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Superconducting hybrid structures based on single nanowires are a new type of nanoscale devices with peculiar transport characteristics. Control over the nanowire structure is essential for understanding hybrid electronic phenomena arising in such complex systems. In this work, we report a technique for the fabrication of cobalt nanowires by template-assisted electrodeposition using iR compensation, which allows revealing the fundamental dependence of the preferred direction of nanowire growth on the deposition potential. Long coarse-grained cobalt nanowires with a diameter of 70 nm have been implemented into Nb/Co/Nb hybrid structures. We demonstrate that using electrode fabrication techniques that do not contaminate the surface of the nanowire leads to a high quality of devices with low-resistance interfaces. Low-temperature resistivity of 4.94 ± 0.83 µ Ω cm and other transport characteristics of Co nanowires are reported. The absence of long-range superconducting proximity effect for Nb/Co/Nb systems with different nanowire length is discussed. [ABSTRACT FROM AUTHOR]

During drug discovery, it is crucial to exclude compounds with toxic effects. The human ether-à-go-go-related gene (hERG) channel is essential for maintaining cardiac repolarization and is a critical target in drug safety evaluation due to its role in drug-induced arrhythmias. Inhibition of the hERG channel can lead to severe cardiac issues, including Torsades de Pointes tachycardia. Understanding hERG inhibition mechanisms is essential to avoid these toxicities. Several structural studies have elucidated the interactions between inhibitors and hERG. However, orientation and resolution issues have so far limited detailed insights. Here, we used digitonin to analyze the apo state of hERG, which resolved orientation issues and improved the resolution. We determined the structure of hERG bound to astemizole, showing a clear map in the pore pathway. Using this strategy, we also analyzed the binding modes of E-4031 and pimozide. These insights into inhibitor interactions with hERG may aid safer drug design and enhance cardiac safety. [Display omitted] • Binding modes of hERG inhibitors were revealed with higher resolution cryo-EM data • Preferred particle orientation issues of cryo-EM data were resolved by using digitonin • The binding modes of hERG to astemizole, E-4031, and pimozide were determined • This study provides insights into hERG-inhibitor interactions for safer drug design Miyashita et al. overcame preferred orientation issue and they obtained improved cryo-EM data, which enabled them to elucidate the binding mechanisms of the hERG inhibitors astemizole, E-4031, and pimozide. These structural data are of interest to guide safer drug design and avoid drug-induced arrhythmias. [ABSTRACT FROM AUTHOR]

The poor anode/electrolyte interface triggered by abysmal dendritic growth and hydrogen evolution reactions (HER) hinders the development of aqueous zinc‐ion batteries (AZIBs). Here, a highly efficient electrolyte is formulated with sucralose (Sucral) additive to refresh solvated structure and steer interfacial renovation, for building highly electronegative Cl‐modulated trinity effect in the bulk‐interface between electrolyte and electrode. Experiment results and theoretical studies jointly reveal that Sucral with highly zincophilic and hydrophilic hydroxyl groups can remodel primary Zn2+ solvation shell and interrupt strong H‐bond network from H2O molecules, thus boosting fast de‐solvation and restricting undesirable HER. Simultaneously, three highly electronegative chlorides in the adsorbed Sucral possessing hydrophobic features can enable a H2O‐poor electric double‐layer (EDL), thus remodeling the Zn surface against corrosion. Additionally, it realizes preferential exposure of the Zn (002) plane for helping uniform interfacial deposition. The synergy of the above factors achieves a prolonged lifespan of 3000 h (1.0 mA cm−2, 1.0 mAh cm−2), much better than that with Sucrose (Suc) electrolyte. The Zn//V2O5 full cell at 5 A g−1 also maintains enhanced stability of 1500 cycles with 160 mAh g−1. [ABSTRACT FROM AUTHOR]

This study explores the synthesis and characterization of ZnO particles with varying morphologies—triangular, spherical, and urchin‐like—that were produced through a simple, solvothermal process. The morphology, surface area, and photocatalytic performance of the ZnO particles could be customized by meticulously regulating the synthesis parameters, particularly the temperature and solvent. The findings indicated that all samples crystallized as pure wurtzite ZnO with a uniform crystallite size of 34.7 ± 1.8 nm and energy band gap of 3.29 eV. The spherical E‐200 particles, which exhibit the highest photocatalytic efficiency, achieved an average of 25.27 ± 5.88% methylene blue (MB) degradation after 24 h. These particles were distinguished by a significant surface area of 30.56 m2/g and an average pore size of 45 nm. Furthermore, all ZnO samples exhibited a significant adsorption capacity (≤ 20%) for MB under dark condition, underscoring their potential as effective adsorbents for environmental pollutants. These results emphasize the significance of precise synthesis and morphology control in the optimization of functional properties of ZnO for environmental remediation applications. [ABSTRACT FROM AUTHOR]

The primary goal of this research outline is the conversion of titanium isopropoxide (TTIP) at 50.0 °C to form a high crystalline preferred oriented predominant (101) with a low crystal strain of 90.0 % anatase-TiO2 phase. With the interval of time, the peptizing agent (IP) reacts to an acidic aqueous medium and preferential growth of anatase-TiO2 has been identified. Exhaustive recombination in X-ray diffraction (XRD) analysis ensures the crystal strain, lattice volume, lattice parameters, d-spacing and crystallite size. UV–vis-NIR showed maximum absorption of 320.0 nm with 0.78 a.u. at blue shift for decreasing nano-size and smaller bandgap 3.0313 eV of larger dimensions anatase-TiO2. The preferred orientation also revealed by nanobeam diffraction (NBD) of TEM enables qualitative lattice type and highly crystal orientated predominant (101) plane 5.60 nm−1 in a diffraction pattern imposed on 200.0 kv parallel electron bean from LaB6 filament.

