Fakultät 2 Mathematik und Naturwissenschaften
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1518 Submissions in this community.

Recent Submissions
Nano-contact transfer with gold nanoparticles on PEG hydrogels and using wrinkled PDMS-stamps

Yesildag, Cigdem; Tyushina, Arina; Lensen, Marga (2017)

In the present work, a soft lithographic process is used to create nanometer-sized line patterns of gold nanoparticles (Au NPs) on PEG-based hydrogels. Hereby nanometer-sized wrinkles on polydimeth...

Novel wet micro-contact deprinting method for patterning gold nanoparticles on PEG-hydrogels and thereby controlling cell adhesion

Yesildag, Cigdem; Bartsch, Christoph; Vicente, Gonzalo de; Lensen, Marga C. (2017)

In the present work we introduce a novel method to create linear and rectangular micro-patterns of gold nanoparticles (Au NPs) on poly(ethylene glycol) (PEG) hydrogels. The strategy consists of rem...

Property-performance relationships of catalysts in the oxidative coupling of methane

Schmack, Roman (2017)

The catalytic oxidative coupling of methane (OCM) is a „dream reaction“ of heterogeneous catalysis, as it provides a direct conversion route of methane to the value-added and easily transportable C...

Anisotropic plasmonic nanoparticle arrays for surface-enhanced biosensors

Gkogkou, Dimitra (2017)

Plasmonic structures exhibiting surface enhancement properties can lead to hypersensitive, label-free and analyte-specific detection of organic molecules. The motivation of this work is the realiza...

Sustainable biomass potential for biofuels

Lossau, Selma (2017)

There is a large interest in biofuels in Brazil and India as a substitute to fossil fuels, with a purpose of enhancing energy security and promoting rural development. The critical question is whet...

Temperature-dependent recombination coefficients in InGaN light-emitting diodes

Nippert, Felix; Karpov, Sergey Yu.; Callsen, Gordon; Galler, Bastian; Kure, Thomas; Nenstiel, Christian; Wagner, Markus R.; Strassburg, Martin; Lugauer, Hans-Jürgen; Hoffmann, Axel (2016)

We obtain temperature-dependent recombination coefficients by measuring the quantum efficiency and differential carrier lifetimes in the state-of-the-art InGaN light-emitting diodes. This allows us...

Determination of recombination coefficients in InGaN quantum-well light-emitting diodes by small-signal time-resolved photoluminescence

Nippert, Felix; Karpov, Sergey; Pietzonka, Ines; Galler, Bastian; Wilm, Alexander; Kure, Thomas; Nenstiel, Christian; Callsen, Gordon; Strassburg, Martin; Lugauer, Hans-Jürgen (2016)

We suggest a novel technique for the evaluation of the recombination coefficients corresponding to Shockley–Read–Hall, radiative, and Auger recombination that occur in InGaN/GaN-based light-emittin...

Polarization-induced confinement of continuous hole-states in highly pumped, industrial-grade, green InGaN quantum wells

Nippert, Felix; Nirschl, Anna; Schulz, Tobias; Callsen, Gordon; Pietzonka, Ines; Westerkamp, Steffen; Kure, Thomas; Nenstiel, Christian; Strassburg, Martin; Albrecht, Martin; Hoffmann, Axel (2016)

We investigate industrial-grade InGaN/GaN quantum wells (QWs) emitting in the green spectral region under high, resonant pumping conditions. Consequently, an ubiquitous high energy luminescence is ...

Comparison of conventional and super-glassy polymers

Konnertz, Nora Magdalena (2017)

In the field of gas separation, polymeric membranes are favorable materials. Polymers are inexpensive compared to ceramics and metals, offer a good processability, and possess the ability to operat...

The role of van der Waals interactions on the electronic properties of molecules and materials

Ferri, Nicola (2017)

Long-range van der Waals (vdW) interactions play a fundamental role in the structure and stability of many systems, ranging from small dimers to complex hybrid inorganic/organic systems (HIOS). How...

Spektrale und transiente Eigenschaften der Lumineszenz von Cu2ZnSn(S,Se)4-Dünnschichten

Kretzschmar, Steffen (2017)

Um die auf der Pariser Klimakonferenz 2015 vereinbarten Ziele zu erreichen, muss die photovoltaische Energieerzeugung weltweit deutlich ausgebaut werden, da diese unter den regenerativen Energieque...

Non-radiative loss mechanisms in InGaN/GaN multiple quantum well light-emitting diodes

Nippert, Felix (2017)

InGaN/GaN quantum wells (QWs) are commonly used for blue and green light-emitting diodes (LEDs), for example in solid-state lighting (SSL). While such structures are already in mass-production, the...

Band gap engineering: the role of anions

Anke, Björn (2017)

The degradation of harmful organic pollutants with the help of semiconductors is regarded as one of the crucial solutions for waste water treatment. The main disadvantage of extensively used photoc...

Opto-mechanical properties of macromolecules on solid surfaces

Liebig, Tobias (2017)

In order to investigate the mechanical properties of macromolecules, the group led by Professor Rabe at the Humboldt Universität zu Berlin developed a “molecular workbench,” a set of methods and te...

Self-assembly and self-organization of magnetic Janus-like colloids in three dimensions

Yener, Arzu Bahar (2017)

In this thesis, we investigate the recent model of laterally shifted dipoles, i.e. spherical particles carrying a magnetic dipole moment in a non-central position, with a view to selfassembly as we...

Investigations of nonlinear surface-wave phenomena and anisotropic photoluminescence of nano-film structures via two-dimensional k-space spectroscopy

Heckmann, Jan (2017)

The investigation of surfaces and thin films is of particular interest in current research as it provides a basis for a multiplicity of applications such as waveguides, sensors, solar cells and opt...

Many body effects in heavily doped GaN

Nenstiel, Marc Christian Siegfried (2017)

In this work the fundamental optical signatures of highly Germanium doped GaN are investigated. This work gives fundamental new insights in interactions of carriers in a three dimensional degenerat...

Synthesis, characterization and catalytic testing of metal tungstates as catalysts for activation of lower alkanes

Li, Xuan (2017)

The electronic and structural properties of vanadium-containing phases govern the formation of isolated active sites at the surface of these catalysts for selective alkane oxidation. This concept i...

In situ observation of reactive oxygen species forming on oxygen-evolving iridium surfaces

Pfeifer, Verena; Jones, Travis E.; Velasco Vélez, Juan J.; Arrigo, Rosa; Piccinin, Simone; Hävecker, Michael; Knop-Gericke, Axel; Schlögl, Robert (2017)

Water splitting performed in acidic media relies on the exceptional performance of iridium-based materials to catalyze the oxygen evolution reaction (OER). In the present work, we use in situ X-ray...

Reactive oxygen species in iridium-based OER catalysts

Pfeifer, Verena; Jones, Travis E.; Wrabetz, Sabine; Massué, Cyriac; Velasco Vélez, Juan J.; Arrigo, Rosa; Scherzer, Michael; Piccinin, Simone; Hävecker, Michael; Knop-Gericke, Axel; Schlögl, Robert (2016)

Tremendous effort has been devoted towards elucidating the fundamental reasons for the higher activity of hydrated amorphous IrIII/IV oxyhydroxides (IrOx) in the oxygen evolution reaction (OER) in ...