Academic literature on the topic 'Composite électroluminescent'
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Dissertations / Theses on the topic "Composite électroluminescent":
Yang, Sheng-Hsiung. "Synthèse et caractérisation des dérivés de poly(2,3-diphényl-1,4-phénylène vinylène) et des composites poly(1,4-phénylène vinylène) / nanoparticules d'oxyde : propriétés optiques et électrique des diodes utilisant des films composites comme couches actives." Nantes, 2004. http://www.theses.fr/2004NANT2030.
In this thesis, we have studied the new materials for the fabrication of organic electroluminescent devices. In the first part, we have synthesized and characterized the poly(2,3-diphenyl-1,4 phenylene vinylene) or DP-PPV. This polymer contains liquid crystalline groups and can emit polarized light. Then we synthesized and characterized the PPV based composites containing silicon and titanium oxide nanoparticles. These light-emitting materials possess a better stability than the bare polymer because of the presence of the oxide nanoparticles. The modifications of the optical and electrical properties obtained in the materials can be explained by physical processes which highlight the role of the particles inside the polymer structure : reduction of the conjugation length of the chains, formation of the conducting pathways inside the polymer matrix, interaction nanoparticles-polymer, increase of the surface contact polymer-electrode
Leopold, Diatezo. "Multifunctional materials for intelligent textile : Toward automotive applications." Electronic Thesis or Diss., Lyon, INSA, 2023. http://www.theses.fr/2023ISAL0114.
This PhD student research project concerns the development and use of printable multifunctional materials, focusing on the trade-offs between material properties and application specification, with a particular emphasis on joule heating and electroluminescence functions. The originality of the work lies in a coupled approach between multifunctional materials and textile integration. The first part of the study concerned the selection of multifunctional materials deemed potentially interesting for the creation of intelligent textiles adapted to TESCA-groupe's target sectors. This involved characterizing the electrical and thermal properties of both the conductive materials and the textile substrate. In addition, analyses using scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were carried out to study the microstructure, including adhesion, the thickness of the deposited layers and the chemical composition of the materials. The second aspect focused on an accelerated ageing study on unit specimens of textile substrates coated with conductive ink, in compliance with the specifications required by Tesca. The aim of this approach was to identify the inherent limitations of each material, such as maximum deformation, temperature variations, adhesion, process compatibility, etc., with a view to proposing areas for optimization or taking these limitations into account when designing transducers integrated on textile substrates. This first step enabled us to establish a base of multifunctional materials that could be used for specific applications, such as heating mats, capacitive or resistive switches, transducers, sensors for mechanical quantities, among others. The third aspect of this research consisted in assembling these basic elements to create sub-functions described as "intelligent". In fact, the production of transducers generally involved combining different multifunctional materials to meet the specific requirements of the target application
Lavernhe, Patrick. "La photopolymérisation en application orthodontique." Toulouse 3, 2007. http://www.theses.fr/2007TOU30013.
Two photopolymerization processes (halogen and LED), two cement types for orthodontic bonding – a composite one : Transbond XT and a CVI hybrid one: Fuji ortho LC II – are assessed; cements are photopolymerised between 20 and 40 s with a halogen lamp and for 5 10 15, 20 or 40 s with a LED lamp. Studying the cement joint is by hardness, thermic measures and traction/ Shearing trials. Increasing photopolymerisation time improves hardness results and bonding resistance whatever the type of lamp, except for CVI, for which beyond 15 s, results go decreasing. Photopolymerisation increases tooth temperature by 2°C and with a halogen lamp, bracket temperature is increased by + 20°C. LED lamps are quite satisfactory. CVI has an easy clinical use, it reinforces resistance to carious lesions, mustn't be photopolymerised for more than 15 s and remains short of the adhesive performances of composites
Lakehal, Merouane. "Etude des matériaux composites à base de poly (p phénylène vinylène) et de nanoparticules inorganiques : application aux dispositifs électroniques." Nantes, 2002. http://www.theses.fr/2002NANT2032.
