A convenient procedure to visualize defects on graphene layers by mapping the surface of carbon materials with an appropriate contrast agent was introduced by a team of researchers from Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences (Moscow) involved in international collaborative project.
Developed imaging procedure has revealed organized patterns of defects on large areas of carbon surfaces. Several types of defects on the carbon surface can be "caught" and captured on the microscopic image within a few minutes.
Graphene and related 2D materials are anticipated to become the compounds of the century. It is not surprising - graphene is extremely thin and strong, as well as possesses outstanding electrical and thermal characteristics.
The impact of material with such unique properties may be really impressive. Scientists foresight the imminent appearance of novel biomedical applications, new generation of smart materials, highly efficient light conversion and photocatalysis reinforced by graphene. However, the stumbling block is that many unique properties and capabilities are related to only perfect graphene with controlled number of defects.
However, in reality ideal defect-free graphene surface is difficult to prepare and defects may have various sizes and shapes. In addition, dynamic behaviour and fluctuations make the defects difficult to locate. The process of scanning of large areas of graphene sheets in order to find out defect locations and to estimate the quality of the material is a time-consuming task. Let alone a lack of simple direct methods to capture and visualize defects on the carbon surface.
Joint research project carried out by Ananikov and co-workers revealed specific contrast agent – soluble palladium complex Pd2dba3 – that selectively attaches to defect areas on the surface of carbon materials. Pd attachment leads to formation of nanopartilces, which can be easily detected using a routine electron microscope.
The more reactive the carbon center is, the stronger is the binding of contrast agent in the imaging procedure. Thus, reactivity centers and defect sites on a carbon surface were mapped in three-dimensional space with high resolution and excellent contrast using a handy nanoscale imaging procedure.
The developed procedure distinguished carbon defects not only due to difference in their morphology, but also due to varying chemical reactivity. Therefore, this imaging approach enables the chemical reactivity to be visualized with spatial resolution.
Mapping carbon reactivity centers with "Pd markers" gave unique insight into the reactivity of the graphene layers. As revealed in the study, more than 2000 reactive centers can be located per 1 μm2 of the surface area of regular carbon material.
The study pointed out the spatial complexity of the carbon material at the nanoscale. Mapping of surface defect density showed substantial gradients and variations across the surface area, which can possess a kind of organized structures of defects.
Medical application of imaging (tomography) for diagnostics, including the usage of contrast agents for more accuracy and easier observation, has proven its utility for many years. The present study highlights a new possibility in tomography applications to run diagnostics of materials at atomic scale.
The article «Spatial imaging of carbon reactivity centers in Pd/C catalytic systems» by E. O. Pentsak, A. S. Kashin, M. V. Polynski, K. O. Kvashnina, P. Glatzel and V. P. Ananikov was published in Chemical Science journal of Royal Society of Chemistry.
Reference: Chem. Sci., 2015, DOI: 10.1039/c5sc00802f
Ananikov Laboratory | ResearchSEA
Etching Microstructures with Lasers
25.10.2016 | Fraunhofer-Institut für Lasertechnik ILT
Applying electron beams to 3-D objects
23.09.2016 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering