate surface. When growth proceeded above the colloidal film, the crystals blossomed outwards to form flower-shaped hopper crystals with a hierarchical 3D structure. The crystal shapes ranging from circular discs to pointed snowflakes were achieved by varying the solution pH and precursor composition. Structural complexity in these crystals was observed across multiple length scales – X-ray diffraction patterns and spatially-resolved photoluminescence mapping revealed three polymorphs present for all compositions tested: two bulk phases and one surface phase. These structures exhibit broad areas for light absorption but small contact areas with the underlying substrate for charge transport, which may be useful for optoelectronic devices, such as 2D photodetectors. [ABSTRACT FROM AUTHOR]

The density functional tight binding (DFTB) method and DFTB-based molecular dynamics (DFTB-MD) simulations were used to study the structure, intermolecular interactions, and dynamic properties of 2,4-dinitroimidazole (2,4-DNI) crystals doped with different amounts of 1,4-dinitroimidazole (1,4-DNI) at different temperatures. As the doping concentration increases, the stability of the system decreases. It is thermodynamically most favorable to arrange the doped defects in molecular layers. The doping of impurities changes the extreme point of the surface electrostatic potential (ESP) of the 2,4-DNI molecules, but would not change the position of the extreme point, which reduces the stability and safety of the 2,4-DNI molecules. The dynamic simulation showed that the doping of the impurities does not change the decomposition mechanism of the 2,4-DNI molecules, but effectively promotes their decomposition and the formation of intermediate products. At the initial decomposition stage, the 2,4-DNI molecules located around the impurity molecules become more easy to decompose. [ABSTRACT FROM AUTHOR]

Langatate (La3Ga5.5Ta0.5O14, LGT) crystals have attracted significant attention due to their excellent piezoelectric properties. However, the volatilization of Ga2O3 during the traditional Czochralski (Cz) growth often hinders the preparation of high-quality LGT crystals. This work replaced the iridium crucible with a platinum crucible and successfully grew an LGT crystal with a diameter of 60 mm under an air atmosphere by the Cz method, effectively eliminating Ga2O3 volatilization. The full width at half maximum of the rocking curve is 25.2′′, and the transmission is 80%. After annealing in Ar at 1100 °C, the resistivity increases to 1.2 × 108 Ω cm at 560 °C. This work has great potential for growing high-quality LGT crystals for use in high-temperature piezoelectric sensors. [ABSTRACT FROM AUTHOR]

Compared with jagged and rod-like raw products, the spherulitic 3-nitro-1,2,4-triazol-5-one (NTO) crystalline powder is generally superior in the formulation. However, the growth mechanism and corresponding influential factors for NTO spherulites remain to be deeply explored. Herein, the morphological evolutions of NTO crystals in alcohol solvents under a range of maximum supersaturation (Smax) are systematically investigated. It was found that differences in solvent-crystal interface interactions determine the primary morphology of the growing crystals while the magnitude of Smax determines the subsequent polycrystalline evolution. The cooling rate, initial concentration and stirring rate all could affect the crystal morphology by changing the Smax. It is demonstrated that there exists a critical Smax range (1.75–1.88) above which the formation of spherulites is kinetically favorable. Face indexing tests suggest that the (0 0 1) plane of NTO is mostly prone to twinning at low supersaturation, which is because that the molecular layers on the (0 0 1) surface are prone to twisting and the energy difference before and after is only 8.77 kJ mol−1. Then, the interfacial growth theory is employed to explain how a growing crystal plane develops from smooth to rough with non-crystallographic sub-individuals as the crystallization driving force increases. The change of morphology has a positive consequence in improving the safety performance of NTO crystalline powder under drop-weight impact. These findings would forward the understanding of the spherulitic crystallization process for energetic crystals. [ABSTRACT FROM AUTHOR]

