This study focuses on the investigation of the key parameters that determine the optical and electrical characteristics of inverted top-emitting organic light emitting diodes (OLED). A co-deposition of small molecules in vacuum is used to establish electrically doped films that are applied in n-i-p layered devices. The knowledge about the functionality of each layer and parameter is important to develop efficient strategies to reach outstanding device performances. In the first part, the thin film optics of top-emitting OLEDs are investigated, focusing on light extraction via cavity tuning, external outcoupling layers (capping layer), and the application of microlens films. Optical simulations are performed to determine the layer configuration with the maximum light extraction efficiency for monochrome phosphorescent devices. The peak efficiency is found at 35%, while varying the thickness of the charge transport layers, the semitransparent anode, and the capping layer simultaneously. Measurements of the spatial light distribution validate, that the capping layer influences the spectral width and the resonance wavelength of the extracted cavity mode, especially for TM polarization. Further, laminated microlens films are applied to benefit from strong microcavity effects in stacked OLEDs by spatial mixing of external and to some extend internal light modes. These findings are used to demonstrate white top-emitting OLEDs on opaque substrates showing power conversion efficiencies up to 30 lm/W and a color rendering index of 93, respectively. In the second part, the charge carrier management of n-i-p layered diodes is investigated as it strongly deviates from that of the p-i-n layered counterparts. The influence of the bottom cathode material and the electron transport layer is found to be negligible in terms of driving voltage, which means that the assumption of an ohmic bottom contact is valid. The hole transport and the charge carrier injection at the anode is much more sensitive to the evaporation sequence, especially when using hole transport materials with a glass transition temperature below 100°C. As a consequence, thermal annealing of fabricated inverted OLEDs is found to drastically improve the device electronics, resulting in lower driving voltages and an increased internal efficiency. The annealing effect on charge transport comes from a reduced charge accumulation due to an altered film morphology of the transport layers, which is proven for electrons and for holes independently. The thermal treatment can further lead to a device degradation. Finally, the thickness and the material of the blocking layers which usually control the charge confinement inside the OLED are found to influence the recombination much more effectively in inverted OLEDs compared to non-inverted ones.

Organic semiconductors combine the benefits of organic materials, i.e., low-cost production, mechanical flexibility, lightweight, and robustness, with the fundamental semiconductor properties light absorption, emission, and electrical conductivity. This class of material has several advantages over conventional inorganic semiconductors that have led, for instance, to the commercialization of organic light-emitting diodes which can nowadays be found in the displays of TVs and smartphones. Moreover, organic semiconductors will possibly lead to new electronic applications which rely on the unique mechanical and electrical properties of these materials. In order to push the development and the success of organic semiconductors forward, it is essential to understand the fundamental processes in these materials. This thesis concentrates on understanding how the charge transport in thiophene-based semiconductor layers depends on the layer morphology and how the charge transport properties can be intentionally modified by doping these layers with a strong electron acceptor. By means of optical spectroscopy, the layer morphologies of poly(3-hexylthiophene), P3HT, P3HT-fullerene bulk heterojunction blends, and oligomeric polyquaterthiophene, oligo-PQT-12, are studied as a function of temperature, molecular weight, and processing conditions. The analyses rely on the decomposition of the absorption contributions from the ordered and the disordered parts of the layers. The ordered-phase spectra are analyzed using Spano’s model. It is figured out that the fraction of aggregated chains and the interconnectivity of these domains is fundamental to a high charge carrier mobility. In P3HT layers, such structures can be grown with high-molecular weight, long P3HT chains. Low and medium molecular weight P3HT layers do also contain a significant amount of chain aggregates with high intragrain mobility; however, intergranular