Crystal Stability Research Articles

The novel cocrystals of acacetin with 4,4′-bipyridine and 2,2′-bipyridine: Crystal structures analysis, stability and dissolution evaluation

To our best knowledge, acacetin has great potential for market development and clinical application due to its various pharmacological effects including antioxidant, anti-inflammatory, anti-cancer, neuroprotective, hepatoprotective, cardioprotective and so on. However, low solubility and poor bioavailability overshadow its prospect for new drug development and application. In order to optimize the solubility of acacetin, a scientific and reasonable cocrystal design was launched. In this study, the cocrystal of acacetin-4,4′-bipyridine and acacetin-2,2′-bipyridine were successfully prepared and systematically characterized by single-crystal X-ray diffraction, powder X-ray diffraction, fourier transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. With the efforts of structural analysis and theoretical calculation, it was found that the two formed cocrystals including acacetin-4,4′-bipyridine and acacetin-2,2′-bipyridine possessed significant distinctions in terms of the type of space group and crystal system, the lattice arrangement as well as the forces and hydrogen bonds connections involved in the generation of cocrystals. By the evaluation of stability and dissolution, the results indicated that two cocrystals could keep stable under high temperature, high humidity as well as light condition and significant enhancement in the solubility and dissolution rate of acacetin were achieved by the formation of two new cocrystals which might be contributed to the increase of its bioavailability. This study was of significance to not only investigate the differences of two cocrystals in the aspects of space group, lattice arrangement, intermolecular force and thermodynamic stability, but also provided a new approach to optimize the solubility of acacetin.

Crystallographic analysis, Hirshfeld surface investigation, and DFT calculations of 2-phenoxy-triazoloquinazoline molecule: Implications for drug design

This study presents a comprehensive structural and computational investigation of 2-phenoxy-1,2,4-triazolo[1,5-a]quinazoline (PTQ), a compound with promising pharmacological potential. Single-crystal X-ray diffraction (SCXRD) analysis revealed the molecular geometry and crystal packing, while density functional theory (DFT) calculations provided insights into electronic properties and reactivity. Hirshfeld surface analysis elucidated intermolecular interactions, highlighting hydrogen bonding, van der Waals forces, and π–π stacking as crucial factors in crystal stability. Fingerprint analysis quantified these interactions, revealing the dominance of hydrogen contacts and the significance of hydrogen bonds and C–H···π interactions. Void analysis identified potential areas for inclusion complex formation. Frontier molecular orbital analysis and molecular electrostatic potential (MEP) mapping identified potential electrophilic and nucleophilic sites, guiding future reactivity studies. Furthermore, in silico ADMET and molecular docking studies were performed to assess the drug-likeness and potential antihistamine activity of PTQ.

In-situ sequential crystallization of fenofibrate and tristearin – Understanding the distribution of API in particles and stability of solid lipid microparticles from the perspective of crystallization

In-situ API crystallization in carrier matrices has attracted extensive attention in recent years for its advantages over traditional preparation processes. However, due to the lack of systemic research on molecular self-assembly behaviors, the products obtained by in-situ crystallization suffer from the problems of polymorphic transformation and drug expulsion during storage, limiting its industrial application. This paper investigates the in-situ sequential crystallization behavior of tristearin (SSS) and fenofibrate (FEN), utilizing SSS as the carrier and FEN as the API. It was found that the behavior of mixed crystallization significantly differs from single-component crystallization, including direct formation of stable form of SSS and the rapid crystallization of FEN. During the crystallization process, the melting FEN promotes the movement of SSS molecules, while the sliding of SSS lamellae, in turn, provides a mechanical stimulus to enhance the nucleation of FEN. Based on the observed synergistic crystallization behavior, the distribution and stability of the API within FEN solid lipid microparticles (SLMs) during storage were evaluated, while also examining the stability variations in SLMs formulated at different cooling rates and drug loading concentrations. The findings indicate that the initial nucleated FEN results in a decrease in the surrounding molten FEN and the irregularity of the SSS lamellas, thereby preventing the remaining molten FEN from achieving complete crystallization within a brief period. Due to the compatibility between FEN and SSS, some SSS may blend with the molten FEN, potentially resulting in further crystallization during storage and consequently increasing the risk of drug expulsion.

