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The anisotropy of crystal structures mandates the direction dependence of materials' mechanical properties. Key properties of interest are the Young's modulus and Poisson ratio in the small strain limit, and the ideal tensile strength in the large strain regime. To date, atomistic computations of these properties have been conducted using two approaches. The first approach explicitly calculates the stress–strain response using computational tensile test experiments. The second approach computes the single crystal elastic constants then derives the mechanical properties using analytical equations. The two approaches have been used interchangeably and their equivalence not assessed. This work systematically computes the mechanical properties of 13 BCC and 12 face centered cubic (FCC) metals via the two approaches using first principles density functional theory calculations and hypothesize the robustness of the first approach. Analysis of the results has revealed the shortcomings of the elastic constants method in detecting instabilities in the structures captured by the first principles computational tensile test approach. Large discrepancies in calculations of Young's moduli using the latter approach are herein reported, as well as auxetic repossess and large Poisson ratio for some metals. Beyond the small strain results, we systematically examined the lateral strain response up to 0.5 applied strain in 3 crystallographic directions and reported large changes in slopes and peculiarities around the Bain transformation strain. From the computational stress–strain results, we validated empirical equations in the literature relating the ideal strength to the direction-dependent Young's modulus and the Bain strain along [001] in BCC and [110] in FCC but also presented further relations for other crystallographic directions. In conclusion, we believe that the elastic constants approach, while computationally efficient, has to be used with caution and should be validated against the computational tensile tests. In addition, we highlight the importance of examining different crystallographic directions with possibly desirable properties. [ABSTRACT FROM AUTHOR]

A model for the porosity formation which occurs in single-crystal nickel-based superalloys when the non-equilibrium eutectic melts during high-temperature heat treatment is proposed. It is assumed that the porosity formation results from plastic deformation of the γ-solid solution of nickel caused by dilatation of the melting eutectic. This mechanism of porosity formation is described analytically using the elasto-plastic properties of superalloy experimentally measured at near solidus temperatures. The proposed model was used to predict the pore formation in the 3rd generation single-crystal nickel-based superalloy CMSX-10. Comparison of the obtained theoretical and experimental results showed a good agreement. [ABSTRACT FROM AUTHOR]

Ni‐rich layered cathode materials are progressively considered as the standard configuration of high‐energy electric vehicles by virtues of their high capacity and eliminated "range anxiety." However, the poor cyclic stability and severe cobalt supply crisis would restrain their wide commercial applicability. Here, a cost‐effective single‐crystal Co‐free Ni‐rich cathode material LiNi0.8Mn0.18Fe0.02O2 (NMF), which outperforms widely commercial polycrystalline LiNi0.83Co0.11Mn0.06O2 (MNCM) and single‐crystal LiNi0.83Co0.11Mn0.06O2 (SNCM) is reported. Surprisingly, NMF can compensate for the reversible capacity loss under the designed conditions of high‐temperature and elevated‐voltage, achieving a competitive energy density compared with conventional MNCM or SNCM. Combining operando characterizations and density functional theory calculation, it is revealed that NMF cathode with improved dynamic structure evolution largely alleviates the mechanical strain issue commonly found in Ni‐rich cathode, which can reduce the formation of intragranular cracks and improve the safety performance. Consequently, this new Co‐free NMF cathode can achieve a perfect equilibrium between material cost and electrochemical performance, which not only reduces the production cost by >15%, but also demonstrates excellent thermal stability and cycling performance.. [ABSTRACT FROM AUTHOR]

As one of the high‐energy cathode materials of lithium‐ion batteries (LIBs), lithium‐rich‐layered oxide with "single‐crystal" characteristic (SC‐LLO) can effectively restrain side reactions and cracks due to the reduced inner boundaries and enhanced mechanical stabilities. However, there are still high challenges for SC‐LLO with diverse performance requirements, especially on their cycle stability improvement. Herein, a novel concentration gradient "single‐crystal" LLO (GSC‐LLO), with gradually decreasing Mn and increasing Ni contents from center to surface, is designed and prepared by combining co‐precipitation and molten‐salt sintering methods, yielding a capacity retention of 97.6% and an energy density retention of 95.8% within 100 cycles at 0.1 C. The enhanced performance is mostly attributed to the gradient‐induced stabilized structure, free of cracks and less spinel‐like structure formation after long‐term cycling. Furthermore, the gradient design is also beneficial to the safety of LLOs as suggested by the improved thermal stability and reduced gas release. This study provides an effective strategy to prepare high‐energy, high‐stability, and high‐safety LLOs for advanced LIBs. [ABSTRACT FROM AUTHOR]

