96 results match your criteria: "Paderborn University: Universitat Paderborn[Affiliation]"

Self-assembled DNA origami lattices on silicon oxide surfaces have great potential to serve as masks in molecular lithography. However, silicon oxide surfaces come in many different forms and the type and history of the silicon oxide has a large effect on its physicochemical surface properties. Therefore, we here investigate DNA origami lattice formation on differently fabricated SiOx films on silicon wafers after wet-chemical oxidation by RCA1.

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Solvent-mediated oxide hydrogenation in layered cathodes.

Science

September 2024

SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.

Self-discharge and chemically induced mechanical effects degrade calendar and cycle life in intercalation-based electrochromic and electrochemical energy storage devices. In rechargeable lithium-ion batteries, self-discharge in cathodes causes voltage and capacity loss over time. The prevailing self-discharge model centers on the diffusion of lithium ions from the electrolyte into the cathode.

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Molecular Orientation-Dependent Photonic Polarization Engineering in Organic Single-Crystal-Filled Microcavities.

J Phys Chem Lett

July 2024

Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China.

Designing the polarization degree of freedom of light is crucial in many fields and has widespread application in, for example, all-optical circuits. In this work, we find that in an organic microcavity filled with anisotropic single crystals the cavity modes can be modulated to be elliptically polarized, i.e.

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Infrared (IR) emission bands by interstellar polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic nitrogen heterocycles (PANHs) are observed towards a large variety of interstellar objects and offer detailed insights into the chemistry and physics of the interstellar medium. The analysis of the emission bands, and thus the interpretation of the molecular characteristics of the carriers, heavily relies on the use of density functional theory (DFT) calculated IR spectra. However, there are significant challenges in accurately predicting the experimental IR band positions, particularly for PANH emission vibrational modes around 6 μm.

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Polycyclic aromatic nitrogen heterocycles (PANHs) are present in various astronomical environments where they are subjected to intense radiation. Their photodissociation pathways give crucial insights into the cycle of matter in the universe, yet so far only the dissociation characteristics of few PANHs have been investigated. Moreover, most experiments use single photon techniques that only reveal the initial dissociation step, and are thus unsuited to replicate astronomical environments and timescales.

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The nonionic surfactant pentaethylene glycol-monododecylether CE forms micelles in aqueous solutions with a lower critical solution temperature. This characteristic solution behavior of CE is independent of the pH. Such micelles are used to solubilize a large variety of active guest molecules like for instance dyestuffs.

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The threshold photoionization and dissociative ionization of benzonitrile (CHCN) were studied using double imaging photoelectron photoion coincidence (PEPICO) spectroscopy at the Vacuum Ultraviolet (VUV) beamline of the Swiss Light Source (SLS). The threshold photoelectron spectrum was recorded from 9.6 to 12.

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Article Synopsis
  • Manipulating bosonic condensates with electric fields is tough because the fields don't directly affect neutral particles, but this study presents a method to control exciton-polariton condensates using electric fields in liquid crystal microcavities.
  • The researchers showed that by applying voltages between 1 to 10 V, they could create vortices with different topological charges in the condensates, utilizing the interplay of potential gradients and liquid crystal properties.
  • This work not only enhances understanding of electric control in polariton systems at room temperature but also opens opportunities for developing micron-sized optical devices that can manipulate light for advanced information processing and photonic circuits.
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Based on a literature review of studies on teachers' professional competence and related assessment tools, this paper introduces a model of teacher education assessment. It is influenced by Miller's (1990) framework of assessment in medical education and includes, among other aspects, performance assessments. This model is used to understand the potential effects of transferring assessment tools into a digital format with assessment feedback.

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Semiconductor quantum dot molecules are considered promising candidates for quantum technological applications due to their wide tunability of optical properties and coverage of different energy scales associated with charge and spin physics. While previous works have studied the tunnel-coupling of the different excitonic charge complexes shared by the two quantum dots by conventional optical spectroscopy, we here report on the first demonstration of a coherently controlled interdot tunnel-coupling focusing on the quantum coherence of the optically active trion transitions. We employ ultrafast four-wave mixing spectroscopy to resonantly generate a quantum coherence in one trion complex, transfer it to and probe it in another trion configuration.

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Rudolph Hermann Lotze's philosophically informed psychology.

J Hist Behav Sci

January 2024

Dipartimento di Lettere e Filosofia, University of Florence, Assisi, Italy.

This essay deals with four main topics: the notion of philosophical psychology; the idea that physical events and mental events cannot be compared to one another; psychophysical mechanism; and the theory of local signs. These are all key elements in the Medicinische Psychologie of Rudolph Hermann Lotze (1817-1881). By philosophical psychology, Lotze understands not only the collection of experimental data regarding physiological and mental states but also their philosophical processing outlining an interpretation of the real nature of the mind-body connection.

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Long-term quantum coherence constitutes one of the main challenges when engineering quantum devices. However, easily accessible means to quantify complex decoherence mechanisms are not readily available, nor are sufficiently stable systems. We harness novel phase-space methods-expressed through non-Gaussian convolutions of highly singular Glauber-Sudarshan quasiprobabilities-to dynamically monitor quantum coherence in polariton condensates with significantly enhanced coherence times.

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A series of new organic donor-π-acceptor dyes incorporating a diquat moiety as a novel electron-acceptor unit have been synthesized and characterized. The analytical data were supported by DFT calculations. These dyes were explored in the aerobic thiocyanation of indoles and pyrroles.

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Integrated electro-optical switches are essential as one of the fundamental elements in the development of modern optoelectronics. As an architecture for photonic systems exciton polaritons, hybrid bosonic quasiparticles that possess unique properties derived from both excitons and photons, have shown much promise. For this system, we demonstrate a significant improvement of emitted intensity and condensation threshold by applying an electric field to a microcavity filled with an organic microbelt.

