Over the past decade, intensive academic and commercial interests have been paid on compounds possessing photochemical properties, namely for their preparation, chemical properties, high efficiency and potential low-cost. Compounds having intense photochemical properties gained great interest due to wide range of potential applications. The sensitizers are one of the key components for high power-conversion efficiency in the dye sensitized solar cells (DSSCs). They are the core components in the organic light-emitting devices (OLEDs) due to their ability to emit light with the wavelengths largely red- shifted from their absorption wavelength. Ruthenium based sensitizers have been tagged “molecular light switches” because, although the fluorescence of these complexes in aqueous solutions is negligible, it increases of greater than 10000 fold in the presence of DNA. Many polypyridyl and dipyrido phenazine ruthenium complexes have achieved high power conversion efficiencies and therefore are of practical interest. Several research groups stated that the dipyrido phenazine ligand may be thought of as comprising two components: a bipyridyl unit and a phenazine unit. These two subunits behave essentially separately, with many molecular orbitals being localised over only one subunit and a redox properties of central phenazine moiety in the dipyrido phenazine ligand are important for the photochemical applications. Therefore a phenazine ligand was selected as a model for the present investigation. The chemistry of phenazine ligand is mostly limited to the late transition metal and f - element complexes. Our laboratory has a rich backgroung in the aluminum and early transition metal chemistry. The aluminum chemistry and early transition metal chemistry are of great interest since aluminum and early transition metal complexes are environmentally friendlier and cheaper than the late transition metal compounds. Another drawback of the ruthenium-based sensitizers is the lack of absorption in the red region of the visible spectrum, and also low molar extinction coefficients. An essential requirement for efficient conversion of solar energy is the good spectral match of the sensitizer absorption to the emission spectrum of solar radiation. In this regard, the ruthenium sensitizers’ spectral response in the lower energy regions is not sufficient. The current project has three parts. In the first part we collected and reviewed known literature regarding the certain classes of non-innocent ligands containing the six-membered carbon- nitrogen heterocycles and regarding the ligands potentially important for the photochemical applications. We also reviewed all available to the data information about the complexes supported by the phenazine ligand. In the second part we have investigated interaction of alkylaluminum compounds and phenazine and observed reduction of phenazine accompanied by formation of dialuminum cage type compounds containing two formally mononegative phenazine ligand. The derivatization of phenazine has been also observed. It resulted in formation of compounds having a stable organic radical. In a third part of our project we have explored interaction of phenazine or thiophenazine with the alkylaluminum compounds and chromium dichloride. The reaction in the three component system resulted in reduction of phenazine ligand and lead to the heterometallic Cr(II) - aluminum complexes containing a formally dinegative phenazine or thiophenazine ligands. When a large excess of triethylaluminum was taken, reduction of phenazine and chromium has been observed leading to the heterometallic multinuclear Cr(I) - aluminum complex containing a formally dinegative phenazine ligands and two chromium atoms in one complex in the rare oxidation state one.