The microstructure and cyclic oxidation behaviour of Hf and Zr co-doped B2 NiAl single-crystal alloys at 1473 K were investigated. Hf and Zr co-precipitated into one phase during alloy manufacturing. The RE-free single-crystal alloy obtained a double-layered alumina film comprised of outer equiaxed grains and inner columnar grains and exhibited lower oxidation rate than the corresponding poly-crystal alloy, while the co-doped single-crystal alloy displayed higher oxidation rate than the RE-free single-crystal alloy and no synergistic effect was discovered. The effect of Hf and Zr co-doping on the growth behaviour of the alumina film was discussed. It is proposed that the existence of grain boundaries is an important precondition for activating the reactive element effect. The absence of grain boundaries significantly weakened the positive effect of Hf and Zr co-doping and distinctly magnified its negative effect on the cyclic oxidation resistance of the alloy in the meantime. Cyclic oxidation behaviour of Hf and Zr co-doped NiAl single-crystals is compared. The undoped alloy obtains a double-layered alumina film during oxidation. The co-doped alloy shows higher alumina film growth rate than the undoped alloy. The absence of alloy grain boundaries suppresses the reactive element effect. [ABSTRACT FROM AUTHOR]

Taking advantage of the unique layered structure of TiSe2, the intrinsic electronic properties of two-dimensional materials can easily be tuned via heteroatomic engineering. Herein, we show that the charge density wave (CDW) phase in 1T-TiSe2 single-crystals can be gradually suppressed through Sn atoms intercalation. Using angle-resolved photoemission spectroscopy (ARPES) and temperature-dependent resistivity measurements, this work reveals that Sn atoms can induce charge doping and modulate the intrinsic electronic properties in the host 1T-TiSe2. Notably, our temperature-dependent ARPES results highlight the role exciton-phonon interaction and the Jahn-Teller mechanism through the formation of backfolded bands and exhibition of a downward Se shift of 4p valence band in the formation of CDW in this material. [ABSTRACT FROM AUTHOR]

Stimuli‐triggered crystal‐to‐crystal and single‐crystal‐to‐single‐crystal (SCSC) transformations have received significant attention in the scientific community. To visualize such phenomenon, controlling the optical properties and the thermodynamic stability of the molecular crystals is a very important research subject. In this report, the selective growth of photoluminescent (PL) 1,8‐bisphenylanthracene polymorphic (cI and cII) and 1,2‐dichloroethane‐inclusion crystals (iC) under various optimized conditions is described. These crystals exhibited unique mechano‐ and thermoresponsive disordering, crystal‐to‐crystal phase transition, and SCSC phase transition. In particular, rapid thermostimulus SCSC occurred from blue‐PL cI into greenish‐blue‐PL cII. Interestingly, the SCSC phase transition of cI into cII was triggered by thermal stimuli and propagated spontaneously. Thermotriggered domino‐like SCSC phase transition was observed on a fully visible timescale (ca. 125 μm min−1). [ABSTRACT FROM AUTHOR]

Nontrivial topological behaviors in superconducting materials provide resourceful ground for the emergence and study of unconventional quantum states. Charge doping by the controlled intercalation of donor atoms is an efficient route for enhancing/inducement of superconducting and topological behaviors in layered topological insulators and semimetals. Herein, we enhanced the superconducting temperature of TaSe2 by 20-folds (∼ 3 K) through Sn atoms intercalation. Using first-principles calculations, we demonstrated the existence of nontrivial topological features. Sn0.5TaSe2 displays topological nodal lines around the K high symmetry point in the Brillouin zone, with drumhead-like shaped surface states protected by inversion symmetry. Altogether, the coexistence of these properties makes Sn0.5TaSe2 a potential candidate for topological superconductivity. [ABSTRACT FROM AUTHOR]

