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MOF-5 ist der Archetyp einer neuartigen Klasse hochporöser Materialien, den Metal Organic Frameworks, die unter anderem zur Anwendung als effektive Gasspeicher geeignet sind. Im Rahmen dieser Arbeit werden die seiner Bildung zugrunde liegenden Reaktionen untersucht. Aus den Erkenntnissen dieser Untersuchungen wurden zwei neue Syntheseverfahren entwickelt. Eines der Verfahren beruht auf der Phasenumwandlung von Zinkterephthalaten und ermöglichte die Laborsynthese von MOF-5 in 100 g-Mengen. Ein zweites Verfahren bedient sich des Strukturaufbaus mit Hilfe vorgefertigter anorganischer Cluster, wodurch erstmals die Synthese von MOF-5-Homologen anderer Metalle als Zink gelang.

We present a novel top-electrode spray-coating process for the solution-based deposition of silver nanowires (AgNWs) onto vacuum-processed small molecule organic electronic solar cells. The process is compatible with organic light emitting diodes (OLEDs) and organic light emitting thin film transistors (OLETs) as well. By modifying commonly synthesized AgNWs with a perfluorinated methacrylate, we are able to disperse these wires in a highly fluorinated solvent. This solvent does not dissolve most organic materials, enabling a top spray-coating process for sensitive small molecule and polymer-based devices. The optimized preparation of the novel AgNW dispersion and spray-coating at only 30 °C leads to high performance electrodes directly after the deposition, exhibiting a sheet resistance of 10.0 Ω □−1 at 87.4% transparency (80.0% with substrate). By spraying our novel AgNW dispersion in air onto the vacuum-processed organic p-i-n type solar cells, we obtain working solar cells with a power conversion efficiency (PCE) of 1.23%, compared to the air exposed reference devices employing thermally evaporated thin metal layers as the top-electrode.

Silizium (Si) wird für eine breite Palette von Anwendungen wie z.B. in Solarzellen, Mikroelektronik, Biochips und so weiter eingesetzt. In dieser Arbeit wurden neue Hybridsysteme aus Si und organischen Molekülen, bezüglich der Oberflächenpassivierung des Halbleiters und der resultierenden elektronischen Eigenschaften untersucht. Insbesondere wurden Methyl-Gruppen (CH3 und CD3), Ethynyl-Derivate (H−C≡C-, CH3−C≡C-, und C6H5−C≡C-), sowie Pyrrol und Thiophen aus Grignardlösungen untersucht. Bezüglich Stabilität und Defektkonzentration konnte gezeigt werden, dass organisch modifizierte Si-Oberflächen eine höhere Stabilität an Luft haben als Standard wasserstoffpassivierte Si-Oberflächen und dabei eine nur geringfügig höhere Defektkonzentration aufweisen. Untersuchungen mit Infrarot Spektroskopischer Ellipsometrie (IRSE) und Synchrotron Röntgen Photoemissions Spektroskopie (SXPS) zeigen, dass die Oxidationsrate für Oberflächen mit CH3-Terminierung stark reduziert ist. In der vorliegenden Arbeit gelang es erstmalig mittels IRSE die charakteristische „Umbrella“-Schwingungsmode zu beobachten und SXPS Messungen zeigten die Spin-Orbit-Aufspaltung der Si 2p Emission für CH3-passivierte Si-Oberflächen. Die CH3-Gruppen besitzen einen hohen Grad von Ordnung auf der Si(111)-Oberfläche. Das Aufbringen von Ethynyl-Derivaten führt zu extrem dünnen polymerisierten Schichten auf Si durch elektrochemische Radikaloxidation der C≡C Dreifachbindung. Diese Schichten sind homogen und haften sehr gut an der Si-Oberfläche. Weiterhin konnte gezeigt werden, dass die Abscheidung von Ethynyl-Derivaten vom Typ des Halogenatoms im Grignard-Precursor abhängig ist, wobei Br im Vergleich zu Cl zu geringeren Rekombinationsgeschwindigkeiten an der Polymer/Si-Grenzfläche führen. Eine Änderung der Austrittsarbeit von bis zu 0.5 eV und der Bandverbiegung von bis zu 0.24 eV wurde nach der Abscheidung dieser Moleküle gemessen. Diese elektronischen Eigenschaften hängen linear vom Oberflächendipol ab. / Organic functionalization of silicon (Si) surfaces has received a tremendous interest in the development of organic/semiconductor hetero-structures for plenty of potential applications from microelectronics, molecular electronics, photovoltaics to bio-applications. In this thesis, tailoring of the electronic properties and passivation properties of such organic hetero-structures have been investigated. Direct grafting of organic layers like methyl groups (CH3 and CD3), ethynyl derivatives (H−C≡C-, CH3−C≡C-, and C6H5−C≡C-), and heterocyclic molecules (pyrrole and thiophene) onto Si(111) surfaces have been performed in a one-step electrochemical process by anodic treatment in Grignard electrolytes. Organically modified Si surfaces show low interface recombination rates as measured by photoluminescence technique and reveal also a much better passivation with respect to stability in ambient air than H-terminated Si surfaces. Grafting of ethynyl derivatives and heterocyclic molecules lead to the formation of ultrathin polymeric layers, where the thickness depends on charge flow applied to the Si electrode, while methyl groups lead to a monolayer on Si(111) surfaces. Only a very small amount of oxidation states of Si has been observed by infrared spectroscopic ellipsometry (IRSE) and synchrotron X-ray photoemission spectroscopy (SXPS). For the first time, IRSE and SXPS measurements reveal the “umbrella” vibrational mode characteristic from methyl groups and a well-defined spin-orbit splitting of the Si 2p core level emission, respectively, in the case of methylated Si(111) surfaces. For all ethynyl derivatives, high-resolution SXPS investigations reveal the incorporation of halogen atoms in the organic layers obtained. Thereby, exchanging Br for Cl in the Grignard compound leads to lower interface recombination rates at the polymer/Si interface. A shift in work function and surface band bending of up to 0.5 and 0.24 eV has been observed, respectively. The electronic properties reveal a linear relation between the work function and the surface dipole.

