Florian Banhart

Bio: Florian Banhart is an academic researcher from University of Strasbourg. The author has contributed to research in topics: Carbon nanotube & Carbon. The author has an hindex of 55, co-authored 198 publications receiving 15420 citations. Previous affiliations of Florian Banhart include Max Planck Society & Rensselaer Polytechnic Institute.

Structural defects in graphene

Abstract: Graphene is one of the most promising materials in nanotechnology. The electronic and mechanical properties of graphene samples with high perfection of the atomic lattice are outstanding, but structural defects, which may appear during growth or processing, deteriorate the performance of graphene-based devices. However, deviations from perfection can be useful in some applications, as they make it possible to tailor the local properties of graphene and to achieve new functionalities. In this article, the present knowledge about point and line defects in graphene are reviewed. Particular emphasis is put on the unique ability of graphene to reconstruct its lattice around intrinsic defects, leading to interesting effects and potential applications. Extrinsic defects such as foreign atoms which are of equally high importance for designing graphene-based devices with dedicated properties are also discussed.

Irradiation effects in carbon nanostructures

Abstract: The paper reviews the principles of interaction of energetic particles with solid carbon and carbon nanostructures. The reader is first introduced to the basic mechanisms of radiation effects in solids with particular emphasis on atom displacements by knock-on collisions. The influence of various parameters on the displacement cross sections of carbon atoms is discussed. The types of irradiation-induced defects and their migration are described as well as ordering phenomena which are observable under the non-equilibrium conditions of irradiation. The main part of this review deals with alterations of carbon nanostructures by the electron beam in an electron microscope. This type of experiment is of paramount importance because it allows in situ observation of dynamic processes on an atomic scale. In the second part, radiation effects in the modifications of elemental carbon, in particular in graphite which forms the crystallographic basis of most carbon nanostructures, are treated in detail. It follows a review of the available experimental results on radiation defects in carbon nanostructures such as fullerenes, nanotubes and carbon onions. Finally, the phenomena of structure formation under irradiation, in particular the self-assembling of spherical carbon onions and the irradiation-induced transformation of graphitic nanoparticles into diamond, are presented and discussed qualitatively in the context of non-equilibrium structure formation.

Spongy Graphene as a Highly Efficient and Recyclable Sorbent for Oils and Organic Solvents

Abstract: In this work, spongy graphene (SG), a shape-mouldable and nanoporous material with a high specific surface area used as a versatile and recyclable sorbent material, is proposed and studied. SG shows highly efficient absorption of not only petroleum products and fats, but also toxic solvents such as toluene and chloroform (up to 86 times of its own weight), requiring no further pretreatment, which is tens of times higher than that of conventional absorbers. Moreover, SG can be regenerated (>10 times) by heat treatment, yielding the full release of adsorbates (>99%). The present work suggests SG a widespread potential for applications in industry as well as topics regarding environmental protection.

Engineering of nanostructured carbon materials with electron or ion beams

Abstract: Irradiating solids with energetic particles is usually thought to introduce disorder, normally an undesirable phenomenon. But recent experiments on electron or ion irradiation of various nanostructures demonstrate that it can have beneficial effects and that electron or ion beams may be used to tailor the structure and properties of nanosystems with high precision. Moreover, in many cases irradiation can lead to self-organization or self-assembly in nanostructures. In this review we survey recent advances in the rapidly evolving area of irradiation effects in nanostructured materials, with particular emphasis on carbon systems because of their technological importance and the unique ability of graphitic networks to reconstruct under irradiation. We dwell not only on the physics behind irradiation of nanostructures but also on the technical applicability of irradiation for nanoengineering of carbon and other systems.

Molecular Junctions by Joining Single-Walled Carbon Nanotubes

Abstract: Crossing single-walled carbon nanotubes can be joined by electron beam welding to form molecular junctions Stable junctions of various geometries are created in situ in a transmission electron microscope Electron beam exposure at high temperatures induces structural defects which promote the joining of tubes via cross-linking of dangling bonds The observations are supported by molecular dynamics simulations which show that the creation of vacancies and interstitials induces the formation of junctions involving seven- or eight-membered carbon rings at the surface between the tubes

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Diamond-like amorphous carbon

Abstract: Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications as protective coatings in areas, such as magnetic storage disks, optical windows and micro-electromechanical devices (MEMs).

Recent Advances in Ultrathin Two-Dimensional Nanomaterials

Abstract: Since the discovery of mechanically exfoliated graphene in 2004, research on ultrathin two-dimensional (2D) nanomaterials has grown exponentially in the fields of condensed matter physics, material science, chemistry, and nanotechnology. Highlighting their compelling physical, chemical, electronic, and optical properties, as well as their various potential applications, in this Review, we summarize the state-of-art progress on the ultrathin 2D nanomaterials with a particular emphasis on their recent advances. First, we introduce the unique advances on ultrathin 2D nanomaterials, followed by the description of their composition and crystal structures. The assortments of their synthetic methods are then summarized, including insights on their advantages and limitations, alongside some recommendations on suitable characterization techniques. We also discuss in detail the utilization of these ultrathin 2D nanomaterials for wide ranges of potential applications among the electronics/optoelectronics, electrocat...