Molecular perovskites have demonstrated great potential for ferroelectrics and nonlinear optics; however, their charge transport properties for optoelectronics have rarely been explored. Here, understanding of charge transport behavior of molecular perovskite under X‐ray excitation based on centimeter‐scale TMCM‐CdCl3 (TMCM+, trimethylchloromethyl ammonium) single crystal is demonstrated. The crystal is fabricated from an aqueous solution and exhibits a large bandgap of 5.51 eV, with the valence band maximum mainly dominated by the Cl‐p/Cd‐d states and the conduction band minimum primarily by Cd‐s/Cl‐p states. Charge mobility exceeding 40 cm2 V−1 s−1 and mobility–lifetime (µτ) product on the order of 10−4 cm2 V−1 for the crystal are observed. These excellent optoelectronic properties translate to an efficient photoresponse under X‐ray excitation, with the sensitivity reaching 128.9 ± 4.64 µC Gyair−1 cm−2 [fivefold higher than that of the commercialized amorphous selenium (α‐Se)] and a low detection limit of 1.06 μC Gyair−1 s−1 (10 V bias). This work pioneers a superior metal‐based molecular perovskite single‐crystal based paradigm for optoelectronic investigation, which may lead to the discovery of a new generation of X‐ray detection and imaging materials. [ABSTRACT FROM AUTHOR]

Representatives of the LixNi1−y−zCoyMnzO2 (NCM) family of cathode active materials (CAMs) with high nickel content are becoming the CAM of choice for high performance lithium‐ion batteries. In addition to high specific capacities, these layered oxides offer high specific energy, power, and long cycle life. Recently, the development of single crystalline particles of NCM has enabled even longer lifetimes due to achieving higher Coulomb efficiencies. In this work, the performance of NCM materials with different particle size and morphology is explored in terms of key parameters such as the charge‐transfer resistance and the chemical diffusion coefficient of lithium. Cracking of secondary particles leads to liquid electrolyte infiltration in the CAM, lowering the charge‐transfer resistance and increasing the apparent diffusion coefficient by more than one order of magnitude. In contrast, these effects are not observed with single‐crystalline NCM, which is mostly free of cracks after cycling. Consequently, severe kinetic limitations are observed when cycling large "uncracked" secondary particles at low potential and capacity. These results demonstrate that cracking of polycrystalline particles of NCM is not solely detrimental but helps to achieve high reversible capacities and rate capability. Thus, optimization of CAMs size and morphology is decisive to achieve good rate capability with high‐nickel NCMs. [ABSTRACT FROM AUTHOR]

Layered oxides, particularly including Li[NixCoyMnz]O2 (NCMxyz) materials, such as NCM523, are the most promising cathode materials for high‐energy lithium‐ion batteries (LIBs). One major strategy to increase the energy density of LIBs is to expand the cell voltage (>4.3 V). However, high‐voltage NCM∥ graphite full cells typically suffer from drastic capacity fading, often referred to as "rollover" failure. In this study, the underlying degradation mechanisms responsible for failure of NCM523∥ graphite full cells operated at 4.5 V are unraveled by a comprehensive study including the variation of different electrode and cell parameters. It is found that the "rollover" failure after around 50 cycles can be attributed to severe solid electrolyte interphase growth, owing to formation of thick deposits at the graphite anode surface through deposition of transition metals migrating from the cathode to the anode. These deposits induce the formation of Li metal dendrites, which, in the worst cases, result in a "rollover" failure owing to the generation of (micro‐) short circuits. Finally, approaches to overcome this dramatic failure mechanism are presented, for example, by use of single‐crystal NCM523 materials, showing no "rollover" failure even after 200 cycles. The suppression of cross‐talk phenomena in high‐voltage LIB cells is of utmost importance for achieving high cycling stability. [ABSTRACT FROM AUTHOR]