2D perovskites are demonstrated as the growth template for the modulation of phase transition and crystallization of formamidinium lead triiodide (FAPbI3). However, it is challenging to obtain highly oriented α‐FAPbI3 and regulate crystallization at the bottom of the FAPbI3 film. Here, a 2D (BA)2PbI4 layer with preferred orientation is introduced to perform as the bottom template for the quasi‐epitaxial growth of FAPbI3, which triggers the α‐FAPbI3 perovskite formation. Owing to the assembly of [PbI6]4− octahedral on the 2D template, the highly (100) oriented FAPbI3 perovskites from the bottom to the top are attained. At the optimum concentration, 2D perovskites gradually vanish due to the extrusion of BA+ cation from the template, which guarantees the charge transport at the bottom. Consequently, the strategy effectively promotes film quality and suppresses non‐radiative recombination. The efficiency of perovskite solar cells (PSCs) is promoted from 23.06% to 24.78%. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries hold promise as alternative systems to lithium‐based batteries. However, practical development faces critical challenges due to parasitic side reactions and dendrite growth in zinc anodes. While introducing electrolyte additives is promising, monofunctional additives offer limited protection to the zinc anode from a single aspect. Herein, a disodium succinate additive is presented to establish a hydrophobic and zincophilic dual electric layer structure on the Zn surface, regulate the solvation structure of Zn2+, and act as a pH buffer during cycling. As a result, the symmetrical cell with an electrolyte containing 0.2 m SADS shows a durable life of over 2200 h, and the Zn||MnO2 full cell still maintains an 80% capacity retention after 1000 cycles. In addition, SADS both show wide applicability in the match with NVO and I2 cathode. This work provides a low‐cost and multifunctional electrolyte additive, facilitating the development of high‐performance aqueous zinc ion batteries. [ABSTRACT FROM AUTHOR]

Based on the theory of crystal anisotropy, it is proposed to improve electrical and optical performance by adjusting the orientation growth of Al-doped ZnO thin films. AZO thin films with preferred (002) and (103) orientation were deposited by stress regulation in the magnetic control sputtering system. The electrical and optical performance for (002) and (103) preferred thin films with identical texture strength and film thickness were analysed in detail. Compared to the conventional (002) preferred AZO thin films, (103) preferentially oriented AZO films exhibit lowering 34.2 % resistivity at the cost of reducing 2.1 % visible light transmittance. XPS fitting analysis of the O1s peak reveals that differences in oxygen vacancy concentration between the two orientations are primarily responsible for variations in electrical properties. It's a promising method by adjusting the orientation growth to improve electrical and optical performance of AZO thin films. [ABSTRACT FROM AUTHOR]

Bidirectional analyses covering a range of incidence angles for several records are essential yet challenging for routine design. Recent studies have shown that the response to bidirectional shaking may be estimated per straightforward unidirectional analysis in the most preferred orientation in conjunction with suitable combination rules, and this can also eliminate the need for various incidence angles. Further, it is well known that the mean response can be estimated with reduced dispersion using fewer spectrum-compatible records. The present investigation aims to combine the advantages of (1) the most preferred orientation; and (2) spectral matching within the context of bidirectional excitation. To this end, with the motivation derived from the Newmark's sliding block theory, a pair of interrelated spectra directly connected to the most preferred orientation is proposed. Since the concept of these spectra is introduced for the first time, to our best knowledge, the mathematical basis of is discussed in rigor. The spectra are then illustrated and compared to other existing alternatives such as GMRotDpp, GMRotIpp, RotDpp, and MaxRotD50. The spectra evolved herein are orientation and period independent, implicitly account for directionality, and bear a clear physical meaning, which was obscured in earlier options. The proposed spectra are interpreted in the context of energy-based design and can be conveniently expressed in both force-based and displacement-based design formats. The proposed spectra help spectrally match two horizontal components independently and can specify bidirectional seismic loading. Response statistics of a simple multistory building demonstrate that, by using fewer spectrum-compatible records, the seismic demand can be estimated with reduced dispersion per bidirectional analyses as well as by unidirectional analyses. [ABSTRACT FROM AUTHOR]

In antiferroelectrics (AFE), the recovery of AFE phase from field‐induced ferroelectric (FEIN) phase occurs at the depolarization temperature, Td. In this study, we report an exceptionally high pyroelectric coefficient, p ≈ 16.00 × 10−2 C/m2 K at ∼70°C in the AFE composition Pb0.982La0.012(Zr0.60Sn0.30Ti0.10)O3 which lies close to FE‐AFE phase boundary. We closely examine this FEIN‐AFE transformation in virgin and poled samples, during heating, by temperature‐dependent X‐ray diffraction, polarization, strain–electric field hysteresis, dielectric and pyroelectric studies and report, for the first time, the mechanism responsible for this behavior. [ABSTRACT FROM AUTHOR]

The plasma-transferred arc technology has been observed to induce preferential grain orientation in multiple directions, leading to nonuniform grain growth within the alloy coating material. The addition of nano-oxides can act as heterogeneous nucleation sites, reducing the preferred orientation of grains. In this study, a low-speed mixing method was employed to coat highly dispersed CeO2 nanorods (CNRs) onto the surface of 14Cr2NiSiVMn alloy powder particles. The aim was to analyze the influence of dispersed CNRs on grain growth orientation in different directions and the refinement and heterogeneous nucleation effect of CNR additives. The addition of 0.5 wt.% CNRs resulted in the refinement of dendritic grains along both the perpendicular and parallel directions to the coating cladding direction, leading to the formation of more uniform equiaxed crystals. The combination of Ce with Si and V elements formed submicron particles, which promoted grain nucleation and reduced defects in the coating. Consequently, the mechanical performance of the sample significantly improved. In the deposition direction, there was a notable improvement in microhardness (20.4%), tensile strength (97.6%), and elongation (59.0%). In the perpendicular deposition direction, the tensile strength increased by 88.1%, and the elongation increased by 33.9%. Additionally, the weight loss due to wear decreased by 44.2%, and the relative wear resistance improved by 79.3%. [ABSTRACT FROM AUTHOR]

The control of diamond film growth is crucial for the application of diamond films. In this article, different diamond film samples were prepared by adding nitrogen and oxygen in different proportions during the growth process. The key conditions for controlling the growth of diamond film with preferred orientation were obtained using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy characterizations. During the growth process, the growth of the diamond film with (100) preferred orientation could be achieved by adjusting nitrogen content. It was necessary to introduce nitrogen and oxygen in the growth process, and precisely regulate the ratio of the two to obtain the (111) preferred orientation of the diamond film. When only oxygen was introduced during growth, the preferred orientation of the diamond could not be achieved, leading to a smaller grain size and poorer crystal quality. From the perspective of grain morphology to film morphology evolution, this study obtained the crystal orientation control conditions during the diamond film growth, which has important guiding significance for the application of the diamond film. This study seeks to drive progress in the large-scale growth of readily machinable diamond and the evolution of diamond-grain optical fiber sensing through comprehensive investigations into the correlation between the preferred orientation in polycrystalline diamonds and reaction conditions.

