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A novel electrocatalyst containing amorphous FeSeO x and Mo doped NiSe 2 (denoted as FeSeO x /Mo-NiSe 2) was developed via pseudocrystalline replication method and selenization treatment, and heteroatom doping and amorphous and crystalline (a-c) interface enables attractive OER performances. [Display omitted] • A novel FeSeO x /Mo-NiSe 2 electrocatalyst was desinged for water oxidation. • The optimized FeSeO x /Mo-NiSe 2 exhibits a low overpotential of 205 mV at 10 mA cm−2 for OER in alkaline solution. • The excellent performance is attributed to amorphous and crystalline (a-c) interface engineering and heteroatom doping strategies. Exploring integrated regulation strategies to boosting electrocatalytic performance is essential to design more efficient and inexpensive OER catalysts. Herein, amorphous and crystalline (a-c) interface engineering and heteroatom doping are integrated to construct a novel electrocatalyst containing amorphous FeSeO x and crystalline Mo-doped NiSe 2 (denoted as FeSeO x /Mo-NiSe 2) via pseudocrystalline replication method and selenization treatment. The resultant FeSeO x /Mo-NiSe 2 electrocatalyst with 3D hierarchical nanoarchitectures of nanorod arrays covered by interlocking nanoblocks exposes more active sites and accelerated reaction kinetics. Furthermore, a-c interface engineering and heteroatom doping can synergistically enhance the intrinsic activity and charge transfer capability of NiSe 2 by decreasing the electron diffusion distance and flexibly modulating the electronic structure, which contributes to boost the oxygen evolution reaction (OER) performance. Consequently, the obtained FeSeO x /Mo-NiSe 2 achieves a low overpotential of 205 mV at 10 mA cm−2, which outperforms many other transitions metal selenides electrocatalysts. Density functional theory (DFT) calculations demonstrate that the formation of an internal electric field between FeSeO x and Mo-NiSe 2 accelerates charge transport and optimizes the adsorption/desorption of oxygen-containing intermediates, thereby accelerating the reaction kinetics and improving the OER performance. This work serves as a point of reference for designing innovative metal selenides based electrocatalysts combining a-c interface engineering and heteroatom doping. [ABSTRACT FROM AUTHOR]

[Display omitted] • The crystallization process of amorphous YAG oxide is investigated from an atomic point of view. • The crystallization proceeds on the surface and interior of the amorphous YAG separately, and which show the preferential crystallization of the surface atoms. • Some atoms in the amorphous phase were controlled by the periodic potential field of the crystal atoms and produced dynamically changing semi-ordered structures at the amorphous/crystalline interface with mainly concentrated within 1–2 nm from the interface. The transformation from amorphous materials to crystals and the corresponding microscopic mechanism have become a research focus in materials science, condensed matter physics, and biophysics etc. In this paper, taking Y 3 Al 5 O 12 (YAG) as an example, the crystallization process of amorphous YAG oxide is investigated from an atomic point of view through the combination of spherical aberration-corrected transmission electron microscopy (SCTEM) with an in situ heating method, and the morphology and structural evolution of the surface and interface are explored. It is observed that the crystallization proceeds on the surface and interior of the amorphous YAG separately. Through atomic-scale imaging, it is determined that semi-ordered structures are formed in a few atomic layers at the amorphous/crystalline interface and that the structural transformation process from the amorphous to the semi-ordered state and then to the crystal structure may be the main reason for the multiple stages of the crystallization of amorphous oxides. This study demonstrates the mechanism of the amorphous-to-crystal transformation on the atomic scale and contributes to gaining a better understanding of the crystallization process of bulk oxides, especially complex metal oxides. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-entropy alloy nanolaminates are obtained. • The coherent interface in nanolaminates is designed to improve ductility. • The crystalline/amorphous hierarchical nanostructure is designed to enhance strength. Introducing nanolaminates structure is a promising strategy to obtain the controllable microstructure and mechanical properties of high entropy alloy (HEA). In this work, the Al 0.5 CoCrFeNi/CoCrCuFeNi nanolaminates with coherent interface and crystalline/amorphous hierarchical nanostructure was designed. On the one hand, the coherent interface with continuous slip direction and planes enables nanolaminates with great deformability. On the other hand, the hierarchical nanostructure in the nanolaminates contributes to high strength via the interaction between crystalline and amorphous structures. Microstructural observations indicated that abundant nanotwins and stack faults were filled in the columnar nanocrystalline cutting across the interface, leading to a high hardness due to the dislocation-interface interactions. The results of nanoindentation tests revealed that the hardness of the nanolaminates up to 8.02 GPa, which markedly exceeds many HEA films with face-centered cubic (FCC) phase. The findings provide a new avenue for improving the mechanical properties of HEA nanolaminates in a controllable manner. [ABSTRACT FROM AUTHOR]

