Veröffentlichungen

Die vorliegende Arbeit präsentiert zum ersten Mal eine systematische Studie der Solvothermalsynthese von CuInS₂ Filmen auf Fluor-dotiertem Zinnoxid auf Glas unter Einsatz der Aminosäure L-Cystein als Schwefelquelle. Das solvothermale Wachstum bei Anwendung von Thioacetamid als Schwefelquelle wurde ebenfalls untersucht. Die Charakterisierung der erhaltenen Filme erfolgte hauptsächlich mit elektronenmikroskopischen Methoden. Es wurden verschiedene Probenpräparationsstrategien für die Transmissionselektronenmikroskopie untersucht.

For the first time this work presents a systematic study of the solvothermal synthesis of CuInS₂ films on fluorine-doped tin oxide coated glass substrates, applying the amino acid L-cysteine as sulfur source. Alternatively, the solvothermal growth of CuInS₂ films was also carried out using thioacetamide as sulfur source as this allowed to obtain different morphologies and chemical compositions of the films. The received films were characterized in detail by means of electron microscopy and related techniques. Different transmission electron microscopy sample preparation techniques have been applied to the solvothermally grown CuInS₂ thin films grown using both sulfur sources.

Single nanowires and networks are considered as promising candidates for miniaturized memristive devices for brain-inspired systems. Moreover, single crystalline nanostructures are useful model systems to gain a deeper understanding in the involved switching mechanism of the investigated material. Here, we report on hydrothermally grown single crystalline Nb3O7(OH) nanowires showing a complementary resistive switching (CRS) behavior. The CRS characteristics can be related to an oxygen vacancy migration at the electrode/metal hydroxide interface.

In this work correlations between thin film crystallinity of plasma ion assisted electron beam evaporated vanadium oxide (VOx) and fluctuations of the deposition parameters during the growth process could be observed by in situ monitoring deposition conditions and electron microscopy studies. In the presented case, unintentional fluctuations in the gas flow at the plasma source caused by inhomogeneous melting of the target material lead to an increase in discharge current and therefore a decrease of the oxygen flow in the plasma source, resulting in the formation of highly crystalline bands due to a temporary increase in energy flux.

This work presents the synthesis of MoO2/MoS2 core/shell nanoparticles within a carbon nanotube network and their detailed electron microscopy investigation in up to three dimensions. The triple-hybrid core/shell material was prepared by atomic layer deposition of molybdenum oxide onto carbon nanotube networks, followed by annealing in a sulfur-containing gas atmosphere.

This study presents a cost-efficient single-step-method to synthesize nanographite from isopropanol by bipolar pulsed electric discharges. The influence of pulse width within the nanosecond range, repetition frequency within the kilohertz range and processing time on the product was systematically investigated by Raman spectroscopy, high-resolution transmission electron microscopy and gas chromatography - mass spectrometry. It was found that long pulses in the microsecond range promote the creation of amorphous and oxidic carbon structures.

Many metal sulfides present a layered structure with large interlayer space and a high theoretical capacity for lithium-ion battery applications. Compared to other transition metal dichalcogenides, vanadium sulfides remain little explored. Vanadium sulfides are commonly obtained by hydrothermal synthesis, which requires further post-processing and coating with binder and carbon additives. Here, we introduce a route to obtain free-standing vanadium sulfide fiber mats with in-built carbon.

We present a facile two-step synthesis of vanadium (III) oxide/carbon core/shell hybrid material for application as lithium-ion battery electrode. The first step is a thermal treatment of a mixture of vanadium carbide (VC) and NiCl2 ⋅ 6H2O at 700 °C in an inert gas atmosphere.

Transition metal dichalcogenides are attractive two-dimensional electrode materials for electrochemical energy storage devices due to their high reversible charge storage capacity. Hybridization of these materials with carbon promises enhanced performance by facilitating the access to reactive sites and extended mechanical stabilization. Herein, we introduce a NbS2/C hybrid material exhibiting a gyroidal microstructure synthesized through macromolecular co-assembly of a tailored block copolymer and an organometallic niobium precursor and subsequent sulfidation.

Transmission electron microscopy (TEM) is a widely used tool to characterize materials. The required samples need to be electron transparent which should be achieved without changing the microstructure. This work describes different TEM sample preparation techniques of nanostructured CuInS2 thin films on fluorine-doped tin oxide substrates, synthesized solvothermally using l‐cysteine as sulfur source. Focused ion beam lamellae, conventional cross section samples and scratch samples have been prepared and investigated. It was possible to prepare appropriate samples with each technique, however, each technique brings with it certain advantages and disadvantages.

This work demonstrates that the solvothermal synthesis of nanocrystalline CuInS2 thin films using the amino acid l-cysteine as sulfur source is facile and robust against variation of reaction time and temperature. Synthesis was carried out in a reaction time range of 3–48 h (at 150 °C) and a reaction temperature range of 100–190 °C (for 18 h).

Adverse health effects of airborne particulate matter depend on parameters like particle size, particle surface and chemical composition. Major emission of indoor particles is caused by combustion processes like tobacco smoking and cooking. Nevertheless, the use of household electrical appliances, such as vacuum cleaners, flat irons or hair dryers, can produce particles as well. In this study the emissions of different hair dryers and flat irons were investigated using a test chamber.

CuInS2 has become a popular and promising candidate as an absorber material in photovoltaic devices and photo-electrochemical cells. Here we report the successful L-cysteine-assisted growth of homogeneous, nanostructured CuInS2 thin films deposited on fluorine-doped tin oxide coated glass. In contrast to existing synthesis routes using thioacetamide as a sulfur source, our method offers the advantage of being environmentally friendly and non-toxic.

Bis(m-methoxyphenyl)(p-methoxyphenyl)phosphine (1) and di(n-butyl)(p-methoxy-phenyl)-phosphine (4) were synthesized and characterized by 1H, 13C, and 31P NMR spectroscopy and 1 also by single crystal X-ray diffraction. The syntheses and analytical data are discussed.

Three new derivatives of methoxyphenyl-substituted bis(picolyl)phosphines 3–5, the CH2TMS substituted bis(picolyl)phosphine (6) and related phosphine oxides 2b–5b have been synthesized. Syntheses were accomplished by reacting the corresponding dichlorophosphines with picolylTMS (7).

In this study we report about the inner and outer structure of CuInS2 microspheres which might be used e.g. in pastes for simple, low-cost solar cell preparation, as well as in electrodes for light-driven water splitting. The microspheres are synthesized via a mild, template-free solvothermal synthesis route and characterised by electron and focused ion beam microscopy, X-ray diffraction, inductively coupled plasma atomic emission and energy dispersive X-ray spectroscopy.