Artificial sunlight and ultraviolet light induced photo-epoxidation of propylene over V-Ti/MCM-41 photocatalyst

• Van-Huy Nguyen,
• Shawn D. Lin,
• Jeffrey Chi-Sheng Wu and
• Hsunling Bai

Beilstein J. Nanotechnol. 2014, 5, 566–576, doi:10.3762/bjnano.5.67

• used to verify the crystalline structure of the photocatalyst. Diffraction peaks were assigned by comparison to known crystalline phases. The light absorption of the photocatalyst was characterized by ultraviolet–visible light spectroscopy (Varian Cary-100). The X-ray absorption near edge spectroscopy

CoPc and CoPcF₁₆ on gold: Site-specific charge-transfer processes

• Fotini Petraki,
• Heiko Peisert,
• Johannes Uihlein,
• Umut Aygül and
• Thomas Chassé

Beilstein J. Nanotechnol. 2014, 5, 524–531, doi:10.3762/bjnano.5.61

• spectroscopy (UPS) as well as X-ray absorption spectroscopy (XAS). Combined XPS and XAES measurements can be employed as a tool to study the contribution of the polarization energy to chemical shifts at interfaces. XAS gives valuable information about the unoccupied electronic structure and the hybridization

• negatively” charged compared to the bulk. For a strongly related system, namely CoPcF16 on Au(100), X-ray absorption spectroscopy measurements at the fluorine K-edge show that the electron density can change at the fluorine site. Since XAS probes transitions from occupied into unoccupied valence states

• -controlled evaporation cell. The thickness of the organic films ranged from sub-monolayer to about 100 Å and was determined by the attenuation of the intensity of the Au 4f substrate peaks in photoemission. X-ray absorption (XAS) measurements were carried out at the third generation synchrotron radiation

Quantum size effects in TiO₂ thin films grown by atomic layer deposition

• Massimo Tallarida,
• Chittaranjan Das and
• Dieter Schmeisser

Beilstein J. Nanotechnol. 2014, 5, 77–82, doi:10.3762/bjnano.5.7

• Massimo Tallarida Chittaranjan Das Dieter Schmeisser Applied Physics - Sensors, Brandenburg University of Technology Cottbus–Senftenberg, Konrad-Wachsmann-Allee 17, 03046 Cottbus, Germany 10.3762/bjnano.5.7 Abstract We study the atomic layer deposition of TiO2 by means of X-ray absorption

• size effects; titanium dioxide (TiO2); water splitting; X-ray absorption spectroscopy (XAS); Introduction Titanium dioxide (TiO2) is an important material for the photoelectrolysis of water [1] and for many other photocatalytic reactions [2]. Its effective conversion of solar light, although limited

• nm thickness and allows for the investigation of similar quantum size effects in TiO2 thin films. In this case interface effects, as those observed in TiO2 ALD films grown on SnO2:F [11], could also become important. We performed the characterization of ALD films by using mostly X-ray absorption

Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al₂O₃-films

• Jörg Haeberle,
• Karsten Henkel,
• Hassan Gargouri,
• Franziska Naumann,
• Bernd Gruska,
• Michael Arens,
• Massimo Tallarida and
• Dieter Schmeißer

Beilstein J. Nanotechnol. 2013, 4, 732–742, doi:10.3762/bjnano.4.83

• , oxygen interstitials may be responsible for the net negative fixed charge [1]. However, the microscopic origin of this charge is still under discussion [1]. Therefore, we plan to conduct X-ray absorption as well as resonant photoemission measurements using synchrotron radiation (SR) in near future. Now

Characterization of electroforming-free titanium dioxide memristors

• John Paul Strachan,
• J. Joshua Yang,
• L. A. Montoro,
• C. A. Ospina,
• A. J. Ramirez,
• A. L. D. Kilcoyne,
• Gilberto Medeiros-Ribeiro and
• R. Stanley Williams

