A5078036358- Advanced Electron Microscopy Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
- Graphene research and applications
- Integrated Circuits and Semiconductor Failure Analysis
- Carbon Nanotubes in Composites
- Electronic and Structural Properties of Oxides
- Advanced Materials Characterization Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Catalytic Processes in Materials Science
- 2D Materials and Applications
- Crystallography and Radiation Phenomena
- Gold and Silver Nanoparticles Synthesis and Applications
- Force Microscopy Techniques and Applications
- Ion-surface interactions and analysis
- Advancements in Photolithography Techniques
- Surface and Thin Film Phenomena
- Machine Learning in Materials Science
- CCD and CMOS Imaging Sensors
- Advancements in Battery Materials
- Advanced Fluorescence Microscopy Techniques
- nanoparticles nucleation surface interactions
- Iron oxide chemistry and applications
- Chalcogenide Semiconductor Thin Films
- MXene and MAX Phase Materials
University of Oxford
2016-2025
Rosalind Franklin Institute
2020-2025
Diamond Light Source
2016-2024
Rutherford Appleton Laboratory
2013-2024
Engineering and Physical Sciences Research Council
2017-2023
Oxfam
2019
Science Oxford
2003-2018
Research Complex at Harwell
2013-2017
University of Bristol
2012
Nanjing University
2012
The complete crystallography of a one-dimensional crystal potassium iodide encapsulated within 1.6-nanometer-diameter single-walled carbon nanotube has been determined with high-resolution transmission electron microscopy. Individual atoms and iodine the were identified from phase image that was reconstructed modified focal series restoration approach. lattice spacings are substantially different those in bulk iodide. This is attributed to reduced coordination surface close proximity van der...
The movement of dislocations in a crystal is the key mechanism for plastic deformation all materials. Studies have focused on three-dimensional materials, and there little experimental evidence regarding dynamics their impact at atomic level lattice structure graphene. We studied dislocation pairs graphene, recorded with single-atom sensitivity. examined stepwise along zig-zag direction mediated either by single bond rotation or through loss two carbon atoms. strain fields were determined,...
Abstract With mounting concerns over climate change, the utilisation or conversion of carbon dioxide into sustainable, synthetic hydrocarbons fuels, most notably for transportation purposes, continues to attract worldwide interest. This is particularly true in search sustainable renewable aviation fuels. These offer considerable potential since, instead consuming fossil crude oil, fuels are produced from using hydrogen and energy. We report here a protocol fixation by converting it directly...
We present an atomic resolution structural study of covalently bonded dopant pairs in the lattice monolayer graphene. Two iron (Fe) metal atoms that are within graphene observed and their interaction with each other is investigated. The two atom dopants can form small paired clusters varied geometry vacancy defects. Fe created a 10 nm diameter predefined location by manipulating focused electron beam (80 kV) on surface containing intentionally deposited precursor reservoir....
Focused electron beam irradiation has been used to create mono and divacancies in graphene within a defined area, which then act as trap sites for mobile Fe atoms initially resident on the surface. Aberration-corrected transmission microscopy at 80 kV study real time dynamics of filling vacancy with atomic resolution. We find that incorporation dopant atom results pronounced displacements surrounding carbon up 0.5 Å, is good agreement density functional theory calculations. Once incorporated...
Transition metal doped chalcogenides are one of the most important classes catalysts that have been attracting increasing attention for petrochemical and energy related chemical transformations due to their unique physiochemical properties. For practical applications, achieving maximum atom utilization by homogeneous dispersion metals on surface is essential. Herein, we report a detailed study deposition method using thiourea coordinated transition complexes. This allows preparation library...
The development of the next generation nanotechnologies requires precise control size, shape, and structure individual components in a variety chemical engineering environments. This includes synthesis, storage, operational environments and, since these products will ultimately be discarded, their interaction with natural ecosystems. Much important information that determines properties is contained within nanoscale phase diagrams, but quantitative maps include surface effects critical...
The crystal growth behaviour of solid phase halides encapsulated within single walled carbon nanotubes (SWNTs) is reviewed. As SWNTs form atomically thin channels a restricted diameter range, their internal van der Waals surfaces regulate the materials in very precise fashion. Crystal therefore regulated and nano-scale crystals with integral layer architectures (i.e. 'Feynman Crystals') can be formed. structural properties resulting 1D are principally dictated by chemistry bulk material...
