[pt] Esta dissertação trata da investigação, simulação e otimização da estrutura de Diodos Orgânicos Emissores de Luz Multicamadas (ML-OLEDs) através da utilização de técnicas da Inteligência Computacional. Além disso, um desses métodos, chamado Otimização por Colônia de Formigas (ACO), foi implementado com base em um modelo proposto na literatura e aplicado pela primeira vez na otimização de diodos orgânicos. OLEDs são dispositivos optoeletrônicos nanométricos fabricados a partir de materiais semicondutores orgânicos. Ao contrário das tecnologias tradicionais, eles conjugam elevada luminescência e baixo consumo energético. Na fabricação de um OLED, o número configurações possíveis é quase ilimitado, em função da quantidade de parâmetros que se pode variar. Isso faz com que determinação da arquitetura ótima torne-se uma tarefa não trivial. Para simular os OLEDs foram empregados dois modelos distintos de simulação. Assim, as Redes Neurais Artificiais (RNA) foram empregadas com o objetivo de emular um dos simuladores e acelerar o cálculo da densidade de corrente. Os Algoritmos Genéticos (AG) foram aplicados na determinação dos valores ótimos de espessura das camadas, mobilidades dos portadores de carga e concentração dos materiais orgânicos em OLEDs com duas camadas, enquanto o ACO foi aplicado para encontrar os valores de concentração em OLEDs com duas e cinco camadas, constituindo assim três estudos de caso. Os resultados encontrados foram promissores, sobretudo no caso das espessuras, onde houve uma confirmação experimental do dispositivo com duas camadas. / [en] This dissertation deals with the research, simulation and optimization of the structure of Multilayer Organic Light Emitting Diodes (ML-OLEDs) by using Computational Intelligence techniques. In addition, one of these methods, called Ant Colony Optimization (ACO), was implemented based on a model proposed in the literature and applied for the first time in the optimization of organic diodes. OLEDs are nanometric optoelectronic devices fabricated from organic semiconducting materials. Unlike traditional technologies, they combine high luminance and low power consumption. In the manufacturing of an OLED, the number of possible configurations is almost unlimited due to the number of parameters that can modified. Because of this the determination of the optimal architecture becomes a non-trivial task. Two different simulation models were used to simulate the OLEDs. Thus, the Artificial Neural Networks (ANN) were employed in order to work as the proxy of the commercial simulator and to accelerate the calculation of the current density. The Genetic Algorithms (GA) were applied to determine the optimal values of thickness of the layers, the charge carrier mobility and the concentration of the organic materials in OLEDs with two layers, while the ACO was applied to find the values of concentration in OLEDs with two and five layers, thus establishing three case studies. The employed strategy has proved to be promising, since it has show good results for two case studies, especially for the optimization of the thickness, where there was an experimental confirmation of the bilayer device.