Beilstein J. Nanotechnol. 2013, 4, 467–473, doi:10.3762/bjnano.4.55

• HfO2 [18][19][20][21][22][23][24]. Recently, physical characterization of Pt/TiO2/Pt unipolar [25] and bipolar [26] resistance-switching devices by TEM and X-ray absorption revealed that the switching involves the creation of localized channels of Ti4O7 within the matrix material. The Ti4O7 channel

• in each of them. Sample preparation and resistance switching MIM crossbar devices were fabricated on a silicon/silicon-nitride substrate. In some areas, the underlying Si was etched to form free-standing membranes allowing transmission characterization by X-ray absorption spectromicroscopy and

• performed using scanning transmission X-ray microscopy (STXM) at the Advanced Light Source in the Lawrence Berkeley National Laboratory. STXM allows spatially-resolved X-ray absorption spectroscopy (XAS) to be performed on a sample and is well-suited for chemical and structural characterization of the thin

Antiferromagnetic coupling of TbPc₂ molecules to ultrathin Ni and Co films

• David Klar,
• Svetlana Klyatskaya,
• Andrea Candini,
• Bernhard Krumme,
• Kurt Kummer,
• Philippe Ohresser,
• Valdis Corradini,
• Valentina de Renzi,
• Roberto Biagi,
• Loic Joly,
• Jean-Paul Kappler,
• Umberto del Pennino,
• Marco Affronte,
• Heiko Wende and
• Mario Ruben

Beilstein J. Nanotechnol. 2013, 4, 320–324, doi:10.3762/bjnano.4.36

• , CNRS UMP 7504, 23 Rue du Loess, 67034 Strasbourg Cedex 2, France 10.3762/bjnano.4.36 Abstract The magnetic and electronic properties of single-molecule magnets are studied by X-ray absorption spectroscopy and X-ray magnetic circular dichroism. We study the magnetic coupling of ultrathin Co and Ni

• films that are epitaxially grown onto a Cu(100) substrate, to an in situ deposited submonolayer of TbPc2 molecules. Because of the element specificity of the X-ray absorption spectroscopy we are able to individually determine the field dependence of the magnetization of the Tb ions and the Ni or Co film

• demonstrate that it is possible to block this relaxation and conserve the magnetization without any external field by coupling the molecules to a ferromagnetic substrate. By X-ray absorption spectroscopy and X-ray magnetic circular dichroism we study the electronic and magnetic properties of a submonolayer

Towards atomic resolution in sodium titanate nanotubes using near-edge X-ray-absorption fine-structure spectromicroscopy combined with multichannel multiple-scattering calculations

• Carla Bittencourt,
• Peter Krüger,
• Maureen J. Lagos,
• Xiaoxing Ke,
• Gustaaf Van Tendeloo,
• Chris Ewels,
• Polona Umek and
• Peter Guttmann

Beilstein J. Nanotechnol. 2012, 3, 789–797, doi:10.3762/bjnano.3.88

• Functional Materials, Albert-Einstein-Str. 15, 12489 Berlin, Germany 10.3762/bjnano.3.88 Abstract Recent advances in near-edge X-ray-absorption fine-structure spectroscopy coupled with transmission X-ray microscopy (NEXAFS–TXM) allow large-area mapping investigations of individual nano-objects with spectral

• ; sodium titanates; Introduction Transmission X-ray microscopy (TXM) is a popular microscopy technique used in biology [1][2][3]. Recently, we have extended the range of its applications to the spectroscopic characterization of nanoscale materials by combining it with near-edge X-ray-absorption fine

• resolution in similar techniques with lower spectral resolution [9][10]. We investigate here the electronic structure of sodium titanate nanotubes ((Na,H)TiNTs) by means of near-edge X-ray-absorption fine-structure spectroscopy (NEXAFS) coupled with first-principles NEXAFS calculations (density functional

X-ray absorption spectroscopy by full-field X-ray microscopy of a thin graphite flake: Imaging and electronic structure via the carbon K-edge

• Carla Bittencourt,
• Adam P. Hitchock,
• Xiaoxing Ke,
• Gustaaf Van Tendeloo,
• Chris P. Ewels and
• Peter Guttmann