The Continuous and Reversible Transformation of the Polymorphs of an MGAT2 Inhibitor (S-309309) from the Anhydrate to the Hydrate in Response to Relative Humidity.

Polymorphic control is vital for the quality control of pharmaceutical crystals. Here, we investigated the relationship between the hydrate and anhydrate polymorphs of a monoacylglycerol acyltransferase 2 inhibitor (S-309309). Solvent evaporation and slurry conversion revealed two polymorphs, the hydrate and the solvate. The solvate was transformed into the hydrate by heating. X-ray powder diffraction demonstrated that the hydrate was transformed into an anhydrate via an intermediate state when heated. These crystal forms were confirmed under controlled humidity conditions; the presence of the anhydrate, the intermediate hydrate, or the hydrate depended on the relative humidity at 25 °C. The stoichiometry of S-309309 in water in the hydrate form was 4:1. The hydrates and anhydrates exhibited similar crystal structures and stability. The water of hydration in the intermediate hydrate was 0.1-0.15 mol according to the dynamic vapor sorption profile. The stability and dissolution profile of the anhydrate and hydrate showed no significant change due to similar crystal lattices and quick rehydration of the anhydrate. A mechanism for the reversible crystal transformation between the anhydrate and pseudo-polymorphs of the hydrate was discovered. We concluded that S-309309 causes a pseudo-polymorphic transformation; however, this is not a critical issue for pharmaceutical use.

Structural, elastic, electronic, optical and anisotropy properties of newly quaternary Tl2HgGeSe4 via DFPT predictions associated to XPES and RS experiments

In the present work, we report on theoretical studies of thermodynamic properties, structural and dynamic stabilities, dependence of unit-cell parameters and elastic constants upon hydrostatic pressure, charge carrier effective masses, electronic and optical properties, contributions of interband transitions in the Brillouin zone of the novel Tl2HgGeSe4 crystal. The theoretical calculations within the framework of the density-functional perturbation theory (DFPT) are carried out employing different approaches to gain the best correspondence to the experimental data. The present theoretical data indicate the dynamical stability of the title crystal and they reveal that, under hydrostatic pressure, it is much more compressible along the a-axis than along the c-axis. Strikingly, the charge effective mass values (me∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$m_{e}^{{^{*} }}$$\\end{document} and mh∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$m_{h}^{{^{*} }}$$\\end{document}) vary considerably when the high symmetry direction changes indicating a relative anisotropy of the charge-carrier’s mobility. Furthermore, the Young modulus and compressibility are characterized by the maximum and minimum values (Emax\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^{max}$$\\end{document} and Emin\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^{\\min }$$\\end{document}) and (βmax\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta^{max}$$\\end{document} and βmin\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta^{\\min }$$\\end{document}) that are equal to (62.032 and 28.812) GPa and (13.672 and 6.7175) TPa–1, respectively. Additionally, we have performed calculations of the Raman spectra (RS) and reached a good correspondence with the experimental RS spectra of the Tl2HgGeSe4 crystal. The XPES associated to RS constitutes powerful techniques to explore the oxidized states of Se and Ge in Tl2HgGeSe4 system.

Crystal-Rigidifying Strategy in Hybrid Manganese Halide to Achieve Narrow Green Emission and High Structural Stability.

Although organic-inorganic hybrid Mn2+ halides have advanced significantly, achieving high stability and narrow-band emission remains enormously challenging owing to the weak ionic nature and soft crystal lattice of the halide structure. To address these issues, we proposed a cationic engineering strategy of long-range cation π···π stacking and C-H···π interactions to simultaneously improve the crystal structural stability and rigidity. Herein, two organic zero-dimensional (0D) manganese halide hybrids of (BACQ)2MnX4 [BACQ = 4-(butylamino)-7-chloroquinolin-1-ium; X = Cl and Br] were synthesized. (BACQ)2MnX4 display strong green-light emissions with the narrowest full width at half-maximum (fwhm) of 39 nm, which is significantly smaller than those of commercial green phosphor β-SiAlON:Eu2+ and most of reported manganese halides. Detailed Hirshfeld surface analyses demonstrate the rigid environment around the [MnX4]2- units originating from the interactions between [BACQ]+. The rigid crystal structure weakens the electron-phonon coupling and renders narrow fwhm of these manganese halides, which is further confirmed by temperature-dependent emission spectra. Remarkably, (BACQ)2MnX4 realizes outstanding structural and luminescence stabilities in various extreme environments. Benefiting from the excellent performance, these Mn2+ halides are used to assemble light-emitting diodes with a wide color gamut of 105% of the National Television System Committee 1931 standard, showcasing the advanced applications in liquid-crystal-display backlighting.