CRT從1940年代開始就主宰著整個電視機的市場，開啟顯示技術的發展，到了二十一世紀，人類為追求高品質、更貼近人性化的生活，顯示器已從傳統的陰極射線管（CRT）進入平面顯示器（FPD）時代。在最新的平面顯示技術OLED （Organic Light Emitting Diode有機發光二極體）問世後，此平面顯示新技術更是吸引了產業及學術界的關注，進而從事開發與研究。 但是OLED歷年的產值與年成長率不如市調機構所預期，甚至在2006年發生了產業崩跌的情形，年營收成長率首度出現負成長，許多國際大廠在這段期間結束了OLED事業部門。不過這個下滑趨勢在2007年止住，且就此之後產值又開始向上攀升。OLED面板在2008年的產值年成長率甚至高過整體平面顯示器，使得整個產業似乎有逐漸抬頭的跡象。同時，知名的市調機構DisplaySearch也指出，儘管2008年全球OLED顯示器產值佔全球整體平面顯示器產值比重不到1%；但預估到了2015年時，OLED產品產值佔整體平面顯示器產值比重將提高到5%，各界對於這項新世代的顯示技術又再度抱持樂觀的看法。 有鑑於上述的產業發展現象，本研究回顧以往對於OLED的研究，研究重點往往放在OLED產業的發展策略、關鍵成功因素的分析，對於探討產業發展歷程的研究少有著墨。故本篇論文針對OLED產業發展的興衰進行研究，透過個案研究的方式，針對國內外OLED產業的發展進行深入探討，希望能夠找出產業衰弱與重新站起的原因，並供實務界參考。 本研究首先透過文獻的探討，瞭解用以分析產業發展的相關理論，其中包括「產業分析理論」、「擴散理論」、「複雜理論」等相關理論，並最後以「複雜理論下的動態創新過程」，結合部分產業分析理論與時間因素，發展出一套用以描述產業發展歷程的研究架構。本研究的命題整理如下： 1.在產業發展歷程中，產業內正向與負向驅動力之間的消長，會決定產業最終的表現。 2.產業有如複雜適應系統，有著非線性的發展，各自獨立自主但受其他個體的影響，因應市場不同變化，彼此互相學習模仿，並尋找有利的方向，共同演化。 3.產業環境如同處於混沌邊緣（the edge of chaos），一種介於有序與無序、現況與創新、穩定與轉型之間的狀態；而OLED產業就在這混沌邊緣不斷演化成長。 4.產業的擴散過程中，因為新的技術、新的應用領域等，都使產業內產生突現的現象，而突現現象的產生，有的會引發正回饋效果，有的引發負回饋效果，都對產業的擴散產生影響。 5.在產業的擴散過程中，具有較明顯自我組織現象的發展階段，比起自我組織現象較不明顯的階段，具有比較理想的擴散效果。 6.產業初始狀態的差異影響日後產業擴散的結果，同時產業內的創新領導者或意見領袖也會引領產業的發展。 7.產業發展初期，體制開放程度越高，可吸引越多的新進者，愈有利產業發展；相反的，體制開放程度低，則不利於產業發展；但若要產業蓬勃發展，產業內需要有規格化的標準。 8.技術突破的難易程度影響產業的擴散。 9.具成本與技術成熟度優勢的競爭性技術，會影響到新興技術的擴散。 10.當新技術進入產業化階段時，對於新技術的需求端，其採用與否會影響到產業的擴散。 11.政府的角色對於一個新興產業的發展，具有降低進入障礙，提高產業體制內自由度的助益。 / From the beginning of the 1940s, CRT was the key to the entire TV market. When the 21th era began, mankind were in pursuit of high-quality, closer to human life, so it changed from traditional display of the cathode ray tube (CRT) to the flat panel display (FPD) era. As the latest flat panel display technology OLED (Organic Light Emitting Diode Organic Light Emitting Diode) was first published, this flat panel display was a new technology which has attracted the concern of industry and academia, and then engaged in the development and research. Nevertheless the production value of OLED was lower than the well-known forecast agent like DisplaySearch predicted, hence many international companies in the 2006 ended OLED business sector. However, this downward trend stopped in 2007, and it began to take-off. OLED panels in 2008,its annual growth rate of output was even higher than the overall flat-panel displays, making the whole industry seemed to be prosperous again. From the above description of industrial development, the study of the past for OLED research, the focus was often on the OLED industry development strategy or on the analysis of critical success factors for OLED. To explore the development of research rarely written. Therefore, this paper is to study the rise and fall of OLED industry, using the way of case study. This study first try to understand some relevant theories which are about industry development, including the "industry analysis", "diffusion theory", "complexity theory" and other related theories, and finally combined "the complex dynamic process of innovation " with some factors of industry analysis and the time factor, to describe the development of OLED. Finishing this study comes out some findings such as following: In the course of industrial development, the positive and negative driving forces which affect the growth of industry, will determine the ultimate performance of industry. The industry, in the process of diffusion , which showed more obvious self-organization than the others will get more satisfactory results. There are still some other findings in the thesis, I hope the study of the cause and effect about OLED industry will be useful for practical reference.

