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This book covers both practical and theoretical aspects of atomic resolution transmission electron microscopy. The discovery of the carbon nanotube, the three-dimensional imaging of the ribosome, and the imaging of a single foreign atom inside a thin crystal by energy-filtered transmission electron microscopy have all demonstrated the immense power of this technique. The recent development of aberration-correction devices has brought the spatial resolution of the method below one Angstrom. The emphasis throughout is on a clear presentation of fundamental concepts, and practical advice. The chapters review simple electron optics, phase contrast theory, coherence theory, and imaging theory for thin crystals. The multiple scattering theory is given in full, and the relationship between the various formulations (Bloch-wave, multislice, scattering matrix, Howie–Whelan equations, phase grating etc) is explained. Applications in biology and materials science are covered, with discussions of radiation damage, sample preparation, image processing and super-resolution, electron holography, and aberration correction. The theory of high-angle annular dark field Z-contrast imaging by scanning transmission electron microscopy is given in full. Additional chapters are devoted to electron sources and detectors, fault diagnosis, experimental methods and associated techniques such as channelling effects in X-ray microanalysis, microdiffraction, cathodoluminescence, environmental microscopy and electron energy-loss spectroscopy.

Within the class of two-dimensional materials, transition metal dichalcogenides (TMDs), are extremely appealing for a variety of technological applications. Moreover, the manipulation of the layered morphology at the nanoscale is a knob for further tailoring their physical and chemical properties towards target applications. Here, the combination of atomic layer deposition (ALD) and chemical vapour deposition (CVD) is presented as a general approach for the fabrication of TMD layers arranged in arbitrary geometry at the nanoscale. Indeed, following such all-chemical based approach, high-resolution electron microscopy shows the conformal growth of MoS2 to nano-trench pattern obtained in SiO2 substrates on large area. Growth is uniform not only in the flat region of the pattern but also at the hinges and throughout vertical faces, without rupture, all along the rectangular shape profile of the trenches. Furthermore, MoS2 bending dramatically affects the electron-phonon coupling as demonstrated by resonant Raman scattering. The proposed approach opens the door to the on-demand manipulation of the TMDs properties by large-scale substrate pattern design.

Advanced high-resolution transmission electron microscopy methods have been used to study structural changes in a 51 at % Cu–Pd solid solution and identify the nature of compositional segregation in the disordered solid solution. The results can be used to account for the low rate of the ordering process near the equiatomic composition.

For the purpose of humidity sensing, the rGO/Fe 2 O 3 nanocomposite was synthesized through precipitation technique that is followed by lyophilization process to enhance the surface area of the prepared nanocomposite. In order to investigate the sensor preparation quality, its activity and efficiency, the prepared nanocomposite has undergone different characterization techniques such as; high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, thermo-gravimetric analysis (TGA), BET surface area and BJH pore diameter distribution. The study showed that Fe 2 O 3 nanoparticles are densely and homogeneously loaded over rGO sheets. The porosity and surface area play an important role on humidity sensing property. In addition, the BET surface area and BJH pore radius of the rGO/Fe 2 O 3 are found to be 2002.09 m 2 g −1 and 1.68 nm, respectively. Furthermore, the humidity-sensing performances were investigated in a wide range of working humidity (11–97% RH) and frequency (100 Hz–100 kHz). The obtained results confirmed that the optimum measuring frequency is 1 kHz, due to in inability of water molecule to be polarized at higher frequency. The humidity sensing performance of rGO/Fe 2 O 3 nanocomposite shows a parabola relationship with the RH value from 11 to 97%. The incorporation of Fe 2 O 3 into rGO creates more active sites, such as vacancies and defects which promote the adsorption of water molecule thereby increasing the sensitivity of the sensor. Molecular models of graphene; graphene/2Fe 2 O 3 , graphene/2Fe 2 O 3 /2H 2 O were built. The model suggested that decorating the graphene with 2Fe 2 O 3 enable it to be sensitive for humidity.

Platinum nanoparticles with diameters less than ∼5 nm were prepared on graphite particles by the coaxial arc plasma deposition, and the structure of platinum nanoparticles was investigated using high-resolution transmission electron microscopy. {110} facets of platinum nanoparticles parallel to the surface (0001) planes of graphite particles were most frequently observed. The platinum nanoparticles were found to be anisotropically deformed from the bulk face-centered cubic structure, and the lattice parameters of platinum nanoparticles were estimated by assuming monoclinic structures. No correlation was observed between the diameter and the lattice parameters of the platinum nanoparticles. Approximately two-thirds of the platinum nanoparticles were compressively strained, and the other platinum nanoparticles showed the expanded unit cells. The cube root of monoclinic unit cell of the platinum nanoparticles varied from a compression of 5.9% to an expansion of 2.8% as compared with the bulk lattice constant of platinum.

Two-dimensional materials with monolayer thickness and extreme aspect ratios are sought for their high surface areas and unusual physicochemical properties 1 . Liquid exfoliation is a straightforward and scalable means of accessing such materials 2 , but has been restricted to sheets maintained by strong covalent, coordination or ionic interactions 3 – 10 . The exfoliation of molecular crystals, in which repeat units are held together by weak non-covalent bonding, could generate a greatly expanded range of two-dimensional crystalline materials with diverse surfaces and structural features. However, at first sight, these weak forces would seem incapable of supporting such intrinsically fragile morphologies. Against this expectation, we show here that crystals composed of discrete supramolecular coordination complexes can be exfoliated by sonication to give free-standing monolayers approximately 2.3 nanometres thick with aspect ratios up to approximately 2,500:1, sustained purely by apolar intermolecular interactions. These nanosheets are characterized by atomic force microscopy and high-resolution transmission electron microscopy, confirming their crystallinity. The monolayers possess complex chiral surfaces derived partly from individual supramolecular coordination complex components but also from interactions with neighbours. In this respect, they represent a distinct type of material in which molecular components are all equally exposed to their environment, as if in solution, yet with properties arising from cooperation between molecules, because of crystallinity. This unusual nature is reflected in the molecular recognition properties of the materials, which bind carbohydrates with strongly enhanced enantiodiscrimination relative to individual molecules or bulk three-dimensional crystals. Sonication of layered metallacycle crystals gives free-standing nanosheets held together by weak non-covalent interactions, with chiral surfaces that show improved binding and enantiodiscrimination compared with individual metallacycle molecules.