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In this work systematic studies of the organic semiconductor CuPc have been presented. In general the investigation can be devided in three parts. In the first one we have studied the electronic structure of clean CuPc thin film. The next two parts are devoted to organic-organic and metal–organic interface formation, where one of the interface components is CuPc thin film. The main results of this thesis are: - The electronic structure of the pristine organic semiconductor CuPc (valence band and empty states) has been obtained by a combination of conventional and resonant photoemission, near-edge X-ray absorption, as well as by theoretical ab initio quantum-chemical calculations. A qualitative assignment of different VB structures has been given, or in other words the contributions of different atomic species as well as sites of the CuPc molecule to the electronic DOS has been established. In particular, it was shown, that the HOMO is mainly comprised of the spectral weights from the orbitals of carbon pyrolle atoms. Additional contributions to the HOMO stems from the benzene atoms. A combined experimental and theoretical study of the unoccupied electronic density of states of CuPc was presented. Our study allows identifying the contributions from different parts of the molecule to the unoccupied DOS and the measured spectra, which lays grounds for future studies of the evolution of the CuPc electronic states upon e.g. functionalization or doping. Application of similar studies to other organic semiconductors will also provide significant insight into their unoccupied electronic states. - The electronic properties of the organic heterointerfaces between fullerite and pristine copper phthalocyanine were studied. Both interfaces, CuPc/C60 and C60/CuPc, were found to be non-reactive with pronounced shifts of the vacuum level pointing to the formation of an interfacial dipole mainly at the CuPc side of the heterojunctions. The dipole values are close to the difference of the work functions of the two materials. Important interface parameters and hole-injection barriers were obtained. The sequence of deposition does not influence the electronic properties of the interfaces. - CuPc doped with potassium was studied by means of photoemission and photoabsorption spectroscopy. A detailed analysis of the core-level PE spectra allows one to propose possible lattice sites, which harbor the potassium ions. Contrasting to a few results reported in the literature, the films prepared in this thesis showed no finite electronic density of states at the Fermi level. - Two stages of the In/CuPc interface formation have been distinguished. The low-coverage stage is characterized by a strong diffusion of the In atoms into the organic film. Metal ions occupy sites close to the pyrolle nitrogen and strongly interact with molecules transferring negative charge to CuPc. Indium diffusion into the organic films saturates at a stoichiometry of In2CuPc. Subsequently, in the second stage the formation of a metallic indium film occurs on the top of the In2CuPc film. - Upon deposition on CuPc film Sn and Ag atoms do not diffuse into the organic film forming metallic clusters and/or thin metallic overlayer. Sharp metal-organic film interface is formed, in contrast to indium and potassium deposition. Presented experimental results also give evidence for absence of noticeable chemical reaction of Sn and Ag with CuPc thin film. - The systematic investigation of interface formation between CuPc thin film and various metals gives us the possibility to summarize all results with demonstrating similarities and differences for all systems studied.

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