Introducing chirality into organic/inorganic hybrid materials can impart chiroptical properties such as circular dichroism. The ability to tune chiroptical properties in self‐assembled materials can have important implications for spintronic and optoelectronic applications. Here, a chiral organic cation, (R/S)‐4‐methoxy‐α‐methylbenzylammonium, is incorporated to synthesize the bismuth‐based hybrid organic–inorganic metal halide semiconductor, (R/S‐MeOMePMA)BiI4. Thin films of this Bi‐based compound demonstrate large chiroptical responses, with circular dichroism anisotropy (gCD) values up to ≈0.1, close to the highest value observed in another chiral metal‐halide semiconductor, (R‐MBA2CuCl4). Detailed investigation reveals that this large gCD in (R/S‐MeOMePMA)BiI4 is caused by the apparent CD effect. Careful selection of deposition conditions and the concomitant thin‐film orientation enables the control of gCD, with maximum value observed when its thin film has a well‐crystallized preferred (001) orientation parallel to the substrate. The results support a growing body of evidence that low symmetry plays an important role in achieving unusually large gCD in these chiral metal–halide materials and provides design rules for achieving large chiroptical response via morphology control. [ABSTRACT FROM AUTHOR]

In the presence of a newly created brightener, the zinc metal is coated on steel using the electro deposition process. Experiments using hull cells are used to optimize the settings and components of plating baths. Tafel Polarization and EIS techniques were used to conduct corrosion experiments, which made it possible to investigate the brilliant zinc coating's effective corrosion resistance. SEM and Reflectance spectroscopy both confirm that the bright zinc coating has modified surface morphology. XRD analysis is used to study and validate changes in crystallite orientation and phase structure. Electrochemical methods and theoretical molecular dynamic (MD) simulations were used to examine the interaction between Zn and the metal surface. FTIR spectroscopy has been used in blend investigations which impacts on the physical characteristics of polymer blends. The results of these research showed how novel brighteners can improve zinc deposits' brightness and corrosion resistance when applied to mild steel substrates.

AlN films are prepared by reactive magnetron sputtering at a floating potential and at the bias –15 V on the substrate. It is found that ion-assisted deposition facilitates the formation of fiber texture AlN (104). This result can be explained by generation of compressive stress in films due to ion bombardment and preferred orientation (104) is favored for stressed films minimizing the elastic strain energy. Ion-assisted deposition provides dense and large-grained structure of AlN films due to high adatom mobility. [ABSTRACT FROM AUTHOR]

In this experiment, Ti-44Al-9Nb-1Cr-0.2W-0.2Y alloy was prepared by the directional solidification method. The effect of different growth rates on tensile properties and microstructure orientation at high temperature was studied. Three kinds of alloys with different growth rates of 10 μm/s, 15 μm/s and 20 μm/s were prepared. The results show that the tensile properties of the alloy at 800 ℃ decrease with increasing growth rate, and recrystallization occurred at the position of intracrystal fracture in the microstructure. The size of columnar crystals decreases with the increase of the growth rate, increasing the number of grains and decreasing the orientation difference between the growth and axial directions as well as the preferred orientation of lamellar, and the anisotropy of the material, which leads to the obvious decrease of the tensile strength and plasticity. Combined with electron backscattering diffraction test results, the lamellar orientation of the effective parts of the three specimens after high temperature stretching was studied. It was found that the axial preferred orientation of the alloy specimens decreased obviously with the increase of the growth rate, and the orientation became disorderly and the uniformity of lamellar thickness decreased gradually with the increase of the growth rate. In addition, it was found that a new single-phase γ phase is formed in the microstructure after high temperature stretching, and the distribution range increased with the increase of the growth rate, which seriously degraded the axial preferred orientation of the alloy. It can be concluded that the directionally solidified alloy with a growth rate of 10 μm/s has better microstructure orientation and high temperature tensile properties.

Aqueous zinc‐ion batteries have been identified as a viable option for grid energy storage. However, their practical application is limited by the poor performances at a high use rate of zinc. A suitable strategy to improve the cycling stability at a high depth of discharge (DOD) is by realizing the (002)‐textured Zn plating to suppress dendrite growth and side reactions. Herein, a novel electrolyte additive sodium 3‐mercapto‐1‐propanesulfonate (MPS) is introduced to regulate the zinc/electrolyte interfacial structure. The MPS anions can form an adsorption layer on the anode surface, which induces Zn deposition in the (002) direction as indicated by first‐principles calculations. Additionally, the adsorption layer can facilitate the reduction of the energy barrier associated with zinc deposition. This modified interface effectively inhibits dendrite and side reactions, resulting in a remarkable cycling lifespan for Zn||Zn symmetric cells, exceeding 800 h at a high DOD of 50%, and over 4500 h at 1.0 mA cm−2/1.0 mAh cm−2. Moreover, the capacity stability of the full cells with V2O5·H2O or polyaniline cathodes is substantially improved. A pouch‐type Zn||V2O5·H2O full cell reveals a high capacity of 42 mAh and good capacity retention of 86.6% after 250 cycles, highlighting significant potential for practical applications. [ABSTRACT FROM AUTHOR]

In this work, α‐Fe2O3 photoanode consisted of (110)‐oriented α‐Fe2O3 single crystals were synthesized by a facile hydrothermal method. By using particular additive (C4MimBF4) and regulation of hydrothermal reaction time, the Fe‐25 consisted of a single‐layer of highly crystalline (110)‐oriented crystals with fewer grain boundaries, which was vertically grown on the substrate. As a result, the charge separation efficiency and photoelectrochemical (PEC) performance of Fe‐25A (Fe‐25 after dehydration treatment) have been greatly improved. Fe‐25A yields a photocurrent of 1.34 mA cm−2 (1.23 V vs RHE) and an incident photon‐to‐current conversion efficiency (IPCE) of 31.95 % (380 nm). With the assistance of cobalt–phosphate water oxidation catalyst (Co−Pi), the PEC performance could be further improved by enhancing the holes transfer at electrode/electrolyte interface and inhibiting surface recombination. Fe‐25A/Co−Pi yields a photocurrent of 2.67 mA cm−2 (1.23 V vs RHE) and IPCE value of 50.8 % (380 nm), which is 3.67 times and 2.39 times as that of Fe‐2A/Co−Pi. Our work provides a simple method to fabricate highly efficient Fe2O3 photoanodes consist of characteristic (110)‐oriented single crystals with high crystallinity and high quality interface contact to enhance charge separation efficiencies. [ABSTRACT FROM AUTHOR]

