Solid state lighting is a new environmentally friendly light source. So far, light emitting diodes (LEDs) and organic LEDs (OLEDs) have been presented as candidates with potentially high efficiency. Recent advances of OLEDs in device architecture, light-out coupling, and materials have ensured high efficiency, exceeding that of incandescent light bulbs. In contrast to conventional point source LEDs, OLEDs distribute light throughout the surface area and are not restricted by their size. Additionally, OLEDs are expected to reach sufficient stability in the near future. The remaining challenge for OLEDs is their cost. New OLED technologies provide cost effective manufacturing methods which could be presented for transparent electrode materials because indium tin oxide (ITO), a widely used material as a transparent electrode for OLEDs, is less than optimal due to its high element price. In this work, alternative transparent electrodes for OLEDs as a replacement of ITO were studied. First, Al doped ZnO (ZnO:Al) which is composed of abundant materials was investigated with DC magnetron sputtering under a wide range of experimental conditions. The optimised ZnO:Al received comparable performance with conventional ITO films, low sheet resistance of 22.8 Ω/sq as well as a high transparency of 93.1 % (average value in the visible range). Various type of p-i-n OLEDs were employed on the structured ZnO:Al using photolithography. Green OLEDs with double emission layers have been archived stable efficiencies even at higher luminance. Also, OLEDs using two fluorescent colour system on ZnO:Al anode showed a purely white emission. It has been found that the OLEDs on ZnO:Al anode has comparable or better device efficiencies and operational lifetime compared to OLEDs on conventional ITO anode. As another alternative electrode, the conductive polymer Baytron®PH510 (PEDOT:PSS) was investigated. Due to a relatively high sheet resistance of PEDOT:PSS, metal grid was designed for large size OLEDs. White OLEDs on PEDOT anode with a size of 5 × 5 cm2 have achieved more than 10 lm/W of power efficiency using a scattering foil. Furthermore, up-scaled devices on 10 × 10 cm2 were also demonstrated. These results showed ZnO:Al and PEDOT are suitable for OLEDs as anode and have high potential as alternative transparent electrode materials.

Due to climate change and its effects, alternative renewable energy sources are needed in the future human society. In the work of this thesis, the Dye-sensitized Solar Cell (DSC) has been investigated and characterized. DSCs are appealing as energy conversion devices, since they have high potential to provide low cost solar light to electricity conversion. The DSC is built up by a working electrode consisting of a conductive glass substrate with a dye-sensitized mesoporous TiO2 film, a counter electrode with a catalyst and, in between, the electrolyte which performs the charge transport by means of a redox mediator. The aim of this thesis was to develop and evaluate cheap and environmentally friendly materials for the DSC. An alternative polymer-based counter electrode catalyst was fabricated and evaluated, showing that the PEDOT catalyst counter electrode outperformed the platinum catalyst counter electrode. Different organic dyes were evaluated and it was found that the dye architecture affected the performance of the assembled DSCs. A partly hydrophilic organic triphenylamine dye was developed and applied in water-based electrolyte DSCs. The partly hydrophilic dye outperformed the reference hydrophobic dye. Small changes in dye architecture were evaluated for two similar dyes, both by spectroscopic and electrochemical techniques. A change in the length of the dialkoxyphenyl units on a triphenylamine dye, affected the recombination and the regeneration electron transfer kinetics in the DSC system. Finally, three water soluble cobalt redox couples were developed and applied in water-based electrolyte DSCs. An average efficiency of 5.5% (record efficiency of 5.7%) for a 100% water-based electrolyte DSC was achieved with the polymer-based catalyst counter electrode and an organic dye with short dimethoxyphenyl units, improving the wetting and the regeneration process.