Highlights • Linear scans in reciprocal space are examined for coplanar diffraction geometry. • Concept of linear scans is extended to non-coplanar set-up. • Scans and resolution in asymmetric non-coplanar geometry are analyzed and discussed. Abstract High resolution X-ray diffraction is commonly used for the analysis of single crystalline epitaxial layers exhibiting high degree of crystal perfection. The method enables to resolve fine variations of the measured intensities and therefore is very efficient in the investigation of the structural parameters of single or multilayered epitaxial systems. In this article the method combining the standard HR technique with grazing incidence set-up is outlined. It is shown that in non-coplanar geometry the intensity distribution within the section of reciprocal space perpendicular to the sample surface, standardly scanned in coplanar geometry, can be measured at constant angle of incidence α. For asymmetric diffractions that are not accessible in coplanar geometry the value of α can be decreased to extremely low values close to zero making the method depth-sensitive. The effect of non-coplanar geometry on the angular resolution is analyzed and the possible application of φ scans in asymmetric non-coplanar geometry is discussed. The proposed scans are illustrated by measurements on selected GaN based epitaxial layers and they can be applied also to other types of epitaxial systems with medium crystal quality. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZB-MnTe thin films are epitaxially grown by MBE in spite of the metastable nature. • High-crystalline quality, atomic surface flatness and sharp interface are yielded. • PL emissions of 4 T 1g (4 G) and 4 T 1 (4 G) related to Mn2+ d - d multiplets are observed. • Two extra PL transitions attributed to STE states are demonstrated below T N. • Dynamics of photoexcited d -electrons are strongly correlated to the AFM transition. Single-crystalline γ -MnTe thin films with zinc-blende structure were grown epitaxially on InP(1 1 1) by molecular beam epitaxy. Two-dimensional growth regime and atomic surface flatness are achieved, and appearance of Laue's oscillation peaks illustrates the superior crystalline quality and interface of γ -MnTe films. A pseudocrystal buffer layer is formed at interface releasing the strain led by the large lattice mismatch between γ -MnTe and InP, and then growth of γ -MnTe films with a perfect lattice evidences the high-quality crystallinity in a fully relaxed state. Photoluminescence (PL) emissions from 4 T 1g (4 G) and 4 T 1 (4 G) related to Mn2+ ions d - d multiplets are observed with their respective activation energies of ∼142.5 meV and ∼323.5 meV. Such high potentials reflecting the nonradiative recombination indicate the thermal stability of these PL. Moreover, two extra PL transitions assigned to be the emissions from self-trapped exciton (STE) states are found below T N. Time-resolved PL (TRPL) spectra at various temperatures indicate that the relaxation dynamics of photoexcited d -electrons is strongly correlated to the antiferromagnetic ordering transition due to the synergy of magnon, phonon and STE states. These findings suggest that introduction of STE states in a material by controlling its magnetic ordering qualifies the competition in optoelectronics devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • MnO 2 /Mn 2 O 3 with amorphous/crystalline interface is facilely synthesized. • A multiple Mn ions redox-driven mechanism with triggered oxygen defects is proposed. • An evaluation criterion to rationally select anode to match cathode is presented. • Superior electrochemical performance is performed by MnO 2 /Mn 2 O 3 //MoS 2 device. Though tremendous efforts are devoted on structure engineering, most of Mn oxides show low capacity under wide work voltage actually caused by the limitation of sluggish reaction kinetics and inferior conductivity. Herein, we present an unprecedented self-improvement in electronic structure and Mn ions redox activity of MnO 2 /Mn 2 O 3 , carried out by a new mechanism of multiple Mn ions redox reaction with self-triggered oxygen-defect (Vo). It is disclosed that the MnO 2 /Mn 2 O 3 electrode mainly indicates capacitive-like surface redox reaction between Mn3+ and Mn4+ when operating within 0–1.2 V, which evolves into an adjustable multiple redox reactions of Mn2+, Mn3+ and Mn4+ accompanied with the self-generation of abundant Vo after changing the lower cut-off work potential (LCWP) from 0 to −0.3 V. Theoretical and experimental results demonstrate the rich Vo in active structure induces new electronic states and electron redistribution between Mn and O, which increase total charge storage more than two-folds to 786. 7 C g−1 (1 A g−1) by promoting multiple Mn ions redox reactions. During assembling MnO 2 /Mn 2 O 3 -based pseudocapacitor, a designed four-electrode system reveals fast reaction kinetics of anode assigns MnO 2 /Mn 2 O 3 with more wide effective work potential, guiding the effective enhancement of energy density by selecting MoS 2 as the anode. [ABSTRACT FROM AUTHOR]