Transient electroluminescence (EL) was used to measure the onset of emission delay in OLEDs based on transition metal, phosphorescent bis[3,5-bis(2-pyridyl)-1,2,4-triazolato] platinum(ΙΙ) and rare earth, phosphorescent Eu(hfa)3 with 4'-(p-tolyl)-2,2":6',2" terpyridine (ttrpy) doped into 4,4'-bis(carbazol-9-yl) triphenylamine (CBP), from which the carrier mobility was determined. For the Pt(ptp)2 doped CBP films in OLEDs with the structure: ITO/NPB (40nm)/mcp (10nm)/65% Pt(ptp)2:CBP (25nm)/TPBI (30nm)/Mg:Ag (100nm), where NPB=N, N'-bis(1-naphthyl)-N-N'-biphenyl-1, 1'-biphenyl-4, MCP= N, N'-dicarbazolyl-3,5-benzene, TPBI=1,3,5-tris(phenyl-2-benzimidazolyl)-benzene, delayed recombination was observed and based on its dependence on frequency and duty cycle, ascribed to trapping and de-trapping processes at the interface of the emissive layer and electron blocker. The result suggests that the exciton recombination zone is at, or close to the interface between the emissive layer and electron blocker. The lifetime of the thin films of phosphorescent emitter Pt(ptp)2 were studied for comparison with rare earth emitter Eu(hfa)3. The lifetime of 65% Pt(ptp)2:CBP co-film was around 638 nanoseconds at the emission peak of 572nm, and the lifetime of neat Eu(hfa)3 film was obtained around 1 millisecond at 616 nm, which supports the enhanced efficiency obtained from the Pt(ptp)2 devices. The long lifetime and narrow emission of the rare earth dopant Eu(hfa)3 is a fundamental factor limiting device performance. Red organic light emitting diodes (OLEDs) based on the rare earth emitter Eu(hfa)3 with 4'-(p-tolyl)-2,2":6',2" terpyridine (ttrpy) complex have been studied and improved with respect performance. The 4.5% Eu(hfa)3 doped into CBP device produced the best power efficiency of 0.53 lm/W, and current efficiency of 1.09 cd/A. The data suggests that the long lifetime of the f-f transition of the Eu ion is a principal limiting factor irrespective of how efficient the energy transfer from the host to the dopant and the antenna effect are.

La presente tesis doctoral va encaminada a avanzar en el conocimiento de dispositivos electroluminiscentes. La tesis consta de dos partes diferenciadas. La primera de ellas ha sido dirigida al diseño y construcción de equipos electrónicos que permitan la caracterización eléctrica y la medida de emisión de luz en dispositivos electroluminiscentes constituidos por nuevos materiales híbridos orgánicos-inorgánicos particulados de baja eficiencia de emisión. En concreto en esta primera parte de la tesis se ha construido un sistema de caracterización eléctrica que permite obtener medidas de pastillas de materiales particulados a presión, Tª y grado de humedad determinadas. Además se ha procedido a la modificación de un equipo de fluorescencia comercial para adaptarlo a medidas de películas electroluminiscentes de eficiencia inferior a 1cd/m2. Con los equipos realizados se ha procedido a la caracterización eléctrica y luminiscente de una serie de materiales híbridos particulados con el fin de entender los mecanismos de conducción de estos sistemas supramoleculares. La segunda parte de la tesis ha ido dirigida a desarrollar un modelo basado en el software de simulación SPICE que permita simular la característica de Luminosidad (L), Corriente (I), Voltaje(V) y Temperatura (Tª) de paneles OLEDs preinsdustriales de gran área enfocados a iluminación general. En la tesis se describen también los procedimientos y medidas para conseguir los valores de los parámetros de entrada a estos modelos. Con estos parámetros de entrada se simularon varios paneles preindustriales de OLEDs y se compararon con la caracterización de paneles reales con el fin de validar el modelo. A continuación se procedió a la realización de simulaciones de tipo predictivo que permitiesen mejorar la homogeneidad luminosa de este tipo de paneles al variar determinados parámetros constructivos de estos comprobándose que es posible eliminar prácticamente los efectos de la inhomogeneidad luminosa. / Fabuel Ruiz, D. (2010). Sistemas electrónicos para la caracterización de la conductividad y electroluminiscencia de materiales inorgánicos y poliméricos. Modelado de dispositivos OLEDs precomerciales [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8961 / Palancia