connectivity and, therefore, efficient macroscopic charge transport are absent. In P3HT-fullerene blend layers, a highly crystalline morphology that favors the hole transport and the solar cell efficiency can be induced by annealing procedures and the choice of a high-boiling point processing solvent. Based on scanning near-field and polarization optical microscopy, the morphology of oligo-PQT-12 layers is found to be highly crystalline which explains the rather high field-effect mobility in this material as compared to low molecular weight polythiophene fractions. On the other hand, crystalline dislocations and grain boundaries are identified which clearly limit the charge carrier mobility in oligo-PQT-12 layers. The charge transport properties of organic semiconductors can be widely tuned by molecular doping. Indeed, molecular doping is a key to highly efficient organic light-emitting diodes and solar cells. Despite this vital role, it is still not understood how mobile charge carriers are induced into the bulk semiconductor upon the doping process. This thesis contains a detailed study of the doping mechanism and the electrical properties of P3HT layers which have been p-doped by the strong molecular acceptor tetrafluorotetracyanoquinodimethane, F4TCNQ. The density of doping-induced mobile holes, their mobility, and the electrical conductivity are characterized in a broad range of acceptor concentrations. A long-standing debate on the nature of the charge transfer between P3HT and F4TCNQ is resolved by showing that almost every F4TCNQ acceptor undergoes a full-electron charge transfer with a P3HT site. However, only 5% of these charge transfer pairs can dissociate and induce a mobile hole into P3HT which contributes electrical conduction. Moreover, it is shown that the left-behind F4TCNQ ions broaden the density-of-states distribution for the doping-induced mobile holes, which is due to the longrange Coulomb attraction in the low-permittivity organic semiconductors. / Organische Halbleiter kombinieren die molekulare Vielfalt und Anpassbarkeit, die mechanische Flexibilität und die preisgünstige Herstellung und Verarbeitung von Kunststoffen mit fundamentalen Halbleitereigenschaften wie Lichtabsorption und -emission und elektrischer Leitfähigkeit. Unlängst finden organische Leuchtdioden Anwendung in den Displays von TV-Geräten und Smartphones. Für die weitere Entwicklung und den Erfolg organischer Halbleiter ist das Verständnis derer physikalischer Grundlagen unabdingbar. Ein für viele Bauteile fundamentaler Prozess ist der Transport von Ladungsträgern in der organischen Schicht. Die Ladungstransporteigenschaften werden maßgeblich durch die Struktur dieser Schicht bestimmt, z.B. durch den Grad der molekularen Ordnung, die molekulare Verbindung von kristallinen Domänen und durch Defekte der molekularen Packung. Mittels optischer Spektroskopie werden in dieser Arbeit die temperatur-, molekulargewichts- und lösemittelabhängigen Struktureigenschaften poly- und oligothiophenbasierter Schichten untersucht. Dabei basiert die Analyse der Absorptionsspektren auf der Zerlegung in die spezifischen Anteile geordneten und ungeordneten Materials. Es wird gezeigt, dass sich hohe Ladungsträgerbeweglichkeiten dann erreichen lassen, wenn der Anteil der geordneten Bereiche und deren molekulare Verbindung in den Schichten möglichst hoch und die energetische Unordnung in diesen Bereichen möglichst klein ist. Der Ladungstransport in organischen Halbleitern kann außerdem gezielt beeinflusst werden, indem die Ladungsträgerdichte und die elektrische Leitfähigkeit durch molekulares Dotieren, d.h. durch das Einbringen von Elektronenakzeptoren oder -donatoren, eingestellt werden. Obwohl der Einsatz dotierter Schichten essentiell für effiziente Leuchtdioden und Solarzellen ist, ist der Mechanismus, der zur Erzeugung freier Ladungsträger im organischen Halbleiter führt, derzeit unverstanden. In dieser Arbeit wird der Ladungstransfer zwischen dem prototypischen Elektronendonator P3HT und dem Akzeptor F4TCNQ untersucht. Es wird gezeigt, dass, entgegen verbreiteter Vorstellungen, fast alle F4TCNQ-Akzeptoren einen ganzzahligen Ladungstransfer mit P3HT eingehen, aber nur 5% dieser Paare dissoziieren und einen beweglichen Ladungsträger erzeugen, der zur elektrischen Leitfähigkeit beiträgt. Weiterhin wird gezeigt, dass die zurückgelassenen F4TCNQ-Akzeptorionen Fallenzustände für die beweglichen Ladungsträger darstellen und so die Ladungsträgerbeweglichkeit in P3HT bei schwacher Dotierung absinkt. Die elektrischen Kenngrößen Ladungsträgerkonzentration, Beweglichkeit und Leitfähigkeit von F4TCNQ-dotierten P3HT-Schichten werden in dieser Arbeit erstmals in weiten Bereichen verschiedener Akzeptorkonzentrationen untersucht.