The results of detailed structural studies trigonal lamellar particles both gold and silver are presented. have been characterized in sol by means optical spectroscopy powder X-ray diffraction ex using high resolution electron microscopy plan view profile imaging modes. these indicated that the a outline shortened along ≺111≻ direction to give plate-like morphology. presence small numbers parallel {111} twin planes has also confirmed used explain formally forbidden ⅓{422} reflections...
We have studied atomic level interactions between single Pt atoms and the surface of monolayer MoS2 using aberration-corrected annular dark field scanning transmission electron microscopy at an accelerating voltage 60 kV. Strong contrast from on atomically resolved lattice enables their exact position to be determined with respect lattice, revealing stable binding sites. In regions free contamination, are localized in S vacancy sites exhibit dynamic hopping nearby driven by energy supplied...
Cation-exchange has been used to synthesize PbS/CdS core/shell colloidal quantum dots from PbS starting cores. These were then incorporated as the active material in solar cell test devices using a solution-based, air-ambient, layer-by-layer spin coating process. We show that can replace their unshelled counterparts with similar band gap layer device, leading an improvement open circuit voltage 0.42 0.66 V. This is attributed reduction recombination result of passivating shell. However, this...
Two distinct configurations of the monovacancy in graphene have been observed using aberration-corrected transmission electron microscopy (AC-TEM) at 80 kV. The predicted lower energy asymmetric (MV), exhibiting a Jahn–Teller reconstruction (r-MV), has observed, but addition, we imaged instances symmetric (s-MV). We used geometric phase analysis (GPA) to quantitatively determine strain lattice surrounding these two defect and show that generates significant extra compared MV case. Density...
Cryo-electron microscopy is an essential tool for high-resolution structural studies of biological systems. This method relies on the use phase contrast imaging at high defocus to improve information transfer low spatial frequencies expense higher frequencies. Here we demonstrate that electron ptychography can recover specimen with continuous across a wide range frequency spectrum, improved lower frequencies, and as such more efficient recovery than conventional imaging. We further show be...
Right to the core: The design of nanocatalysts with maximized catalytic performance relies on control size, shape, and composition. shell thickness nanocrystals core–shell structures can be controlled, thus enabling over nanocrystal electronic structure properties. Monodisperse faceted icosahedral Au–Pd (see picture) were synthesized, optimized for oxidation benzyl alcohol benzaldehyde.
Knowing the three-dimensional structural information of materials at nanometer scale is essential to understanding complex material properties. Electron tomography retrieves using a tilt series two-dimensional images. In this paper, we report an alternative combination electron ptychography with inverse multislice method. We demonstrate depth sectioning nanostructured into slices 0.34 nm lateral resolution and corresponding about 24-30 nm. This imaging method has potential applications for...
Dopants in two-dimensional dichalcogenides have a significant role affecting electronic, mechanical, and interfacial properties. Controllable doping is desired for the intentional modification of such properties to enhance performance; however, unwanted defects impurity dopants also detrimental impact, as often found chemical vapor deposition (CVD) grown films. The reliable identification, subsequent characterization, therefore importance. Here, we show that Cr V atoms are CVD MoS2 monolayer...
Abstract Defects in materials give rise to fluctuations electrostatic fields that reflect the local charge density, but imaging this with single atom sensitivity is challenging. However, if possible, provides information about energetics of adatom binding, localized conduction channels, molecular functionality and their relationship individual bonds. Here, ultrastable electron-optics are combined a high-speed 2D electron detector map around atoms monolayers using 4D scanning transmission...
Abstract Advances in cryogenic transmission electron microscopy have revolutionised the determination of many macromolecular structures at atomic or near-atomic resolution. This method is based on conventional defocused phase contrast imaging. However, it has limitations weaker for small biological molecules embedded vitreous ice, comparison with cryo-ptychography, which shows increased contrast. Here we report a single-particle analysis use ptychographic reconstruction data, demonstrating...
The controlled formation of branched palladium nanostructures has been performed using a simple reaction procedure carried out at room temperature. Structural characterization an as-synthesized tripod gives insight into anisotropic growth occurring from highly symmetrical face centered cubic crystal structures.