Materials with oriented structures exhibit excellent mechanical, electrical, and tribological properties. In this study, WS 2 films with a preferred orientation along the (002) plane were prepared using shear flow technology, and the influence of polyvinyl alcohol (PVA) concentration and wedge angle on the oriented structure of the WS 2 films was systematically studied. The results indicated that the diffraction peak intensity ratio of the (002) and (103) planes of the WS 2 films (I (002) /I (103)), increased from 46.68 to 116.11 when the PVA concentration increased from 5 to 25 g/L. When the wedge angle increased from 5° to 40°, I (002) /I (103) showed a similar trend, increasing from 80.99 to 347.22. Thus, the higher I (002) /I (103) value confirmed a preferred (002) plane orientation of WS 2 in the films, indicating that an increase in PVA concentration and wedge angle significantly enhanced the shear stress of the slurry. Under shear stress, the WS 2 particles had a tendency to orient along the shear stress direction, forming a preferred (002) plane-oriented structure. Therefore, this research may provide theoretical and technical support for preparing preferred orientation 2D materials. [ABSTRACT FROM AUTHOR]

Cr coatings were deposited on the Zircaloy‐4 alloy by multi‐arc ion plating under different bias voltages from −50 to −110 V, and the microstructure, mechanical properties, and high‐temperature steam oxidation behavior of these coatings were systematically investigated. The results indicate that the bias voltage significantly affects the crystal orientation, surface morphology, deposition rate, nanohardness, and bonding strength of Cr coating on the Zircaloy‐4 alloy. The high‐temperature oxidation behavior of the Cr coating is closely related to its crystallographic orientation. Compared with the Cr coating with relatively random grain orientations, the Cr coating with (211) preferred orientation has a dense and uniform oxide scale and has the best oxidation resistance in the steam environment at 1200°C. [ABSTRACT FROM AUTHOR]

Layered silicon nanosheets (SiNSs) have attracted considerable attention owing to their unique combination of chemical and physical properties, which makes them an exciting candidate for next-generation on-chip light sources and lasers. Despite over 150 years of research on SiNSs, the effects of the CaSi2 precursor quality on SiNSs have not been studied. Here, we report a comparison of CaSi2 (and SiNSs derived therefrom) synthesized from two reaction pathways: (1) melting Ca and Si (elemental melting, or EM-CaSi2) and (2) the less-explored reaction between CaH2 and Si (hydride synthesis, or HS-CaSi2). We demonstrate that both reaction pathways lead to CaSi2, but the HS-CaSi2 pathway requires only a single step without the need to melt the CaSi2 product and at a temperature below the peritectic decomposition of CaSi2. We find that the EM-CaSi2 exhibits grains that lay flat against the substrate, whereas the HS-CaSi2 has little preferred orientation. We deintercalated both EM- and HS-CaSi2 with HCl at −35 °C to yield hydrogen-terminated SiNSs. We characterized the SiNSs and found that the HS-SiNSs and EM-SiNSs exhibit properties that are nearly identical, with the exception that the morphology of the precursor is imparted to the SiNSs. These results provide the community with a one-step method to synthesize CaSi2 and demonstrate that the morphology of CaSi2 and SiNSs can be controlled with different synthetic techniques. [ABSTRACT FROM AUTHOR]

Least-squares analysis on the diffraction intensity values certified for NIST SRM676a and SRM1976c α -Al2O3 (corundum) have shown that the intensities of SRM1976c can be simulated by the March-Dollase preferred orientation model along the (001)-direction. Diffraction intensities of randomly oriented corundum crystallites have been calculated from electron density data obtained by conventional and density functional theory (DFT) calculations, on the assumption of independent and similar atomic displacements for Al and O atoms. The results of DFT calculations support that the strongest peak of randomly oriented α -Al2O3 crystalline powder should be 113-reflection, though the intensities simulated by DFT calculations are not closer to NIST SRM676a intensities than those expected for a fully ionized model ${\rm Al}_2^{3 + } {\rm O}_3^{2-}$. Diffraction data of two types of relatively fine (nominally 2–3 μm and ca 0.3 μm) α -Al2O3 powder have been collected and processed by a deconvolutional treatment (DCT). Integrated peak intensities extracted from the DCT data by an individual peak profile fitting method also support that the 113-reflection is the strongest reflection of randomly oriented α -Al2O3 crystalline powder. [ABSTRACT FROM AUTHOR]

Abstract Preferred orientation in polycrystalline materials is one of the most challenging problems for structural analysis. Significant preferred orientation can severely affect the structure‐property analysis of the systems having substantial crystallographic anisotropy. Here, an extremely high degree of preferred orientation has been demonstrated in R‐block hollandite hexagonal PbFexV6−xO11 compounds, which has recently been shown to exhibit an unusual colossal electroresistance response that has a strong dependence on structural modifications. The present results warn against possible errors in understanding the evolution of the crystal structure of these hollandites, which might adversely affect the estimation of the influence of the same on their spectacular physical properties.

Crystallization kinetic controls the crystallographic orientation, inducing anisotropic properties of the materials. As a result, preferential orientation with advanced optoelectronic properties can enhance the photovoltaic devices' performance. Although incorporation of additives is one of the most studied methods to stabilize the photoactive α‐phase of formamidinium lead tri‐iodide (α‐FAPbI3), no studies focus on how the additives affect the crystallization kinetics. Along with the role of methylammonium chloride (MACl) as a "stabilizer" in the formation of α‐FAPbI3, herein, the additional role as a "controller" in the crystallization kinetics is pointed out. With microscopic observations, for example, electron backscatter diffraction and selected area electron diffraction, it is examined that higher concentration of MACl induces slower crystallization kinetics, resulting in larger grain size and [100] preferred orientation. Optoelectronic properties of [100] preferentially oriented grains with less non‐radiative recombination, a longer lifetime of charge carriers, and lower photocurrent deviations in between each grain induce higher short‐circuit current density (Jsc) and fill factor. Resulting MACl40 mol% attains the highest power conversion efficiency (PCE) of 24.1%. The results provide observations of a direct correlation between the crystallographic orientation and device performance as it highlights the importance of crystallization kinetics resulting in desirable microstructures for device engineering. [ABSTRACT FROM AUTHOR]

Realizing durative flattened and dendrite‐free zinc (Zn) metal configuration is the key to resolving premature battery failure caused by the internal short circuit, which is highly determined by the crystal growth in the electrocrystallization process. Herein, we report that regulating the molecular structure of the inner Helmholtz plane (HIP) can effectively convert the deposition into activation control by weakening the solvated ion adsorption at the interface. The moderated electrochemical reaction kinetics lower than the adatom self‐diffusion rate steers conformal stratiform Zn growth and dominant Zn (0001) texture, achieving crystallographic optimization. Through in situ mediation of electrolyte engineering, orientational plating and stripping behaviors at edge‐sites and tailored solvation structure immensely improve the utilization efficiency and total charge passed of Zn metal, even under extreme conditions, including high areal capacity (3 mAh cm−2) and wide temperature range (−40–60 °C). [ABSTRACT FROM AUTHOR]

