scholarly journals Synthesis and nanoscale characterization of hierarchically assembled molecular nanosheets

2021 ◽  
Author(s):  
Marie Richard-Lacroix ◽  
Maria Küllmer ◽  
Anna Laurine Gaus ◽  
Christof Neumann ◽  
Christian Tontsch ◽  
...  
Keyword(s):  
Single Molecule ◽  
Photoelectron Spectroscopy ◽  
2D Materials ◽  
Chemical Characterization ◽  
Chemical Information ◽  
Surface Distribution ◽  
Grafting Reaction ◽  
Nanoscale Characterization ◽  
Tip Enhanced Raman Spectroscopy

Chemical functionalization of molecular two-dimensional (2D) materials towards the assembly of hierarchical functional nanostructures is of great importance for nanotechnology including areas like artificial photocatalytic systems, nanobiosensors or ultrafiltration. To achieve the desired functionality of 2D materials, these need to be characterized down to the nanoscale. However, obtaining the respective chemical information is challenging and generally requires the application of complementary experimental techniques. Here, we demonstrate the synthesis and chemical characterization of hierarchically assembled molecular nanosheets based on about 1 nm thin, molecular carbon nanomembrane (CNM) and covalently grafted, single-molecule layer cobalt(III) catalysts for the light-driven hydrogen evolution reaction (HER). We employ X-ray photoelectron spectroscopy (XPS) and tip-enhanced Raman spectroscopy (TERS) to access both the transversal and lateral chemical information of the synthesized nanosheets with nanometer resolution. TERS and XPS data provide detailed information on the average and local surface distribution of the catalyst as well as mechanistic details of the grafting reaction. The proposed approach represents a general route towards a nanoscale structural analysis for a variety of molecular 2D materials - a rapidly growing materials class with broad prospects for fundamental science and applications.

scholarly journals Recent Applications of Advanced Atomic Force Microscopy in Polymer Science: A Review

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1142 ◽  
Author(s):  
Phuong Nguyen-Tri ◽  
Payman Ghassemi ◽  
Pascal Carriere ◽  
Sonil Nanda ◽  
Aymen Amine Assadi ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Chemical Characterization ◽  
Super Resolution ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
Polymer Science ◽  
Force Microscopy ◽  
Atomic Force ◽  
Nanoscale Characterization

Atomic force microscopy (AFM) has been extensively used for the nanoscale characterization of polymeric materials. The coupling of AFM with infrared spectroscope (AFM-IR) provides another advantage to the chemical analyses and thus helps to shed light upon the study of polymers. This paper reviews some recent progress in the application of AFM and AFM-IR in polymer science. We describe the principle of AFM-IR and the recent improvements to enhance its resolution. We also discuss the latest progress in the use of AFM-IR as a super-resolution correlated scanned-probe infrared spectroscopy for the chemical characterization of polymer materials dealing with polymer composites, polymer blends, multilayers, and biopolymers. To highlight the advantages of AFM-IR, we report several results in studying the crystallization of both miscible and immiscible blends as well as polymer aging. Finally, we demonstrate how this novel technique can be used to determine phase separation, spherulitic structure, and crystallization mechanisms at nanoscales, which has never been achieved before. The review also discusses future trends in the use of AFM-IR in polymer materials, especially in polymer thin film investigation.

XPS Studies of the Interactions of Biocells with Various Silicon Based Surfaces

1995 ◽  
Vol 414 ◽  
Author(s):  
S. Seal ◽  
S. Krezoski ◽  
T. L. Barr ◽  
D. H. Petering
Keyword(s):  
Surface Chemistry ◽  
Tumor Cells ◽  
Photoelectron Spectroscopy ◽  
Freeze Drying ◽  
Chemical Characterization ◽  
Chrysotile Asbestos ◽  
X Ray ◽  
Silicon Based ◽  
Rat Tumor

AbstractSiliceous materials are the principal components of Earth's crust and also have become key ingredients of modem technology. Recently, we have expanded our chemical characterization of complex silicates (e.g., framework [1] and sheet types [2]) to include studies of their interaction with select biocells [3,4]. It is becoming apparent that the surface chemistry of these silicates, and perhaps that of silica itself, plays a key role in the oft resulting cell pathogenesis, thus enhancing the value of further investigations with X-ray photoelectron spectroscopy. The present research describes the unique growth of Ehrlich (murine or rat tumor) cells on Sio and SiO2 wafers, and also on select seaentine silicates (such as chrysotile asbestos). Tbese growth studies were followed by both cell/silicate separations and unique freeze drying [3,4]. XPS examination at select stages discovered cell induced alterations in the Si, O, Mg and particularly Fe chemistry of the silicon based systems as well as corresponding changes in the cell chemistry. Many of these features were confirmed by atomic absorption spectroscopy.