Conductive polymers, since from their discovery, have become a prominent area of research and found many useful applications in all fields of our daily life. Examples are light emitting diodes, heat generation, chemical sensors and electro-active membranes. Polymer coated textile substrates give flexible and lightweight materials. One well utilized and thoroughly explored conductive polymer is poly(3,4-ethylenedioxythiophene) also known as PEDOT. Although there are different ways to produce PEDOT one of the most common is the VPP technique. The typical procedure when using VPP is to introduce the monomer vapor to an oxidant coated substrate so that it polymerizes on the surface of the substrate. Throughout this study, the VPP technique has been used to produce PEDOT on different textile fibers. Aim was first of all optimizing the process gaining low electric resistance, i. e. high conductivity, of produced coated fibers but also multilayer coatings of fibers. Outcome indicates some parameters not having a clear influence over the results while others had a more distinct impact. A noteworthy result was obtained by coating a substrate, namely lyocell fiber, multiple times with layers deposited directly on each other. This decreased the resistance from 5.1 (± 1.6) kΩ/10 cm to 1.0 (± 0.1) kΩ/10 cm, for one layer and multiple layers respectively. Adding 15 wt. % of the copolymer PEG-PPG-PEG to the oxidant solution decreased the resistance from 6.8 (± 1.2) kΩ/10 cm to 3.9 (± 0.8) kΩ/10 cm. Final conclusion is that among the ways, to improve conductivity for PEDOT coated fibers, applied in this study are best results obtained by multi-layer coating.

Solid-state dye-sensitized solar cells (ssDSSCs) and recently developed perovskite solar cells (PSCs) have attracted a great attention in the scientific field of photovoltaics due to their low cost, absence of solvent, simple fabrication and promising power conversion efficiency (PCE). In these types of solar cell, the dye molecule or the perovskite can harvest the light on the basis of electron excitation. Afterwards, the electron and hole are collected at the charge transport materials. Photoelectrochemical polymerization (PEP) is employed in this thesis to synthesize conducting polymer hole transport materials (HTMs) for ssDSSCs. We have for the first time developed aqueous PEP in comparison with the conventional organic PEP with acetonitrile as solvent. This water-based PEP could potentially provide a low-cost, environmental-friendly method for efficient deposition of polymer HTM for ssDSSCs. In addition, new and simple precursors have been tested with PEP method. The effects of dye molecules on the PEP were also systematically studied, and we found that (a) the bulky structure of dye is of key importance for blocking the interfacial charge recombination; and (b) the matching of the energy levels between the dye and the precursor plays a key role in determining the kinetics of the PEP process. In PSCs, the HTM layer is crucial for efficient charge collection and its long term stability. We have studied different series of new molecular HTMs in order to understand fundamentally the influence of alkyl chains, molecular energy levels, and molecular geometry of the HTM on the photovoltaic performance. We have identified several important factors of the HTMs for efficient PSCs, including high uniformity of the HTM capping layer, perovskite-HTM energy level matching, good HTM solubility, and high conductivity. These factors affect interfacial hole injection, hole transport, and charge recombination in PSCs. By systematical optimization, a promising PCE of 19.8% has been achieved by employing a new HTM H11. We believe that this work could provide important guidance for the future development of new and efficient HTMs for PSCs.

Li-ion battery technology is currently the most efficient form of electrochemical energy storage. The commercialization of Li-ion batteries in the early 1990’s revolutionized the portable electronics market, but further improvements are necessary for applications in electric vehicles and load levelling of the electric grid. In this thesis, three new iron based electrode materials for positive electrodes in Li-ion batteries were investigated. Utilizing the redox activity of iron is beneficial over other transition metals due to its abundance in the Earth’s crust. The condensed phosphate Li2FeP2O7 together with two different LiFeSO4F crystal structures that were studied herein each have their own advantageous, challenges, and scientific questions, and the combined insights gained from the different materials expand the current understanding of Li-ion battery electrodes. The surface reaction kinetics of all three compounds was evaluated by coating them with a conductive polymer layer consisting of poly(3,4-ethylenedioxythiophene), PEDOT. Both LiFeSO4F polymorphs showed reduced polarization and increased charge storage capacity upon PEDOT coating, showing the importance of controlling the surface kinetics for this class of compounds. In contrast, the electrochemical performance of PEDOT coated Li2FeP2O7 was at best unchanged. The differences highlight that different rate limiting steps prevail for different Li-ion insertion materials. In addition to the electrochemical properties of the new iron based energy storage materials, also their underlying material properties were investigated. For tavorite LiFeSO4F, different reaction pathways were identified by in operando XRD evaluation during charge and discharge. Furthermore, ligand involvement in the redox process was evaluated, and although most of the charge compensation was centered on the iron sites, the sulfate group also played a role in the oxidation of tavorite LiFeSO4F. In triplite LiFeSO4F and Li2FeP2O7, a redistribution of lithium and iron atoms was observed in the crystal structure during electrochemical cycling. For Li2FeP2O7, and increased randomization of metal ions occurred, which is similar to what has been reported for other iron phosphates and silicates. In contrast, triplite LiFeSO4F showed an increased ordering of lithium and iron atoms. An electrochemically induced ordering has previously not been reported upon electrochemical cycling for iron based Li-ion insertion materials, and was beneficial for the charge storage capacity of the material.

