A5103101811- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Microstructure and mechanical properties
- Perovskite Materials and Applications
- Advanced Sensor and Energy Harvesting Materials
- Lanthanide and Transition Metal Complexes
- Surface and Thin Film Phenomena
- Magnetism in coordination complexes
- X-ray Diffraction in Crystallography
- Corrosion Behavior and Inhibition
- Microstructure and Mechanical Properties of Steels
- Wireless Power Transfer Systems
- Semiconductor materials and interfaces
- Advanced MEMS and NEMS Technologies
- Magnetic Field Sensors Techniques
- Aluminum Alloy Microstructure Properties
- Electron Spin Resonance Studies
- High Temperature Alloys and Creep
- Aerogels and thermal insulation
- Crystallization and Solubility Studies
- Metallurgy and Material Forming
- Metallurgical Processes and Thermodynamics
- Mesoporous Materials and Catalysis
- Catalysis and Oxidation Reactions
- Organic Light-Emitting Diodes Research
German Cancer Research Center
2024
Heidelberg University
2024
University of Stuttgart
2013-2020
Stuttgart Observatory
2018-2019
University of Freiburg
2012
BASF (United States)
1986
Macroscopic P3HT spherulitic crystals are grown in 25-nm-thick films via precise control of solvent swelling during polymer crystallization, which allow placement transistor channels within single oriented crystal domains.Charge-transport anisotropy the b–c (π-stacking & main chain) plane and role order–disorder grain boundaries reported.
The nanomorphology of the high mobility polymer poly{[N,N′‐bis(2‐octyldodecyl)‐1,4,5,8‐naphthalenedicarboximide‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)} P(NDI2OD‐T2) in thin films is explored as a function different annealing conditions and correlated to optical electrical properties. While nanofibrils with face‐on orientation form I are obtained directly after spin‐coating below melt transition temperature, clear evidence lamellar structures found melt‐annealing followed by slow cooling room...
The field dependence and yield of free charge carrier generation in polymer:fullerene blends with varying energetic offsets is not affected when the excitation energy varied from above band-gap to direct CT state excitation. Instead, ability split dictated by offset between relaxed separated (CS) state.
We present the in-depth determination of magnetic properties and electronic structure luminescent volatile dysprosium-based single molecule magnet [Dy<sub>2</sub>(bpm)(fod)<sub>6</sub>] (Hfod = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione, bpm 2,2-bipyrimidine).
We highlight the influence of processing conditions on polymorphism and structure formation mesoscale for family PCPDTBT polymers with branched alkyl side chains. Direct correlations morphology to chemical transistor device performance are established. found that up four different packing motifs could be realized depending polymer derivative conditions: amorphous, π-stacked, cross-hatched dimer-containing polymorphs. While C- F-PCPDTBT display similar behavior organizing in π-stacked...
PCPDTBT, a marginally crystallizable polymer, is crystallized into new crystal structure using solvent-vapor annealing. Highly ordered areas with three different polymer-chain orientations are identified TEM/ED, GIWAXS, and polarized Raman spectroscopy. The optical structural properties differ significantly from films prepared by standard device preparation protocols. Bilayer solar cells, however, show similar performance.
ABSTRACT The low‐bandgap polymer poly{[4,4‐bis(2‐ethylhexyl)‐cyclopenta‐(2,1‐ b ;3,4‐ ′)dithiophen]‐2,6‐diyl‐ alt ‐(2,1,3‐benzo‐thiadiazole)−4,7‐diyl} (PCPDTBT) is widely used for organic solar cell applications. Here, we present a comprehensive study of the optical properties as function temperature PCPDTBT in solution and thin films with two distinct morphologies. Using absorption photoluminescence spectroscopy well Franck‐Condon analyses, show that undergoes phase transformation at 300 K...
We present a systematic study of the morphology and absorption properties typical donor–acceptor polymer (PCPDTBT) with semicrystalline behavior in solution thin films. In-situ spectroelectrochemical data give information about evolution spectra from neutral to charged species. The experimental are supported by theoretical calculations framework density functional theory (DFT). Regarding film structures, we show that choice solvent has significant influence on films: whereas CS2 CHCl3 rather...
We investigate the photogeneration of polaron pairs (PPs) in neat films semicrystalline donor-acceptor semiconducting copolymer PCPDTBT. Carefully selecting solution-processing procedures, we obtain with different amounts crystallinity and interchain aggregation. compare PPs between by monitoring their photoinduced absorption ultrafast pump-probe experiments, selectively exciting nonaggregated or aggregated polymer chains. The direct photoexcitation π-aggregates results prompt (<100 fs)...
Magneto-oscillatory devices have been recently developed as very potent wireless miniature position trackers and sensors with an exceptional accuracy sensing distance for surgical robotic applications. However, it is still unclear to which extend a mechanically resonating sub-millimeter magnet interacts external magnetic fields or gradients, induce frequency shifts of sub-mHz several Hz and, therefore, affect the accuracy. Here, we investigate this effect experimentally on cantilever-based...
A so called “energy river” originates in the active layer of a bulk-heterojunction solar cell as described work by D. Neher, K. Vandewal, and co-workers on page 2533. This river contains polymer chains cools down from its hot origin to cold front. The riverbank is created “fullerene walls” with different heights. Flashes create electrons energy river. These need decrease temperature during their refrigerating evolution right side cannot escape river, hidden big fullerene wall, get lost. left...
In this atomistic study on the copper–nickel system, a new embedded-atom alloy potential between copper and nickel is fitted to experimental data mixing enthalpy, taking available potentials for pure components from literature. The resulting phase boundaries of are in very good agreement with recent CALPHAD prediction. Using potential, high angle symmetrical tiltΣ5 coherent Σ3 twin grain boundary (GB) chosen systematic investigation equilibriumGB segregation semi-grandcanonical ensemble at...
In this theoretical study, a recently proposed segregation model is applied to data of an exemplary Σ5 grain boundary (GB), which investigated using copper-nickel embedded-atom method potential. Segregation in the semi-grandcanonical ensemble systematically studied by varying chemical potential order explore full composition range for temperatures from 500 K 1000 K. As major thermodynamic feature, mentioned avoids usage interface compositions, arbitrary volume must be defined, but rather...