Search results for "Optical"
showing 10 items of 7671 documents
Structure and dynamics of CaO films: A computational study of an effect of external static electric field
2017
Oxide films play a significant role in a wide range of industrial fields, mostly due to the thickness-dependent variation of their properties. Recently, it has been proposed based on the experimental study that carrier transport in CaO films proceeds via strong phonon excitations with a variable signal depending on the film thickness. In this paper, we report a detailed investigation in the frame of the density functional theory of structural and electronic properties of freestanding and Mo(100)-supported CaO films, as well as phonons therein, as functions of the film thickness and intensity of the external static electric field. Our calculations demonstrate that phonon frequencies negligib…
Influence of the filling factor on the spectral properties of plasmonic crystals
2006
Plasmonics crystals (PCs) comprised of finite-size triangular lattices of gold bumps deposited on a gold thin film are studied by means of a near-field optical microscope. The plasmonic crystals fabricated by electron-beam lithography are illuminated by an incident surface plasmon polariton excited in the Kretschmann-Raether configuration at the gold/air thin-film interface for incident free-space wavelengths in the range $740--820\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. Based on the measurement of the surface plasmon polariton (SPP) damping distance in the crystals, the existence of a band gap for an incident SPP traveling along the two symmetry axes $\ensuremath{\Gamma}M$ and $\ensuremath…
Acid–Base Properties and Surface Charge Distribution of the Water-Soluble Au102(pMBA)44 Nanocluster
2016
The pKa of the p-mercaptobenzoic acid (pMBA) ligands in the Au102(pMBA)44 nanocluster was measured by using acid–base and IR titration. The observed macroscopic pKa = 6.18 ± 0.05 is significantly more basic than that of free pMBA (pKa = 4.16), and the protonation behavior is anticooperative according to the Hill coefficient n = 0.64 ± 0.04. The cluster is truly water-soluble when more than 22 and insoluble when fewer than 7 ligands are in the deprotonated state. In order to obtain more insight into the anticooperative character, the cluster was modeled at pH ∼6.2 using constant pH molecular dynamics simulations. The pKa values of the individual pMBAs are in the range of 5.18–7.58, depending…
Carbon-Coated Anatase TiO2Nanotubes for Li- and Na-Ion Anodes
2014
aInstitute of Physical Chemistry and MEET Battery Research Centre, University of Muenster, 48149 Muenster, Germany bHelmholtz-Institute Ulm (HIU), Electrochemistry I, 89081 Ulm, Germany cKarlsruher Institute of Technology (KIT), 76021 Karlsruhe, Germany dInstitute for Organic Chemistry, University of Mainz, 55128 Mainz, Germany eGraduate School Materials Science in Mainz, 55128 Mainz, Germany fInstitute for Inorganic and Analytical Chemistry, University of Mainz, 55128 Mainz, Germany gMax Planck Institute for Polymer Research, 55128 Mainz, Germany
Electrostatic Anchoring of Mn4 Single-Molecule Magnets onto Chemically Modified Multiwalled Carbon Nanotubes
2012
Two different routes that enable the electrostatic grafting of cationic single-molecule magnets (SMMs) onto the surface of chemically modified anionic multi-walled carbon nanotubes (MWNTs) are described. The chemical nature and physical properties of the resulting hybrids are discussed on the basis of a complete battery of experimental techniques. The data show that the chemical nature of the SMM unit remains intact, while its magnetic response is significantly affected by the grafting process, which is likely due to surface effects.
<title>Performance problems of electrochromic coatings</title>
2003
The performance is actual problem of electrochromic coatings. The service and shelf life and cycling capacity are main performance characteristics. By solid-state ionics point of view any electrochromic cell based on phenomena with ion insertion - extraction processes is functioning as solid-state rechargeable battery. The main performance characteristics of electrochromic cells are similar. Performance of electrochromic coatings based on amorphous WO3 films and protons conducting electrolytes is limited by reversibility of ion insertion-extraction reactions, which causes degradation of cell components. The migration of water in the cell and hydration together with ion insertion-extraction …
Composite polymer electrolytes with improved lithium metal electrode interfacial properties: II. Application in rechargeable batteries
1998
The application of a liquid-free, ceramic-added composite polymer electrolyte in a Li/LiMn{sub 2}O{sub 4} rechargeable battery is presented and discussed. As expected by the high stability of the electrolyte toward the lithium metal anode, the battery has promising characteristics in terms of reliability and cyclability.
Atomic Layer Deposition of Spinel Lithium Manganese Oxide by Film-Body-Controlled Lithium Incorporation for Thin-Film Lithium-Ion Batteries
2013
Lithium manganese oxide spinels are promising candidate materials for thin-film lithium-ion batteries owing to their high voltage, high specific capacity for storage of electrochemical energy, and minimal structural changes during battery operation. Atomic layer deposition (ALD) offers many benefits for preparing all-solid-state thin-film batteries, including excellent conformity and thickness control of the films. Yet, the number of available lithium-containing electrode materials obtained by ALD is limited. In this article, we demonstrate the ALD of lithium manganese oxide, LixMn2O4, from Mn(thd)3, Li(thd), and ozone. Films were polycrystalline in their as-deposited state and contained le…
Analysis of a microwave time delay line based on a perturbed uniform fiber Bragg grating operating at constant wavelength
2000
This paper presents the modeling of a new microwave time delay line based on a uniform fiber Bragg grating (FBG) with a section which period has been perturbed. The time delay can be modified by changing the position of the perturbation along the grating. Theoretical results are presented for a 5-cm long uniform grating and optical signal is modulated up to 18 GHz. Experimental setup used magnetic fields to change the period locally along the grating and a 330 ps maximum time delay is shown. Comparison between calculations and measurements show a perfect agreement. Such a delay line offers many advantages for beamforming applications in phased array antennas where the operation at a fixed w…
Acene-type donors bearing one 1,3-dithiole ring
1999
Abstract A series of acene-type donors bearing only one 1,3-dithiole ring have been synthesized by following a Wittig-Horner reaction from 7 H -benz[ d,e ]anthracen-7-one and several phosphonate esters. The excellent donor properties have been studied using both experimental techniques and quantum-chemical calculations and reveal that the extraction of the first electron in the oxidation process occurs from the dithiole ring (0.42 e) and the acene unit (0.58 e).