Poly (p phenylene vinylene) (PPV) is particularly well adapted to the fabrication of organic light emitting diodes because it has a good optical properties (absorption, photoluminescence,. . . ) and can easily be deposited in films
Jama, Mariel Grace. "Semiconductor composites for solid-state lighting." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0207/document.
Luminescent organic phases that are embedded in a conductive inorganicmatrix is proposed in this study for the active layer of a hybrid light-emitting diode. Inthis composite, the organic dye acts as the radiative recombination site for chargecarriers that are injected into the inorganic ambipolar transporting matrix. As one ofthe candidate material combinations, bilayer and composite thin films of ZnSe and ared iridium complex (Ir(BPA)) organic light emitter were prepared in situ via UHVthermal evaporation technique. The energy band alignments measured byphotoelectron spectroscopy (PES) for the ZnSe/Ir(BPA) bilayer and ZnSe+Ir(BPA)composite reveal that the HOMO and LUMO of the organic dye are positioned in theZnSe bandgap. This lineup provides the required energetic driving forces for electronand hole transfers from ZnSe to Ir(BPA). By interpreting PES data, the chemicalcomposition of the interfaces were also determined. The ZnSe/Ir(BPA) interface isreactive even though it is of high material purity. Meanwhile, the Ir(BPA)/ZnSeinterface does not exhibit material purity. This is accounted to the nature of ZnSeevaporation as individual Zn and Se2 fluxes, coupled with chemical interactions withthe Ir(BPA) substrate. The interface is, thereby, composed of an abundance of Se0phases, sparse ZnSe phases, reduced Se and oxidized dye molecules, and Znatoms that are intercalated into the Ir(BPA) substrate. PES of the ZnSe+Ir(BPA)composites reveals similar trends to the Ir(BPA)/ZnSe interface. A faded areal andintermittent red light emissions were observed from devices that incorporatedalternating layer sequences of ZnSe and Ir(BPA) for the active layer
Retailleau, Matthieu. "De la photopolymérisation aux matériaux avancés : nouvelles combinaisons de chimies et de photoamorceurs." Thesis, Mulhouse, 2016. http://www.theses.fr/2016MULH9373.
The goal of this thesis was to evaluate the potential of the free radical photopolymerization (FRP) for new applications that require higher thicknesses or require different properties regarding the 3D network structure, the ultimate objective being to achieve advanced materials. The subject of this thesis has focused on two main thematics: composites and intelligent materials. The first part of this manuscript was devoted to the COMPOSFAST project which aimed to automate the production of composites via FRP. Our goal has been to develop a two-stage photopolymérisable formulation for the manufacture of glass fiber composites by a pre-impregnation process. Regarding the second part of this manuscript, this one has been dedicated to the creation of smart materials by a multi-stage process. The objective has been to manufacture homogeneous polymer networks possessing smart properties by modifying the chemistry usually involved in FRP. Through the thesis, potential industrial applications have emerged thanks to the research carried out on these advanced materials and have led to the patenting of the technology
Chapel, Anthony. "Etude du comportement photochimique de revêtements composites polymère/particules luminescentes pour applications à l'éclairage éco-énergétique à base de LEDS. Impact du vieillissement sur les performances optiques." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22672/document.