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Die Photobiotechnologie nutzt photosynthesegetriebene Bioprozesse zur nachhaltigen Synthese von Wertstoffen und Energieträgern. Diese Bioprozesse rücken vor allem durch die stoffliche Nutzung von CO2 als Kohlenstoff- und Licht als regenerative Energiequelle in den Fokus von Forschung und Entwicklung. Trotz der enormen Vielfalt von geschätzten 500.000 Algenspezies werden zurzeit nur ca. 15 Mikro- und 220 Makroalgen technisch genutzt. Dieser Umstand ist u.a. dem geringen Prozessverständnis und den spezifischen Anforderungen der photobiotechnologische Prozesse an die technischen Systeme geschuldet. Im Rahmen der vorliegenden Arbeit wurden Kultivierungssysteme für die photosynthetisch aktiven Mikroorganismen Rhodobacter sphaeroides DSM158, Chlamydomonas reinhardtii 11.32b und Chlorella sorokiniana UTEX1230 entwickelt und evaluiert. Die photofermentative Wasserstoffproduktion mittels R. sphaeroides DSM158 erfolgte in einem eigens dafür konzipierten gerührten Halogen-Photobioreaktor durchgeführt. Im Satzbetrieb wurde der Einfluss des volumetrischen Leistungseintrages (P0/VL) und der mittlere Bestrahlungsstärke (I0) untersucht. Es konnte gezeigt werden, dass R. sphaeroides DSM158 bei einer durchschnittlichen I0 von 2250 W m-2 und einem P0/VL von 0,55 kW m-3 im Satzbetrieb eine maximale Wasserstoffproduktionsrate (rH2) von 195 mL L-1 h-1 erzielt. Das Reaktorsystem wurde mittels optischer Ray Tracing Simulation, einer empirischer Simulation der Strahlungsverteilung und Computational Fluid Dynamics (CFD) charakterisiert, um die Prozessbedingungen für R. sphaeroides DSM158 zu analysieren. Der photofermentative Prozess wurde in ein kontinuierliches Verfahren überführt, welches unter optimalen Bedingungen von I0 = 2250 W m-1, einer Durchflussrate von 0,096 h-1 und einem C:N-Verhältnis von ca. 22,5 eine rH2 von 170,5 mL L-1 h-1 lieferte. Für Mikroalgen wurden Kultivierungssysteme für Suspensions- und immobilisierte Kulturen entwickelt und charakterisiert. Zur Kultivierung immobilisierter Mikroalgen wurde die Methode des Green Bioprinting etabliert, die auf der 3D-Bioprinting Technologie des Tissue Engineerings beruht. Bei diesem Verfahren werden Algenzellen über einen Extrusionsprozess in ein strukturiertes Hydrogel eingebettet. In vergleichenden Studien zum Wachstum in Suspensionskulturen konnte gezeigt werden, dass die Hydrogelumgebung ideale Bedingungen für das photoautotrophe Wachstum und die Zellviabilität von C. reinhardtii 11.32b und C. sorokiniana UTEX1230 liefert. Der MicrOLED-Bioreaktor bezeichnet ein miniaturisiertes Flat-Panel-Airlift (FPA)-Bioreaktor-system mit 15 mL Arbeitsvolumen und nichtinvasiver optischer Prozessüberwachung in Bezug auf zellspezifische Parameter (Zelldichte und Fluoreszenz) und Suspensionsparameter (pH, dO2 und dCO2). Hydrodynamische Untersuchungen der miniaturisierten FPA-Kultivierungskammer zeigten vergleichbare und damit skalierbare Eigenschaften zu Labor- und Produktions-FPA-Bioreaktoren. Im Zuge des MicrOLED-Bioreaktors wurden erstmals organische Leuchtdioden für den Einsatz in Photobioreaktoren verwendet und charakterisiert. Die geometrisch komplexen Bioreaktorkomponenten wurden mittels additiver Fertigungstechnologien aus Polyamid hergestellt und erlauben die Integration der optischen Elemente zur Überwachung des Bioprozesses in Echtzeit.

