Search results for "Diodes"
showing 10 items of 70 documents
An inconvenient influence of iridium(III) isomer on OLED efficiency.
2010
The recently reported heteroleptic cyclometallated iridium(III) complex [Ir(2-phenylpyridine)(2)(2-carboxy-4-dimethylaminopyridine)] N984 and its isomer N984b have been studied more in detail. While photo- and electrochemical properties are very similar, DFT/TDDFT calculations show that the two isomers have different HOMO orbital characteristics. As a consequence, solution processed OLEDs made using a mixture of N984 and isomer N984b similar to vacuum processed devices show that the isomer has a dramatic detrimental effect on the performances of the device. In addition, commonly used thermogravimetric analysis is not suitable for showing the isomerization process. The isomer could impact pe…
Audiodescription et problématique de la traduction de contenus sexuels : le cas de La vie d’Adèle d’Abdellatif Kechiche
2018
L’audiodescription est une modalité émergente de traduction audiovisuelle dont l’objectif principal est de rendre accessible à des personnes malvoyantes ou non voyantes des films, de façon à ce qu’elles puissent comprendre et profiter du film comme un spectateur qui peut voir les images. Dans cet article, nous présentons une étude sur un sujet considéré tabou : la traduction d’images de contenu sexuel en mots. Dans un premier temps, nous avons identifié les scènes de contenu sexuel explicite dans le film français La vie d’Adèle (Kechiche, 2013). Nous avons analysé l’audiodescription qui les accompagne et déterminé les stratégies traductologiques utilisées pour le faire. Nous avons observé d…
Luminiscences pētījumi ar diviem retzemju joniem aktivētos oksifluorīdu stiklos un stikla keramikās
2015
Baltās gaismas LED lampas ir ļoti aktuāls pētījumu objekts- tiek meklētas labākās izgatavošanas tehnoloģijas un veiksmīgākais luminoforu sastāvs. Svarīgi ir ne tikai iegūt baltu gaismu, bet arī nodrošināt augstu gaismas kvalitāti. Kā perspektīvi luminoforu materiāli tiek minēti ar retzemju joniem aktivēti oksiflorīdu stikli un stikla keramikas, jo šiem materiāliem piemīt labas mehāniskās un optiskās īpašības. Literatūras apskatā sniegta informācija par luminiscences mehānismu, baltās gaismas LED diožu ražošanas tehnikām un gaismas avotu krāsas raksturlielumiem, kā arī, apskatīti oksifluorīdu materiāli un retzemju jonu vispārīgās un luminiscences īpašības. Darba praktiskajā daļā izgatavoti a…
Ar eiropiju un disproziju koaktivētu oksifluorīdu stiklu luminiscence
2016
Baltās gaismas diodes ir aktuāls pētniecības virziens apgaismes tehnoloģiju attīstībā. Pēdējos gados par aktuālu pētniecības virzienu ir kļuvusi ar retzemju joniem aktivētu oksifluorīdu stiklu un stikla keramiku materiālu pētniecība. Dotie materiāli ir perspektīvi baltās gaismas luminofori, jo tiem piemīt labas optiskās, ķīmiskās un mehāniskās īpašības. Darbā tiek veikti ar Eu3+ un Dy3+ joniem aktivētu oksifluorīdu stiklu spektroskopiskie pētījumi, ar mērķi izpētīt doto jonu savstarpējo mijiedarbību caur enerģijas pārnesi, kas ļautu novērtēt dotā materiāla kā baltās gaismas luminofora izstrādes iespējas. Literatūras apskatā tiek apskatīti luminiscences mehānisma principi, retzemju elementi …
Perimeter leakage current in polymer light emitting diodes
2009
Observation of leakage current paths through the device perimeter in standard poly(phenylene vinylene)-based light-emitting devices is reported. Perimeter leakage currents govern the diode performance in reverse and low positive bias and exhibit an ohmic character. Current density correlates with the perimeter-to-area ratio thus indicating that leakage currents are mainly confined on polymer regions in the vicinity of metallic contact limits (device perimeter). © 2008 Elsevier B.V. All rights reserved.
Deep traps in InGaN/GaN single quantum well structures grown with and without InGaN underlayers
2020
The electrical properties and deep trap spectra were compared for near-UV GaN/InGaN quantum well (QW) structures grown on free-standing GaN substrates. The structures differed by the presence or absence of a thin (110 nm) InGaN layer inserted between the high temperature GaN buffer and the QW region. Capacitance-voltage profiling with monochromatic illumination showed that in the InGaN underlayer (UL), the density of deep traps with optical threshold near 1.5 eV was much higher than in the QW and higher than for structures without InGaN. Irradiation with 5 MeV electrons strongly increased the concentration of these 1.5 eV traps in the QWs, with the increase more pronounced for samples witho…
Effects of InAlN underlayer on deep traps detected in near-UV InGaN/GaN single quantum well light-emitting diodes
2019
Two types of near-UV light-emitting diodes (LEDs) with an InGaN/GaN single quantum well (QW) differing only in the presence or absence of an underlayer (UL) consisting of an InAlN/GaN superlattice (SL) were examined. The InAlN-based ULs were previously shown to dramatically improve internal quantum efficiency of near-UV LEDs, via a decrease in the density of deep traps responsible for nonradiative recombination in the QW region. The main differences between samples with and without UL were (a) a higher compensation of Mg acceptors in the p-GaN:Mg contact layer of the sample without UL, which correlates with the presence of traps with an activation energy of 0.06 eV in the QW region, (b) the…
Audiodescripción de referentes culturales: estudio descriptivo-comparativo y de recepción
2017
La audiodescripción (AD) entendida como un servicio de apoyo a la comunicación con personas ciegas o con baja visión está adquiriendo cada vez más importancia profesional, social y académica. Las cifras actuales de programas que se ofrecen con AD en la televisión española, los congresos y seminarios sobre AD que se celebran en todo el mundo y el avance legislativo en materia de accesibilidad dan buena cuenta de ello. La accesibilidad reivindica su lugar en los Estudios sobre Traducción (y más concretamente, sobre Traducción Audiovisual) y aunque el interés investigador es bastante reciente, sobre todo en España, también es prolífica y ha abordado con profundidad numerosos aspectos específic…
Surface poling in lithium niobate waveguide creates efficient wavelength conversion
2004
Used with red or IR emitting laser diodes, nonlinear crystals for frequency doubling can result in a small blue emitting laser that is a viable alternative to gallium nitride-based laser diodes.
Molecular dynamics simulations of heavy ion induced defects in SiC Schottky diodes
2018
Heavy ion irradiation increases the leakage current in reverse-biased SiC Schottky diodes. This letter demonstrates, via molecular dynamics simulations, that a combination of bias and ion-deposited energy is required to produce the degradation. Peer reviewed