This diploma thesis deals with optical properties of organic semiconductors and measuring method of absorption edge. Project is focused on absorption of light in organic semiconductors. This work also describes device for measuring of absorption edge.

A l’heure où les impacts du changement climatique sont devenus indéniables, le développement des énergies décarbonées s’impose. Potentiellement bas coût comparées aux technologies établies, les technologies organiques émergentes offrent une alternative éco-efficiente pour l’exploitation de l’énergie solaire et de l’énergie thermique (< 473 K). Dans le premier chapitre, les avantages et inconvénients des différentes technologies actuellement développées sont discutés. Les dispositifs photovoltaïques, tout comme thermoélectriques, requièrent deux types de matériaux conduisant respectivement les trous (type p) et les électrons (type n). Malgré des avancées remarquables, le développement de semi-conducteurs de type n constitue un levier d’amélioration majeur pour les technologies organiques. Dans ce contexte, ce travail doctoral présente la conception, la synthèse, la caractérisation et la mise en œuvre au sein de dispositifs, de polymères et petites molécules pi-conjugués de type n.Basées sur trois unités électro acceptrices – l’isoindigo (ISI), le naphtalène diimide (NDI) et le benzodifurandione-oligo(p-phénylènevinylène) fluoré (FBDOPV) – la conception et la synthèse de copolymères alternés sont présentées dans le deuxième chapitre. Ces polymères démontrent de hautes affinités électroniques comprises entre 3,5 eV et 4,1 eV. Les études de modélisations DFT et de diffraction de rayons X en couches minces ont permis d’identifier les principaux facteurs structuraux à l’origine des hautes mobilités en électron obtenues en transistor organique à effet de champ allant jusqu’à 0,26 cm2.V-1.s-1.Pour une application thermoélectrique, le dopage moléculaire de ces semi conducteurs organiques est requis et fait l’objet du troisième chapitre. Les conditions nécessaires à la thermo- et photo activation du dopant N-DMBI ont été identifiées. En particulier, la dégradation du dopant activé en présence d’oxygène a été mise en évidence par diffraction de rayons X sur monocristaux. Les polymères et deux petites molécules à base d’ISI et NDI ont été dopés avec succès. Les mécanismes de dopage et les conductivités obtenues sont discutés au cas par cas à l’aide d’expériences spectroscopiques UV Visible-Proche-Infrarouge et Résonance Paramagnétique Electronique. Des conductivités de l’ordre de 10-4 S.cm-1 sont obtenues sans apport énergétique ni avant ni après dépôt. Des conductivités encourageantes de l’ordre de 10-3 S.cm-1 pour une petit molécule à base de NDI et de 10-2 S.cm-1 pour un polymère à base de FBDOPV ont été atteintes. La stabilité et la réversibilité des conductivités des couches minces exposées à l’air ont été examinées et corrélées au niveau LUMO des matériaux. Le contrôle minutieux des conditions de dépôts et de dopage ont permis l’obtention d’un facteur de puissance de l’ordre de 0,3 µW.m 1.K-2 associé à une conductivité thermique de 0,53 W.m-1.K-1. Des figures de mérite d’environ 2.10-4 à 303 K et 5.10-4 à 388 K ont été mesurées, lesquelles représentent les premières valeurs reportées à ce jour pour un semi-conducteur organique dopé n sur un même dispositif.Ces matériaux permettent également le remplacement des dérivés fullerènes en dispositif photovoltaïque comme présenté dans le dernier chapitre. Ils démontrent notamment de forte propriétés d’absorption, étendue jusqu’au domaine proche infrarouge pour l’un des polymères. Un rendement de conversion de 1,3% a été obtenu en cellule solaire à hétérojonction en volume « tout-polymère » avant optimisation. Suivant une conception moléculaire de type donneur-espaceur-accepteur, deux dérivés d’ITIC ont été conçus et caractérisées. La modification de substituants alkyles sur l’espaceur permet d’obtenir des propriétés d’absorptions et d’organisations améliorées comparé à ITIC. De hautes tensions de circuit-ouvert allant jusqu’à 1,10 V et des rendements de 4,2% ont été obtenus avec ces accepteurs non-fullerènes. / At a time when the impacts of climate change have become undeniable, the development of low-carbon energies is crucial. Potentially low cost compared to established technologies, emerging organic technologies offer an eco-efficient alternative for harvesting solar and thermal (< 473 K) energies. In the first chapter, the advantages and drawbacks