Crystal Solid State Research Articles

Transition Metals Coordination by Bis-imidazole-calix[4]arene Ligands with and Without Pyrene Units Grafted at the Large Rim.

Herein, the presented results show that previously studied DNA/RNA-interacting bis-imidazole-calix[4]arene systems can, in aqueous solutions, efficiently bind a series of biorelevant transition metal cations by coordination with the two imidazole arms at the small rim of their macrocyclic basket. The SCXRD and NMR results structurally characterised the complexes formed by referent bis-imidazole-calix[4]arene with Cu2+ and Zn2+. In solid-state (crystal), the bis-anilino derivative/Cu2+ complex, only upon exposure to the air, undergoes intramolecular dehydrogenative coupling of two neighbouring aniline units, yielding an azo bridge at the large rim of the calix[4]arene basket. In the biorelevant aqueous solution, the comparison of fluorometric titrations of referent calix[4]arene, with its analogues having one or two pyrene units grafted at the opposite (large) rim, revealed moderate-to-strong affinity towards transition metal cations, and, more importantly, a strong impact of pyrene on the binding affinity towards some cations. The pyrene arm(s) significantly diminished the affinity of the calix[4]arene-imidazole ligand towards Cu+ and strongly increased the affinity towards divalent Co2+ and Cd2+ cations. Moreover, the fluorometric response of some studied derivatives was strappingly sensitive to cation type. Since the counter-anion plays only a marginal role, such a change in selectivity is attributed to the intramolecular interaction of pyrene(s) with the calix[4]arene-imidazole system, sterically controlling the metal cation binding site.

Multi-layer formation by oxidation and solid-state crystallization of cold sprayed amorphous coatings during dry sliding wear

Amorphous alloy coatings, known for the exceptional wear resistance, have emerged as a key solution for enhancing the wear performance of magnesium alloys under harsh environments. In this study, Fe-based amorphous alloy coatings were deposited on magnesium alloy by cold spraying technology, and the influence of microstructural evolution on the wear performance of coatings under dry sliding wear conditions was discussed. The results showed that a dense adherent oxide layer with a thickness of ∼700 nm comprising nanograins of less than 8 nm was formed at the outmost surface, which played a role of self-lubricating. Underneath, a 1 μm thick nanocrystalline-amorphous layer with nanograins of ∼20 nm dispersed in the amorphous alloy matrix was formed through in-situ crystallization induced by flash temperature. This composite structure prevented the formation of shear bands in amorphous alloys and enhanced the durability. Therefore, the transition from abrasive wear to adhesive wear was a consequence of the microstructural evolution from a dual-phase composite layer to a self-lubricating oxide layer.

Water-mediated super-correlated proton-assisted transport mode for solid-state K−O2 batteries

A comprehensive understanding of the behavior nature of fast ions at the atomic level is essential for the development of advanced solid-state ionic conductors. The inadequate inter-ion correlation effects of current ion transport models lead to a conductivity bottleneck in designing conductors. Herein, based on water-mediated proton-assisted ion transport, a novel transport mode with simultaneous anion-cation and inter-cation coupling is designed, enabling the K-ions of the modeled solid-state ionic conductor K2Fe4O7 crystals to achieve an ultra-high conductivity of 7.6 × 10–2 S cm–1, an enhancement of two orders of magnitude. The principle of the accelerated K-ion diffusion through the rotation and vibration of water molecules around the framework oxygen atom is elaborated, and the coupling correlation between proton and K-ion transport is confirmed using in-situ impedance spectroscopy under labeled isotopes. The application of this mechanism enabled the fabricated K−O2 solid-state battery exhibit an ultra-low overpotential (0.1 V) and excellent rate performance. Further, the mechanism is also applicable for Li and Na-ion conductors, providing significant theoretical guidance for breaking existing universal design rules and for the development for faster ionic conductors.