Comprehensive information on in situ microstructural and crystallographic changes during the preparation/manufacturing processes of various materials is highly necessary to precisely control the microstructural morphology and the preferred orientation (or texture) characteristics for achieving an excellent strength–ductility–toughness balance in advanced engineering materials. In this study, in situ isothermal annealing experiments with cold-rolled 17Ni-0.2C (mass%) martensitic steel sheets were carried out by using the TAKUMI and ENGIN-X time-of-flight neutron diffractometers. The inverse pole figures based on full-profile refinement were extracted to roughly evaluate the preferred orientation features along three principal sample directions of the investigated steel sheets, using the General Structure Analysis System (GSAS) software with built-in generalized spherical harmonic functions. The consistent rolling direction (RD) inverse pole figures from TAKUMI and ENGIN-X confirmed that the time-of-flight neutron diffraction has high repeatability and statistical reliability, revealing that the principal preferred orientation evaluation of steel materials can be realized through 90° TD ➜ ND (transverse direction ➜ normal direction) rotation of the investigated specimen on the sample stage during two neutron diffraction experiments. Moreover, these RD, TD, and ND inverse pole figures before and after the in situ experiments were compared with the corresponding inverse pole figures recalculated from the MUSASI-L complete pole figure measurement and the HIPPO in situ microstructure evaluation, respectively. The similar orientation distribution characteristics suggested that the principal preferred orientation evaluation method can be applied to the in situ microstructural evolution of bulk orthorhombic materials and spatially resolved principal preferred orientation mappings of large engineering structure parts.

Abstract Crystallization kinetic controls the crystallographic orientation, inducing anisotropic properties of the materials. As a result, preferential orientation with advanced optoelectronic properties can enhance the photovoltaic devices' performance. Although incorporation of additives is one of the most studied methods to stabilize the photoactive α‐phase of formamidinium lead tri‐iodide (α‐FAPbI3), no studies focus on how the additives affect the crystallization kinetics. Along with the role of methylammonium chloride (MACl) as a “stabilizer” in the formation of α‐FAPbI3, herein, the additional role as a “controller” in the crystallization kinetics is pointed out. With microscopic observations, for example, electron backscatter diffraction and selected area electron diffraction, it is examined that higher concentration of MACl induces slower crystallization kinetics, resulting in larger grain size and [100] preferred orientation. Optoelectronic properties of [100] preferentially oriented grains with less non‐radiative recombination, a longer lifetime of charge carriers, and lower photocurrent deviations in between each grain induce higher short‐circuit current density (Jsc) and fill factor. Resulting MACl40 mol% attains the highest power conversion efficiency (PCE) of 24.1%. The results provide observations of a direct correlation between the crystallographic orientation and device performance as it highlights the importance of crystallization kinetics resulting in desirable microstructures for device engineering.

The native amorphous silicon oxide (SiO2) layer formed on the Si substrate leads to the (100) preferred orientation for β-phase gallium oxide (β-Ga2O3), which encounters various defects in β-Ga2O3, such as twin boundaries and stacking faults etc. The (111) preferred orientation of titanium nitride (TiN) hetero-buffer layer can be used in the interface between β-Ga2O3 and Si substrates to reduce the lattice mismatch between them and increase the (˗201) preferred orientation for β-Ga2O3. The lattice mismatch between TiN (111) and β-Ga2O3 (˗201) is 0.76%, which is less than the β-Ga2O3 (˗201)/Si (111) about ˗6.3%. The β-Ga2O3 and TiN films were grown using radio-frequency magnetron sputtering on Si substrates, which possess polycrystalline nature as revealed using X-ray diffraction patterns and high-resolution transmission electron micrographs. The optimal parameters are found as, process atmosphere: Ar = 10 sccm, RTA: 800 °C for β-Ga2O3/TiN (300 nm)/Si. This work highlights the effect of the TiN hetero-buffer layer, the process atmosphere, and annealing temperatures on the microstructural and surface morphology of β-Ga2O3 films. The lateral Schottky barrier diode (SBD) were fabricated using the optimized β-Ga2O3/TiN (300 nm)/Si film. The Baliga's Figure of Merit (BFOM) of the lateral SBD is 7.60 × 10−2 kW/cm2, which exhibits 4 order of BFOM higher than that of β-Ga2O3/Si SBD due to interface engineering. The β-Ga2O3/TiN (300 nm)/Si hetero-structure demonstrates a promising material to be employed in the next generation β-Ga2O3 based power devices.

Thermoelectric refrigeration is one of the mature techniques used for cooling applications, with the great advantage of miniaturization over traditional compression refrigeration. Due to the anisotropic thermoelectric properties of n‐type bismuth telluride (Bi2Te3) alloys, these two common methods, including the liquid phase hot deformation (LPHD) and traditional hot forging (HF) methods, are of considerable importance for texture engineering to enhance performance. However, their effects on thermoelectric and mechanical properties are still controversial and not clear yet. Moreover, there has been little documentation of mechanical properties related to micro‐refrigeration applications. In this work, the above‐mentioned methods are separately employed to control the macroscopic grain orientation for bulk n‐type Bi2Te3 samples. The HF method enabled the stabilization of both composition and carrier concentration, therefore yielding a higher quality factor to compare with that of LPHD samples, supported by DFT calculations. In addition to superior thermoelectric performance, the HF sample also exhibited robust mechanical properties due to the presence of nano‐scale distortion and dense dislocation, which is the prerequisite for realizing ultra‐precision machining. This work helps to pave the way for the utilization of n‐type Bi2Te3 for commercial micro‐refrigeration applications. [ABSTRACT FROM AUTHOR]