scholarly journals Study of Coating Geometries and Photoluminescence Properties of Metal Nanoparticles/Graphite Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Pasquale Barone ◽  
Marianna Barberio ◽  
Fabio Stranges ◽  
Fang Xu
Keyword(s):  
Metal Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Carbon Surface ◽  
Chemical Information ◽  
Graphite Structure ◽  
Scattering Study ◽  
Carbon Surfaces ◽  
Local Defects ◽  
Graphite Composites

In this work we present the results of a study of growth and characterization of metal nanoparticles (Ag, Au, and Co)/carbon surfaces. The nanoparticles grew by laser ablation technique and their dimensions were controlled by light scattering study and AFM microscopy before their insertion on graphite surface. Nanoparticles appear randomly disposed on carbon surfaces aggregating to form big particles only in the case of silver. The different behavior of metal nanoparticles on carbon surface was explained in terms of different metal wetting of surface, in agreement with previous theoretical results of He et al. Chemical information, obtained by X-ray photoelectron spectroscopy, indicated that the doping process is a simple physisorption while the interfacial interaction between particles and carbon layers causes local defects in graphite structure and the appearance of a strong photoluminescence signal for all composites. Moreover, the visible optical absorption decreases about 10% indicating the progressive metallization of carbon surface.

scholarly journals Combined Pulsed RF GD-OES and HAXPES for Quantified Depth Profiling through Coatings

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 702
Author(s):  
Muriel Bouttemy ◽  
Solène Béchu ◽  
Ben F. Spencer ◽  
Pia Dally ◽  
Patrick Chapon ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Depth Profiling ◽  
Chemical Characterization ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
Chemical Information ◽  
Sampling Depth ◽  
Energy Excitation ◽  
X Ray ◽  
Pulsed Rf

Chemical characterization at buried interfaces is a real challenge, as the physico-chemical processes operating at the interface govern the properties of many systems and devices. We have developed a methodology based on the combined use of pulsed RF GD-OES (pulsed Radio Frequency Glow Discharge Optical Emission Spectrometry) and XPS (X-ray Photoelectron Spectroscopy) to facilitate the access to deeply buried locations (taking advantage of the high profiling rate of the GD-OES) and perform an accurate chemical diagnosis using XPS directly inside the GD crater. The reliability of the chemical information is, however, influenced by a perturbed layer present at the surface of the crater, hindering traditional XPS examination due to a relatively short sampling depth. Sampling below the perturbed layer may, however, can be achieved using a higher energy excitation source with an increased sampling depth, and is enabled here by a new laboratory-based HAXPES (Hard X-ray PhotoElectron Spectroscopy) (Ga-Kα, 9.25 keV). This new approach combining HAXPES with pulsed RF GD-OES requires benchmarking and is here demonstrated and evaluated on InP. The perturbed depth is estimated and the consistency of the chemical information measured is demonstrated, offering a new route for advanced chemical depth profiling through coatings and heterostructures.

Raman Analysis in Document Examination

2018 ◽  
Vol 28 ◽  
pp. 65-76
Author(s):  
Kenneth J. Smith
Keyword(s):  
Raman Spectroscopy ◽  
Chemical Characterization ◽  
Background Information ◽  
Chemical Information ◽  
Raman Analysis ◽  
Questioned Documents ◽  
Document Examination ◽  
Visual Difference

Analysis of questioned documents can often be aided by chemical characterization of the ink or toner on the document. In cases where there is little visual difference between reference and questioned areas, Raman analysis can provide chemical information about the pigments and resins which may show similarities or differences in printing materials on the documents.This paper provides background information about Raman spectroscopy, as well as examples of its applicability to the analysis of inks, toners, and pencil leads on documents. Purchase Article - $10

Quantum Chemical Characterization of Single Molecule Magnets Based on Uranium

2017 ◽  
Vol 121 (8) ◽  
pp. 1726-1733 ◽  
Author(s):  
Mariano Spivak ◽  
Konstantinos D. Vogiatzis ◽  
Christopher J. Cramer ◽  
Coen de Graaf ◽  
Laura Gagliardi
Keyword(s):  
Single Molecule ◽  
Quantum Chemical ◽  
Chemical Characterization ◽  
Single Molecule Magnets
Sign in / Sign up

Export Citation Format

Share Document