Ressonância magnética detectada eletricamente (RMDE) de banda-X (9 GHz) e de banda-K (24 GHz) foram usadas para estudar diversos diodos baseados em tris-8(hidroxiquinolinolato) de alumínio III (Alq3). A técnica de RMDE consiste, basicamente, em medir a variação da condutividade quando o sistema entra na condição de ressonância magnética; assim, é possível relacionar propriedades de transporte elétrico com as funções de onda das moléculas envolvidas no processo. Para este estudo foram confeccionados diodos eletroluminescentes e unipolares de multicamadas no Laboratoire d'Optoélectronique des Materiaux Moléculaire (LOMM), da École Polytechnique Fédérale de Lausane (EPFL), Suíça, pelo Dr. Frank Nüesch. Faz parte também deste trabalho a montagem experimental do sistema de RMDE de banda-K, onde a maior parte dos dados foram obtidos. O sinal de RMDE dos diodos unipolares, da ordem de 1E-6, é atribuído ao processo dependente de spin de saltos eletrônicos que ocorre próximo às interfaces. O sinal típico de RMDE dos diodos eletroluminescentes é mais intenso, da ordem de 1E-4, e é atribuído à ressonância de spin-1/2 na formação dos éxcitons. O espectro de RMDE, por meio de ajuste de curvas, pôde ser decomposto em duas gaussianas: uma com largura de linha pico-a-pico DHPP de 1,6 mT, independente do campo elétrico aplicado no dispositivo, e outra variando de 2,0 mT a 3,4 mT. A componente mais estreita se deve à ressonância do radical positivo de Alq3, enquanto que a componente mais larga àquela do negativo. O estudo da forma de linha e de sua dependência com o campo elétrico dos espectros de RMDE de diodos unipolares dão suporte à ambas as atribuições. Neste trabalho, a questão da eficiência quântica e da zona de recombinação também são discutidas. / Electrically Detected Magnetic Resonance (EDMR) at X-band (9GHz) and K-band (24 GHz) were used to investigate Alq3 based diodes. EDMR technique consists basically of measuring conductivity variation at magnetic resonance conditions; thus, it is possible to correlate electrical transport properties with wave functions of the molecules involved in the process. Electroluminescent and unipolar multilayer diodes were prepared in the Laboratoire d'Optoélectronique des Materiaux Moléculaire (LOMM), at on École Polytechnique Fédérale de Lausane EPFL, Switzerland by Dr. Frank Nüesch. The experimental setup of the K-band EDMR system, where most of the data were obtained, was also part of this work. The unipolar diodes EDMR signal is of the order of 1E-6 and is attributed to spin dependent hopping process close to the interfaces. The electroluminescent diodes typical EDMR signal is more intense, of the order of 1E-4 , and is attributed to exciton´s formation spin-1/2 resonance. The EDMR spectrum can be decomposed into two Gaussians: one with peak-to-peak line width (DHPP) of 1.6 mT, independent of the electrical field applied to the devices, and other one whit DHPP of 2.0 mT to 3.4 mT. The narrower component is due to the resonance of positive Alq3 radical, while the larger component is due to the negative. Both attributions are supported by the investigation of line shape and its dependence of electrical field in the unipolar diodes EDMR spectra. In this work, the quantum efficiency and the recombination zone issues are also discussed.

One of the major challenges in the field of organic semiconductors is to develop molecular design rules and processing routes which optimise the charge carrier mobility, whilst independently controlling the radiative and non-radiative processes. To date there has existed a seeming trade-off between charge carrier mobility and photoluminescence efficiency, which limits the development of some devices such as electrically pumped laser diodes. This thesis investigates fluorescence enhancement strategies for high-mobility polymer semiconductor systems and the mechanisms by which they currently display poor emission properties. Four independent approaches were taken and are detailed as follows. 1. Solubilising chain engineering It is shown that for the high mobility polymer poly(indacenodithiophene-co-benzothiadiazole), the addition of a phenyl- initiated side chain can enhance the solid-state fluorescence quantum yield, exciton lifetime and exciton diffusion length significantly in comparison to that without phenyl-addition. 2. Energy transfer to a highly fluorescent chromophore It is shown that for the high mobility polymer poly(indacenodithiophene-co-benzothiadiazole) efficient energy transfer to a more emissive squaraine dye molecule is possible despite fast non-radiative decay short exciton diffusion lengths. This results in a significant fluorescence enhancement, which in turn facilitates an order of magnitude increase of the efficiency of polymer light emitting diodes made from this material combination. 3. Energy gap engineering The well known Energy Gap Law predicts an increase in the non-radiative rate as the optical bandgap of an organic chromophore decreases in energy. In combination with this, almost all polymer semiconductors reported to date with high charge carrier mobility have low optical bandgaps. Therefore, molecular design principles which act to increase the optical bandgap of polymer semiconductors whilst retaining a high mobility were sought out. One specific system was successfully identified and showed a significant fluorescence enhancement compared to is predecessor poly(indacenodithiophene-co-benzothiadiazole) in both the solution and the solid state. It is found that the Frenkel exciton lifetime in this new system is a factor of four larger which also results in a significantly increased exciton diffusion length. An inter-chain electronic state is also identified and discussed. 4. Hydrogen substitution For some low-bandgap material systems such as erbium chromophores, high energy vibrational modes such as the C-H stretching mode can act as non-radiative pathways. The effect of hydrogen substitution with deuterium and fluorine was therefore investigated in a series of polythiophene derivative families. It was found that in the solid state, fluorescence and exciton lifetime enhancement occurred when the backbone hydrogen atoms were replaced with fluorine. However, evidence is given that this was not owing to the initial hypothesis, and is more likely owing to structural differences which occur in these substituted material systems.