Tracer-diffusion of constituting elements in single-crystalline CoCrFeNi and CoCrFeMnNi is measured from 923 K to 1373 K. In CoCrFeMnNi, low-temperature deviations from otherwise linear Arrhenius-type dependencies are seen for all elements excluding Mn. The kinks are prominent at about 1100 K for Co and Ni and at 900 K for Cr and Fe indicating the existence of a low-temperature modification of the equiatomic solid-solution phase in CoCrFeMnNi. The temperature-dependent correlation factors of all elements are determined within the framework of the random alloy model providing insights into potential mechanisms of the kinetic anomaly. [ABSTRACT FROM AUTHOR]

2D Ruddlesden–Popper perovskites (RPPs) have recently drawn significant attention because of their structural variability that can be used to tailor optoelectronic properties and improve the stability of derived photovoltaic devices. However, charge separation and transport in 2D perovskite solar cells (PSCs) suffer from quantum well barriers formed during the processing of perovskites. It is extremely difficult to manage phase distributions in 2D perovskites made from the stoichiometric mixtures of precursor solutions. Herein, a generally applicable guideline is demonstrated for precisely controlling phase purity and arrangement in RPP films. By visually presenting the critical colloidal formation of the single‐crystal precursor solution, coordination engineering is conducted with a rationally selected cosolvent to tune the colloidal properties. In nonpolar cosolvent media, the derived colloidal template enables RPP crystals to preferentially grow along the vertically ordered alignment with a narrow phase variation around a target value, resulting in efficient charge transport and extraction. As a result, a record‐high power conversion efficiency (PCE) of 14.68% is demonstrated for a (TEA)2(MA)2Pb3I10 (n = 3) photovoltaic device with negligible hysteresis. Remarkably, superior stability is achieved with 93% retainment of the initial efficiency after 500 h of unencapsulated operation in ambient air conditions. [ABSTRACT FROM AUTHOR]

The processes of coherent bremsstrahlung (CB) and coherent pair production (CPP) based on aligned crystal targets have been studied in the energy range 20-170 GeV. The experimental arrangement allowed for measurements of single photon properties of these phenomena including their polarization dependences. This is significant as the theoretical description of CB and CPP is an area of active debate and development. With the approach used in this paper, both the measured cross sections and polarization observables are predicted very well. This indicates a proper understanding of CB and CPP up to energies of 170 GeV. Birefringence in CPP on aligned crystals is applied to determine the polarization parameters in our measurements. New technologies for high-energy photon beam optics including phase plates and polarimeters for linear and circular polarization are demonstrated in this experiment. Coherent bremsstrahlung for the strings-on-strings (SOS) orientation yields a larger enhancement for hard photons than CB for the channeling orientations of the crystal. Our measurements and our calculations indicate low photon polarizations for the high-energy SOS photons.

Molecular dynamics simulations of cracked nanocrystals of aluminum were performed in order to investigate the crack length and grain boundary effects. Atomistic models of single-crystals and bi-crystals were built considering 11 different crack lengths. Novel approaches based on fracture mechanics concepts were proposed to predict the crack length effect on single-crystals and bi-crystals. The results showed that the effect of the grain boundary on the fracture resistance was beneficial increasing the fracture toughness almost four times for bi-crystals.

Electrochemically driven chemical transformations play the key role in controlling storage of energy in chemical bonds and subsequent conversion to power electric vehicles and consumer electronics. The promise of coupling anionic oxygen redox with cationic redox to achieve a substantial increase in capacities has inspired research in a wide range of electrode materials. A key challenge is that these studies have focused on polycrystalline materials, where it is hard to perform precise structural determinations, especially related to the location of light atoms. Here a different approach is utilized and a highly ordered single crystal, Na2−xIrO3 is harnessed, to explore the role of defects and structural transformations in layered transition metal oxide materials on redox‐activity, capacity, reversibility, and stability. Within a combined experimental and theoretical framework, it is demonstrated that 1) it is possible to cycle Na2−xIrO3, offering proof of principle for single‐crystal based batteries 2) structural phase transitions coincide with Ir 4+/Ir 5+ redox couple with no evident contribution from anionic redox 3) strong irreversibility and capacity fade observed during cycling correlates with the Na + migration resulting in progressive growth of an electrochemically inert O3‐type NaIrO3 phase. [ABSTRACT FROM AUTHOR]

