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This contribution aims at reporting, from the subjective point of view of a witness based in Orsay, the fundamental role of Ondrej Krivanek in the spectacular emergence of EELS (Electron Energy-Loss Spectroscopy) as a key tool in analytical electron microscopy. In this regard, he has successively designed and built while he was at Gatan, serial EELS spectrometers, parallel EELS spectrometers and post-column energy filters which have been fitted to many different (S)TEM columns installed around the world. More recently the implementation of monochromators on the NION dedicated STEM together with the realization and performance of aberration correctors (which lie out of the scope of the present review), have placed the most advanced instrumental tool in the hands of continuously increasing populations of users in many domains of materials science and in life sciences. Furthermore, the impact of Ondrej Krivanek has spread widely beyond his technical achievements into that of a highly respected organizer of workshops, bringing together at regular intervals, all the experts from around the world and building up a real community of scientists. [ABSTRACT FROM AUTHOR]

In the scanning transmission electron microscope, multiple signals can be simultaneously collected, including the transmitted and scattered electron signals (bright field and annular dark field or Z-contrast images), along with spectroscopic signals such as inelastically scattered electrons and emitted photons. In the last few years, the successful development of aberration correctors for the electron microscope has transformed the field of electron microscopy, opening up new possibilities for correlating structure to functionality. Aberration correction not only allows for enhanced structural resolution with incident probes into the sub-Ångstrom range, but can also provide greater probe currents to facilitate mapping of intrinsically weak spectroscopic signals at the nanoscale or even the atomic level. In this issue of MRS Bulletin, we illustrate the power of the new generation of electron microscopes with a combination of imaging and spectroscopy. We show the mapping of elemental distributions at atomic resolution and also the mapping of electronic and optical properties at unprecedented spatial resolution, with applications ranging from graphene to plasmonic nanostructures, and oxide interfaces to biology. [ABSTRACT FROM AUTHOR]

The article discusses nanoparticle research and nanoparticles in solution derived from electron microscopy, referencing a study and research conducted by the scientist J. Park which appears within the issue. An overview of the use of graphene liquid cell (GLC) in the development of nanocrystals is provided.

This review intends to illustrate how electron energy-loss spectroscopy (EELS) techniques in the electron microscope column have evolved over the past 60 years. Beginning as a physicist tool to measure basic excitations in solid thin foils, EELS techniques have gradually become essential for analytical purposes, nowadays pushed to the identification of individual atoms and their bonding states. The intimate combination of highly performing techniques with quite efficient computational tools for data processing and ab initio modeling has opened the way to a broad range of novel imaging modes with potential impact on many different fields. The combination of Angström-level spatial resolution with an energy resolution down to a few tenths of an electron volt in the core-loss spectral domain has paved the way to atomic-resolved elemental and bonding maps across interfaces and nanostructures. In the low-energy range, improved energy resolution has been quite efficient in recording surface plasmon maps and from them electromagnetic maps across the visible electron microscopy (EM) domain, thus bringing a new view to nanophotonics studies. Recently, spectrum imaging of the emitted photons under the primary electron beam and the spectacular introduction of time-resolved techniques down to the femtosecond time domain, have become innovative keys for the development and use of a brand new multi-dimensional and multi-signal electron microscopy. [ABSTRACT FROM AUTHOR]

Over the past two or three decades, nanoscience and nanotechnology have clearly established themselves as prominent domains in research in physics, not only because of the innovative concepts and properties that they display but also for their capacity to generate many important applications and commercial developments. As many of these new devices exhibit a range of properties (transport, optical, magnetic, catalysis) which are governed by local structural and electronic configurations, such as coordination and bonding at the atomic level, it is no surprise that new tools of investigation are constantly being developed for imaging, analyzing, understanding and controlling at the relevant scale. Among them, electron microscopy has recently demonstrated its ability to meet many of these requirements. In particular, Å-sized probes are nowadays generated by aberration correctors in a scanning transmission electron microscope (STEM) and they can investigate the electron excitation spectrum of the specimen (through electron energy-loss spectroscopy, EELS) with a typical energy resolution of 0.1–0.3 eV over a broad spectral band from the IR to the X ray domain. In the high energy range, characteristic signals due to the excitation of atomic core levels are quite useful because they identify the atoms in the analyzed volume (which can itself be as small as a single atom) and can therefore deliver atomically-resolved elemental maps. But the pixel-by-pixel recording of the fine structures beyond the characteristic threshold is much more informative and tells us how the excited atom is surrounded by its neighbors, what is its exact structural environment and its charge population. The present review focuses on this particularly exciting field, with a special interest in the types of information accessible and their signature. After summarizing the ingredients required for successful experiments (instrumental as well as theoretical), examples encountered in different situations, in particular in single layers of 2D materials and at the interfaces in oxide heterostructures, will demonstrate the present capabilities of this STEM-EELS technique. [ABSTRACT FROM AUTHOR]