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State Properties (state + property)

Distribution by Scientific Domains

Polymers and Materials Science	50%
Physics and Astronomy	33%

Selected Abstracts

A Series of Red-Light-Emitting Ionic Iridium Complexes: Structures, Excited State Properties, and Application in Electroluminescent Devices

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2008
Shu-Juan Liu
Abstract A series of ionic diiminoiridium complexes [Ir(piq-C,N)2(L-N,N)](PF6) were prepared, where piq-C,N is 1-phenylisoquinolinato and L-N,N are bidentate N-coordinating ligands: 2,2,-bipyridine (bpy), 4,4,-dimethyl-2,2,-bipyridine (mbpym), 5,5,-bis(thiopen-2-yl)-2,2,-bipyridine (tbpyt), and 5,5,-bis(9,9-dioctylfluoren-2-yl)-2,2,-bipyridine (FbpyF). X-ray diffraction studies of [Ir(piq)2(mbpym)](PF6) revealed that the iridium center adopts a distorted octahedral geometry. All complexes exhibited intense and long-lived emission at room temperature. The substituents on the 2,2,-bipyridine moieties influence the photophysical and electrochemical properties. The excited states were investigated through theoretical calculations together with photophysical and electrochemical properties. It was found that the excited state of the [Ir(piq)2(FbpyF)](PF6) complex can be assigned to a mixed character of 3LC (,N,N,,*N,N), 3MLCT, 3LLCT (,C,N,,*N,N), and 3LC (,C,N,,*C,N). In addition, the alkylfluorene-substituted complex, [Ir(piq)2(FbpyF)](PF6), hadrelatively high quantum efficiency and good film-forming ability, and it was expected to be a good candidate for lighting and display applications. A nondoped, single-layer device that incorporates this complex as a light-emitting layer was fabricated and red phosphorescence was obtained.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

Advancing the Solid State Properties of Metallo-Supramolecular Materials: Poly(, -caprolactone) Modified , -Conjugated Bis(terpyridine)s and their Zn(II) Based Metallo-Polymers

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 20 2008
Andreas Winter
Abstract A set of rigid , -conjugated bis(terpyridine) macroligands with poly(, -caprolactone) (pCL) on their side chains was synthesized and investigated. The introduced pCL chains gave rise to enhanced processability and film-forming properties of the materials. Blue photoluminescence with high quantum yields was observed in dilute solution and in the solid state, indicating that intermolecular aggregation of the , -conjugated systems was effectively suppressed. The macroligands were further used for coordination with zinc(II) ions leading to new metallo-polymers with high solubility, improved film-forming behavior and promising photophysical properties with respect to potential OLED applications. [source]

Sol,Gel Derived Nanocomposites for Optical Applications

ADVANCED ENGINEERING MATERIALS, Issue 5 2010
Peter W. de Oliveira
This paper provides a selective description of the development of nanostructured materials and the fabrication of the devices for optical applications. Examples are interference coatings, refractive and diffractive lenses, and macro- and micro-GRIN (graded refractive index) optical elements. Hybrid materials containing nanoparticles are of particular interest for the production of optical elements because, by exploiting the intrinsic solid state properties of the nanoparticles, nanocomposites can be tailored to exhibit the desired properties. A particular advantage of wet chemical processing lies in its great flexibility for depositing functional coatings. [source]

Synthesis and characterization of zwitterionic organogels based on Schiff base chemistry

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010
Nazia Tarannum
Abstract Poly(sulfobetaine)s and poly(carboxybetaine)s have been extensively studied for their zwitterionic and biocompatible nature. The specific features that make such zwitterionic structures technologically important are their chemical structure, a straight forward synthetic route, high ionic contents with interesting dilute solution, and solid state properties. The objective of this work is to synthesize novel zwitterionic polymers having gel characteristics. Here, p- phenylene diamine/melamine react as nucleophiles with glutaraldehyde to produce poly(schiff base)s. In the subsequent step, the poly(sulfobetaine)s and poly(carboxybetaine)s were produced on treatment with 1,3-propane sultone/,-butyrolactone. Hence, a catalyst free facile approach to novel zwitterionic polymers was obtained. The polymers were characterized by elemental analyses, FTIR, XRD analyses, SEM, pH metric titrations, conductometric titrations, and thermal analyses (TGA/DTA). The polymeric samples carry the gel characteristics, showing lamellar structure with porous network. XRD pattern shows Bragg peaks indicative of superstructures. Thermal analysis indicates the Hoffman elimination of , hydrogen and subsequent release of sulfopropyl/carboxybutyl group. One of the gel polymers shows fluorescence also. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

Forward scattering peak in the electron,phonon interaction and impurity scattering of cuprate superconductors

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2005
M. L. Kuli
Abstract The important role of the electron,phonon interaction (EPI) in explaining the normal state properties and pairing mechanism in high- Tc superconductors (HTSC) is discussed. A number of experiments are analyzed such as: dynamical conductivity, Raman scattering, neutron scattering, ARPES, tunnelling measurements, and etc. They give convincing evidence that the EPI dominantly contributes to pairing in HTSC oxides. Strong electronic correlations cause the forward scattering peak (FSP) in the EPI and in the non-magnetic impurity potential. The theory based on the FSP (whatever is its origin) explains several puzzling experimental results in ARPES and transport: (1) much smaller transport coupling constant than the pairing one (,tr , ,ph); (2) the ARPES non-shift puzzle , where the nodal kink at 70 meV is unshifted in the superconducting state while the anti-nodal one at 40 meV is shifted; (3) d-wave superconductivity due to the EPI; (4) robustness of d-wave pairing in the presence of nonmagnetic impurities; (5) collapse of the elastic scattering rate near the anti-nodal point in the superconducting state; (6) anomalous temperature dependence of the Hall angle in optimally doped HTSC. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Unconventional superconductivity and magnetism in Sr2RuO4 and related materials

ANNALEN DER PHYSIK, Issue 3 2004
I. Eremin
Abstract We review the normal and superconducting state properties of the unconventional triplet superconductor Sr2RuO4 with an emphasis on the analysis of the magnetic susceptibility and the role played by strong electronic correlations. In particular, we show that the magnetic activity arises from the itinerant electrons in the Ru d -orbitals and a strong magnetic anisotropy occurs (,+- < ,zz) due to spin-orbit coupling. The latter results mainly from different values of the g -factor for the transverse and longitudinal components of the spin susceptibility (i.e. the matrix elements differ). Most importantly, this anisotropy and the presence of incommensurate antiferromagnetic and ferromagnetic fluctuations have strong consequences for the symmetry of the superconducting order parameter. In particular, reviewing spin fluctuation-induced Cooper-pairing scenario in application to Sr2RuO4 we show how p -wave Cooper-pairing with line nodes between neighboring RuO2 -planes may occur. We also discuss the open issues in Sr2RuO4 like the influence of magnetic and non-magnetic impurities on the superconducting and normal state of Sr2RuO4. It is clear that the physics of triplet superconductivity in Sr2RuO4 is still far from being understood completely and remains to be analyzed more in more detail. It is of interest to apply the theory also to superconductivity in heavy-fermion systems exhibiting spin fluctuations. [source]