[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.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-05-10T11:48:36Z No. of bitstreams: 1 jeffersondasilvamartins.pdf: 3798520 bytes, checksum: 36b404dfc17447ab2b47b8addd04eceb (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-05-22T15:42:34Z (GMT) No. of bitstreams: 1 jeffersondasilvamartins.pdf: 3798520 bytes, checksum: 36b404dfc17447ab2b47b8addd04eceb (MD5) / Made available in DSpace on 2018-05-22T15:42:34Z (GMT). No. of bitstreams: 1 jeffersondasilvamartins.pdf: 3798520 bytes, checksum: 36b404dfc17447ab2b47b8addd04eceb (MD5) Previous issue date: 2018-01-19 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O projeto contínuo de desenvolvimento de pesquisas em novos materiais orgânicos mais eficientes, mais puros e com boa estabilidade térmica e morfológica é fundamental para a aplicação em novos dispositivos orgânicos. Nesse contexto, o objetivo dessa tese é a fabricação e caracterização de novos dispositivos orgânicos emissores de luz (OLEDs). Essa pesquisa foi desenvolvida com duas abordagens e aplicações distintas. Na primeira, utiliza-se uma nova classe de derivados de xanteno (XD) como materiais transportadores de buracos, e na segunda, apresenta-se dois novos complexos de Európio como materiais emissores de luz. Na aplicação dos XD como camada transportadora de buracos (CTB) foram fabricados OLEDs bicamada, utilizando-se o material comercial Alq3 como emissor de luz. Os resultados desse estudo foram comparados com dispositivos de referência fabricados com o material comercial α-NPD no lugar dos XD. Todos os dispositivos baseados nos XD apresentaram uma eficiência de corrente mais elevada quando comparados com dispositivos de referência α-NPD. Um estudo teórico e experimental sobre a mobilidade de buracos dos XD e α-NPD mostram que todos os XD possuem mobilidade de buraco mais elevada que o material comercial. A mobilidade de buraco mais elevado na camada dos XD proporcionou um melhor equilíbrio de buracos e elétrons e, portanto, maior recombinação, resultando em eficiência aprimorada. Na segunda parte deste trabalho, foram estudados dois complexos de Európio como emissores de luz na região do vermelho do espectro visível. Os complexos de Európio, [Eu(btfa)3(dmbpy)2] e [Eu (TTA)3(PhenSe)], apresentaram as transições características ⁵D₀ → ⁷FJ (J = 0-4), em solução e em filme fino evaporado termicamente. Com o complexo [Eu(btfa)3(dmbpy)2] foram fabricados dispositivos com duas configurações de diferentes e, embora os OLEDs tenham apresentado uma banda larga devido à contribuição do Alq3, demonstrou-se a fabricação de um OLED eficiente. Já o complexo [Eu (TTA)3(PhenSe)] as eletroluminescências dos dispositivos apresentaram uma banda larga centrada em 580 nm, dificultando assim a observação das transições ⁵D₀ → ⁷FJ (J = 0,1). / The continuing research project to develop new organic materials that are more efficient, purest and with a good morphological and thermal stability is essential to apply them to new organic devices. Therefore, the aim of this thesis is the fabrication and the characterization of organic electroluminescent devices (OLEDs). This research was developed based on two distinctive approaches. At first, it was used a new xanthene derivative (XD) class as a hole transporting material and, secondly, it is shown two new Europium complex as light emitters. The use of XD as hole transporting layer (HTL) was made to fabricated bilayers OLEDs using the commercial material Alq3 as light emitters. Their results were compared to the reference device previously fabricated with the commercial material α-NPD. All XD devices presented a higher current efficiency when compared to the α-NPD reference device. A theoretical and experimental study of the XD and α-NPD holes mobility showed that all XD has a higher hole mobility than the commercial material. The higher hole mobility of the XD layer resulted in a better balance between hole and electrons and consequently, in a higher number of combinations, resulting in devices with improved efficiency. At the second part of this study, it was studied two Europium complexes as red-light emitters. The Europium complex, [Eu(btfa)3(dmbpy)] and [Eu(TTA)3(PhenSe)], showed the transitions characteristic of ⁵D₀ → ⁷FJ (J = 0-4) in solution and in a thermal evaporated thin film. The [Eu(btfa)3(dmbpy)] complex was used to fabricate devices with two different configurations and, although the OLEDs have shown a wide band due to the Alq3 contribution, the OLEDs presented good efficiency. In contrast, the electroluminescence of the [Eu (TTA)3(PhenSe)] complex based devices showed a wide band centered in 580 nm, in this case, covering the narrow ⁵D₀ → ⁷FJ (J = 0,1) transitions.