Au cours de cette thèse, nous avons synthétisé et caractérisé de nouveaux composés en utilisant le macrocycle porphyrinique comme brique moléculaire de départ. Le but de ce travail étant l’étude des propriétés optiques de ces nouveaux composés obtenus. Après avoir effectué l’étude bibliographique sur les porphyrines, nous avons fait une présentation générale des porphyrines symétriques et non symétriques, de leurs propriétés et de leurs synthèses. D’autre part, nous avons aussi considéré l’unité fluorène qui possède des propriétés photophysiques très intéressantes comme antenne collectrice de lumière. Puis, nous avons abordé des méthodes de synthèse permettant d’associer le macrocycle porphyrinique avec de nombreuses unités fluorènes. Cette association a pu être réalisée de différentes manières : soit de façon dendritique ou par connexion directe sur la porphyrine (dimère et trimère). Nous avons également décrit l’obtention d’une nouvelle famille de porphyrines substituées par des groupements organométalliques de type acétylure de ruthénium et de fer pour l’optique non linéaire de troisième ordre (ONL TO). Lors de la dernière partie de mes travaux de thèse, comme application de ces composés luminescents dans le rouge, nous avons reporté l’élaboration de différents dispositifs de diodes électroluminescentes (OLED) émettant dans le rouge. / During this thesis, we have worked on the synthesis and characterization of new compounds using the porphyrin macrocycle as a starting material. The aim, after synthesis, is to study the photophysical properties of these new molecules. A general bibliographic study was presented followed by introducing the synthetic methods of porphyrins and characterization means. Then, fluorene was considered to be an attracting unit due to its interesting photophysical properties: acting as efficient antennae for collecting light. First, we have presented the synthesis of porphyrin dendrimers having fluorenyl arms of different generations. That is to test the effect of number of fluorenes on the photophysical properties. Another way is to connect the fluorenes directly to the porphyrin core by synthesizing porphyrin dimer and trimer. We have also detailed the synthesis and characterization of a new family of porphyrin organometallic assemblies possessing ruthenium and iron moieties. In addition, a new organometallic porphyrin dendrimer bearing twelve ruthenium species was reported as well. These organometallic porphyrins are of interest in the third order of Nonlinear Optics (NLO). In the last chapter of this thesis we showed an example of application of porphyrin chemistry. We reported the elaboration of a new organic light emitting Diode (OLED) using these new porphyrins that emits in the red region.