Phosphor-converted LEDs are emerging as an eco-friendly solution for the next generation lighting. Despite lifetimes claimed over 50 000h, a loss of the optical properties was noticed. This work focuses on the influence of photodegradation of the materials on the optical properties of the polymer/phosphor composite that is used to encapsulate the semiconductor chip. Luminescent composites were made from a polymer matrix (EVA or PMMA) and an inorganic phosphor: Y3BO6 :15% Eu3+. The evolution of physical, chemical and optical properties of these composites was investigated under irradiation in accelerated conditions (λ>300 nm) and in the use conditions of UV LED (λ=365 nm). The phosphor showed no pro-degrading effect on the photooxidation of the polymer. A loss of the optical properties of the composite was observed and ascribed to the photodegradation of the polymer in the case of the EVA matrix. The evolution of photometric parameters of the emitted light by the luminescent composite during photoaging can be attributed to the accumulation of photoproducts in films. However, for PMMA/phosphor composites, the chemical structure and optical properties of such composites are kept for accelerated photoaging time up to 4000h
Cambril, Edmond. "Films composites or-carbone obtenus par décharge luminescente radio-fréquence." Toulouse 3, 1992. http://www.theses.fr/1992TOU30027.
Legentil, Paul. "Développement de poudres hybrides "Hydroxydes Doubles Lamellaires-luminosphores" sans terres rares. Intégration dans des revêtements composites compatibles avec des sources d'excitation LED." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC013.
These works have the ambition to offer alternative solutions to phosphors with rare-earth elements, displaying suitable performance for LED devices applications as well as signage or display applications. We have been interested in organic as well as inorganic phosphors such as quantum dots (QD). The main problem encountered with these compounds is their relative instability under thermal and/or photonic stresses. Thus, in order to overcome this issue, we decided to use inorganic materials called layered double hydroxide (LDH) as host matrix to protect these phosphors. Several experimental techniques (XRD, SAXS, IR, SEM, TEM…) have been used to characterize structural and morphological properties. Optical properties have also been recorded (emission and excitation spectra, photoluminescence quantum yields, fluorescence decay…). Using extremely small amounts of phosphors, it is demonstrated here that Zn2Al cation-based LDH tethering acts as a «solid solvent» for the dye, enabling its luminescence even in powder form. Additionally, LDH platelets are found to help the dispersion of the dye or QD in silicone to obtain homogeneous composite films, which exhibit luminescent properties. Finally, the stability of composite coatings (LDH-phosphor/silicone) under different stresses (thermal and photonic) is most often improved
Provost, Marion. "Intégration de couches hybrides de base sol-gel dans les architectures de passivation de dispositifs OLED." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT056.
Due of the ongoing growth of smartphones and TVs displays markets, the application of OLED (Organic Light Emitting Diode) technology for displays has become a major center of interest. The materials and substrates used in such architectures allow to develop lightweight, compact and even foldable displays, demonstrating an excellent image quality and fast refresh rates. Currently, the technological drawbacks restricting the exploitation on industrial scale mainly concern the lifespan of the devices. First, materials used in OLED architecture are highly sensitive to moisture and oxygen ingress and require a high barrier encapsulation. In addition, a specific protection needs to be included to secure the device from mechanical failures. As so various options from glass lids to flexible barriers are likely to be considered depending on the intended use. This work deals with the production of OLED microdisplays deposited on silicon substrates, and aims to develop an alternative packaging solution, based on organic-inorganic nanocomposite layers, both on top and embedded into the multi-barrier passivation architecture previously developed at the CEA-LETI. Synergistic properties can be obtained from composite materials, enhancing the advantages of both the organic (flexibility, processability) and inorganic phase (barrier properties, mechanical and chemical resistance). As a high control on the morphology in required, the sol-gel process was therefore selected for its versatility. Several composite materials were designed. One selected formulation, based on silica nanoparticles dispersed in a polymer matrix, proved to be fully compatible with the monolithic encapsulation of OLED circuits, including, among other properties, the recovery of the electrical bonding. Passivation architectures using the composite as interface layer showed improved barrier properties as well as an enhanced durability of devices stored in warm and damp environment. Obviously, a thin hard-coat layer does not equal a glass lid in terms of mechanical resistance, yet our formulation provided a sufficient protection during the overall process and handling of the displays. The main advantages of this alternative packaging rely on the reduced thickness, increasing the contrast by minimizing the loss of luminous efficacy through guided mode and offering the prospect of flexible substrate manufacturing