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Organic Films (organic + film)

Distribution by Scientific Domains
Polymers and Materials Science44%
Physics and Astronomy33%

Selected Abstracts

Laser-Writable, Electrically Erasable Photoelectrochromic Organic Film

ADVANCED MATERIALS, Issue 4 2003
M. Macchione
An organic photoelectrochromic film, in which methylene blue can change from blue to transparent on absorption of light, and return to blue by an oxidation reaction induced by an external electric field, is presented (see Figure). The resulting device presents the remarkable advantage of being driven by a red HeNe laser (5 mW) for the "writing process", and by a very low voltage (0.4 V) for the "erasing process". [source]

Characteristics of Solution-Processed Small-Molecule Organic Films and Light-Emitting Diodes Compared with their Vacuum-Deposited Counterparts

ADVANCED FUNCTIONAL MATERIALS, Issue 10 2009
Tae-Woo Lee
Abstract Although significant progress has been made in the development of vacuum-deposited small-molecule organic light-emitting diodes (OLEDs), one of the most desired research goals is still to produce flexible displays by low-cost solution processing. The development of solution-processed OLEDs based on small molecules could potentially be a good approach but no intensive studies on this topic have been conducted so far. To fabricate high-performance devices based on solution-processed small molecules, the underlying nature of the produced films and devices must be elucidated. Here, the distinctive characteristics of solution-processed small-molecule films and devices compared to their vacuum-deposited counterparts are reported. Solution-processed blue OLEDs show a very high luminous efficiency (of about 8.9,cd A,1) despite their simplified structure. A better hole-blocking and electron-transporting layer is essential for achieving high-efficiency solution-processed devices because the solution-processed emitting layer gives the devices a better hole-transporting capability and more electron traps than the vacuum-deposited layer. It is found that the lower density of the solution-processed films (compared to the vacuum-deposited films) can be a major cause for the short lifetimes observed for the corresponding devices. [source]

Flexible Organic Solar Cells: Nanoscale Phase Separation and High Photovoltaic Efficiency in Solution-Processed, Small-Molecule Bulk Heterojunction Solar Cells (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2009
Mater.
The inside cover of this issue illustrates the fabrication of lightweight and flexible organic solar cells, developed by B. Walker et al. on page 3063, from a solution of fullerene and diketopyrrolopyrrole-based materials. The texture of the organic film on the substrate was taken from an atomic force microscope phase image of the high performance device (4.4% power conversion efficiency), showing the phase separation behavior of the two molecular semiconducting materials. [source]

Modeling of extraction behavior of docosahexaenoic acid ethyl ester by utilizing slug flow prepared by microreactor

AICHE JOURNAL, Issue 8 2010
Eiji Kamio
Abstract The liquid,liquid extraction dynamics of an ethyl ester of docosahexaenoic acid (DHA-Et) with silver ion was investigated. The kinetic model was derived according to the following stepwise processes: Diffusion of DHA-Et across the organic film, complex-formation between DHA-Et and silver ion at the interface, and diffusion of extracted complex across the aqueous film. The kinetic parameters for the complex-formation reaction were determined from the investigation with the stirred transfer cell. With the proposed model and determined parameters, we predicted the uptakes of DHA-Et for the extraction system utilizing a slug flow prepared by a microchip. The calculated uptakes showed good correlation to the experimental data. The theoretical investigation suggested that the fast equilibration realized for the slug flow extraction system was due to the large specific interfacial area of the slug caused by the presence of wall film and the thin liquid film caused by the internal circulation. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source]

Influence of top layer geometries on the electronic properties of pentacene and diindenoperylene thin films