Le travail présenté porte sur le contrôle de la couleur d'émission d'une diode électroluminescente organique (OLED), élément de base pour des écrans d'affichage ou des nouveaux écrans de télévision ou encore des futures sources de lumière, par l'étude de la diffusion des excitons. Après optimisation de l'épaisseur de la couche d'émetteurs fluorescents jaunes incorporés dans une matrice émettrice bleue, la variation de leur position depuis la zone de recombinaison a permis d'ajuster la couleur d'émission de l'OLED, variant du bleu au jaune avec un passage par un blanc pur de coordonnées chromatiques (0.32; 0.33). Ce contrôle très fin de la couleur émise est obtenu en tirant parti de la diffusion des excitons dans la structure OLED ; cette diffusion des excitons singulets et triplets est étudiée en détails, et les longueurs de diffusions de ces quasi-particules ont été déterminées à partir des mesures d'électroluminescence dans deux matériaux connus, le NPB et le DPVBi. Dans le cas des triplets, il faut faire appel à une technique utilisant une fine couche dopée d'un émetteur phosphorescent dans une matrice épaisse de CBP. Une attention particulière a été accordée aux phénomènes de microcavité, prépondérants dans ce type de diodes, pour une meilleure compréhension des phénomènes mis en jeux dans ces dispositifs.

Les travaux précédemment réalises au sein du LPICM ont mis en évidence que le silicium microcristallin est un semi-conducteur a faible cout, possédant une mobilité importante avec malgré tout une très bonne stabilité. Ce qui en fait un matériau particulièrement intéressant pour les transistors TFTs des écrans plats OLED 2. Il nous a donc paru logique de nous intéresser, dans le cadre de cette thèse, a la conception et a la réalisation expérimentalement des structures de pixel OLED à base de transistors TFTs en silicium microcristallin. Pour ce faire, il est indispensable de posséder des modèles comportementaux performants des composants. Ainsi, notre objectif primordial a été de concevoir des modèles Spice de transistors c-Si TFT mais aussi d'OLED. D'un point de vue technologique, nous nous sommes attaches à maitriser l'ensemble de la chaine de fabrication (conception de masques et lithographie en salle blanche). La caractérisation de nos transistors a révèle des mobilités de l'ordre de 1 cm2V−1s−1, des tensions de seuil de 4 V et a montre une bonne stabilité, sous stress, de la tension de seuil et de la mobilité. La faisabilité de ces transistors sur substrats flexibles comme le polyimide a aussi été démontre dans le cadre du Projet Intégré FlexiDis. Du point de vue de la modélisation, un modèle statique et dynamique Spice de transistor en silicium microcristallin est propose. L'écriture de ce modèle dans le langage Verilog-A nous permet de garantir une bonne portabilité et de pouvoir ainsi utiliser facilement des simulateurs professionnels comme Spectre de chez Cadence. De manière complémentaire, un modèle Spice efficient de diode OLED est également propose. Grace à ces outils, nous avons pu simuler des circuits utilisant les TFTs en silicium microcristallin. Ces simulations nous permettent de prédire que ces composants sont pertinents pour la conception de pixel OLED, de drivers de lignes, mais aussi de portes logiques NMOS simples comme l'inverseur et l'oscillateur en anneau.

No description available.

No description available.

El estudio del transporte de carga en semiconductores orgánicos contribuye al desarrollo y optimización de LEDs orgánicos y nuevas células solares. En OLEDs de un sólo portador se ha encontrado una fórmula explícita de la característica densidad de corriente y potencial (J-V) con movilidad dependiente del campo eléctrico. Un test para diferenciar la movilidad dependiente del campo y de la densidad ha sido dado por medio de una ley universal de escalado. Los espectros de capacidad y los tiempos de tránsito han sido examinados con la inclusión de la movilidad dependiente del campo eléctrico y comparado con los datos experimentales, verificándose el modelo teórico planteado. Se ha descrito la movilidad de portadores de carga a través de un modelo de transporte con una densidad exponencial de trampas. Se han utilizado técnicas de espectroscopía de impedancia para explicar la movilidad dependiente del campo eléctrico en términos del múltiple atrapamiento ejercido por los estados energéticamente localizados. Este modelo ha explicado de forma coherente los espectros de capacidad recogidos en medidas experimentales, particularmente su comportamiento a bajas e intermedias frecuencias. La respuesta de los OLED (polímero SY) ha sido estudiada en los regímenes estacionario y transitorio. En el régimen estacionario, se han descrito las corrientes de fuga a bajos potenciales. Se ha analizado la existencia de mayor corriente circulando por el perímetro que por el área del dispositivo. En el régimen transitorio, se ha proporcionado una explicación sobre las colas de luz emitida observadas al cesar la perturbación de potencial escalón: procede de la inyección limitada de electrones en el cátodo.