of the different technologies currently being developed are discussed. Photovoltaic devices, like thermoelectric devices, require two types of materials conducting holes (p type) and electrons (n-type) respectively. Despite remarkable advances, the development of n-type semiconductors represents a major lever for improving organic technologies. In this context, this doctoral work presents the design, synthesis, characterization and device developments of innovative pi-conjugated n-type polymers and small molecules.Based on three electron-accepting units – isoindigo (ISI), naphthalene diimide (NDI) and fluorinated benzodifurandione-oligo(p-phenylenevinylene) (FBDOPV) – the design and synthesis of alternated copolymers are presented in the second chapter. These polymers exhibit high electron affinities ranging from 3.5 eV to 4.1 eV. DFT modelling and thin-film X-ray diffraction studies allowed to identify the main structural aspects leading to electron mobility as high as 0.26 cm2.V 1.s 1 achieved in organic field effect transistors.For thermoelectricity, molecular doping of these organic semiconductors is required. It is the subject of the third chapter. The necessary conditions for thermo- and photo-activation of N DMBI dopant have been identified. In particular, the degradation of the activated dopant in the presence of oxygen has been demonstrated by single crystal X-ray diffraction. Each polymer and two small molecules based on ISI and NDI cores have successfully being doped. The doping mechanisms and conductivities obtained are discussed on a case by case basis using UV-Visible-Near-Infrared and Electron Paramagnetic Resonance spectroscopies. In particular, conductivities in the range of 10-4 S.cm-1 were obtained without external energy supply neither before nor after deposition. Encouraging conductivities in the range of 10-3 S.cm 1 for a small molecule based on NDI and 10-2 S.cm 1 for a polymer based on FBDOPV have been achieved. The stability and reversibility of thin film conductivities when exposed to air were investigated and correlated to the LUMO level of the materials. The thorough control of deposition and doping conditions have afforded to achieve a power factor of about 0.3 µW.m-1.K-2 associated to a thermal conductivity of 0.53 W.m 1.K 1. Figure of merits of approximately 2.10-4 at 303 K and 5.10-4 at 388 K have been obtained, which represent the first values reported to date for an n-doped organic semiconductor measured on a single device.These materials also allow the replacement of fullerene derivatives in photovoltaic devices as presented in the last chapter. In particular, they demonstrate strong absorption properties, extended to the near infrared domain for one of the polymers. A conversion efficiency of 1.3% was obtained in all polymer bulk-heterojunction solar cell before optimization. Following the donor-spacer-acceptor approach, two ITIC derivatives have been designed and characterized. The modification of alkyl substituents on the spacer provides improved absorption and molecular packing properties compared to ITIC. High open-circuit voltages up to 1.10 V and conversion efficiencies of 4.2% have been achieved with these non-fullerene acceptors.

Polyaromatic molecules functionalized with carboxylic groups have served as model systems for the growth of organic semiconducting films on a large variety of substrates. Most non-reactive substrates allow for a growth mode compatible with the bulk phase of the molecular crystal with two molecules in the unit cell, but some more reactive substrates including Ag(111) and Ag(110) can induce substantial changes in the first monolayer (ML). In the specific case of Ag(110), the adsorbate unit cell of both NTCDA and PTCDA resembles a brickwall structure, with a single molecule in the unit cell. From this finding, it can be concluded that the adsorbate-substrate interaction is stronger than typical inter-molecular binding energies in the respective bulk phases. In the present work, the interactions between small Ag(110) clusters and a single NTCDA or PTCDA molecule are investigated with different ab initio techniques. Four major ingredients contribute to the binding between adsorbate and substrate: Directional bonds between Ag atoms in the topmost layer and the oxygen atoms of the molecule, Pauli repulsion between filled orbitals of molecule and substrate, an attractive van-der-Waals interaction, and a negative net charge on the molecule inducing positive image charges