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2008
M. Scharnberg
Abstract Top layers have a pronounced influence on the electronic properties of molecular organic thin films. Here, we report about the changes induced by metallic and polymeric top layers and contacts. As test structures, model systems of diindenoperylene and pentacene crystalline molecular organic thin films are used. A very sensitive radiotracer technique is introduced to study the details of metal penetration during top contact formation. The influence of temperature, evaporation time, adhesion promoter and grain size of the organic film were examined. The electric currents passing through metal top contacts were found to vary by more than a factor of three, depending on the preparation conditions of the metal contact. Furthermore, the series resistance of chemically identical contacts that only differed in the morphology of the interface were found to show pronounced asymmetric conductivity behaviour. We also show that with the help of electret top layers, based on the Teflon-AF fluropolymer, the threshold voltage of an organic field effect transistor can be tuned by several volts. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

ON THE TUBE ULTRASTRUCTURE AND ORIGIN OF CALCIFICATION IN SABELLIDS (ANNELIDA, POLYCHAETA)

PALAEONTOLOGY, Issue 2 2008
OLEV VINN
Abstract:, Tube ultrastructure of Jurassic and Cretaceous Glomerula is very similar to that of Recent Calcisabella, supporting the synonymy of these genera and the early Mesozoic origin of calcification in sabellids. Tube structure of serpulids differs from that of Glomerula; calcareous tubes probably evolved convergently within Sabellida. The tube wall in Recent Glomerula piloseta is composed of subparallel lamellae of aragonitic, irregular spherulitic prisms in the inner layer, and spherulites in the outer layer. Calcified lamellae are separated by organic films of different thickness. The structure of the internal tube layer in Glomerula piloseta, and the structure of entire wall in fossil Glomerula, are similar to the tube structure of Dodecaceria (Polychaeta, Cirratulidae). The irregular spherulitic prisms of Glomerula are similar to those found in the external layer of Hydroides dianthus and the internal layer of Spiraserpula caribensis. [source]

Anomalous current,voltage characteristics of thin polymer films

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2003
V. A. Kolesnikov
Abstract In this paper we have investigated organic light emitting diodes with such electroluminescent materials as aromatic polyimide, poly,N-vinylcarbazole (PVK) and dye doped PVK. N-type current,voltage characteristics with negative differential resistance for the thin polymeric and organic films are analyzed. No reasonable explanation has been provided for this phenomenon until now. Here we suggest that a polymer(organic)/metal interface containing various inhomogeneities and metal spikes is responsible for this effect. We detect also the black-body radiation, whose temperature exceeds both the melting point and the sublimation temperature of the metal of the electrode. We suppose that the current density through the spike in any cases is large enough to cause the explosion of the tip of the spike and the detected radiation has the hot plasma origin. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

In-situ IR synchrotron mapping ellipsometry on stimuli-responsive PAA-b-PS/PEG mixed polymer brushes

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2010
Dennis Aulich
Abstract A binary polymer brush consisting of weak polyelectrolytes was investigated with infrared synchrotron mapping ellipsometry in-situ under the influence of different aqueous solutions. Thickness of the brush layer in dry state was ,15 nm. The brush, consisting of poly(ethylene glycol) and poly(acrylic acid)-b-poly(styrene) in a 50/50 composition was switched between two different states by changing the pH of the solution. An IR mapping ellipsometer at the IRIS beamline located at the BESSY II synchrotron facility in Berlin, Germany, was used for high lateral resolution in-situ measurements. The results show strong chemical changes in the brush layer due to COOH , COO, conversion of the PAA's carboxylic groups. Measurements with spot sizes of ,1 mm on different positions on the samples proved good homogeneity of the brush layer and the qualification of this method for investigation of ultrathin organic films in aqueous solutions in-situ with IR ellipsometry. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Structured Ti/Hydrocarbon Plasma Polymer Nanocomposites Produced By Magnetron Sputtering with Glancing Angle Deposition

PLASMA PROCESSES AND POLYMERS, Issue 1 2010
Andrei Choukourov
Abstract Structured Ti/hydrocarbon plasma polymer nanocomposite films are deposited at a glancing angle by magnetron sputtering of titanium in an Ar/hexane mixture and by sequential magnetron sputtering of titanium and polypropylene. The surface chemistry of such films is tuned by adjusting the gas mixture composition. The structure of the substrate may convert the morphology of organic films deposited at a glancing angle from continuous to nanostructured thin films. [source]