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Conduction Current (conduction + current)
Selected AbstractsThermal properties of conduction current and carrier behavior in an organic electroluminescent deviceELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 3 2009Masahiro Minagawa Abstract Organic electroluminescent device (OLED) was fabricated using a vacuum evaporation method and thermal properties were investigated. The OLED has an indium tin oxide (ITO)/N,N,-diphenyl- N,N,-bis(3-methylphenyl)-1,1,-biphenyl-4,4,-diamine (TPD)/tris(8-hydroxyquinoline) aluminum (Alq)/lithium fluoride (LiF)/aluminum (Al) structure. An electron-dominant device of Al/Alq/LiF/Al structure, or a hole-dominant device of ITO/TPD/Al structure was also fabricated in order to study the carrier behavior in the OLEDs. The current density versus voltage (J,V) properties with various thickness of organic layers were investigated in both electron- and hole-dominant devices, and the thermal dependence of J,V properties was observed in the devices. At room temperature, conductions in a wide current region were considered to be due to space-charge-limited current for all of the devices. Especially for the Al/Alq/LiF/Al device and the OLED, relationships were observed across a wide current region. At low temperature, tunnel currents were estimated for the ITO/TPD/Al device. For the Al/Alq/LiF/Al device and the OLED, relationships were observed across a wide current region at low temperature. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(3): 24,31, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10048 [source] Space Charge Measurement in MgO/LDPE Nanocomposite up to Breakdown under DC Ramp VoltageIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 4 2010Yoshinobu Murakami Member Abstract To understand the basic electric properties of nanosized magnesium oxide (MgO)/low-density polyethylene (LDPE) nanocomposites under an applied DC voltage, the DC breakdown strength and space charge up to the breakdown under a DC ramp voltage were investigated. Compared to that of the LDPE sample, the sample containing a MgO nanofiller (hereafter, called a nanocomposite) had a higher DC breakdown strength. In the case of the LDPE sample, the homo charges, which contained a large negative charge and a small positive charge, were only observed near the electrodes just prior to breakdown. However, in the case of the nanocomposite sample, the positive charge increased as the average field increased until the average field reached a certain value. After that, the positive charge decreased as the average field increased until breakdown occurred. The field enhancement rate (=maximum field/average field) of the nanocomposite sample increased with the average field, until it became saturated. After peaking, the field enhancement rate of the nanocomposite sample decreased as the average field increased. These observations suggest that, instead of the MgO nanofiller suppressing the electronic avalanche, it suppresses the conduction current, which was determined by the space charge, leading to the higher DC breakdown strength. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Effect of magnetic field on electrical properties of nanocrystalline poly(vinylidene fluoride) samplesPOLYMER INTERNATIONAL, Issue 11 2009Prashant Shukla Abstract BACKGROUND: The electrical properties of nanocrystalline poly(vinylidene fluoride) (PVDF) samples of 20 µm in thickness were measured in terms of thermally stimulated current (TSC), conduction current and dielectric constant after application of a magnetic field. RESULTS: TSC shows the release of trapped charges inside the material that enhances the current with magnetic field. The reason for the polarity reversal of the current with reversal of the magnetic field polarity is due to the change in spin of electrons depending upon the direction of the magnetic field. CONCLUSION: The magnetic field causes trapping of charge carriers in different traps, as the reason for the increase of activation energy with increasing field. The flow of conduction current at constant temperature in magnetically polarized PVDF is governed by Poole,Frenkel and Schottky,Richardson mechanisms. The decrease in dielectric constant at a certain alternating current (AC) frequency and magnetic field with temperature is caused by magnetic polarization in addition to the AC field. Copyright © 2009 Society of Chemical Industry [source] Redox-induced configuration conversion for thioacetamide dimer can function as a molecular switchJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 14 2010Haiying Liu Abstract The electronic switching properties of thioacetamide dimer (TAD) were investigated using the nonequilibrium Green's function method combined with density functional theory for design of a novel molecular switch. The H-bonded TAD can be converted upon hole-trapping to a three-electron (3e)-bonded configuration with a S,S linkage which could provide a more favorable channel for charge transfer than the before. The redox-induced configuration conversion between the H-bonded and the 3e-bonded TADs could govern the charge migration through the molecular junction with a considerable difference in conduction currents. The calculated I,V characteristic curves of two configurations exhibit a switching behavior with an On-Off ratio in a range of about 4.3,7.6 within the applied voltages. Clearly, this hypothetical scheme provides a potential way to explore the novel conformation-dependent molecular switch. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010 [source] | ||||||||||