De nos jours, efficacité et précision des diagnostics médicaux sont des éléments essentiels pour la prévention en termes de santé et permettre une prise en charge rapide des maladies des patients. Les récentes innovations technologiques, particulièrement dans les domaines de la microélectronique et des sciences des matériaux ont permis le développement de nouvelles plateformes personnalisées de diagnostics portatifs. Les matériaux électroniques organiques qui ont déjà par le passé démontré leur potentiel en étant intégrés dans des produits de grande consommation tels que les écrans de smartphones ou encore les cellules solaires montrent un fort potentiel pour une intégration dans des dispositifs biomédicaux. En effet, de par leurs natures et leurs propriétés physiques et chimiques, ils peuvent être à la fois en contact avec les milieux biologiques et constituer l’interface entre les éléments biologiques à l’étude, et les dispositifs électroniques. L’objectif de mes travaux de thèse et d’étudier et évaluer les performances des matériaux organiques électroniques intégrés dans des dispositifs biomédicaux en étudiant leurs interactions avec des milieux biologiques et par l’utilisation et l’optimisation de ces dispositifs permettre la détection de métabolites tel que le glucose ou lactate par exemple. Pendant ma thèse, j’ai notamment créé une plateforme de diagnostics combinant à la fois microfluidique et électronique organique permettant la multi détection de métabolites présents dans des fluides corporels humains, j’ai également conçu des capteurs intégrant des transistors organiques au sein des circuits électroniques classiques afin de détecter la présence des cellules tumorales. D’autres applications biologiques ont également été envisagées telles que la détection d’acides nucléiques par l’utilisation d’une approche simple de biofonctionnalisation. Bien que l’objectif ma thèse était de de créer des capteurs biomédicaux en utilisant une approche in vitro, il pourrait être également possible d’intégrer ces dispositifs « in vivo » ou encore dans des e-textiles. / Rapid and early diagnosis of disease plays a major role in preventative healthcare. Undoubtedly, technological evolutions, particularly in microelectronics and materials science, have made the hitherto utopian scenario of portable, point-of-care personalized diagnostics a reality. Organic electronic materials, having already demonstrated a significant technological maturity with the development of high tech products such as displays for smartphones or portable solar cells, have emerged as especially promising candidates for biomedical applications. Their soft and fuzzy nature allows for an almost seamless interface with the biological milieu rendering these materials ideally capable of bridging the gap between electronics and biology. The aim of this thesis is to explore and validate the capabilities of organic electronic materials and devices in real-world biological sensing applications focusing on metabolite sensing, by combining both the right materials and device engineering. We show proof-of-concept studies including microfluidic integrated organic electronic platforms for multiple metabolite detection in bodily fluids, as well as more complex organic transistor circuits for detection in tumor cell cultures. We finally show the versatility of organic electronic materials and devices by demonstrating other sensing strategies such as nucleic acid detection using a simple biofunctionalization approach. Although the focus is on in vitro metabolite monitoring, the findings generated throughout this work can be extended to a variety of other sensing strategies as well as to applications including on body (wearable) or even in vivo sensing.