Luminescence properties of a palmierite-type K5Eu(MoO4)4 crystal were studied in a wide temperature range of 7–650 K. Eu3+ ions are shown to occupy at least three non-equivalent positions in the palmierite-type structure, forming emission centres with slightly different characteristics due to an incommensurate modulated disordering. The relative intensity of the Eu3+ emission bands originating from the 5D0 and 5D1 terms is shown to depend on excitation energy and the origin of the observed differences is discussed. It is shown that quenching temperature of the Eu3+ emission depends on excitation energy that is explained by energetical overlap of the 4f–4f Eu3+ transitions with the Urbach tail of the fundamental absorption region. Energy transfer processes to the Eu3+ emission centres were studied using the methods of time resolved spectroscopy. [ABSTRACT FROM AUTHOR]

Persistent luminescence is reported for a series of SrAl2O4 single crystals co-doped with 1.0 mol% Eu2O3 and (0.5–3.0 mol%) Nd2O3. Crystals were successfully grown under an Ar atmosphere in an optical floating zone furnace and consisted of a single phase with a monoclinic structure. The maximum intensity of the photoexcitation spectra (PLE) of all samples peaked at 421 nm. Under excitation at 421 nm, the photoluminescence (PL) spectra showed a broad emission in the visible region centered on 522 nm, which corresponds to the Eu2+ 4f65d1 → 4f7 transition, and three additional emissions in the near infrared region, corresponding to the 4F3/2 → 4I9/2 (880/907 nm), 4F3/2 → 4I11/2 (1062/1114 nm) and 4F3/2 → 4I13/2 (1332 nm) transitions from Nd3+. Thermoluminescence (TL) spectra showed that traps in the conduction band are shallower than that of the singly Eu-doped sample, and their concentration gradually increased with increasing Nd3+ content, reaching a maximum in the crystal prepared with 2.5 mol% Nd2O3. The lifetime of the afterglow decay curve also increased with increasing Nd3+ content of the crystals, reaching a maximum value of almost 35 seconds with 2.5 mol% Nd2O3. A mechanism for the long afterglow is proposed in which Eu2+ electrons are first excited, then transported through the conduction band to defect centers which function as traps (produced by Nd3+ doping), and the thermal energy at room temperature is sufficient to reverse this process, so that equilibrium is established and a long residual luminescence results. [ABSTRACT FROM AUTHOR]

Top-seeded solution growth (TSSG) is a crucial technique for producing high-quality SiC crystals, with the quality of the crystal being significantly influenced by the temperature, flow, and carbon concentration in the solution. A global numerical simulation has been performed to investigate the effects of solution height and crystal rotation in SiC crystal growth. The simulation results indicate that as the solution height increases, there are two distinct flow patterns: single-vortex pattern and double-vortex pattern. Because of the change in the flow pattern, the flow field beneath the seed crystal and free surface will undergo a significant change. The varying effects of seed crystal rotation are also demonstrated under different solution height scenarios. Increasing the rotational speed of the seed crystal will enhance the stability of the solution flow field and crystal growth rate for the single-vortex pattern. Increasing the rotational speed or solution height appropriately is beneficial for enhancing the crystal growth rate in the double-vortex pattern. Excessively high rotational speeds or solution heights, however, will reduce the rate of crystal growth. [ABSTRACT FROM AUTHOR]

