A5032556643- Force Microscopy Techniques and Applications
- Mechanical and Optical Resonators
- Surface Modification and Superhydrophobicity
- Conducting polymers and applications
- Adhesion, Friction, and Surface Interactions
- Polymer Surface Interaction Studies
- Advanced biosensing and bioanalysis techniques
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- Organic Electronics and Photovoltaics
- Advanced Sensor and Energy Harvesting Materials
- RNA Interference and Gene Delivery
- Advanced MEMS and NEMS Technologies
- Nanofabrication and Lithography Techniques
- Advanced Polymer Synthesis and Characterization
- Carbon Nanotubes in Composites
- Analytical Chemistry and Sensors
- Fluid Dynamics and Heat Transfer
- Integrated Circuits and Semiconductor Failure Analysis
- Electronic and Structural Properties of Oxides
- Diatoms and Algae Research
- DNA and Nucleic Acid Chemistry
- thermodynamics and calorimetric analyses
- Dendrimers and Hyperbranched Polymers
- Electrowetting and Microfluidic Technologies
Max Planck Institute for Polymer Research
2016-2025
University of Applied Sciences Mainz
2014-2021
Johannes Gutenberg University Mainz
2007-2018
Czech Academy of Sciences, Institute of Physics
2018
Max Planck Society
2006-2015
Seoul National University
2010
Fraunhofer Institute for Silicon Technology
2009
Eindhoven University of Technology
2009
University of Konstanz
2008
China Agricultural University
2008
Surface stress changes and kinetics were measured in situ during the self-assembly of alkanethiols on gold by means a micromechanical sensor. Self-assembly caused compressive surface that closely followed Langmuir-type adsorption up to monolayer coverage. The at coverage increased linearly with length alkyl chain molecule. These observations interpreted terms differences potential. This highly sensitive sensor technique has broad range applicability specific chemical biological interactions.
We monitor the self-cleaning process on a single-particle level and quantify involved forces.
In this study, we use time-resolved Kelvin probe force microscopy to investigate current–voltage hysteresis in a hybrid lead-halide perovskite solar cell.
Abstract Water drops moving on surfaces are not only an everyday phenomenon seen windows but also form essential part of many industrial processes. Previous understanding is that drop motion dictated by viscous dissipation and activated dynamics at the contact line. Here we demonstrate these two effects cannot fully explain complex paths sliding or impacting drops. To accurately determine forces experienced drops, imaged their trajectory when down a tilted surface, applied relevant equations...
Abstract The growth of lithium dendrites in inorganic solid electrolytes is an essential drawback that hinders the development reliable all-solid-state metal batteries. Generally, ex situ post mortem measurements battery components show presence at grain boundaries electrolyte. However, role nucleation and dendritic metallic not yet fully understood. Here, to shed light on these crucial aspects, we report use operando Kelvin probe force microscopy map locally time-dependent electric...
Nanocapsules composed of a poly(vinylferrocene)-block-poly(methyl methacrylate) shell and hydrophobic liquid core are prepared in water. The nanocapsule shells display patchy structure with poly(vinylferrocene) patches sizes 25 ± 3 nm surrounded by poly(methyl methacrylate). functional nanopatches can be selectively oxidized, thereby influencing the colloidal morphology introducing polar domains shell. to hydrophilic transition redox-responsive advantageously used release payload...
We report the use of Y(3+)-substituted TiO2 (0.5%Y-TiO₂) in solid-state mesoscopic solar cells, consisting CH₃NH₃PbI₃ as light harvester and spiro-OMeTAD hole transport material. A power conversion efficiency 11.2% under simulated AM 1.5 full sun illumination was measured. 15% improvement short-circuit current density obtained compared with pure TiO₂, due to effect Y(3+) on dimensions perovskite nanoparticles formed semiconductor surface, showing that surface modification is an effective way...