Nanocrystalline anatase TiO2 films were deposited on glass and silicon substrates by using radio frequency reactive magnetron sputtering. Microstructural and optical properties were characterized by using X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), Raman spectra, optical absorption and photoluminescence (PL). XRD and Raman spectroscopy detected a nanocrystalline anatase titania films for input power at 250 W, for argon/oxygen ratio at 50 sccm/5.0 sccm and for substrate temperature at 500 °C. Visible broad widened photoluminescence peak is interpreted as the emission of self-trapped excitons localized on TiO6 octahedra. [Copyright &y& Elsevier]

Scanning photoelectron microscopy was used to study the lateral distribution of a 0.5 monolayer (ML) of Au on a polycrystalline Ni surface after Au deposition at room temperature (RT) and following annealing at 620 K for different durations. The effect of the grain structure on the interfacial interactions and Au surface mobility was examined. The Ni 3p and the Au 4f photoelectron images revealed that annealing leads to lateral heterogeneity in the Au distribution. The contributions of the two processes of surface diffusion and surface alloying are considered to explain the changes in Au surface concentrations observed on different grains after deposition and annealing. [Copyright &y& Elsevier]

[Display omitted] • Nanoindentation of a glass/crystal interface is studied by molecular dynamics. • The response of the interface is asymmetric. • The interface weakens the composite if dislocations arrive from the crystalline side. • It strengthens the composite if shear bands approach from the amorphous side. We perform molecular dynamics simulations of nanoindentation in bilayer systems composed of a Cu 64.5 Zr 35.5 metallic glass and a pure Cu crystalline sample. Both the cases where the glass and where the crystal is top are studied. We find a strong asymmetry in the response of the glass-top and the crystal-top system. The crystal-top system is the weakest one. Here, dislocations nucleate at the interface and also induce considerable strain in the glass layer beneath; hence the interface acts to reduce the plastic activity in the top crystal layer. In contrast, the glass-top system is the hardest system of the four systems studied. Shear bands form considerably earlier in the glass-top system than in a pure glass. The interface hinders shear band propagation; it thus causes a deflection of the load exerted by the indenter and hardens the material. Dislocations in the bottom crystal can be generated only when the indenter has penetrated the interface. [ABSTRACT FROM AUTHOR]

• A method to modify the epitaxial Si interface for layer transfer was developed. • Strong correlation between interface porosity and layer transfer was found. • After testing several bonding techniques and materials, epitaxial Si layer was transferred successfully to glass. • Defect density was reduced in epitaxial Si with bilayer interface after anodic bonding. • Fragile interface of epitaxial Si with bilayer interface was evidenced. Recently, epitaxial Si layers have attracted strong attention, particularly in photovoltaics. This successful application depends mainly on the easiness of their transfer to a foreign carrier substrate. Therefore, developing a simple and efficient method to realize the transfer is a key issue. A most delicate point is the lift-off of the epitaxial layer from its parent substrate. In this work, we present a method to weaken the interface based on hydrogen incorporation. We have been able to control the hydrogen content at the interface between the crystalline silicon substrate and the epitaxial films by changing the epitaxial growth conditions. Several bonding techniques have been tested and epitaxial Si films have been transferred successfully via anodic bonding. A hydrogen-assisted transferring mechanism is presented. [ABSTRACT FROM AUTHOR]

• The crystalline and amorphous interface of FeS 2 and polyaniline is constructed. • The S element is doped into the PANI by forming C S covalent bond. • The crystalline and amorphous interface improves the electrocatalytic activity. • The potential is 1.49 V at 10 mA cm−2 for oxygen evolution in 1 M KOH solution. We report a facile strategy to synthesize the FeS 2 /polyaniline/exfoliated graphene (FeS 2 /PANI /EG) with the formation of crystalline and amorphous interface for enhanced electrocatalytic activity. The PANI layer consists of nanowires roughly 100 nm in diameters and exhibits randomly distributed porous structure and the diameters of FeS 2 distributed from 5 nm to 15 nm. The transmission electron microscopy image indicates the successful construction of crystalline and amorphous interface between FeS 2 and PANI. In addition, the S element is doped into the PANI by forming C S covalent bond. Thus, the prepared FeS 2 /PANI/EG film shows excellent catalytic activity with the potential of 1.49 V at 10 mA cm−2 for oxygen evolution reaction in 1 M KOH solution, comparing with the 1.59 V and 1.65 V for FeS 2 /EG and PANI/EG, respectively. [ABSTRACT FROM AUTHOR]