Ultrahigh electrochemical properties of Na3V2(PO4)3 under synergistic effects of Er3+ substitution and CNTs coating

Currently, the low ionic and electronic conductivities of Na3V2(PO4)3 (NVP) have been hindered its further application. In this paper, a simultaneous optimized method of Er3+ substitution and carbon nanotubes (CNTs) enwrapping is proposed for the first time. Due to the large ionic radius of Er3+ (89 pm vs 64 pm of V3+), Er3+ occupying the position of V3+ makes the crystal structure more stable and alleviates the deformation of the crystal cell. Meanwhile, the interplanar spacing of NVP is broadened after introducing Er3+, so the de-intercalation rate of Na+ can be accelerated and the kinetic properties are improved. In addition, the enwrapped CNTs connecting with amorphous carbon layers construct a conductive substrate for the fast electronic transportation, which significantly modifies the electronic conductivity. Moreover, the CNTs benefits to inhibit the agglomeration of NVP active materials and make the distribution more uniform and grain size more smaller. The decreasing size indicates a shorter pathway for Na+ migration, which improves its apparent ionic diffusivity. Through the above analysis, the dual modification strategy can efficiently improve the kinetic properties of NVP system. Notably, Na3V1.93Er0.07(PO4)3/C@CNTs (NVEP-0.07) submits a high capacity of 84.2 mAh g−1 at 50 C and maintains 70.6 mAh g−1 after 8000 cycles, corresponding to a high retention ratio of 83.9 %. The assembled NVEP-0.07//CHC full cell reveals 146.2 mAh g−1 at 0.1 C, which successfully lightens the LED bulbs, indicating the excellent application potential of NVEP-0.07. Impressively, the recycled XRD/SEM/XPS results demonstrate the significantly improved crystal stability and chemical state of NVEP-0.07.

Engineering Single-Atom Sites with the Irving-Williams Series for the Simultaneous Co-photocatalytic CO2 Reduction and CH3CHO Oxidation.

The bonding effects between 3d transition-metal single sites and supports originate from crystal field stabilization energy (CFSE). The 3d transition-metal atoms of the spontaneous geometrical distortions, that is the Jahn-Teller effect, can alter CFSE, thereby leading to the Irving-Williams series. However, engineering single-atom sites (SASs) using the Irving-Williams series as an ideal guideline has not been reported to date. Herein, alkynyl-linked covalent phenanthroline frameworks (CPFs) with phenanthroline units are developed to anchor the desired 3d single metal ions from d5 to d10 (Mn2+, Fe3+, Co2+, Ni2+, Cu2+, and Zn2+). The Irving-Williams series was employed to accurately predict the bonding effects between 3d transition-metal atoms and phenanthroline units. To verify this, theoretical calculations and experimental results reveal that Cu-SASs/CPFs exhibits higher stability and faster charge-transfer efficiency, far surpassing other metal-SASs/CPFs. As expected, Cu-SASs/CPFs demonstrates a high photoreduction of CO2-to-CO activity (~30.3 μmol ⋅ g-1 ⋅ h-1) and an exceptional photooxidation of CH3CHO-to-CH3COOH activity (~24.7 μmol ⋅ g-1 ⋅ h-1). Interestingly, the generated *O2 - is derived from the process of CO2 reduction, thereby triggering a CH3CHO oxidation reaction. This work provides a novel design concept for designing SASs by the Irving-Williams to regulate the catalytic performances.