Solid-state surfactant templating for controlled synthesis of amorphous 2D oxide/oxyhydroxide nanosheets

As a member of 2D family, amorphous 2D nanosheets have received increasing attention due to their unique properties that are distinct from crystalline 2D nanosheets. However, compared with the vast library of crystalline 2D nanosheets, amorphous 2D nanosheets are still infancy due to the lack of an efficient synthetic approach. Here, we present a strategy that yields a library of 10 distinct amorphous 2D metal oxides/oxyhydroxides using solid-state surfactant crystals. A key feature of this process is a stepwise reaction using solid surfactant; the solid-state surfactant crystals have metal ions arranged in the interlayer space, and hydrolysis of the metal ions leads to the formation of isolated clusters in the surfactant crystals via limited condensation reactions. Immersing the surfactant crystals in formamide promotes nanosheet formation through the self-assembly of clusters by templating the morphologies of the crystals generated from surfactants crystals. Our approach opens a flatland in amorphous 2D world.

Leveraging Insulator's Tacticity in Semiconducting Polymer Blends.

Blending conjugated polymers with insulating matrices is often utilized for engineering extrinsic properties in organic electronics. Semiconductor/insulator blends are typically processed to form a uniformly distributed network of conductive domains within the insulating matrix, marrying electronic and physical properties from individual components. Understanding of polymer-polymer interactions in such systems is thus crucial for property co-optimization. One of the commonly overlooked parameters is the structural configuration of the insulator on the resulting properties, especially the electronic properties. This study investigated how the tacticity of the matrix polymer, among other relevant parameters in play, impacts solid state crystallization in semiconductor/matrix blends and hence the resulting charge transport properties. We found an intricate dependence of the film morphology, aggregation behavior, electronic charge transport, and mixed ionic-electronic coupling properties on the insulator's tacticity. Our experimentally iterative approach shows that for a given application, when selecting semiconductor/insulator combinations, the tacticity of the matrix can be leveraged to optimize performance and vary solid-state structure.

Solid-state continuous time crystal in a polariton condensate with a built-in mechanical clock.

Time crystals (TCs) are many-body systems that display spontaneous breaking of time translation symmetry. We demonstrate a TC by using driven-dissipative condensates of microcavity exciton-polaritons, spontaneously formed from an incoherent particle bath. The TC phases are controlled by the power of a continuous-wave nonresonant optical drive exciting the condensate and the interaction with cavity phonons. Those phases are, for increasing power, Larmor-like precession of the condensate pseudo-spins-a signature of continuous TC; locking of the frequency of precession to self-sustained coherent phonons-stabilized TC; and doubling of TC's period by phonons-a discrete TC with continuous excitation. These results establish microcavity polaritons as a platform for the investigation of time-broken symmetry in nonhermitian systems.

Nonclassical solid-state organic crystallization via particle migration and disintegration

Crystallization processes of organic molecules remain inadequately understood compared to their inorganic counterparts. Recent discoveries challenging classical theories of crystallization underscore the complexity of organic crystallization mechanism. We herein report the growth of rod-shaped diethyl 2,5-dihydroxyterephthalate (DDT) crystals at room temperature. Utilizing in-situ atomic force microscope (AFM) imaging, we observed multifaceted crystal growth which includes coalescence, ripening, and the long-range migration of micro-sized DDT particles. Additionally, we noted their simultaneous disintegration into nanoclusters before integrating into larger crystals. This study offers fresh insights into the non-classical crystallization processes of organic molecules.