The revolutionary improvement of hardware and algorithm in cryogenic electron microscopy (cryo‐EM) has made it a routine method to obtain structures of macromolecules at near‐atomic resolution. Nevertheless, this technique still faces many challenges. The structure‐solving efficiency of cryo‐EM can be significantly reduced by the biomolecules' denaturation on the air–water interfaces, the preferred orientation, strong background noise from supporting films and particle motion, and so forth. To overcome these problems, nanomaterials with ultrahigh electronic conductivity and ultrathin thickness are explored as promising cryo‐EM specimen supporting films. Herein, we summarize the structural engineering of graphene, for example, surface and interface modification, as supporting films for grids and the application on high‐resolution cryo‐EM and discuss potential future perspectives. The functionalized graphene‐based cryogenic electron microscopy (cryo‐EM) grids show superior properties, such as good conductivity, mechanical strength, selectivity on target macromolecules, hydrophilicity, and very low background noise. We believe that the structural engineering of graphene and even other 2D materials will broaden the application for high‐resolution cryo‐EM and significantly improve the development of methodology.

Purpose This paper aims to discuss the scanning methodology depending on the close-range photogrammetry technique, which is appropriate for the precise three-dimensional (3D) modelling of objects in millimetres, such as the dimensions and structures in sub-millimetre scale. Design/methodology/approach The camera was adjusted to be tilted around the horizontal axis, while coded dot targets were used to calibrate the digital camera. The experiment was repeated with different rotation angles (5°, 10°, 15°, 20°, 25°, 30°, 50° and 60°). The images were processed with the PhotoModeler software to create the 3D model of the sample and estimate its dimensions. The features of the sample were measured using high-resolution transmission electron microscopy, which has been considered as a reference and the comparative dimensions. Findings The results from the current study concluded that changing the rotation angle does not significantly affect the results, unless the angle of imagery is large which prevent achieving about 20: 30% overlap between the images but, the more angle decreases, the more number of images increase as well as the processing duration in the programme. Originality/value Develop an automatic appropriate for the precise 3D modelling of objects in millimetres, such as the dimensions and structures in sub-millimetre scale using photogrammetry.

The interplay between surface reconstruction and depolarization of ferroelectric oxide surfaces is strongly influenced by oxygen vacancies (VO). Using in‐situ atomic‐resolution electron microscopy imaging and spectroscopy techniques, it is directly observed that a clean BaTiO3 (001) surface stabilizes into (2 × 1) BaO‐terminated reconstruction during vacuum annealing. This surface reconstruction is achieved with accommodating BaO deficiency and incorporates TiOx adunits. The cooperative atomic rumpling in both the surface and subsurface layers, arranged in a tail‐to‐tail configuration, is stabilized by planar accumulation of VO in the subsurface TiO2 layer. This reduces the net polarization of surface unit cells, contributing to overall depolarization. Under this atomic rumpling, the polarization‐down (P↓) state is energetically favored over the polarization‐up (P↑) state, as the P↓ state requires less atomic relaxation in the bulk layers to achieve dipole inversion at the subsurface. The energetic preference for VO in the subsurface TiO2 layer of the P↓ state is confirmed through calculations of VO formation energy and the energy barrier for surface‐to‐subsurface migration. These findings reveal that the presence of VO in the subsurface layer lifts the degeneracy in the double‐well potential between the P↓ and P↑ states in BaTiO3 (001). In‐situ atomic‐scale electron microscopy reveals that vacuum‐annealed ferroelectric BaTiO3 (001) surfaces exhibit BaO termination with periodic Ba deficiency and TiOx adunits. Planar oxygen vacancy accumulation in the subsurface TiO2 layer mitigates the depolarization field, facilitating cooperative rumpling of surface and subsurface layers in a tail‐to‐tail dipole configuration, where downward polarization is relatively more stable than upward polarization.

The authors describe the preparation of magnetic cobalt/nitrogen-doped carbon microspheres (Co-N/Cs) by combining a hydrothermal procedure with a carbonization process. The textures of the Co-N/Cs were investigated by powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, nitrogen adsorption-desorption isotherms and vibration sample magnetometry. The Co-N/Cs possess a high surface area and strong magnetism. This results in good adsorption capability and enables magnetic separation. The Co-N/Cs are shown to be an effective magnetic solid-phase extraction adsorbent for the enrichment of various phthalate esters (diethyl phthalate, diallyl phthalate and diisobutyl phthalate) from sport beverages and milk samples prior to their determination by HPLC. The limits of detection (at an S/N ratio of 3) are between 0.1–0.2 and 0.08–0.3 ng mL −1 for sport beverages and milk samples, respectively. The recoveries when extracting all the spiked samples varied from 80.3% to 116.2%. Graphical abstract Magnetic cobalt/nitrogen-doped carbon microspheres (Co-N/Cs) were prepared and used as an effective magnetic solid phase extraction adsorbent for the enrichment of phthalate esters from beverages and milk samples.