Engineering Single‐Atom Sites with the Irving–Williams Series for the Simultaneous Co‐photocatalytic CO2 Reduction and CH3CHO Oxidation

AbstractThe bonding effects between 3d transition‐metal single sites and supports originate from crystal field stabilization energy (CFSE). The 3d transition‐metal atoms of the spontaneous geometrical distortions, that is the Jahn–Teller effect, can alter CFSE, thereby leading to the Irving–Williams series. However, engineering single‐atom sites (SASs) using the Irving–Williams series as an ideal guideline has not been reported to date. Herein, alkynyl‐linked covalent phenanthroline frameworks (CPFs) with phenanthroline units are developed to anchor the desired 3d single metal ions from d5 to d10 (Mn2+, Fe3+, Co2+, Ni2+, Cu2+, and Zn2+). The Irving–Williams series was employed to accurately predict the bonding effects between 3d transition‐metal atoms and phenanthroline units. To verify this, theoretical calculations and experimental results reveal that Cu‐SASs/CPFs exhibits higher stability and faster charge‐transfer efficiency, far surpassing other metal‐SASs/CPFs. As expected, Cu‐SASs/CPFs demonstrates a high photoreduction of CO2‐to‐CO activity (~30.3 μmol ⋅ g−1 ⋅ h−1) and an exceptional photooxidation of CH3CHO‐to‐CH3COOH activity (~24.7 μmol ⋅ g−1 ⋅ h−1). Interestingly, the generated *O2− is derived from the process of CO2 reduction, thereby triggering a CH3CHO oxidation reaction. This work provides a novel design concept for designing SASs by the Irving–Williams to regulate the catalytic performances.

Fabrication and Characterization of PLA/PBAT Blends, Blend-Based Nanocomposites, and Their Supercritical Carbon Dioxide-Induced Foams.

In this study, a twin-screw extruder was used to fabricate poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends and blend-based nanocomposites with carbon nanotube (CNT) or nanocarbon black (CB) as nanofillers. The fabricated samples were subsequently treated with supercritical carbon dioxide (scCO2) to fabricate the corresponding foams. Bi-phasic morphology and selective distribution of CNTs or CBs in the PBAT phase were observed in the blends/composites through scanning electron microscopy. After the scCO2 treatment, the selective foaming of the PBAT phase in the prepared blends/composites was confirmed. The cellular structure of PBAT phase in scCO2-treated blends is similar to the size/shape of PBAT domains in untreated blends or treated neat PBAT foam. The addition of CNTs or CBs in the blends led to a slight reduction in cell size of the foamed PBAT phase, demonstrating CNT/CB-induced cell nucleation. Differential scanning calorimetry (DSC) results showed that CNTs and CBs played as nucleating agents and increased the initial crystallization temperature up to 14 °C compared with neat PBAT for PBAT in different composites during cooling. The scCO2 treatment induced the bimodal stability of PBAT crystals in different samples, which melted mainly in two temperature regions in DSC studies. Thermogravimetric analyses revealed that compared with parent blends, the addition of CNTs or CBs increased the temperature at 80 wt.% loss (degradation of PBAT portion) up to 6 °C. The electrical resistivity decreased by more than six orders of magnitude for certain CNT- or CB-added composites compared with the parent blends. The hardness of the blends slightly increased after forming the corresponding composites and then declined after the scCO2 treatment.

Se‐Elemental Concentration Gradient Regulation for Efficient Sb2(S,Se)3 Solar Cells with High Open‐Circuit Voltages

Antimony selenosulfide (Sb2(S,Se)3), featuring large absorption coefficient, excellent crystal structure stability, benign non‐toxic characteristic, outstanding humidity and ultraviolet tolerability, has recently attracted enormous attention and research interest regarding its photoelectric conversion properties. However, the open‐circuit voltage (Voc) for Sb2(S,Se)3‐based photovoltaic devices is relatively low, especially for the device with a high power conversion efficiency (η). Herein, an innovative Se‐elemental concentration gradient regulation strategy has been exploited to produce high‐quality Sb2(S,Se)3 films on TiO2/CdS substrates through a thioacetamide(TA)‐synergistic dual‐sulfur source hydrothermal‐processed method. The Se‐elemental gradient distribution produces a favorable energy band structure, which suppresses the energy level barriers for hole transport and enhances the driving force for electron transport in Sb2(S,Se)3 film. This facilitates efficient charge transport/separation of photogenerated carriers and boosts significantly the Voc of Sb2(S,Se)3 photovoltaic devices. The champion TA‐Sb2(S,Se)3 planar heterojunction (PHJ) solar cell displays an considerable η of 9.28% accompanied by an exciting Voc rising to 0.70 V that is currently the highest among Sb2(S,Se)3‐based solar cells with efficiencies exceeding 9.0%. This research is anticipated to contribute to the preparation of high‐quality Sb2(S,Se)3 thin film and the achievement of efficient inorganic Sb2(S,Se)3 PHJ photovoltaic device.