Aptameric photonic structure-based optical biosensor for the detection of microcystin

An optical photonic biosensor for the detection of microcystin (MC) has been developed using an aptamer-immobilized interpenetrating polymeric network (IPNaptamer) intertwined with solid-state cholesteric liquid crystals (CLCsolids). The IPN was constructed with a polyacrylic acid hydrogel (PAA). Aptamer immobilization enhances polarity while blocking hydrogen bonding between the carboxylic groups of PAA-IPN hydrogel, thereby increasing the swelling ratio of the PAA-IPN hydrogel. This leads to an expansion in the helical pitch of the corresponding IPNaptamer-CLCsolid biosensor chip and results in a red-shift in the reflected color. Upon exposure to an aqueous MC solution, the IPNaptamer-CLCsolid biosensor chip exhibits aptamer-mediated engulfment of MC, resulting in reduced polarity of the IPNaptamer complex and a consequential blue-shift in the biosensor chip color occurred. The wavelength shift of the IPNaptamer-CLCsolid biosensor chip demonstrates a linear change with an increase in MC concentration from 3.8 to 150 nM, with a limit of detection of 0.88 nM. This novel optical biosensor is characterized by its low cost, simplicity, selectivity, and sensitivity, offering a promising strategy for designing similar toxin biosensors through the modification of biological receptors.

Crystallization of SrB4O7 in a glass tape and its electrical, dielectric, ferroelectric and nonlinear optical properties

This paper presents the results of an investigation of the electrical, dielectric, ferroelectric, and second-order nonlinear optical properties of SrB4O7 synthesized by methods of both solid-state reaction (SSR) and crystallization of a glass tape (GT). To obtain GTs of SrB4O7, the melt consisting of appropriate precursors was rapidly cooled using a twin-roller. The prepared GTs were crystallized at 730°C for different durations and analyzed by X-ray diffraction. The formation of “extended” crystals in the central part of GTs due to the application of the GT technology is discussed. The investigation of the current-voltage characteristic of the sample prepared by SSR showed that its breakdown voltage is higher than 1000 V. The measurements of the dielectric parameters in the frequency range of 1 KHz–1 MHz showed that the dielectric constant is about 7.5, and the dielectric loss varies from 0.002 to 0.0008. These parameters are sufficiently stable in the temperature range from room temperature to 150°C. The ferroelectric properties of the GT crystallized at 730°C for 3 h were also investigated. At 20 kV/cm, a remnant polarization of 0.18 μC/cm2 was measured. Optical measurements showed that the intensity of second-harmonic generation in the GT crystallized at 730°C for 3 h is 5.4 times higher than that of KH2PO4 (KDP).

Vibrational circular dichroism of adenosine crystals

Adenosine is one of the building blocks of nucleic acids and other biologically important molecules. Spectroscopic methods have been among the most utilized techniques to study adenosine and its derivatives. However, most of them deal with adenosine in solution. Here, we present the first vibrational circular dichroism (VCD) spectroscopic study of adenosine crystals in solid state. Highly regular arrangement of adenosine molecules in a crystal resulted in a strongly enhanced supramolecular VCD signal originating from long-range coupling of vibrations. The data suggested that adenosine crystals, in contrast to guanosine ones, do not imbibe atmospheric water. Relatively large dimensions of the adenosine crystals resulted in scattering and substantial orientational artifacts affecting the spectra. Several strategies for tackling the artifacts have been proposed and tested. Atypical features in IR absorption spectra of crystalline adenosine (e.g., extremely low absorption in mid-IR spectral range) were observed and attributed to refractive properties of adenosine crystals.

Photonic Interpenetrating Polymer Network Fibers Comprising Intertwined Solid-State Cholesteric Liquid Crystal and Polyelectrolyte Networks for Sensor Applications.