Conducting polymer coating is the new developing area in the field of advanced textiles. In this project the rheological behaviour of paste containing conducting polymer was studied during formulation to coating application. The literature study is done by keeping all the contents of project in mind and a wide area of conductive polymer, coating methods, binder system and rheology modifier is covered. The rheological behaviour of different fluid containing newtanion and non-newtanion behaviour is discussed for better understanding of the project working. Polyester fabric was coated by knife coating method. In paste formulation, the chemicals used were polyurethane binder with two HEUR based rheology modifiers. A lot of experiments were performed to determine the right amount of rheology modifier alone or in combination for paste formulation and coating application and interesting findings were observed during the experimental work which had been justified in results and analysis. After application, the coated fabric was checked for resistivity. / Program: Magisterutbildning i textilteknologi

Les propriétés optiques et vibrationnelles du PEDT et de certains dérivés sont étudiées, au moyen de spectroscopies optiques : diffusion Raman, absorption infrarouge, absorption optique. Ces résultats permettent d'interpréter les modifications de structure électronique qui se produisent le long de la chaîne polymère lors du dopage électrochimique, et d'en proposer un mécanisme. Nous présentons tout d'abord une étude optique du polymère synthétisé par voie électrochimique, puis celle des propriétés d'un polymère résultant d'une synthèse chimique. Nous présentons également l'étude du polymère synthétisé à l'état neutre. Ensuite sont présentées la synthèse d'un composé intrinsèquement soluble, comportant une chaîne alkyle avec 14 carbones, et l'étude de ses propriétés optiques, afin de dégager l'influence de la chaîne latérale sur ces propriétés. Des calculs de dynamique moléculaire sont effectués afin de permettre une interprétation en termes de modes de vibrations de ces expériences, ce qui conduit alors à la proposition d'un mécanisme d'oxydation des polymères. L'étude de l'influence du groupement latéral sur les propriétés du polymère a été poursuivie sur d'autres dérivés comportant cette fois-ci une chaîne alkoxy. Enfin, nous présentons la synthèse de nanotubes de PEDT ainsi que les premiers résultats obtenus dans cette nouvelle orientation.

L'électrochromisme est le changement réversible de couleur d'un matériau lors de son oxydation ou de sa réduction électrochimique. Cette thèse porte sur l'étude d'électrolytes à base de liquide ionique (BMIPF6 et BMITFSI), de sel de lithium (LiTFSI) et de polymère (PMMA) et sur la préparation de systèmes électrochromes à base de ces électrolytes et du PEDOT, du Bleu de Prusse ou d'InHCF comme matériaux électrochromes. La conduction ionique mesurée par EIS, les analyses thermo gravimétriques, les spectroscopies IR et Raman et la mesure des coefficients de diffusion informent sur les interactions entre les espèces dans l'électrolyte. Les matériaux électrochromes (PEDOT, BP, InHCF) sont ensuite étudiés dans un électrolyte modèle LiTFSI 0.03 / BMITFSI 0.97. Enfin, des systèmes électrochromiques flexibles sont réalisés et leur propriétés de coloration et de cyclage étudiées.

Symmetric and fast (∼5 ms) on-to-off and off-to-on drain current switching characteristics have been obtained in screen printed organic electrochemical transistors (OECTs) including PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid)) as the active transistor channel material. Improvement of the drain current switching characteristics is made possible by including a carbon conductor layer on top of PEDOT:PSS at the drain electrode that is in direct contact with both the channel and the electrolyte of the OECT. This carbon conductor layer suppresses the effects from a reduction front that is generated in these PEDOT:PSS-based OECTs. In the off-state of these devices this reduction front slowly migrate laterally into the PEDOT:PSS drain electrode, which make off-to-on switching slow. The OECT including carbon electrodes was manufactured using only standard printing process steps and may pave the way for fully integrated organic electronic systems that operate at low voltages for applications such as logic circuits, sensors and active matrix addressed displays. / <p>Funding Agencies|Lintec Corporation||</p>