Frank Marlow

Thin metal‐organic framework films grown in a layer‐by‐layer manner have been the subject of growing interest. Herein we investigate one of the most popular frameworks, the type HKUST‐1. Firstly, we show a special synthesis procedure resulting in quick but optically perfect growth. This enables the synthesis of films of excellent optical quality within a short timeframe. Secondly and most importantly, we address the known, but not fully understood observation that the expected growth rate of one monolayer per cycle is strongly exceeded, e. g. by a factor of 4. This is an often‐ignored inconsistency in the literature. We offer a growth model using a reconstruction process in every cycle leading to a deterministic reconstruction‐by‐reconstruction (RbR) cycle growth with a 4‐times higher growth rate. It represents an up‐to‐now hidden chemical assembly mechanism.

Thin metal-organic framework films grown in a layer-by-layer manner have been the subject of growing interest. Herein we investigate one of the most popular frameworks, type HKUST-1. Firstly, we show a synthesis procedure resulting in quick but optically perfect growth. This enables the synthesis of films of excellent optical quality within a short timeframe. Secondly and most importantly, we address the already known, but not fully understood observation that the expected monolayer growth is strongly exceeded in every single deposition cycle. This is an often-ignored contradiction in the literature. We offer a growth model using mid-cycle reconstruction process leading to a mathematically determined reconstruction-by-reconstruction (RbR) cycle growth with a 4-times higher growth rate representing an up-to-now hidden chemical assembly mechanism.

A novel opto‐ionic device based on the recently reported Ionic Voltage Effect Soft Triode (IVEST) is introduced. This device can convert optical to ionic signals as it is shown here. The characterization of the opto‐IVEST points to an optically induced charging mechanism and to various potential applications. The opto‐IVEST shows the ability to detect and memorize optical signals. Furthermore, the device exhibits learning behavior and a hybrid logic gate function.

This work investigates the demixing behavior of Pickering emulsions consisting of water, n-hexadecane, and two different types of Pickering particles. The first type is uniform, and the second consists of one-side modified Janus particles influencing the emulsion behavior significantly. Both particle types are able to stabilize the emulsions, but lead to clear differences in the emulsion drop size and size distribution. This results in different creaming times varying between minutes and hours and different clearance processes of the water excess phase. Large pH effects were found in addition. At some conditions, non-adsorbed particles were observed that sediment over time in addition to the creaming of the emulsion.

A recently developed, new ionic device called the ionic voltage effect soft triode (IVEST) was optimized, tuned and embedded into a memory application concept.

The work functions of different stainless steels were investigated and found to be in the range of 4.08–4.19 eV. They characterize the passive layer, an oxide layer on top of the stainless steel bulk material. This layer makes the steels corrosion-resistant, and it also controls the possible electronic and electrochemical applications of such materials. Structured samples were measured that are especially important for applications of these materials, e.g., in solar cells or fuel cells. The effects of composition changes of the stainless steel on the work function are unexpectedly small, which is likely related to a similar number of d electrons responsible for the electronic band structure.

The self-assembly of soft colloidal particles into three-dimensional ordered structures called artificial opals is promising approach for realization of photonic crystals. Self-assembly is simple, relatively fast and cost-effective. Despite its versatility, self-assembled opals often contain unintended internal defects like vacancies, domains and cracks. The occurrence of defects might not be so crucial for some applications such as sensors, catalyst, and adsorbent, but limit the applicability of artificial opals to be used as building block of optical devices. Colloidal particles in suspension possess surface charges that can be used to tune self-assembly process by applying external electric fields. The coupling between colloidal particles flow due to solvent evaporation and direct current (DC) electric fields may serve as a promising way to control the crystallization process. In this work we report the influences of an in-plane DC field on the formation and optical properties of the opal films made by using the capillary deposition method. The formation of opal films was followed using a camera and the optical properties were measured using UV-Vis spectrophotometry. We found that a low electric field can improve the crystallinity of opal films that is manifested in a high and sharp Bragg peak.

The construction of an ionic soft triode based on interfacial ion adsorption and redox oxidizer depletion is reported.

Self-assembled opals that are considered as a promising candidate for three-dimensional photonic crystals often suffer from the existence of internal defects. Defects influence optical properties and limit the applicability of opal films. Directed assembly using external fields may offer a certain degree of tunability in the opal formation process. We investigate the effect of an out-of-plane electric field on the formation and optical properties of opal films deposited using the capillary deposition method. The application of an electric field of intermediate strength (20–30 V/cm) can improve opal quality. The quality of opal films was found to depend on the polarity of the bottom substrate resulting from the beneficial influence of an asymmetry between the growths and the interplay with gravity. The negatively charged bottom substrate results in slightly better opal quality. This finding shows the potential of electric fields to tune opal formation in order to reduce the defect content.