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Circularly polarized electroluminescence from a single-crystal organic microcavity light-emitting diode based on photonic spin-orbit interactions.

Nat Commun

January 2023

Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, 100048, Beijing, People's Republic of China.

Circularly polarized (CP) electroluminescence from organic light-emitting diodes (OLEDs) has aroused considerable attention for their potential in future display and photonic technologies. The development of CP-OLEDs relies largely on chiral-emitters, which not only remain rare owing to difficulties in design and synthesis but also limit the performance of electroluminescence. When the polarization (pseudospin) degrees of freedom of a photon interact with its orbital angular momentum, photonic spin-orbit interaction (SOI) emerges such as Rashba-Dresselhaus (RD) effect.

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Hydrogel-Based Biosensors.

Gels

November 2022

Department of Chemistry, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany.

There is an increasing interest in sensing applications for a variety of analytes in aqueous environments, as conventional methods do not work reliably under humid conditions or they require complex equipment with experienced operators. Hydrogel sensors are easy to fabricate, are incredibly sensitive, and have broad dynamic ranges. Experiments on their robustness, reliability, and reusability have indicated the possible long-term applications of these systems in a variety of fields, including disease diagnosis, detection of pharmaceuticals, and in environmental testing.

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Circularly Polarized Lasing from a Microcavity Filled with Achiral Single-Crystalline Microribbons.

Angew Chem Int Ed Engl

February 2023

Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing, 100048, China.

Organic circularly polarized (CP) lasers have received increasing attention due to their future photoelectric applications. Here, we demonstrate a CP laser from a pure organic crystal-filled microcavity without any chiral molecules or chiral structures. Benefited from the giant anisotropy and excellent laser gain of organic crystals, optical Rashba-Dresselhaus spin-orbit coupling effect can be induced and is conductive to the CP laser in such microcavities.

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Doping halide perovskites (HPs) with extrinsic species, such as alkali metal ions, plays a critical, albeit often elusive role in optimising optoelectronic devices. Here, we use solid state lithium ion battery inspired devices with a polyethylene oxide-based polymer electrolyte to dope HPs controllably with lithium ions. We perform a suite of material analysis techniques while dynamically varying Li doping concentrations.

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P-Terminated InP (001) Surfaces: Surface Band Bending and Reactivity to Water.

ACS Appl Mater Interfaces

October 2022

Department of Materials- and Geosciences, Surface Science Laboratory, Technical University of Darmstadt, Otto-Berndt-Straße 3, 64287Darmstadt, Germany.

Stable InP (001) surfaces are characterized by fully occupied and empty surface states close to the bulk valence and conduction band edges, respectively. The present photoemission data show, however, a surface Fermi level pinning only slightly below the midgap energy which gives rise to an appreciable surface band bending. By means of density functional theory calculations, it is shown that this apparent discrepancy is due to surface defects that form at finite temperature.

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Helical Polariton Lasing from Topological Valleys in an Organic Crystalline Microcavity.

Adv Sci (Weinh)

October 2022

Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing, 100048, P. R. China.

Topological photonics provides an important platform for the development of photonic devices with robust disorder-immune light transport and controllable helicity. Mixing photons with excitons (or polaritons) gives rise to nontrivial polaritonic bands with chiral modes, allowing the manipulation of helical lasers in strongly coupled light-matter systems. In this work, helical polariton lasing from topological valleys of an organic anisotropic microcrystalline cavity based on tailored local nontrivial band geometry is demonstrated.

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Spin-orbit coupling plays an important role in the spin Hall effect and topological insulators. Bose-Einstein condensates with spin-orbit coupling show remarkable quantum phase transition. In this work we control an exciton polariton condensate - a macroscopically coherent state of hybrid light and matter excitations - by virtue of the Rashba-Dresselhaus (RD) spin-orbit coupling.

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Unraveling the Unconventional Order of a High-Mobility Indacenodithiophene-Benzothiadiazole Copolymer.

ACS Macro Lett

October 2021

Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States.

A new class of donor-acceptor (D-A) copolymers found to produce high charge carrier mobilities competitive with amorphous silicon (>1 cm V s) exhibit the puzzling microstructure of substantial local order, however lacking long-range order and crystallinity previously deemed necessary for achieving high mobility. Here, we demonstrate the application of low-dose transmission electron microscopy to image and quantify the nanoscale and mesoscale organization of an archetypal D-A copolymer across areas comparable to electronic devices (≈9 μm). The local structure is spatially resolved by mapping the backbone (001) spacing reflection, revealing nanocrystallites of aligned polymer chains throughout nearly the entire film.

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The functionality of phonon-based quantum devices largely depends on the efficiency of the interaction of phonons with other excitations. For phonon frequencies above 20 GHz, generation and detection of the phonon quanta can be monitored through photons. The photon-phonon interaction can be enormously strengthened by involving an intermediate resonant quasiparticle, e.

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Recent trends in chemistry, structure, and various applications of 1-acyl-3-substituted thioureas: a detailed review.

RSC Adv

April 2022

CEQUINOR (UNLP, CONICET-CCT La Plata), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata Bv. 120 1465 La Plata 1900 Argentina.

The interest in acyl thioureas has continually been escalating owing to their extensive applications in diverse fields, such as synthetic precursors of new heterocycles, pharmacological and materials science, and technology. These scaffolds exhibit a wide variety of biological activities such as antitumor, enzyme inhibitory, anti-bacterial, anti-fungal, and anti-malarial activities and find utilization as chemosensors, adhesives, flame retardants, thermal stabilizers, antioxidants, polymers and organocatalysts. In addition, the synthesis, and applications of coordination complexes of these ligands have also been overviewed.

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