in the substrate, resulting therefore in an attractive Coulomb interaction between these opposite charges. As both Hartree-Fock theory and density functional theory with typical gradient-corrected density functional do not contain any long range correlation energy required for dispersion interactions, we compare these approaches with the fastest numerical technique where the leading term of the van-der-Waals interaction is included, i.e. second order Møller-Plesset theory (MP2). Both Hartree-Fock and density functional theories result in bended optimized geometries where the adsorbate is interacting mainly via the oxygen atoms, with the core of the molecule repelled from the substrate. Only at the MP2 level, the inclusion of the major part of the attractive van-der-Waals interaction brings the adsorbate back to an arrangement close to parallel to the substrate, with very small differences in height between the different subunits. With respect to experimental data obtained on Ag(111), the calculated distance between adsorbate and substrate is somewhat smaller, indicating that the open Ag(110) surface interacts more strongly with the organic compounds. This is consistent with the fact that only Ag(110) induces a brickwall unit cell of the adsorbate, a clear sign for a particularly large adsorption energy. The resulting model geometries are analysed in terms of cohesive energy, Mulliken charges, core level shifts, and vibrational properties. / Polyaromatische Moleküle, die mit Carboxylgruppen funktionalisiert wurden, haben als Modellsysteme für das Wachstum von organischen Halbleiterfilmen für eine breite Palette von Substraten gedient. Für die meisten nichtreaktiven Substrate ist ein zum molekularen Kristall kompatibles Wachstum mit zwei Monolagen pro Einheitszelle möglich, jedoch erzeugen reaktivere Substrate wie z.B. Ag(111) oder Ag(110) bereits substanzielle Modifikationen in der ersten Monolage. Im speziellen Fall von Ag(110) bildet die Adsorbateinheitszelle sowohl von NTCDA als auch PTCDA eine sogenannte brickwall structure heraus mit einem einzigen Molekül pro Einheitszelle. Aus dieser Beobachtung kann geschlussfolgert werden, dass die Adsorbat-Substrat-Wechselwirkung stärker ist als die typischen intermolekularen Bindungsenergien in der entsprechenden Bulk-Phase. In der vorliegenden Arbeit werden die Wechselwirkungen zwischen kleinen Ag(110)-Clustern und einem einzelnen NCTDA oder PTCDA-Molekül mit verschiedenen ab initio-Techniken untersucht. Im Wesentlichen tragen vier Hauptbestandteile zur Bindung zwischen Adsorbat und Substrat bei: Gerichtete Bindungen zwischen Ag-Atomen in der obersten Substratschicht und den Sauerstoffatomen des Moleküls, Pauli-Abstoßung zwischen besetzten Orbitalen von Molekül und Substrat, eine anziehende Van-der-Waals-Wechselwirkung sowie einer negativen Ladung des Moleküls und der dazugehörigen positiven Spiegelladung im Substrat, die zu einer anziehenden Coulombwechselwirkung führen. Da weder die Hartree-Fock-Theorie noch die Dichtefunktionaltheorie mit dem typischen gradientenkorrigierten Dichtefunktional die für Dispersionswechselwirkungen benötigte langreichweitige Korrelationsenergie beinhalten, vergleichen wir diese beiden Ansätze mit der schnellsten numerischen Methode, die den dominierenden Term der Van-der-Waals-Wechselwirkung beinhaltet, nämlich der Møller-Plesset-Theorie zweiter Ordnung (MP2). Sowohl die Hartree-Fock-Theorie als auch die Dichtefunktionaltheorie sagen verbogene optimierte Geometrien voraus, die vorwiegend durch die Sauerstoffatome interagieren, wohingegen die zentralen Teile des Moleküls vom Substrat abgestoßen werden. Lediglich die MP2, die den wesentlichen Teil der anziehenden Van-der-Waals-Wechselwirkung beinhaltet, sagt eine beinahe parallele Anordnung des Moleküls an das Substrat voraus, wobei die einzelnen Untereinheiten des Moleküls nur unwesentlich verschiedene Abstände zum Substrat haben. Im Vergleich zu experimentellen Daten für Ag(111) ist die berechnete Distanz zwischen Adsorbat und Substrat etwas kleiner, woraus sich schlussfolgern lässt, dass die offene Ag(110)-Oberfläche stärker mit den organischen Verbindungen interagiert. Das ist im Einklang mit der Tatsache, dass nur Ag(110) die brickwall-Struktur des Adsorbats besitzt, was ein deutliches Zeichen für eine hohe Adsorptionsenergie ist. Die resultierenden Modellgeometrien wurden bezüglich ihrer Kohäsionsenergie, Mullikenladungen, Kernelektronenniveauverschiebungen und vibrationeller Eigenschaften untersucht.