Uniform-sized photonic interpenetrating polymer network (IPN) fibers comprising intertwined solid-state cholesteric liquid crystal (CLCsolid) and anionic poly(acrylic acid) (PAA) or cationic poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) networks (photonic IPNPAA or IPNPDMAEMA fibers) were developed for sensor applications. IPNPAA or IPNPDMAEMA fibers with a perfect photonic structure were fabricated inside Teflon tube templates without any treatments for realizing a planar orientation in those fibers. The dominant wavelength of the photonic color from a photograph taken with a cellular phone was used to measure the photonic color change. Photonic IPNPAA fibers treated with KOH (IPNKOH fibers) were used for sensing humidity and divalent metal ions. The linear ranges for relative humidity and Ca2+ detection were 21-92% and 0.5-3.5 mM, and their limits of detection (LODs) were 7.86% and 0.07 mM, respectively. The photonic IPNPAA (or IPNPDMAEMA) fiber immobilized with urease (IPNPAA-urease) (or glucose oxidase (IPNPDMAEMA-GOx)) was used for urea (or glucose) biosensor application. The photonic IPNPAA-urease (or IPNPDMAEMA-GOx) fiber was red-shifted in response to urea (or glucose) in the linear range of 10-60 mM (or 2-16 mM) with an LOD of 2.54 mM (or 0.76 mM). These photonic IPN fibers are promising because of their easy fabrication and miniaturization, battery-free device, cost-effectiveness, and visual detection without using sophisticated analytical instruments. The developed photonic IPN fibers provide new possibilities for the widespread use of photonic sensors in cutting-edge wearable technology and beyond.

Predictions of Boron Phase Stability Using an Efficient Bayesian Machine Learning Interatomic Potential.

Thermodynamic phase stability of three elemental boron allotropes, i.e., α-B, β-B, and γ-B, was investigated using a Bayesian interatomic potential trained via a sparse Gaussian process (SGP). SGP potentials trained with data sets from on-the-fly active learning achieve quantum mechanical level accuracy when employed in molecular dynamics (MD) simulations to predict wide-ranging thermodynamic, structural, and vibrational properties. The simulated phase diagram (500-1400 K and 0-16 GPa) agrees with experimental measurements. The SGP-based MD simulations also successfully predicted that the B13 defect is critical in stabilizing β-B below 700 K. At higher temperatures, the entropy becomes the dominant factor, making β-B the more stable phase over α-B. This letter demonstrates that SGP potentials based on a training set consisting of defect-free-only systems could make correct predictions of defect-related phenomena in solid-state crystals, paving the path to investigate crystal phase stability and transitions.

Growth and characterization of Dy1−xSmxMnO3 single crystals by optical floating zone technique

Dy1−xSmxMnO3 powders were synthesized by solid-state reaction and single crystals were grown using optical floating zone method for the full composition range 0 ≤ x ≤ 1.0. Energy dispersive x-ray spectroscopy (EDS) confirms the nominal composition for all the grown crystals of Dy1−xSmxMnO3. Rietveld refinement analysis using synchrotron X-ray powder diffraction data on powders obtained after crushing the crystals confirms the orthorhombic phase with Pnma space group for all the compositions studied. The lattice parameters and unit cell volume are shown to increase with increasing Sm3+ content at the Dy3+ site in DyMnO3. Magnetization measurements on Dy1−xSmxMnO3 single crystals reveal that the Sm3+ substitution systematically decreases the rare-earth ordering temperature (TDy3+).

Hybrid fiber–solid-state laser with 3D-printed intracavity lenses

Microscale 3D-printing has revolutionized micro-optical applications ranging from endoscopy, imaging, to quantum technologies. In all these applications, miniaturization is key, and in combination with the nearly unlimited design space, it is opening novel, to the best of our knowledge, avenues. Here, we push the limits of miniaturization and durability by realizing the first fiber laser system with intra-cavity on-fiber 3D-printed optics. We demonstrate stable laser operation at over 20 mW output power at 1063.4 nm with a full width half maximum (FWHM) bandwidth of 0.11 nm and a maximum output power of 37 mW. Furthermore, we investigate the power stability and degradation of 3D-printed optics at Watt power levels. The intriguing possibilities afforded by free-form microscale 3D-printed optics allow us to combine the gain in a solid-state crystal with fiber guidance in a hybrid laser concept. Therefore, our novel ansatz enables the compact integration of a bulk active media in fiber platforms at substantial power levels.