Beilstein J. Nanotechnol. 2012, 3, 345–350, doi:10.3762/bjnano.3.39

• Jean Rouxel (IMN), Université de Nantes, CNRS, Nantes, France Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Soft Matter and Functional Materials, D-12489 Berlin, Germany 10.3762/bjnano.3.39 Abstract We demonstrate that near-edge X-ray-absorption fine-structure spectra

• graphene-based materials [14]. The near-edge X-ray-absorption fine-structure technique (NEXAFS) is ideally suited for the study of graphene-based materials, because the carbon K-edge is very sensitive to the bonding environment, providing diagnostic information about the structure, defects and doping [15

X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

• Hicham Hamoudi,
• Ping Kao,
• Alexei Nefedov,
• David L. Allara and
• Michael Zharnikov

Beilstein J. Nanotechnol. 2012, 3, 12–24, doi:10.3762/bjnano.3.2

• nitrile moiety, which served as a spectroscopic marker group, to the OPEn backbone did not significantly affect the molecular orientation in the SAMs. Keywords: nitrile substitution; oligo(phenylene ethynylene); self-assembled monolayers; twist angle; X-ray absorption spectroscopy; Introduction Current

• ) SAMs on Au(111). Furthermore, in addition to the STM/AFM characterization, molecular organization in OPE3/Au was probed by infrared-reflection spectroscopy (IRS) [36] and near-edge X-ray absorption fine-structure (NEXAFS) spectroscopy [37]. The average tilt angle of the OPE3 backbone was estimated at

• procedures. The reference SAMs included those formed from DDT [50], HDT [71], TPT [42][43], and NC-BPT [30]. The SAMs were characterized by several complementary spectroscopic techniques, viz., high-resolution X-ray photoelectron spectroscopy (HRXPS), angle-resolved near-edge X-ray absorption fine-structure

Nanostructured, mesoporous Au/TiO₂ model catalysts – structure, stability and catalytic properties

• Matthias Roos,
• Dominique Böcking,
• Kwabena Offeh Gyimah,
• Gabriela Kucerova,
• Joachim Bansmann,
• Johannes Biskupek,
• Ute Kaiser,
• Nicola Hüsing and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 593–606, doi:10.3762/bjnano.2.63

• -modulation infrared reflection absorption spectroscopy (PM-IRAS) [15][16][17] or X-ray absorption spectroscopy (XAS) techniques [18][19], which allow us to gain detailed information on the structure, elemental/molecular chemical composition and electronic/vibrational properties of the catalyst surface and

Nanoscaled alloy formation from self-assembled elemental Co nanoparticles on top of Pt films

• Luyang Han,
• Ulf Wiedwald,
• Johannes Biskupek,
• Kai Fauth,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 473–485, doi:10.3762/bjnano.2.51

• alloy formation by X-ray absorption spectroscopy and SQUID magnetometry. The excellent sensitivity of SQUID magnetometers can be exploited, at suitably selected temperatures, to detect the magnetic response corresponding to the Co particles and nanoscale alloys. X-ray magnetic circular dichroism (XMCD

• systems due to the structural anisotropy in the chemically ordered L10 phase [31], only µSeff will be discussed for the NPs in this study. Figure 4a compares two XMCD difference spectra, i.e., the difference in the X-ray absorption spectra, for antiparallel external fields (here µ0H = ± 1 T) collinear to

Extended X-ray absorption fine structure of bimetallic nanoparticles

• Carolin Antoniak

Beilstein J. Nanotechnol. 2011, 2, 237–251, doi:10.3762/bjnano.2.28

• absorption spectroscopy. In this review, recent developments in the field of extended X-ray absorption fine structure measurements and in the analysis methods for structural investigations of bimetallic nanoparticles are highlighted. The standard analysis based on Fourier transforms is compared to the

• on state-of-the-art X-ray absorption spectroscopy (XAS) on 3rd generation synchrotron sources such as the ESRF and BESSY II. In general, XAS deals with the excitation of core-level electrons, with their element-specific binding energies, by incident X-rays. After absorption of an X-ray photon, a core