This study focuses on the investigation of the key parameters that determine the optical and electrical characteristics of inverted top-emitting organic light emitting diodes (OLED). A co-deposition of small molecules in vacuum is used to establish electrically doped films that are applied in n-i-p layered devices. The knowledge about the functionality of each layer and parameter is important to develop efficient strategies to reach outstanding device performances. In the first part, the thin film optics of top-emitting OLEDs are investigated, focusing on light extraction via cavity tuning, external outcoupling layers (capping layer), and the application of microlens films. Optical simulations are performed to determine the layer configuration with the maximum light extraction efficiency for monochrome phosphorescent devices. The peak efficiency is found at 35%, while varying the thickness of the charge transport layers, the semitransparent anode, and the capping layer simultaneously. Measurements of the spatial light distribution validate, that the capping layer influences the spectral width and the resonance wavelength of the extracted cavity mode, especially for TM polarization. Further, laminated microlens films are applied to benefit from strong microcavity effects in stacked OLEDs by spatial mixing of external and to some extend internal light modes. These findings are used to demonstrate white top-emitting OLEDs on opaque substrates showing power conversion efficiencies up to 30 lm/W and a color rendering index of 93, respectively. In the second part, the charge carrier management of n-i-p layered diodes is investigated as it strongly deviates from that of the p-i-n layered counterparts. The influence of the bottom cathode material and the electron transport layer is found to be negligible in terms of driving voltage, which means that the assumption of an ohmic bottom contact is valid. The hole transport and the charge carrier injection at the anode is much more sensitive to the evaporation sequence, especially when using hole transport materials with a glass transition temperature below 100°C. As a consequence, thermal annealing of fabricated inverted OLEDs is found to drastically improve the device electronics, resulting in lower driving voltages and an increased internal efficiency. The annealing effect on charge transport comes from a reduced charge accumulation due to an altered film morphology of the transport layers, which is proven for electrons and for holes independently. The thermal treatment can further lead to a device degradation. Finally, the thickness and the material of the blocking layers which usually control the charge confinement inside the OLED are found to influence the recombination much more effectively in inverted OLEDs compared to non-inverted ones.

In this thesis, we study the physical properties of doped organic semiconductors. We first demonstrate the impact of doping on C60 films. In contrast to previous reports for organic thin films, the n-doped C60 films show a decrease of mobility with increasing doping levels; i.e., they follow the well-known Matthiessen rule which is generally observed in inorganic semiconductors. Using further strong organic donors and acceptors, we realize p-i-n homojunctions of several organic matrices: zinc-phthalocyanine, pentacene, and an iridium-complex TER004. We observe stable and reproducible diode characteristics, which can be described by the standard Shockley theory with an exception concerning the temperature dependence of the diode parameters. The current-voltage characteristics of the pentacene homojunctions under illuminated conditions indicate that the thermodynamic limitation of the open-circuit voltage is determined by the built-in voltage of 1.65 V, and that the recombination process is influenced by the distinct charge transport properties of electrons and holes. The very high built-in voltage of 2.2 V in the TER004 homojunction allows a red phosphorescent homo-OLED, which shows visible emission around 650 nm with low operation voltage. We examine the charge balance status in the homojunction structure, revealing that TER004 has superior electron transport properties.