Complex-Shape Solid-State Photonic Droplets Prepared via Phase Separation and Microfluidics.

Complex-shape solid-state cholesteric liquid crystal (CLCsolid) droplets were prepared via solvent removal, phase separation, and photopolymerization of uniformly sized reactive CLC (rCLC)/fluorocarbon oil (FCO)/dichloromethane (solvent) droplets produced via a microfluidic method. The interfacial energies between rCLC and FCO, rCLC and water, and FCO and water of a rCLC/FCO droplet in an aqueous solution were precisely controlled through the specified surfactants. The shape of the rCLC/FCO droplet was strongly dependent on the balances among these interfacial energies, enabling the preparation of complex-shape droplets through the controlled concentration of the used surfactants. The complex-shape rCLC/FCO droplets showed photonic patterns consisting of a central reflection from a convex surface, cross-communication from a convex surface between adjacent particles, a photonic reflection band from the outer upward-facing concave surface, and total internal reflection from the inner upward-facing surface. Complex-shape CLCsolid particles obtained after photopolymerization and extraction of a nonreactive chiral dopant and FCO showed photonic patterns similar to those before photopolymerization without much deterioration of the photonic structure. These complex patterns make CLCsolid and rCLC/FCO droplets promising anticounterfeiting materials.

Microscopic Cracks Modulate Nucleation and Solid-State Crystallization Tendency of Amorphous Celecoxib.

Drugs have been classified as fast, moderate, and poor crystallizers based on their inherent solid-state crystallization tendency. Differential scanning calorimetry-based heat-cool-heat protocol serves as a valuable tool to define the solid-state crystallization tendency. This classification helps in the development of strategies for stabilizing amorphous drugs. However, microscopic characteristics of the samples were generally overlooked during these experiments. In the present study, we evaluated the influence of microscopic cracks on the crystallization tendency of a poorly water-soluble model drug, celecoxib. Cracks developed in the temperature range of 0-10 °C during the cooling cycle triggered the subsequent crystallization of the amorphous phase. Nanoindentation study suggested minimal differences in mechanical properties between samples, although the cracked sample showed relatively inhomogeneous mechanical properties. Nuclei nourishment experiments suggested crack-assisted nucleation, which was supported by Raman data that revealed subtle changes in intermolecular interactions between cracked and uncracked samples. Celecoxib has been generally classified as class II, i.e., a drug with moderate crystallization tendency. Interestingly, classification of amorphous celecoxib may change depending on the presence or absence of cracks in the amorphous sample. Hence, subtle events such as microscopic cracks should be given due consideration while defining the solid-state crystallization tendency of drugs.

Solid-state crystallization, oxygen-vacancy rich mesopores and stable triad-silanol nests in ZSM-5 catalyst induced by electron-beam irradiation and calcination

Mesopores and silanol nests are known two technological keys that essentially control the catalytic performance of ZSM-5 zeolite. However, designing and controlling them without using chemicals so that the produced ZSM-5 can have strongly enhanced catalytic properties and more importantly can be applied at industrial scale have still been a big challenge up to now. The present study employed the 10 MeV electron beam (EB) generated from an industrial linear accelerator to introduce both the O-vacancy rich mesopores and stable triad-silanol nests in ZSM-5. The structural modification of irradiated ZSM-5 samples was explored by using SEM and FTIR combined with positron annihilation spectroscopy (PAS) including positron annihilation lifetime (PAL), Doppler broadening (DB) of electron–positron annihilation energy and electron momentum distribution (EMD). Obtained results indicated that EB irradiation could recover the defective-crystal structure as well as intensively modify the structures of ZSM-5. In particular, the mechanism for the solid-state crystallization and the formation of the O-vacancy rich mesopores (maximum size of ∼4.5 nm) in ZSM-5 under the combined EB irradiation (10−110 kGy) and calcination (600 °C) was, for the first time, proposed. The mechanism for the formation of stable triad-silanol nests in the channels of irradiated and calcined ZSM-5 zeolites was also explored. The present study, therefore, opens a new research path of applying both EB irradiation and calcination to produce ZSM-5 with novel features for industrial catalytic application at large-production scale.