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Due to the environmental friendliness, cost-effectiveness and inherent safety, rechargeable aqueous zinc ion batteries have attracted much interest as a promising energy storage device. VO2 is one of the most common materials for rechargeable zinc ion batteries. The insertion/extraction of zinc ions within VO2 is highly anisotropic, with different channel sizes along different axes. Therefore, it is quite important to control the orientation of VO2 crystals so as to manipulate the transportation of Zn2+ ions more effectively and sufficiently. Herein, a novel intercalation-type two-dimensional VO2 nanosheet with preferred orientation (PO-VO2) of the c-axis was prepared. Benefitting from the structural merits, the PO-VO2 nanosheets demonstrate an attractive capacity of 511.6 mAh g−1 at a current density of 0.05 A g−1 in a voltage of 0.2–1.6 V, which is obviously better than that of many vanadium oxide-based cathodes reported until now. The PO-VO2//Zn aqueous zinc ion full cell exhibits a high energy density of 290.5 Wh kg−1 at a power density of 38.4 W kg−1 (based on the mass of the VO2 cathode electrode). The outstanding energy storage behavior, together with the facile and affordable synthesis route, endows the PO-VO2 nanosheets with promising applications for aqueous zinc ion batteries. [ABSTRACT FROM AUTHOR]

For thermoelectric thin film, the substrate plays an important role during the growing process and produces effects on its thermoelectric properties. Some special kinds of substrates provide an optimal combination of influences on both the structure and thermoelectric properties. In this work, Bi-Sb-Te films are deposited on Si substrates with different initial orientations by magnetron sputtering in two ways: with and without a pre-coating process. The preferred orientations of the Bi-Sb-Te films are greatly affected by the substrates, in which the thin film tends to deposit on Si substrate with (100) initial orientation and high (015)-texture, while the (00l)-textured Bi-Sb-Te film easily deposits on Si substrate with (110) initial orientation. The experimental and theoretical calculation results indicate that Bi-Sb-Te film with (00l)-texture presents good electrical conductivity and a higher power factor than that of film with (015)-texture. [ABSTRACT FROM AUTHOR]

In the application of a solar cell and photocatalytic system, anodized titanium dioxide nanotube arrays (TNTs) have one-dimensional highly ordered nanotube structure, so they have attracted much attention. In order to form ordered TNTs, many factors, such as voltage, anodizing time, solvent type, and so on, need to be controlled. However, these factors have mainly focused on the effect of external conditions, while the effect of internal factors such as the crystal structure of the titanium substrate on the growth of nanotubes have been less investigated. In this paper, the titanium substrate tissue structure with a (002) preferred orientation was obtained by a rolling treatment. On this basis, TNTs with highly ordered structure were constructed, and the effect of the titanium substrate structure on the nanotube growth morphology was investigated. The changes in morphology were characterized by scanning electron microscopy, and the relationship between the changes in the crystal structure and morphology of TNTs was systematically analyzed by combining metallographic structure and X-ray diffraction data. The changes in the electrochemical behavior of the titanium substrates after rolling were examined through electrochemical methods. The above results show that there are a large number of dislocations and microscopic internal stresses in the grain structure of the titanium substrate after rolling, which leads to improvement of the corrosion resistance of the materials. The changes in the microstructure of these materials make the nanotube arrays have highly ordered structure and better photoelectrochemical properties, which provides an idea for improving their applications in photoelectrochemistry. [ABSTRACT FROM AUTHOR]

The main objective of this work was to assess and compare the structure and mechanical properties of the TiN and TiAlN coatings deposited on a new WC-Co tool using the cathodic arc evaporation vacuum deposition (CAE-PVD) technique. The cutting tool was sintered at high temperature and high pressure using a powder tungsten carbide matrix ligated with cobalt (WC-Co). Powdered grain growth inhibitors (TiC, TaC, and NbC) were admixed into the matrix to enhance its strength and to facilitate the adhesion of the Ti base coatings. Detailed scanning electron microscopy with energy-dispersive spectrometry (SEM-EDS) and X-ray diffraction (XRD) analyses were performed, aiming to substantiate the effectiveness of the inhibitor additions. XRD data were thoroughly exploited to estimate the phase contents, average crystallite sizes (D), coating thicknesses (t), texture coefficients (Thkl), and residual stress levels (σ). Atomic force microscopy (AFM) was used to calculate the average roughness (Ra) and the root mean square (Rq). The microhardness (µHV) was measured using the Vickers method. The TiAlN characteristics (D = 55 nm, t = 3.6 μm, T200 = 1.55, µHV = 3187; σ = −2.8 GPa, Ra = 209 nm, Rq = 268 nm) compared to TiN ones (D = 66 nm, t = 4.3 μm, T111 = 1.52, µHV = 2174; σ = +2.2 GPa, Ra = 246 nm, Rq = 309 nm) substantiate the better adequacy of the TiAlN coating for the WC-Co substrate. The structural features and data on the TiN and TiAlN coatings, the tool type, the different stress kinds exerted into these coatings, and the way of discrimination of the coating adequacy are the novelties addressed in the paper. [ABSTRACT FROM AUTHOR]

Intensity-correlation measurements allow access to nanostructural information on a range of ordered and disordered materials beyond traditional pair-correlation methods. In real space, this information can be expressed in terms of a pair-angle distribution function (PADF) which encodes three- and four-body distances and angles. To date, correlation-based techniques have not been applied to the analysis of microstructural effects, such as preferred orientation, which are typically investigated by texture analysis. Preferred orientation is regarded as a potential source of error in intensity-correlation experiments and complicates interpretation of the results. Here, the theory of preferred orientation in intensity-correlation techniques is developed, connecting it to the established theory of texture analysis. The preferred-orientation effect is found to scale with the number of crystalline domains in the beam, surpassing the nanostructural signal when the number of domains becomes large. Experimental demonstrations are presented of the orientation-dominant and nanostructure-dominant cases using PADF analysis. The results show that even minor deviations from uniform orientation produce the strongest angular correlation signals when the number of crystalline domains in the beam is large.

BackgroundTitanium and its alloys are widely utilized within the military, aerospace, shipping, nuclear energy, and biomedical fields because of the advantages of low density, high strength, good corrosion resistance, and high biocompatibility. Moreover, titanium films are important materials for surface protection due to their high hardness and good compactness. During the preparation of titanium films, the surface morphology and phase structure will be influenced by substrate properties (e.g., surface morphology and temperature), working gas pressure, and other factors. Substrate temperature mainly influences the growth process of thin films, which directly affects the grain structure of the films, and thus changes the corresponding mechanical properties.PurposeThis study aims to establish the relationship between substrate temperature and mechanical properties of titanium films.MethodsFirstly, titanium film samples were prepared at a substrate temperature range of 600~750 ℃ by using resistance evaporation coating on the surface of molybdenum substrate. Then, the structural characterization of the film was examined using X-ray diffraction (XRD) so as to obtain the preferred orientation of titanium film. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to identify the surface morphologies of the titanium films, including grain size distribution and surface roughness. Finally, an AFM nano-indentation method was performed to examine the mechanical properties of the titanium films and obtain the elastic modulus of titanium film.ResultsThe results demonstrate that the substrate temperature significantly influences the microstructure and mechanical properties of titanium films. When the substrate temperature increases from 600 ℃ to 750 ℃, the preferred orientation of titanium films changes from (101) to (002) due to the competition between the minimization of strain energy and surface energy. With the increase of substrate temperature, the mobility of titanium atoms on the substrate increases, resulting in increased average grain size, surface roughness, and elastic modulus of the titanium films. The average grain size increases by 26% as the substrate temperature increased from 600 ℃ to 750 ℃.ConclusionsThe microstructure, surface morphology, and mechanical properties of titanium films are sensitive to substrate temperature. A high substrate temperature in the process of resistance evaporation is more desirable to obtain titanium films with high mechanical properties.