La photo-isomérisation de l’azopolymère cause des mouvements de masse permettant d'inscrire des figures d'interférences à la surface de films minces. Les films sont répliqués sur un substrat en PDMS transparente t étirable. Il forme des réseaux de phase. Les figures de diffraction décrivent les surfaces, elles sont utilisées pour modéliser numériquement les réseaux, quelles que soient les contraintes.Le projet WOLF vise à fabriquer des nano lasers blancs à colorants organiques. Un montage complexe de caractérisation est développé. Le module d’excitation permet d’illuminer les nanotubes un à un. Le pompage tente de maximiser l’émission laser d’un unique nano objet. La collection du signal repose pricipalement sur l’utilisation d’une fibre optique ouvrant la porte de la microscopie confocale. La spectroscopie associée au montage révèle la formation de cavités au sein des nano bâtonnets organiques. Malgré la faible puissance du signal, les modes sont étudiés,mettant en évidence des nano-cavités. Les nano-objets sont parfois étudiés dans des liquide. La micro-fluidique est développée au laboratoire. Sans salle blanche une méthode photolithographique est développée à bas coûts. Les puces nouvellement créées sont testées dans le mélange de deux fluides et lors de la caractérisation de nanoparticules en suspension par leur mouvement Brownien. Cette thèse à permis de mettre en place les outils d’observation de nano-objets uniques / Azopolymer photo-isomerization causes matter motion. This phenomena is responsible for the inscription of the interference pattern on surface of thin films. The films are replicated by pouring PDMS on it. PDMS is a transparent and stretchable polymer. The diffraction pattern of these gratings describes the surface. These informations are used to numerically simulate the surface irrespective of the mechanical constraints.The WOLF project try to synthetize white lightorganic nanolasers. For that purpose, a complex setup has been realised. The excitation part of the setup illuminates a single nano-laser or a few. The pump source is designed to optimise the amplified emission of the nanolasers. The collection of the signal is based on an optical fiber.This fibre has given us the chance to use confocal microscopy. Spectroscopy combined with our setup show the existence of nanocavities among nanotubes. In spite of the low signal power, the emitting modes are studied and show the cavity effect of these lasers. In another context, nano-objets are sometimes studied in solution. For that reason, a new experiment has been setup, namely, microfluidic. Without the use of a clean room, a low cost photolithograpic method is developped. The microfluidic chips are tested during the mixing of to liquids and during the obsevation of the brownian motion of particules. This PhD thesis has given the tools needed for the characterization of single nano-objects.

This master´s thesis deals with organic materials for use in electronics and photonics. Attention was paid to low molecular weight materials. The theoretical part of this thesis contains brief introduction to organic electronics and photonics. In particular, organic transistors, organic solar cells and organic light-emitting diodes are mentioned. The experimental part is focused on study of electrical and optical properties of two types of phthalocyanines. Thin films and solutions of phthalocyanines were characterized by UV-VIS spectroscopy. Thin films were also characterized by current voltage characteristics, spectral response measurement of photocurrent and by method of transient photoconductivity. It was found that illumination affects the electrical properties of thin layers of phthalocyanines, the performance of the prepared thin films depends on the type phthalocyanine and also depends on the thickness of the layer.

In the present work, charge transfer in organic semiconductors is investigated by means of photoemission spectroscopy. Organic charge transfer systems consist of electron donors and acceptors and in some cases exhibit new electronic properties that are not observed in the individual constituents. Examples are metallic conductivity and changed optical or transport gaps. The main focus were interfaces between donor and acceptor molecules that were prepared as thin films by thermal evaporation in ultra-high vacuum. In particular, the strong electron acceptor F6TCNNQ was combined with several scientifically relevant donors, with the aim of achieving a large charge transfer. As reference systems, potassium doped F6TCNNQ and the interface between F6TCNNQ and gold were studied. In both systems, a large electron transfer to F6TCNNQ with similar spectroscopic signatures was observed. The investigated organic interfaces all showed charge transfer that manifested itself in form of changes in the core levels of F6TCNNQ that were similar for each system. Also, new occupied states in the former gaps of the molecules were found. For every investigated interface the Fermi energy was pinned above the respective highest occupied molecular orbitals which entails semiconducting behaviour and no metal-like delocalised charge carriers. For the combination of F6TCNNQ and dibenzopentacene, a blended film was prepared by co-deposition and compared with the corresponding interface. It was found that the electronic properties of the blend are initially determined by electrostatic interactions, whereas annealing leads to a large charge transfer due to a temperature induced change of molecular orientation. Moreover, the acceptors F2TCNQ and F16CoPc were used in order to compare systems with the same donor and different acceptors. Differences in the degree of charge transfer and interface morphology were observed. The last part of this work addresses the electronic properties of an organic rectifier that was fabricated by collaboration partners. It is built up of an organic heterojunction of two phtalocyanines (CuPc and F16CoPc) between two gold contacts. The energy level alignment across the device and the charge transfer reactions at the different interfaces are discussed with regard to the functionality of the device.