This paper focuses on the generation and transformation of defects associated with subsurface damages (SSDs) in seed crystals during the physical vapor transport (PVT) growth of 4H-SiC crystals. SSDs in the 4H-SiC seed crystal were first revealed and labeled through photo-chemical etching. After 30 min of PVT growth on the 4H-SiC seed crystal, we found that ridge-like substances with a height ranging from 0.2 to 1.5 μm were formed in the region above the SSDs in the 4H-SiC seed crystal. Raman spectra analysis indicated that these ridge-like substances were 4H-SiC under tensile strain. We then continued the PVT growth to obtain a 4H-SiC boule and carried out a wafering process to obtain 4H-SiC single-crystal wafers. For the bottom wafer, above the 4H-SiC seed wafer, the full width at a half maximum (FWHM) of the rocking curves of the region above the SSDs of the seed wafer was higher than that in the other regions, indicating that the SSDs degrade the crystalline quality of 4H-SiC single crystal. The average value of the FWHM of the rocking curves of the top wafer became lower than that of the bottom wafer, indicating that the effect of SSDs gradually recovers. Molten-KOH etching indicated that SSDs in the 4H-SiC seed crystal give rise to the formation of low-angular grain boundaries (LAGBs) that consist of a wall of threading edge dislocations (TEDs) in 4H-SiC single crystals. [ABSTRACT FROM AUTHOR]

Raltegravir (RLT) is a human immunodeficiency virus integrase strand transfer inhibitor that is prescribed for the treatment of HIV-1 infection. The drug belongs to biopharmaceutics classification system (BCS) class II category and has poor aqueous solubility and chemical stability in acidic/basic medium. Polymorph screening was performed to search for an alternative solid form with improved drug attributes. By serendipity, this screening gave anhydrous RLT (form A) and two crystalline solid phases of impurity C. The RLT form A and impurity C were characterised using powder X-ray diffraction (XRD), thermal analysis (differential scanning calorimetry/thermogravimetric analysis) and vibrational spectroscopy (Fourier-transform infrared). The crystal structures of form A and impurity C were determined from the high resolution powder XRD patterns using Rietveld refinement, thus revealing their conformational and synthon differences. The crystal structure of impurity C1 (MeOH solvate) was solved from single crystal XRD and demonstrates the packing and conformational differences compared to parent phase C. The dissolution/solubility experiments confirmed that form A has a higher solubility than its hydrate in aqueous ethanol medium. Compared to the commercialized RLT potassium salt (RLT-K), form A did not offer improved chemical stability during acid hydrolysis (high-performance liquid chromatography data). Rather, impurity C exhibited higher thermal stability and aqueous stability compared to other RLT solid forms in an acidic medium. [ABSTRACT FROM AUTHOR]

Understanding the growth of needle-shaped molecular crystals and the factors that influence the needle morphology is not only a fundamental research question but is also important in the design of industrial crystallization processes. Needle-like crystals have poor flow properties, are difficult to filter and to dry and – in the case of pharmaceuticals – difficult to formulate. While the morphology can often be controlled by changing the solvent, some compounds are persistent needle-formers that grow from all solvents as highly anisotropic crystals. In this highlight article we discuss the structural properties that lead to (persistent) needle growth. We also review strategies to modify the morphology such as the use of tailor-made additives, polymeric growth modifiers and cocrystallization. [ABSTRACT FROM AUTHOR]

Laser induced damage sites on the surface of a KDP crystal component tend to grow with subsequent laser irradiation, which substantially decrease the lifetime of these optics. The structural investigation suggests that this may be related to the surface damage products of the crystals. In this work, the differences in the crystal structures, electronic properties and optical absorption between the KDP crystal and its surface laser-induced decomposition products K2H2P2O7 and KPO3 are investigated by using first-principles calculations. The theoretical results show that the nonlinear optical active units of KDP crystals are disrupted after irradiation dehydration to K2H2P2O7 and KPO3, which leads to the optical properties at the surface damage being deteriorated. In terms of the electronic structure, the dehydration products K2H2P2O7 and KPO3 have a shorter band gap compared with the KDP crystal. In addition, K2H2P2O7 and KPO3 have a wider optical absorption band than that of the KDP crystal and introduce more ultraviolet absorption in the optical elements. Compared to polycrystalline KDP at the bulk damage sites, the dehydration products at the surface damage increase the ultraviolet absorption of the crystals and cause the surface damage to continually grow under subsequent irradiation, whereas the bulk damage does not continue to increase in subsequent laser irradiation. [ABSTRACT FROM AUTHOR]