Solid-State Cholesteric Liquid Crystals as an Emerging Platform for the Development of Optical Photonic Sensors.

Over the past decade, solid-state cholesteric liquid crystals (CLCsolid ) have emerged as a promising photonic material, heralding new opportunities for the advancement of optical photonic biosensors and actuators. The periodic helical structure of CLCsolid s gives rise to their distinctive capability of selectively reflecting incident radiation, rendering them highly promising contenders for a wide spectrum of photonic applications. Extensive research is conducted on utilizing CLCsolid 's optical characteristics to create optical sensors for bioassays, diagnostics, and environmental monitoring. This review provides an overview of emerging technologies in the field of interpenetrating polymeric network-CLCsolid (IPN) and CLCsolid -based optical sensors, including their structural designs, processing, essential materials, working principles, and fabrication methodologies. The review concludes with a forward-looking perspective, addressing current challenges and potential trajectories for future research.

Reversible Acid‐Base Responsive Fluorescence Changes of Solutions and Crystals Based on Anthracenyl Pyridyl Derivatives

AbstractOrganic compounds that can respond to external stimuli and exhibit fluorescence changes have drawn increasing attention recently because of their potential applications in intelligent displays, optical data storage, anticounterfeiting, bioimaging, and sensors. Herein, we have synthesized two new organic compounds based on frameworks of anthracene and pyridine groups: 4‐(anthracen‐9‐yl) pyridine (AN9P) and 4‐(anthracen‐2‐yl) pyridine (AN2P). Both compounds, in solution and solid state, including polycrystals and single crystals, display reversible fluorescence transformations under alternate acid and base treatments. AN9P and AN2P solutions could be regulated to emit white‐light luminescence. The photoluminescence of the AN9P and AN2P polycrystals showed fast fluorescence changes with wide ranges (>300 nm) upon alternate acid and base stimuli and still exhibited remarkable fluorescence emission with almost no attenuation after 15 cycles of the reversible process. Both experimental and computational results suggested that the heteroatom nitrogen in the AN9P and AN2P molecules significantly influenced the intra‐ and intermolecular electronic interactions during the reversible protonation and deprotonation processes, resulting in changes in their frontier molecular orbitals and fluorescence emission characteristics. Our results provide a new facile approach to design molecular structures that realize highly dynamic photoluminescence changes in both liquid solution and solid crystal.

A Team for the Development and Characterization of Next-Generation Hybrid Semiconductors.

This invited Team Profile was created by the Spanopoulos group, University of South Florida, Tampa (USA), the Guo group, Yale University, West Haven (USA), the Trikalitis group, University of Crete, Heraklion (Greece), the Zimbouche group, Lancaster University, Lancaster (UK), and the Reddy group, University of Lille, Lille (France). They recently published an article on the development of a new family of hybrid semiconductors, namely porous metal halide semiconductors (PMHS). The first member of this series was characterized by using a battery of techniques, shedding light on the corresponding structure-property relationships and its unparalleled water stability. This work provides a solution to address the stability deficiency of metal halide semiconductors and render them suitable for yet unexplored applications, such as solid-state batteries, photonic crystals, sensing and environmental remediation: "Porous and Water Stable 2D Hybrid Metal Halide with Broad Light Emission and Selective H2 O Vapor Sorption", A. Azmy, S. Li, G. K. Angeli, C. Welton, P. Raval, M. Li, N. Zibouche, L. Wojtas, G. N. M. Reddy, P. Guo, P. N. Trikalitis, I. Spanopoulos, Angew. Chem. Int. Ed. Engl. 2023, 62, e202218429.