Blocked up: Amphiphilic DNA-block copolymers were prepared in a fully automated single process by using DNA synthesizer. These materials formed micelles aqueous solution which applied as scaffold for DNA-templated organic reactions (see picture, red and green balls=reactants, yellow bar=new bond). For novel fluorogenic reaction, the conversions detected fluorescence spectroscopy. Supporting information this article is available on WWW under...
Methylammonium lead iodide (MAPbI3) perovskite shows an outstanding performance in photovoltaic devices. However, certain material properties, especially the possible ferroic behavior, remain unclear. We observed distinct nanoscale periodic domains piezoresponse of MAPbI3(Cl) grains. The structure and orientation these striped indicate ferroelasticity as their origin. By correlating vertical lateral force microscopy experiments performed at different sample orientations with X-ray...
Transforming micelle structure: Amphiphilic DNA block copolymers form spherical micelles in solution. They can be transformed into rodlike by hybridization with long sequences, which consist of parallel aligned double-stranded molecules "glued" together hydrophobic interactions the organic polymer (see picture). The template determines length aggregates. Supporting information for this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z603064_s.pdf or from...
We measured the forces required to slide sessile drops over surfaces. The were by means of a vertical deflectable capillary stuck in drop. drop adhesion force instrument (DAFI) allowed investigation dynamic lateral water 0.1 2 μL volume at defined velocities. On flat PDMS surfaces, increases linearly with diameter contact area solid–liquid interface and sliding velocity. movement relative surfaces enabled us resolve pinning three-phase line individual defects. further investigated 3D...
Efficient charge extraction within solar cells explicitly depends on the optimization of internal interfaces. Potential barriers, unbalanced extraction, and interfacial trap states can prevent from reaching high power conversion efficiencies. In case perovskite cells, slow processes happening time scales seconds cause hysteresis in current–voltage characteristics. this work, we localized investigated these using frequency-modulation Kelvin probe force microscopy (FM-KPFM) cross sections...
Abstract Photoactuators based on liquid crystal elastomers or networks are smart materials that show photoinduced motions. However, their crosslinked make repair reprocessing difficult. Here, a healable and reprocessable photoactuator is fabricated using entangled high‐molecular‐weight azobenzene‐containing polymers (azopolymers) non‐crosslinked. A series of linear azopolymers with different molecular weights synthesized. The low‐molecular‐weight (5–53 kg mol −1 ) cannot form freestanding...
Methylammonium lead halide perovskites (MAPbI3) are very sensitive to humid environments. We performed in situ scanning force microscopy and X-ray diffraction measurements on MAPbI3 films track changes the film morphology crystal structure upon repeated exposure a high relative humidity environment (80%). found that appearance of monohydrate (MAPbI3·H2O) Bragg reflections coincided with additional grain boundaries. Prolonging time induced more boundaries steps films, peak intensities...
Many surfaces reversibly change their structure and interfacial energy upon being in contact with a liquid. Such adapt to specific We propose the first order kinetic model describe dynamic angles of such adaptive surfaces. The is general does not refer particular adaptation process. aim proposed provide quantitative description wetting link changes microscopic processes. By introducing exponentially relaxing energies applying Young's equation locally, we predict advancing receding depending...
To better understand the wetting of cross-linked polydimethylsiloxane (PDMS), we measured advancing and receding contact angles sessile water drops on PDMS as a function line velocity (up to 100 μm/s). Three types samples were investigated: pristine PDMS, where oligomers removed by toluene treatment, with an enriched concentration oligomers. Depending lines time water, different modes observed: one relatively low angle hysteresis (Δθ ≈ 10°) larger hysteresis. We attribute state, called...
Liquid drops sliding on tilted surfaces is an everyday phenomenon and important for many industrial applications. Still, it impossible to predict the drop's velocity. To make a step forward in quantitative understanding, we measured velocity [Formula: see text], contact width length advancing receding angle text] of liquid down inclined flat made different materials. We find friction force acting polar non-polar liquids with viscosities ([Formula: text]) ranging from 10-3 1 can empirically...