Search results for " spin coating"

showing 3 items of 3 documents

Increased conductivity of a hole transport layer due to oxidation by a molecular nanomagnet

2008

Thin film transistors based on polyarylamine poly?N,N?-diphenyl-N,N ?bis?4-hexylphenyl?- ?1,1?biphenyl?-4,4?-diamine ?pTPD? were fabricated using spin coating in order to measure the mobility of pTPD upon oxidation. Partially oxidized pTPD with a molecular magnetic cluster showed an increase in mobility of over two orders of magnitude. A transition in the mobility of pTPD upon doping could also be observed by the presence of a maximum obtained for a given oxidant ratio and subsequent decrease for a higher ratio. Such result agrees well with a previously reported model based on the combined effect of dipolar broadening of the density of states and transport manifold filling. Peer Reviewed

Electron mobilityMaterials scienceOrganic compounds.Analytical chemistryDipolar broadeningGeneral Physics and AstronomySpin coatingHole mobilityElectronic density of statesConductivityOxidacióCompostos orgànicsElectrical resistivity and conductivity:FÍSICA [UNESCO]Molecular clustersOrganic compoundsOxidationDopingElectrical conductivityOxidation.Molecular nanomagnetMolecular magnetic clusterMolecular magnetism Nanostructured materialsSpin coatingDopingUNESCO::FÍSICAElectric conductivity.Thin film transistorsNanostructured materialsConductivitat elèctricaNanomagnet:Enginyeria electrònica::Microelectrònica [Àrees temàtiques de la UPC]Doping ; Electrical conductivity ; Electronic density of states ; Hole mobility ; Molecular clusters ; Molecular magnetism Nanostructured materials ; Organic compounds ; Oxidation ; Spin coating ; Thin film transistorsDensity of statesNanostructured materials.Hole transport layerMaterials nanoestructuratsOrder of magnitude
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Frequency-Downconversion Stability of PMMA Coatings in Hybrid White Light-Emitting Diodes

2015

We report on the properties of a poly(methyl methacrylate)-based coating used as a host for an organic dye in hybrid white light-emitting diodes. The device is composed by a pump source, which is a standard inorganic GaN/InGaN blue light-emitting diode (LED) emitting at around 450 nm, and a spin-coated conversion layer making use of Lumogen® F Yellow 083. Under prolonged irradiation, the coating exhibits significant bleaching, thus degrading the color rendering performance of the LED. We present experimental results that confirm that the local temperature rise of the operating diode does not affect the conversion layer. It is also proven that, during the test, the photostability of the orga…

Materials scienceInfraredSettore AGR/13 - Chimica Agraria02 engineering and technologyengineering.materialSettore ING-INF/01 - Elettronica01 natural sciencesCoating0103 physical sciencesMaterials ChemistryElectrical and Electronic EngineeringPhotodegradationDiode010302 applied physicschemistry.chemical_classificationSpin coatingbusiness.industryPMMA hybrid LEDs Lumogen polymer degradation photostability spin coatingPolymer021001 nanoscience & nanotechnologyCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsColor rendering indexchemistryengineeringOptoelectronics0210 nano-technologybusinessLayer (electronics)Journal of Electronic Materials
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Stability improvement of PMMA and Lumogen® coatings for hybrid white LEDs

2014

Hybrid white LEDs employing perylene-based dyes for the frequency down-conversion of blue light, generated by a standard inorganic source, suffer from colour rendering variations due to the degradation of the organic molecule under prolonged irradiation. To avoid such inconvenient, proper encapsulation of the dyes in resins or other polymer matrices can prevent their accelerated ageing; nevertheless, embedding polymers can also exhibit significant bleaching caused by chemico-physical agents. Among all, polymethyl methacrilate (PMMA) is one of the most used materials for the fabrication of hybrid LEDs' colour conversion coatings, therefore its stability needs to be investigated.

PMMA white LEDs hybrid LEDs perylene-based dyes Lumogen® polymer degradation LED optical characterization spin coating.Settore ING-INF/01 - Elettronica
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