Se-Elemental Concentration Gradient Regulation for Efficient Sb2(S,Se)3 Solar Cells With High Open-Circuit Voltages.

Antimony selenosulfide (Sb2(S,Se)3), featuring large absorption coefficient, excellent crystal structure stability, benign non-toxic characteristic, outstanding humidity and ultraviolet tolerability, has recently attracted enormous attention and research interest regarding its photoelectric conversion properties. However, the open-circuit voltage (Voc) for Sb2(S,Se)3-based photovoltaic devices is relatively low, especially for the device with a high power conversion efficiency (η). Herein, an innovative Se-elemental concentration gradient regulation strategy has been exploited to produce high-quality Sb2(S,Se)3 films on TiO2/CdS substrates through a thioacetamide(TA)-synergistic dual-sulfur source hydrothermal-processed method. The Se-elemental gradient distribution produces a favorable energy band structure, which suppresses the energy level barriers for hole transport and enhances the driving force for electron transport in Sb2(S,Se)3 film. This facilitates efficient charge transport/separation of photogenerated carriers and boosts significantly the Voc of Sb2(S,Se)3 photovoltaic devices. The champion TA-Sb2(S,Se)3 planar heterojunction (PHJ) solar cell displays an considerable η of 9.28 % accompanied by an exciting Voc rising to 0.70 V that is currently the highest among Sb2(S,Se)3-based solar cells with efficiencies exceeding 9.0 %. This research is anticipated to contribute to the preparation of high-quality Sb2(S,Se)3 thin film and the achievement of efficient inorganic Sb2(S,Se)3 PHJ photovoltaic device.

Diisopropylammonium hydrogen squarate: Synthesis and comprehensive analysis of non-linear optical co-crystal using X-ray, Hirshfeld, mechanical, optical and DFT methods

This research successfully synthesized a single co-crystal of diisopropylammonium hydrogen squarate using prolonged vaporization for crystal growth. Single-crystal X-ray spectrometry confirmed its monoclinic structure, and morphological predictions were made. UV–visible spectroscopy revealed its optical transmittance with a direct optical energy band gap of 3.45 eV. Photoluminescence studies showed a strong violet emission at 402 nm when excited by a 260 nm source. Microhardness study examined the crystal's mechanical attributes portraying the normal indentation size effect followed by a qualitative overview of half-penny crack dynamics. FTIR study aided in the discernment of varied vibrational modes with NH stretching being observed at 3078 cm−1. Thermal examination further revealed the crystal's stability up till 244 °C. Proton and carbon-13 NMR spectra were analyzed to verify the presence of functional groups and the overall molecular integrity. Intermolecular interactions were analyzed using Hirshfeld surface and fingerprint mapping. The Z-scan technique demonstrated the crystal's applicative potential in its third harmonic generation capability. Theoretical calculations with Density Functional Theory (DFT) supported the experimental findings, offering insights into optimized geometries, frontier molecular orbitals, natural population and bond orbital distributions, hyperpolarizability, molecular electrostatic potentials, IR vibrational modes, and UV absorbance profiles.

Insights into the difference between diglyceride-oil based and triglyceride-oil based oleogels: Physical property, crystal structure and stability

This paper investigated the differences in the structure and properties of diglyceride (DAG) oleogels (DAG as the oil phase) and triglyceride (TAG) oleogels (TAG as the oil phase) with different gelator concentrations of beeswax (BW) and monoacylglycerol (MAG). When BW was used as gelator, compared with TAG oleogels, the mass of β′ crystals in DAG-oil based oleogels increased, the crystal network stability improved, and the G′ increased. In addition, the DAG-oil based oleogels prepared with BW showed hydrogen bonds. When MAG was used as gelator, the G′, the thermal and crystal network stability of DAG-oil based oleogels decreased compared to TAG oleogels, and large number of crystal clusters were formed. In addition, DAG-oil based oleogels showed lower oxidative stability than TAG oleogels. These results contribute to a better understanding the properties of DAG oil based oleogels and facilitate the development of low-fat functional plastic products.