Glycerol adsorption and oxidation reactivity at platinum single crystal electrodes in alkaline media using electrochemical and Fourier transform infrared (FTIR) techniques are reported. The behavior of Pt(100) and Pt(110) for the glycerol electrooxidation reaction (GEOR) were compared and analyzed altogether with those previously reported for Pt(111) (R. M. L. M. Sandrini, J. R. Sempionatto, E. Herrero, J. M. Feliu, J. Souza‐Garcia, C. A. Angelucci, Electrochem. commun. 2018, 86, 149–152). The voltammetric profiles confirm the structure sensitivity of GEOR as well as the role of the surface atoms orientation on the electrocatalytic activity. The Pt(100) surface has shown to be less prone to poisoning during multiple potential cycles in contrast to Pt(110), which suffers an accentuate deactivation at the first positive‐going scan. Spectroscopic results show that the GEOR on all three surfaces is characterized by the presence of two broad bands, centered at circa 1400 cm−1 and 1600 cm−1. This provides evidence that the GEOR mechanism undergoes glycerol dehydrogenation to alkoxydes followed by the formation of aldehyde intermediates adsorbed as η1(O)‐aldehyde and η1(C)‐acyl geometry, respectively. The surface atomic arrangement induces different selectivity in the oxidation process. [ABSTRACT FROM AUTHOR]

In this publication, molecular dynamics simulations are used to investigate the fracture behavior of single-crystal aluminum. The stress intensity factor is estimated by means of four different methods, the accuracy is assessed for each approach and the fracture toughness is estimated. The proposed methodology is also applied to estimate the fracture toughness for graphene and diamond using published data from other scientific articles. The obtained fracture toughness for the single-crystal aluminum is compared with other nanomaterials that have similar microstructures. Dislocation emission during the fracture simulation of the cracked nano-crystal of aluminum is analyzed to study the fracture behavior. Brittle fracture behavior is the predominant failure mode for the nanomaterials studied in this research.

The elastic properties of the single-crystal nickel-base superalloy CMSX-4 used as a blade material in gas turbines were investigated by the sonic resonance method in the temperature interval between room temperature and 1300 °C. Elastic constants at such high temperatures are needed to model the mechanical behavior of blade material during manufacturing (hot isostatic pressing) as well as during technical accidents which may happen in service (overheating). High reliability of the results was achieved using specimens of different crystallographic orientations, exciting various vibration modes as well as precise measurement of the material density and thermal expansion required for modeling the resonance frequencies by finite element method. Combining the results measured in this work and literature data the elastic constants of the γ- and γ′-phases were predicted. This prediction was supported by measurement of the temperature dependence of the γ′-fraction. All data obtained in this work are given in numerical or analytical forms and can be easily used for different scientific and engineering calculations.

The research on systems with coexistence of superconductivity and nontrivial band topology has attracted widespread attention. However, the limited availability of material platforms severely hinders the research progress. Here, it reports the first experimental synthesis and measurement of high-quality single crystal van der Waals transition-metal dichalcogenide InNbS 2 , revealing it as a topological nodal line semimetal with coexisting superconductivity. The temperature-dependent measurements of magnetization susceptibility and electrical transport show that InNbS 2 is a type-II superconductor with a transition temperature T c of 6 K. First-principles calculations predict multiple topological nodal ring states close to the Fermi level in the presence of spin-orbit coupling. Similar features are also observed in the as-synthesized BiNbS 2 and PbNbS 2 samples. This work provides new material platforms ANbS 2 (A = In, Bi, and Pb) and uncovers their intriguing potential for exploring the interplay between superconductivity and band topology., (© 2023 Wiley-VCH GmbH.)

