The virtual conference platform will allow you to listen and network with like minded scientists from the comfort of your own desk; listening to presentations, posting questions to speakers in real time and networking in the chat areas.
We have also brought a carefully selected group of some of the key industrial players in the field to help you find the solutions you are looking for in your day to day research, be sure to visit their booths and download must have whitepapers, videos, podcasts and documents detailing some of their products launched in the field of microscopy analysis.
One of the current major driving forces behind instrument development in transmission electron microscopy (TEM) is the ability to observe materials processes as they occur in situ within the microscope. For many processes, such as nucleation and growth, phase transformations and mechanical response under extreme conditions, the beam current in even the most advanced field emission TEM is insufficient to acquire images with the temporal resolution (∼1 μs to 1 ns) needed to observe the fundamental interactions taking place. The dynamic transmission electron microscope (DTEM) avoids this problem by using a short pulse laser to create an electron pulse of the required duration through photoemission which contains enough electrons to form a complete high resolution image. The current state-of-the-art in high time resolution electron microscopy in this paper describes the development of the electron optics and detection schemes necessary to fully utilize these electron pulses for materials science. In addition, developments for future instrumentation and the experiments that are expected to be realized shortly will also be discussed.
Carbon nanotube (CNT) membranes offer an exciting opportunity to mimic natural protein channels due to (1) a mechanism for dramatically enhanced fluid flow, (2) ability to place ‘gatekeeper’ chemistry at the entrance to pores, and (3) being electrically conductive to localize electric field or perform electrochemical transformations. The transport mechanisms through CNT membranes are primarily (1) ionic diffusion near bulk expectation, (2) gas flow enhanced 1–2 orders of magnitude primarily due to specular reflection, and (3) fluid flow 4–5 orders of magnitude faster than conventional materials due to a nearly ideal slip-boundary interface. Transport can be modulated by ‘gatekeeper’ chemistry at the pore entrance using steric hindrance, electrostatic attraction/repulsion, or biochemical state. Electroosmotic flow is seen to be highly power efficient and can act as a pump through regions of chemical selectivity. The fundamental requirements of mimicking protein channels are present in the CNT membrane system. This membrane structure is mechanically far more robust than lipid bilayer films, allowing for large-scale chemical separations, delivery or sensing based on the principles of protein channels. Applications ranging from water purification, energy generation and bio-separations are highlighted.
Transmission electron microscopy of chalcogenide thin-film photovoltaic materials - Professor Yanfa Yan
Thin-film photovoltaic modules hold great promise to produce sustainable, low-cost, and clean electricity from sunlight, because thin-film solar cells can potentially be fabricated by economical, high-volume manufacturing techniques. However, to achieve high sunlight-to-electricity conversion efficiency, thin-film solar cells require sophisticated control on interface formation and materials qualities. Transmission electron microscopy (TEM) provides unique methods to access this information at the nanometer scale. In this paper, we provide a brief review on TEM studies of the interfaces, microstructure, and lattice defects in chalcogenide thin-film photovoltaic materials. We analyze the potential effects of the observed interface formation and materials quality that could affect the performance of solar cells.
Torsional tapping atomic force microscopy for the study of soft matter and biological systems - Dr Nic Mullin
It is well known that the resolution obtainable by AFM is limited by a variety of factors, including the sharpness of the tip, the dynamics of the cantilever, and the noise associated with detecting cantilever motion. In the presentation a relatively new addition to the family of AFM methods: torsional tapping AFM is described.
In torsional tapping, a T shaped cantilever with the tip offset from the long axis is driven into torsional oscillation to yield a tapping motion at the tip. Due to the favourable dynamics of torsional oscillation (high resonant frequency and high Q) and the geometry of the optical lever, we find that the detection noise is reduced by a factor of 12 in torsion as compared to regular tapping mode (for the same cantilever in an identical system). The dynamics of the torsional mode also allow increased force sensitivity, as the increase in Q and resonant frequency are greater than the increase in spring constant. Passive bending in the flexural mode of the cantilever effectively limits the tip-sample force in the case of high feedback error signal, ensuring that the tip remains sharp.
The combination of these factors allows carbon "whisker" tips to be used to obtain true molecular resolution on rough, soft surfaces in air. Furthermore, the high resonant frequency and passive flexural deflection of torsional tapping also allow the scan rate to be increased by a factor of 5 compared to regular tapping mode on the same instrument.
Data collected on a variety of soft matter systems, including liquid crystals, semicrystalline polymers, organic semiconductors, 2d protein crystals and erythrocytes is presented. The operation and development of the instrument will also be discussed.
Atom probe crystallography: Direct measurements of structure and composition at the atomic scale - Dr Baptiste Gault
This presentation will address new developments about the emerging area of ‘atom probe crystallography’, a characterisation tool that provides the unique ability to simultaneously measure composition and structure at the atomic scale. The ability to access this information is crucial to scientists working across a broad range of material science disciplines, such as researchers working on the design of both structural and functional materials with optimised physical properties (mechanical, optoelectronic, magnetic, superconducting) that find application in, for example, nanoelectronics or energy generation. Additionally, the ability to extract crystallographic information from 3D atomistic atom probe reconstruction has exciting potential synergies with modern modeling techniques, blending experimental and computational methods to extend our insight.
Nanostructural and chemical characterization of supported metal oxide catalysts by aberration corrected analytical electron microscopy - Professor Wu Zhou
The performance of catalyst materials are usually governed by the precise atomic structure and composition of very specific catalytically active sites. Therefore, structural and chemical characterization at the atomic scale becomes a vital requirement in order to identify any structure-performance relationships existing in heterogeneous catalyst systems. Aberration-corrected scanning transmission electron microscopy (STEM) represents an ideal means to probe the atomic scale structural and chemical information via a combination of various imaging and spectroscopy techniques. We will review some applications of aberration-corrected STEM to catalyst research, firstly in the context of supported metal catalysts, which serve as ideal material systems to illustrate the power of these techniques. Then we will discuss some recent progress relating to the characterization of supported metal oxide catalysts using aberration-corrected STEM. We will show that it is now possible to directly image supported surface oxide species, study oxide wetting characteristics, identify the catalytic active sites and develop new insights into the structure-activity relationships for complex double supported oxide catalysts. Future possibilities for in-situ and gentle low voltage electron microscopy studies of oxide-on-oxide materials are also discussed.
Transient absorption microscopy in the label free imaging of semiconducting and metallic carbon nanotubes - Professor Ji-Xin Cheng
As interest in the potential biomedical applications of carbon nanotubes increases1, there is a need for methods that can image nanotubes in live cells, tissues and animals. Although techniques such as Raman2, 3, 4, photoacoustic5 and near-infrared photoluminescence imaging6, 7, 8, 9, 10 have been used to visualize nanotubes in biological environments, these techniques are limited because nanotubes provide only weak photoluminescence and low Raman scattering and it remains difficult to image both semiconducting and metallic nanotubes at the same time. Here, we show that transient absorption microscopy offers a label-free method to image both semiconducting and metallic single-walled carbon nanotubes in vitro and in vivo, in real time, with submicrometre resolution. By using appropriate near-infrared excitation wavelengths, we detect strong transient absorption signals with opposite phases from semiconducting and metallic nanotubes. Our method separates background signals generated by red blood cells and this allows us to follow the movement of both types of nanotubes inside cells and in the blood circulation and organs of mice without any significant damaging effects. (Reference: Tong et al., Nature Nanotechnology (2012), 7, 56)