The structural, mechanical and chemical stability properties of HEG and YIG in response to α-irradiation

Ceramic materials with excellent radiation resistance stability play an indispensable role in the treatment of nuclear waste. This article uses spark plasma sintering (SPS) to synthesize high-entropy (HE) Y0.6Gd0.6Sm0.6Eu0.6Dy0.6Fe5O12 (HEG) and traditional garnet Y1.2Nd1.8Fe5O12 (YIG). Studied the effects of 2 MeV He2+ irradiation (1 × 1014 ions/cm2 - 1 × 1017 ions/cm2) on the crystal structure, mechanical properties, and chemical stability of ceramics. Research shows that the surface of YIG becomes completely amorphous under ∼30dpa irradiation. Under irradiation at∼30dpa, HEG underwent a small amount of amorphization (with an amorphization rate of 38 %), maintaining the structure of garnet, and the lattice expansion rate of HEG caused by irradiation was lower than that of YIG. After irradiation, the mechanical properties of HEG were improved, while YIG's hardness decreased due to its amorphous state. Radiation has almost no effect on the chemical stability of HEG, and its long-term release mechanism is dominated by diffusion. This study identified HEG as an ideal candidate substrate for immobilizing high-radioactive waste (HLW) the perspective of radiation resistance.

Metal atom doping with GeC: Tuning electronic, magnetic and electrocatalytic hydrogen evolution

The crystal structure stability, electronic and magnetic properties, field emission, and catalytic properties of the metal-doped GeC systems are investigated by the first principles. The Ef (formation energy) in the range of −5.713 to −14.240 eV indicates that the metal-doped GeC systems have energy stability. The Al-, Cr-, Fe-, Co-, Cu-, and Zn-doped GeC systems exhibit metallic properties, but the Ti-, V-, Mn-, and Ni-doped GeC systems retain semiconductor properties. Notably, the V-, Cr-, Mn-, Fe-, Co-, Cu-, and Zn-doped GeC systems exhibit magnetism due to doping effects. In addition, the Ti-, V-, Cr-, Mn-, Fe-, and Co-doped GeC systems have field emission properties relative to the intrinsic GeC due to the decrease of work function. Importantly, the low over-potential indicates that the doping systems have strong electro-catalytic hydrogen production ability. Therefore, the metal-doped GeC has potential applications in spintronic, field emission devices, and electro-catalytic hydrogen production.

X-ray crystallography derived diffraction properties of cuprite crystal as revealed by transmission electron microscopy

To produce high crystalline and unified cuprite nano single crystals from copper sulfate pentahydrate a unique bi-polarized methanol-water mixture reduces surface energy and enhances capping efficiency. Exhaustive significance lattice parameters, crystal volume, peak profiling, lattice constant, percent of crystallinity and crystal strain were analyzed by the whole powder pattern fitting (WFPP) Rietveld refinement method. A red shift at 636.0 nm in UV spectrophotometry is associated with a high surface plasmon effect and the zeta potential of 89.0 mV confirms the excellent stability of the cuprite crystal. Crystallographic data, d-spacing 0.25188 nm, lattice parameters a = b = c = 3.78 Å, α = β = γ = 90° of cuprite single crystal was further established by the selected area electron diffraction (SAED) in TEM. Energy dispersive spectroscopy (EDS) reveals the formation of the 100.0 % unified cuprite single crystal.

Tailoring Interface Energies via Phosphonic Acids to Grow and Stabilize Cubic FAPbI3 Deposited by Thermal Evaporation.