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-05-10T14:07:53Z No. of bitstreams: 1 monicacristinamelquiades.pdf: 3336410 bytes, checksum: b0292bcffca349c4979d58c19d8cfc83 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-09-03T16:03:10Z (GMT) No. of bitstreams: 1 monicacristinamelquiades.pdf: 3336410 bytes, checksum: b0292bcffca349c4979d58c19d8cfc83 (MD5) / Made available in DSpace on 2018-09-03T16:03:10Z (GMT). No. of bitstreams: 1 monicacristinamelquiades.pdf: 3336410 bytes, checksum: b0292bcffca349c4979d58c19d8cfc83 (MD5) Previous issue date: 2017-10-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesse trabalho são apresentados os resultados da produção e caracterização de diodos orgânicos emissores de luz sensível ao infravermelho próximo, OLEDs de conversão ascendente de energia que são conhecidos como OLEDs tipo up-converter. O desempenho da camada sensível ao infravermelho é um fator fundamental para o funcionamento do dispositivo. Neste sentido, moléculas de ftalocianinas apresentam respostas eletrônicas quando são expostas a radiação infravermelha. Na primeira parte do trabalho foram investigadas as propriedades ópticas e elétricas de filmes de ftalocianinas fabricados por evaporação térmica a vácuo. As ftalocianinas estudadas foram: ftalocianina de cobalto, ftalocianina de cobre, ftalocianina de magnésio, ftalocianina de platina e naftalocianina de estanho. Essas moléculas foram caracterizadas usando diferentes técnicas, tais como, espectroscopia de absorção UV-VIS e voltametria cíclica, espectrometria de massa, difratometria de raios-X e medidas elétricas, a fim de se obter suporte para o uso dessas moléculas como camada ativa nos dispositivos up-converters. Entre as ftalocianinas estudadas, a naftalocianina de estanho se mostrou a melhor candidata para atuar como camada sensível para a fabricação dos dispositivos. Porém, OLEDs up-converters usando naftalocianina de estanho como camada sensível ao infravermelho apresentaram baixa resposta a radiação infravermelha e baixa eficiência de conversão. Assim, para tentar solucionar esse problema, foi necessário fabricar alguns OLEDs up-converters usando uma camada de ftalocianina codepositada com fulereno como a camada sensível ao infravermelho. A codeposição consiste em uma técnica em que as moléculas de ftalocianinas e de fulereno são sublimadas simultaneamente. A partir da técnica de codeposição, é possível obter uma blenda com diferentes propriedades ópticas e elétricas. A camada codepositada apresentou uma redução significativa na mobilidade de buracos, o que levou a um aumento da eficiência de conversão do dispositivo, evidenciando o uso destes materiais para a fabricação de OLEDs sensíveis ao infravermelho para aplicações em sistemas de visão noturna. / In this work the results of the production and characterization of Organic Light Emitting Diodes with near-infrared sensitive layer up-converter are presented. The infrared sensitive layer performance is a key factor for the operation of the device. Phthalocyanine molecules have an electronic response when they are exposed to the infrared radiation. In the first part of the work the optical and electrical properties of phthalocyanine films manufactured by vacuum thermal evaporation were investigated. The phthalocyanines studied were: cobalt phthalocyanine, copper phthalocyanine, magnesium phthalocyanine platinum phthalocyanine and tin naphthalocyanine. These molecules were characterized using different techniques, such as UV-VIS absorption spectroscopy and cyclic voltammetry, mass spectrometry, X-ray diffractometry and electrical measurements, in order to obtain support for the use of these molecules as active layer of up-converter devices. Among the studied phthalocyanines, tin naphthalocyanine was the best candidate to act as a sensitive layer for the manufacture of the devices. However, OLEDs up-converters using tin naphthalocyanine as an infrared sensitive layer showed low response to infrared radiation and low conversion efficiency. Thus, to solve this problem, it was necessary to manufacture OLEDs up-converters using a phthalocyanine layer co-deposited with fullerene as infrared sensitive layer. Co deposition consists of a technique in which the phthalocyanine and fullerene molecules are simultaneously sublimated. From the co-deposition technique, it is possible to obtain a blend with different optical and electrical properties. The co-deposited layer showed a significant reduction in hole mobility, which led to an increase in the conversion efficiency of the device, evidencing the use of these materials for the manufacture of infrared sensitive OLEDs for applications in night vision systems.