Abstract Thermoelectric refrigeration is one of the mature techniques used for cooling applications, with the great advantage of miniaturization over traditional compression refrigeration. Due to the anisotropic thermoelectric properties of n‐type bismuth telluride (Bi2Te3) alloys, these two common methods, including the liquid phase hot deformation (LPHD) and traditional hot forging (HF) methods, are of considerable importance for texture engineering to enhance performance. However, their effects on thermoelectric and mechanical properties are still controversial and not clear yet. Moreover, there has been little documentation of mechanical properties related to micro‐refrigeration applications. In this work, the above‐mentioned methods are separately employed to control the macroscopic grain orientation for bulk n‐type Bi2Te3 samples. The HF method enabled the stabilization of both composition and carrier concentration, therefore yielding a higher quality factor to compare with that of LPHD samples, supported by DFT calculations. In addition to superior thermoelectric performance, the HF sample also exhibited robust mechanical properties due to the presence of nano‐scale distortion and dense dislocation, which is the prerequisite for realizing ultra‐precision machining. This work helps to pave the way for the utilization of n‐type Bi2Te3 for commercial micro‐refrigeration applications.

Preferred orientation in polycrystalline materials is one of the most challenging problems for structural analysis. Significant preferred orientation can severely affect the structure‐property analysis of the systems having substantial crystallographic anisotropy. Here, an extremely high degree of preferred orientation has been demonstrated in R‐block hollandite hexagonal PbFexV6−xO11 compounds, which has recently been shown to exhibit an unusual colossal electroresistance response that has a strong dependence on structural modifications. The present results warn against possible errors in understanding the evolution of the crystal structure of these hollandites, which might adversely affect the estimation of the influence of the same on their spectacular physical properties. [ABSTRACT FROM AUTHOR]

In the present study, arrayed nano-precipitated TiC in a ferrite matrix was obtained through thermal treatment. The size and shape of the arrayed interphase nano-precipitates were unaffected by fatigue deformation in this Ti-microalloyed steel. In addition, arrayed arrangement of the interphase nano-precipitates was not disrupted by fatigue and still remained only at low cycle numbers, which corresponded to the shortest fatigue life. The interphase nano-precipitated steel was strengthened through a bowing mechanism through which unpinning occurred, dislocation loops were formed, and the microhardness of ferrite was increased. The development of an incipient cell structure in the ferrite matrix was caused by wavy dislocation. After the onset of fatigue, the grain was preferentially rotated toward the {101}α orientation. Higher strain amplitude or lower strain rate led to a more favorable degree of misorientation in the low-angle grain boundaries.

In 3D IC integration, a critical demand of interfacial joints in high-end devices is ultra-fine pitch, below 2 μm. The pitch cannot be fabricated by using solder joints because of its low melting point. Microelectronic industry prefers a solid state process, but the processing temperature cannot be too high, preferable near 250 °C. Thus, Cu-to-Cu direct bonding has attracted much attention. We have bonded the highly (111)-oriented Cu microbumps to highly (111)-oriented Cu films as well as to randomly-oriented Cu films for comparison, at temperatures from 200 to 350 °C. We examined the microstructures of bonded interfaces and conducted shear tests to evaluate the mechanical strength of the Cu joints. The bonded interfaces for the (111) Cu microbumps to (111) Cu films had fewer voids than those bonded to randomly oriented Cu films. In addition, the bonding strength of the latter is much less than the former. We propose that the fast surface diffusivity on the (111) surfaces play a critical role on surface creep, which increases the bonding strength of the Cu joint. A surface creep model and its creep rate are presented, and a comparison to the experimental data has been made; the agreement is reasonable.

The His-tag is a widely used affinity tag that facilitates purification by means of affinity chromatography of recombinant proteins for functional and structural studies. We show here that His-tag presence affects how coproheme decarboxylase interacts with the air-water interface during grid preparation for cryoEM. Depending on His-tag presence or absence, we observe significant changes in patterns of preferred orientation. Our analysis of particle orientations suggests that His-tag presence can mask the hydrophobic and hydrophilic patches on a protein’s surface that mediate the interactions with the air-water interface, while the hydrophobic linker between a His-tag and the coding sequence of the protein may enhance other interactions with the air-water interface. Our observations suggest that tagging, including rational design of the linkers between an affinity tag and a protein of interest, offer a promising approach to modulating interactions with the air-water interface.

In materials and earth science, but also in chemistry, pharmaceutics and engineering, the quantification of elements and crystal phases in solid samples is often essential for a full characterization of materials. The most frequently used techniques for this purpose are X-ray fluorescence (XRF) for elemental analysis and X-ray powder diffraction (XRPD) for phase analysis. In both methods, relations between signal and quantity do exist but they are expressed in terms of complex equations including many parameters related to both sample and instruments, and the dependence on the active element or phase amounts to be determined is convoluted among those parameters. Often real-life samples hold relations not suitable for a direct quantification and, therefore, estimations based only on the values of the relative intensities are affected by large errors. Preferred orientation (PO) and microabsorption (MA) in XRPD cannot usually be avoided, and traditional corrections in Rietveld refinement, such as the Brindley MA correction, are not able, in general, to restore the correct phase quantification. In this work, a multivariate approach, where principal component analysis is exploited alone or combined with regression methods, is used on XRPD profiles collected on ad hoc designed mixtures to face and overcome the typical problems of traditional approaches. Moreover, the partial or no known crystal structure (PONKCS) method was tested on XRPD data, as an example of a hybrid approach between Rietveld and multivariate approaches, to correct for the MA effect. Particular attention is given to the comparison and selection of both method and pre-process, the two key steps for good performance when applying multivariate methods to obtain reliable quantitative estimations from XRPD data, especially when MA and PO are present. A similar approach was tested on XRF data to deal with matrix effects and compared with the more classical fundamental-parameter approach. Finally, useful indications to overcome the difficulties of the general user in managing the parameters for a successful application of multivariate approaches for XRPD and XRF data analysis are given. [ABSTRACT FROM AUTHOR]