Coevaporation of formamidinium lead iodide (FAPbI3) is a promising route for the fabrication of highly efficient and scalable optoelectronic devices, such as perovskite solar cells. However, it poses experimental challenges in achieving stoichiometric FAPbI3 films with a cubic structure (α-FAPbI3). In this work, we show that undesired hexagonal phases of both PbI2 and FAPbI3 form during thermal evaporation, including the well-known 2H-FAPbI3, which are detrimental for optoelectronic performance. We demonstrate the growth of α-FAPbI3 at room temperature via thermal evaporation by depositing phosphonic acids (PAc) on substrates and subsequently coevaporating PbI2 and formamidinium iodide. We use density-functional theory to develop a theoretical model to understand the relative growth energetics of the α and 2H phases of FAPbI3 for different molecular interactions. Experiments and theory show that the presence of PAc molecules stabilizes the formation of α-FAPbI3 in thin films when excess molecules are available to migrate during growth. This migration of molecules facilitates the continued presence of adsorbed organic precursors at the free surface throughout the evaporation, which lowers the growth energy of the α-FAPbI3 phase. Our theoretical analyses of PAc molecule-molecule interactions show that ligands can form hydrogen bonding to reduce the migration rate of the molecules through the deposited film, limiting the effects on the crystal structure stabilization. Our results also show that the phase stabilization with molecules that migrate is long-lasting and resistant to moist air. These findings enable reliable formation and processing of α-FAPbI3 films via vapor deposition.

Order-disorder structural transition and thermal expansion properties in Ce-substituted Y2Zr2O7 system

In the pursuit of advancing inert matrix fuel (IMF) applications, zirconate pyrochlores have emerged as promising candidates for the incorporation of minor actinides and plutonium. This study employs CeO2 as a nonradioactive surrogate for PuO2 and focuses on the synthesis of cerium-substituted Y2Zr2O7 samples (Y2-xCexZr2O7, 0.0 ≤ x ≤ 2.0) through a solid-state route under both reducing and oxidizing conditions to mimic plutonium incorporation. The impact of cerium content and its valence state, which in turn is influenced by synthesis conditions, on crystal structure and phase stability has been investigated through X-ray diffraction and Raman spectroscopic studies. Samples synthesized under reduced conditions undergo a defect fluorite to pyrochlore phase transition through a biphasic mixture consisting of these two phases upon increasing Ce-substitution. Conversely, the high temperature oxidizing synthesis conditions yield a defect fluorite phase field over a wide composition range (0.0 ≤ x ≤ 1.6) and a tetragonal phase at x = 2.0. Intriguingly, pyrochlore-type phases obtained under reducing conditions transform into the metastable kappa-phases upon mild oxidation at a relatively low temperature (1073 K), as confirmed by Raman spectroscopic studies. A combination of thermo-gravimetric and Raman spectroscopic investigations confirms the complete reduction of Ce4+ to Ce3+ under reducing conditions. The lattice thermal expansion behavior has also been investigated for the defect fluorite phases, synthesized under oxidizing conditions, by means of high temperature XRD spanning the temperature range 298–1273 K. Notably, the thermal expansion of compositions exhibits an increasing trend with increasing cerium content.

Reflectivity and Angular Anisotropy of Liquid Crystal Microcapsules with Different Particle Sizes by Complex Coalescence.

Cholesteric liquid crystal microcapsules (CLCMs) are used to improve the stability of liquid crystals while ensuring their stimulus response performance and versatility, with representative applications such as sensing, anticounterfeiting, and smart fabrics. However, the reflectivity and angular anisotropy decrease because of the anchoring effect of the polymer shell matrix, and the influence of particle size on this has not been thoroughly studied. In this study, the effect of synthesis technology on microcapsule particle size was investigated using a complex coalescence method, and the effect of particle size on the reflectivity and angular anisotropy of CLCMs was investigated in detail. A particle size of approximately 66 µm with polyvinyl alcohol (PVA, 1:1) exhibited a relative reflectivity of 16.6% and a bandwidth of 20 nm, as well as a narrow particle size distribution of 22 µm. The thermosetting of microcapsules coated with PVA was adjusted and systematically investigated by controlling the mass ratio. The optimized mass ratio of microcapsules (66 µm) to PVA was 2:1, increasing the relative reflectivity from 16.6% (1:1) to 32.0% (2:1) because of both the higher CLCM content and the matching between the birefringence of the gelatin-arabic shell system and PVA. Furthermore, color based on Bragg reflections was observed in the CLCM-coated ortho-axis and blue-shifted off-axis, and this change was correlated with the CLCM particle size. Such materials are promising for anticounterfeiting and color-based applications with bright colors and angular anisotropy in reflection.