• photon or an Auger electron. The X-ray absorption can be measured by detection of the emitted fluorescence photons (fluorescence yield, FY) or by detection of the Auger and secondary electrons (electron yield, EY). For thin samples, the absorption can also be measured in transmission geometry by

Zirconium nanoparticles prepared by the reduction of zirconium oxide using the RAPET method

• Michal Eshed,
• Swati Pol,
• Aharon Gedanken and
• Mahalingam Balasubramanian

Beilstein J. Nanotechnol. 2011, 2, 198–203, doi:10.3762/bjnano.2.23

• reaction of commercial ZrO2 with Mg powder was carried out in a closed stainless steel cell, at 750 °C. On completion of the reaction, the additionally formed MgO is removed by treatment with acid. The characterization of the product was performed by XRD, X-ray absorption spectroscopy, SEM, TEM and

• between 20° and 24° in Figure 1b, is due to the mylar layer that covers the sample in the specially inert XRD cell [12] designed to avoid the oxidation of the Zr sample. However, further proof for the successful fabrication of metallic zirconium is required. X-ray absorption spectroscopy (XAS) was

• employed to confirm the formation of metallic Zr synthesized (Zr-syn) by RAPET of ZrO2. The techniques of XAS, namely X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), are used to probe local structural details [13] around specific metal atoms and to discern

Structure, morphology, and magnetic properties of Fe nanoparticles deposited onto single-crystalline surfaces

• Armin Kleibert,
• Wolfgang Rosellen,
• Mathias Getzlaff and
• Joachim Bansmann

Beilstein J. Nanotechnol. 2011, 2, 47–56, doi:10.3762/bjnano.2.6

• show X-ray absorption spectra in the vicinity of the L2 and L3 edges of both, the Ni(111) substrate and Fe nanoparticles with D = (7.6 ± 1.5) nm, respectively. The data were recorded with circularly polarized synchrotron radiation provided by the helical undulator beamline UE46-PGM1 at the electron

• of the equilibrium shape of pure crystalline Fe particles as expected from a Wulff construction in the present particle size range [32]. (a) X-ray absorption spectra of the Ni(111) substrate. Inset: Schematics of the experiment. (b) XAS spectra of the Fe NPs with a diameter of (7.6 ± 1.5) nm. (c),(d

Ultrafine metallic Fe nanoparticles: synthesis, structure and magnetism

• Olivier Margeat,
• Marc Respaud,
• Catherine Amiens,
• Pierre Lecante and
• Bruno Chaudret

Beilstein J. Nanotechnol. 2010, 1, 108–118, doi:10.3762/bjnano.1.13

• , monodisperse, with a diameter below 2 nm, which corresponds to a number of around 200 atoms. The X-ray absorption near-edge structure and Mössbauer spectrum are characteristic of metallic Fe. The structural studies by wide angle X-ray scattering indicate an original polytetrahedral atomic arrangement similar

• synthesis of well-isolated Fe NPs embedded in a polymer, with diameters of less than 2 nm. The structural and chemical properties have been investigated by transmission electron microscopy, wide angle X-ray scattering (WAXS), and X-ray absorption near-edge structure (XANES). Preliminary results of this work

• oxidation. The particles were characterized by transmission electron microscopy (TEM), wide angle X-ray scattering (WAXS) [22], and X-ray absorption near-edge structure (XANES). TEM micrographs show the presence of well-dispersed small particles of ca. 1.8 nm mean size with a narrow size distribution (15

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

• Ulf Wiedwald,
• Luyang Han,
• Johannes Biskupek,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5

• formation on the corresponding magnetic properties are by no means clear-cut [64], one nevertheless has to take this into consideration. Indeed, close inspection of in situ X-ray absorption spectra (XAS) on Co NPs immediately after reduction in a hydrogen plasma revealed a significant shoulder 2 eV above

• total electron yield was recorded as function of photon energy in external fields up to 3 T and at variable temperatures between 11 K and 300 K [78]. Due to its surface sensitivity, it becomes possible to measure X-ray absorption spectra and hysteresis loops with high precision, even of NPs. Note that