Output Characteristics (output + characteristic)

Distribution by Scientific Domains


Selected Abstracts


Modifying the Output Characteristics of an Organic Light-Emitting Device by Refractive-Index Modulation,

ADVANCED FUNCTIONAL MATERIALS, Issue 18 2006
T. Höfler
Abstract In order to modify the output characteristics of organic light-emitting devices (OLEDs), the optical properties of an active layer within the device are patterned without introducing any thickness modulation. For this purpose a new conjugated copolymer, which serves as a hole-transporting material and at the same time can be index patterned using UV techniques, is synthesized. Poly(VC- co -VBT) (VC: N -vinylcarbazole; VBT: 4-vinylbenzyl thiocyanate) is prepared by free-radical copolymerization of VC and VBT. The material contains photoreactive thiocyanate groups that enable altering of the material's refractive index under UV illumination. This copolymer is employed as a patternable hole-transporting layer in multilayer OLEDs. Refractive-index gratings in poly(VC- co -VBT) are inscribed using a holographic setup based upon a Lloyd mirror configuration. The fourth harmonic of a Nd:YAG (YAG: yttrium aluminum garnet) laser (266,nm) serves as the UV source. In this way 1D photonic structures are integrated in an OLED containing AlQ3 (tris(8-hydroxyquinoline) aluminum) as the emitting species. It is assured that only a periodical change of the refractive index (,n,=,0.006 at ,,=,540,nm) is generated in the active material but no surface-relief gratings are generated. The patterned devices show more forward-directed out-coupling behavior than unstructured devices (increase in luminosity by a factor of five for a perpendicular viewing direction). This effect is most likely due to Bragg scattering. For these multilayer structures, optimum outcoupling was observed for grating periods ,,,,390,nm. [source]


Efficiency analysis of a combined PEFC and bioethanol-solar-reforming system for individual houses

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2010
Shin'ya Obara
Abstract In this research, the development of a bioethanol reforming system for fuel cells (FBSR: fuel cell with bioethanol steam reforming) using sunlight as a heat source was investigated. The system was investigated using the experimental result of catalyst performance, and numerical analysis. If ethanol purity is high, the production method of the bioethanol used for the proposal system will not be limited. The overall efficiency of the production of electricity and heat power of this system was determined by examining its thermal output characteristic. The FBSR was introduced into standard individual houses in Sapporo, Japan, for analysis. The amount of hydrogen production, the production-of-electricity characteristic, and the thermal output characteristic were examined using meteorological data on representative days in March and August. Compared with the representative day in March (28.0,MJ,day,1), the solar radiation of the representative day in August (37.0,MJ,day,1) is large. However, the amount of solar radiation fluctuation of the representative day in August in this analysis is large compared with the representative day in March. It depends for the overall efficiency of the system on the amount of solar radiation fluctuation rather than the amount of solar radiation. As a result, the overall efficiency of the system, defined as the rate of power and heat output compared with the amount of solar heat collected, was calculated to be 47.4 and 41.9% on the representative days in March and August, respectively. Copyright © 2009 John Wiley & Sons, Ltd. [source]


Ambient and temperature dependent electric properties of backgate graphene transistors

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 4 2010
Christian Hummel
Abstract The electrical behavior of backgate graphene field effect (GFET) transistor was studied at different ambient conditions. Backgate p-channel GFET transistors were fabricated on oxidized silicon wafers by exfoliation of graphite. The carrier mobilities were determined from the measured transconductance. For all ambients investigated (N2, Ar, and air), the graphene transistors show enhanced mobilities at elevated temperatures. This behavior can be explained by a stronger screening of scattering centers, i.e., defects in graphene and at the graphene oxide interface, with increasing temperature. For operation in air the transistors showed a higher transconductance compared to the operation in nitrogen and argon due to the strong acceptor-like behavior of gases adsorbed on the graphene surface. Effect of temperature and ambient on the output characteristic of a backgate GFET. [source]


Modifying the Output Characteristics of an Organic Light-Emitting Device by Refractive-Index Modulation,

ADVANCED FUNCTIONAL MATERIALS, Issue 18 2006
T. Höfler
Abstract In order to modify the output characteristics of organic light-emitting devices (OLEDs), the optical properties of an active layer within the device are patterned without introducing any thickness modulation. For this purpose a new conjugated copolymer, which serves as a hole-transporting material and at the same time can be index patterned using UV techniques, is synthesized. Poly(VC- co -VBT) (VC: N -vinylcarbazole; VBT: 4-vinylbenzyl thiocyanate) is prepared by free-radical copolymerization of VC and VBT. The material contains photoreactive thiocyanate groups that enable altering of the material's refractive index under UV illumination. This copolymer is employed as a patternable hole-transporting layer in multilayer OLEDs. Refractive-index gratings in poly(VC- co -VBT) are inscribed using a holographic setup based upon a Lloyd mirror configuration. The fourth harmonic of a Nd:YAG (YAG: yttrium aluminum garnet) laser (266,nm) serves as the UV source. In this way 1D photonic structures are integrated in an OLED containing AlQ3 (tris(8-hydroxyquinoline) aluminum) as the emitting species. It is assured that only a periodical change of the refractive index (,n,=,0.006 at ,,=,540,nm) is generated in the active material but no surface-relief gratings are generated. The patterned devices show more forward-directed out-coupling behavior than unstructured devices (increase in luminosity by a factor of five for a perpendicular viewing direction). This effect is most likely due to Bragg scattering. For these multilayer structures, optimum outcoupling was observed for grating periods ,,,,390,nm. [source]


Functionalized Arylacetylene Oligomers for Organic Thin-Film Transistors (OTFTs),

ADVANCED MATERIALS, Issue 10 2005

Oligo(arylacetylene)-based organic thin-film transistors (OTFTs) possess good structural order and smooth film morphologies, and exhibit field-effect mobilities of 0.3,cm2,V,1,s,1, one of the highest field-effect mobilities reported for an OTFT device that does not possess a self-assembled-layer configuration. The Figure shows the measured output characteristics (drain,source current, IDS versus drain,source voltage, VDS) at different gate voltages (VG). [source]


Development and validation of time-series synthesizers of rain attenuation for Ka-band and Q/V -band satellite communication systems

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 6 2007
Joël Lemorton
Abstract The aim of this paper is to present recent developments in terms of propagation time-series synthesizers, carried out in the framework of the ESA study 16865/03/NL/EC ,Development of propagation models for telecommunication satellite systems' (ONERA Final Report RF 4/07757/DEMR, 2004). The paper is composed of three parts: a review of the initial requirements related to propagation time series for system performance simulation, a description of a collection of rain attenuation time-series synthesizers and of their related input parameters, and a comparative analysis of the output characteristics of these time-series synthesizers as compared with experimental data collected during the OLYMPUS and ITALSAT propagation experiments. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Nanostructuring of an AlGaInP light emitting diode for surface plasmon enhanced emission of light output

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2008
R. M. Perks
Abstract This work describes a successful post fabrication method of applying a plasmonic grating to the surface of a mounted AlGaInP LED device. A Carl Zeiss 1540 XB Focused Ion beam system was used to mill holes in a thin gold layer with a periodicity of around 540 nm. Measurements of the total light output of the device compared with a standard un-textured device show that the plasmonic grating was found to significantly affect the light output characteristics such that the overall light output was reduced. This is attributed to the fact that only p-polarised light can interact with the hole array. Furthermore, the onset of saturation in the textured device was not evident as compared with the un-textured device. This is attributed to improved current spreading in the device due to the top gold layer. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]