Pore solution expression (PSE) is the most commonly used method to obtain the aqueous phase in cementitious material. However, the high pressure applied on the sample during PSE can affect the composition of the solid phase. An experimental study on the chemical and mineral composition of cement paste before and after PSE was conducted. The results indicate that a small part of the alkali contained in the samples was excluded during PSE, depending mainly on the alkali concentration in the pore solution. Due to the expulsion of interlayer water in calcium silicate hydrate under high pressure, PSE reduced the bound water content (measured by thermogravimetric analysis (TGA)). The portlandite content determined by TGA was not affected by PSE, but it led to an overestimation of portlandite by means of quantitative X-ray diffraction, because of the enhanced preferred orientation of the (001) plane under the applied high pressure. In addition, the size of the portlandite crystals decreased to some extent due to the creep caused by pressure. The content of the hemicarbonate phase was found to decrease slightly after PSE, which may be due to increased solubility under high pressure. [ABSTRACT FROM AUTHOR]

BACKGROUND The polytype species and the content of synthetic fluorophores have a considerable influence on the physiochemical properties of fluorphlogopites. However, conventional methods (e.g., front loading and side loading) of sample preparation tend to generate a strongly preferred orientation on the 00l basal plane, limiting the X-ray diffraction (XRD) analysis of the composition and content of fluorphlogopite polytypes. The conventional spraying method was utilized to prepare samples with random orientations for XRD analysis. However, the sample surface was not flat enough to perform the analysis. OBJECTIVES To decrease the preferred orientation and develop a method for quantitative analysis of fluorphlogopite polytypes. METHODS In this study, the conventional spraying method was improved. The sample holder was rotated evenly during the spraying process to obtain a flat surface sample. RESULTS XRD data suggested that the orientation index (OI=I001/I060) obtained by the rotation-spraying method was 3.9, which was close to the theoretical value (4.5). The OIs of the front and side loading methods were 38.7 and 18.1, respectively, which were significantly larger than the theoretical value (4.5). The results showed that the rotation-spraying method significantly decreased the preferred orientation of mica along the 00l basal plane compared with the front and side loading methods. Microscopic observations revealed that the surface of the sample prepared by the rotation-spraying method exhibited a canine tooth staggered distribution. This increased the random distribution between the crystal particles and reduced the preferred orientation. Rietveld quantitative phase analyses of fluorphlogopites were successfully performed based on the XRD data for the samples prepared by the rotation-spraying method. In this study, Rietveld refinement showed that the contents of 1M and 2M1 polytypes of synthetic fluorphlogopites were 86% and 14%, respectively. The systematic investigations of eight commercial fluorphlogopites revealed that these samples were composed of 28%-43% 2M1 polytype and 57%-72% 1M polytype. In addition, significant stacking faults were observed in these eight commercial samples. CONCLUSIONS The rotation-spraying method significantly weakened the effect of preferential orientation. This study provides technical support for understanding the mica crystal growth, polymorphism, and structure-performance relationship.

This paper presents the first effort to extract the hydromechanical properties of montmorillonite quasi-crystals via nanoindentation testing of highly oriented montmorillonite thin films with varying degrees of water intercalation. By preparing highly preferentially oriented montmorillonite thin films, the evolution of basal spacing, isothermal adsorption of water, microstructure, and mechanical properties of montmorillonite quasi-crystals equilibrated with different relative humidity (RH) was examined by the grazing incidence X-ray diffraction (GIXRD), sorptometry, environmental scanning electron microscopy (ESEM), and nanoindentation, respectively. Results indicate that the montmorillonite thin films exhibit depth-dependent mechanical properties across different RH. At a 40 % RH, the Young's modulus and hardness of a montmorillonite quasi-crystal consisting of ∼60 platelets are 4.85 and 0.20 GPa, which remain relatively stable upon increasing the RH to 50 % but experienced a remarkable decrease to 3.31 and 0.12 GPa when the RH reaches 65 %. Simultaneous GIXRD and isothermal adsorption results reveal the interlayer swelling as the key factor contributing to the mechanical property variation of montmorillonite quasi-crystal, while the capillarity dominates the mechanical behavior at high RH. This study shed light on the hydromechanical behavior of montmorillonite upon hydration and swelling, and paves a solid foundation for the multiscale modeling of unsaturated compacted bentonites. • Oriented montmorillonite film is characterized by GIXRD, ESEM, isothermal sorption and nanoindentation. • Mechanical properties of montmorillonite quasi-crystal can be extracted from continuous nanoindentation curves. • E and H of montmorillonite quasi-crystal are mainly influenced by the interlayer space. • Multiscale pores accounted for the depth-dependent behaviors of oriented montmorillonite film. [ABSTRACT FROM AUTHOR]

Cryogenic electron microscopy (cryo-EM) single particle analysis has become one of the major techniques used to study high-resolution 3D structures of biological macromolecules. Specimens are generally prepared in a thin layer of vitrified ice using a holey carbon grid. However, the sample quality using this type of grid is not always ideal for high-resolution imaging even when the specimens in the test tube behave ideally. Various problems occur during a vitrification procedure, including poor/nonuniform distribution of particles, preferred orientation of particles, specimen denaturation/degradation, high background from thick ice, and beam-induced motion, which have become important bottlenecks in high-resolution structural studies using cryo-EM in many projects. In recent years, grids with support films made of graphene and its derivatives have been developed to efficiently solve these problems. Here, the various advantages of graphene grids over conventional holey carbon film grids, functionalization of graphene support films, production methods of graphene grids, and origins of pristine graphene contamination are reviewed and discussed.

The specimen preparation process is a key determinant in the success of any cryo electron microscopy (cryoEM) structural study and until recently had remained largely unchanged from the initial designs of Jacques Dubochet and others in the 1980s. The process has transformed structural biology, but it is largely manual and can require extensive optimisation for each protein sample. The chameleon instrument with its self-wicking grids and fast-plunge freezing represents a shift towards a robust, automated, and highly controllable future for specimen preparation. However, these new technologies require new workflows and an understanding of their limitations and strengths. As early adopters of the chameleon technology, we report on our experiences and lessons learned through case studies. We use these to make recommendations for the benefit of future users of the chameleon system and the field of cryoEM specimen preparation generally.