Heat-resistant nickel alloys with single-crystal structure are used in such branches of industry as turbine manufacture, aerospace engineering and power engineering. However, their further mastering is restrained by complexity, and sometimes impossibility of production of structure elements of large size and developed geometry. Production as well as repair using traditional methods of single-crystal products with developed geometry such as, for example, long or cooled gas turbine blades etc., represent a complex technological and expensive problem. Manufacture of assemblies, parts, structures of such type by means of their welding from separate elements or building-up often seems to be more reasonable and allows developing products with single-crystal structure on virtually new basis. The aim of the presented work is development of new approaches applicable to manufacture of the single-crystal welded structures of critical designation with increased mechanical characteristics and service parameters. The results of investigations and examples of pilot welded structures of such type, produced at the E.O. Paton Electric Welding Institute of the NAS of Ukraine, are presented. 30 Ref., 9 Fig. [ABSTRACT FROM AUTHOR]

Heat-temperature nickel alloys with single-crystal structure are used in such branches of production as turbine manufacture, aerospace engineering and power engineering. However, their further mastering is restrained by complexity, and sometimes impossibility of production of structure elements of large sizes and developed geometry. Production as well as repair using traditional methods of single-crystal products with developed geometry such as, for example, long or cooled gas turbine blades etc., represents a complex technological problem. Manufacture of assemblies, parts, structures of such type by means of their welding from separate elements or building-up often seems to be more reasonable and allows developing products with single-crystal structure on virtually new basis. The aim of the presented work is development of new approaches applicable to manufacture of the single-crystal welded structures of critical designation with increased mechanical characteristics and service parameters. The results of investigations and examples of pilot welded structures of such type, produced at the E.O. Paton Electric Welding Institute of the NAS of Ukraine, are presented. 30 Ref., 9 Figures. [ABSTRACT FROM AUTHOR]

The morphology, chemical composition and formation mechanism of non-metallic inclusions in magnetic alloy of Fe-Co-Ni-Cu-Al-Ti-Hf system were investigated. These alloys are used in manufacturing single-crystal permanent magnets. Modern methods for the identification of non-metallic inclusions, as well as computer simulation of the processes of their formation by Thermo Calc software were used in the work. It was found that studied alloy contains (Ti, Hf)S titanium and hafnium sulfides, (Ti, Hf)2SC titanium and hafnium carbosulfides, Ti2O2S titanium oxisulfide, HfO2 hafnium oxide, and Al2O3 aluminum oxide. No titanium and hafnium nitrides were found in the alloy. The bulk of nonmetallic inclusions are (Ti, Hf)2SC carbosulfides and (Ti, Hf)S sulfides. All carbides and many oxides are within carbosulfides and sulfides. When the sulfur content in the alloy is no more than 0.2%, and carbon content does not exceed 0.03%, carbosulfides are formed in the solidification range of the alloy and has an faceted compact form. If the sulfur content in the alloy becomes more than 0.2% and carbon content more than 0.03%, the carbosulfide formation begins before the alloy solidification or at the begining stages of solidification. In this case, carbosulfides are dendritic and coarse. Such carbosulfides actively float in the solidified melt and often come to the surface of the castings. In this case, specific surface defects are formed in single-crystal magnets, which are called sulfide stains. All titanium and hafnium sulfides are formed at the lower part of solidification range and have elongated shape. [ABSTRACT FROM AUTHOR]

Molten salt synthesis is a universal approach to synthesizing single-crystal cathodes. However, complicated processes, such as washing to remove the molten salt and repeated heat treatments, have hindered its practical application in the synthesis of high-Ni NCMs. In this work, using LiNi 0.8 Mn 0.1 Co 0.1 O 2 as a model material, a one-step strategy was developed to prepare Li 2 MoO 4 -coated and Mo6+-doped single-crystals, where the formation of single crystals, coating, and doping are achieved simultaneously by adding 2% Li 2 MoO 4 as a sacrificial molten salt. The proposed one-step strategy does not require washing to remove molten salt and repeated heat treatment. Furthermore, Li 2 MoO 4 coating and Mo6+ doping can further enhance the structural/interfacial stability and the electrode kinetics of single-crystal LiNi 0.8 Mn 0.1 Co 0.1 O 2. Therefore, the cyclic stability (83% after 200 cycles at 1C) and rate performance (169 mAh·g−1 at 10C) of single-crystal LiNi 0.8 Co 0.1 Mn 0.1 O 2 is superior to that of polycrystal LiNi 0.8 Co 0.1 Mn 0.1 O 2 prepared without the addition of Li 2 MoO 4 (67% and 134 mAh·g−1). This one-step strategy using sacrificial molten salts reveals an attractive pathway for developing single-crystal electrode materials with stable structure/interface and good electrode kinetics. [Display omitted] • Single-crystal NCM811 co-modified by coating/doping is prepared by a one-step method. • Small content of Li 2 MoO 4 is used as sacrificial molten salt in the one-step method. • Formation, coating, and doping of single-crystal NCM811 are achieved simultaneously. • The proposed one-step strategy does not require washing to remove the molten salt. • Single-crystal NCM811 performs better due to higher structural stability and kinetics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Crystallographic phase stability of the poly and single crystalline lead nitrate at shocked conditions is reported. • XRD and Raman results show the stable crystal structure of poly-crystalline samples at shocked conditions. • Poly-crystalline lead nitrate sample has relatively high structural stability and shock resistance compared to the single crystal. In the present work, we report the crystallographic structural stability of the poly-crystalline lead nitrate samples at shocked conditions with which a systematic comparison is made for the previously reported single-crystalline lead nitrate crystal at shocked conditions. X-ray diffractometry (XRD) and Raman spectroscopic measurements have been performed to assess the crystallographic structural stability of poly-crystalline Pb(NO 3) 2 samples at shocked conditions and the observed XRD and Raman results disclose that the title poly-crystalline samples retain the original crystallographic structure even at 100 shocked conditions interacting with the shock waves of 2.2 Mach number. But the single crystals of Pb(NO 3) 2 undergo crystalline to amorphous phase transition at shocked conditions. Based on the observed results, poly-crystalline samples have higher-structural stability than that of single crystals. The outcome of this work provides glimpses of possible further contributions to crystal engineering for the design of new materials with specific physical and chemical properties. [ABSTRACT FROM AUTHOR]

In view of serious environmental concerns with traditional Pb-based piezoelectrics, the search for new Pb-free alternatives has intensified recently. A thorough investigation of structure-property relationships in Pb-free piezoelectrics is desired in order to design new material compositions with high electromechanical properties that can be operated over a broader range of conditions. Recent availability of high-quality single crystals has not only opened the possibility for achieving multifold enhancements in the electromechanical properties in this new class of materials, but has also provided opportunities to undertake fundamental studies on their structure-property relationships. In the following pages, I review some of the recent X-ray and neutron diffraction studies of Pb-free piezoelectric single crystals, which have provided novel insights into their multiscale stimuli-induced structural mechanisms, including phase transitions, nanoscale structural ordering, lattice instability, and domain re-orientation. Opportunities and challenges for future progress in this area of study are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Single crystal microwires of a well‐studied organic semiconductor used in organic solar cells, namely p‐DTS(FBTTh2)2, are prepared via a self‐assembly method in solution. The high level of intermolecular organization in the single crystals facilitates migration of charges, relative to solution‐processed films, and provides insight into the intrinsic charge transport properties of p‐DTS(FBTTh2)2. Field‐effect transistors based on the microwires can achieve hole mobilities on the order of ≈1.8 cm2 V−1 s−1. Furthermore, these microwires show photoresponsive electrical characteristics and can act as photoswitches, with switch ratios over 1000. These experimental results are interpreted using theoretical simulations using an atomistic density functional theory approach. Based on the lattice organization, intermolecular couplings and reorganization energies are calculated, and hole mobilities for comparison with experimental measurements are further estimated. These results demonstrate a unique example of the optoelectronic applications of p‐DTS(FBTTh2)2 microwires. [ABSTRACT FROM AUTHOR]

The article discusses a study related to electrochemical deposition method in situ large-area uniform growth of densely packed single-crystal copper nanocones on copper surface. Topics discussed include the condensation heat transfer in metals, small scale condensation of microdrops, and the fabrication of copper nanostructures. Also mentioned is the introduction of polyethylene glycol in copper nanocones.