A5010342430- Molecular Junctions and Nanostructures
- Organic Electronics and Photovoltaics
- Quantum and electron transport phenomena
- Organic Light-Emitting Diodes Research
- Porphyrin and Phthalocyanine Chemistry
- Analytical Chemistry and Sensors
- Advanced Memory and Neural Computing
- Magnetism in coordination complexes
- Graphene research and applications
- Mesoporous Materials and Catalysis
- Surface Chemistry and Catalysis
- Advanced Chemical Physics Studies
- Semiconductor materials and devices
- Electron and X-Ray Spectroscopy Techniques
- Ionic liquids properties and applications
- Conducting polymers and applications
- Photochemistry and Electron Transfer Studies
- Catalysis and Oxidation Reactions
- Magnetic properties of thin films
- Quantum Dots Synthesis And Properties
- Copper-based nanomaterials and applications
- Organic and Molecular Conductors Research
- Ion-surface interactions and analysis
- TiO2 Photocatalysis and Solar Cells
- Luminescence and Fluorescent Materials
Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
2023-2024
University of Kaiserslautern
2005-2022
Abstract Electrons in organic semiconductors (OSC) possess remarkably long spin relaxation times. Hybrid spintronic devices that combine OSC with ferromagnetic (FM) substrates are therefore expected to provide a route improved and new functionalities. A crucial role is played by the FM‐OSC interface which governs injection into OSC. Using spin‐resolved photoelectron spectroscopy ab initio calculations we study here such possible channels metal phthalocyanines (MPc). We report first direct...
Large organic molecules and metal complexes are promising candidates for electronics, optoelectronics, spintronics, with interfaces to metals being critical. Clean preparation in ultra-high vacuum (UHV) is ideal, but many systems fragile cannot be thermally sublimed. This study details the of thin films metallacrown Cu(II)[12-MCCu(II)N(Shi)-4] (short: CuCu4) from liquid phase using electrospray injection (ESI) and, particular, (LI). Both methods produce intact CuCu4 complexes, they differ...
Immobilization of the palladium complex [Pd(L1)Cl2] (Pd1), where L1 = N,N'E,N,N'E)-N,N'-(3-(3-(triethoxysilyl)propyl)pentane-2,4-diylidene)dianiline, on MCM-41 and SBA-15 supports at 100 °C Pd loading 10% afforded respective materials [Pd1@MCM-41] (Pd2) [Pd1@SBA15] (Pd3) in moderate yields. Calcination temperatures 150 200 using support gave corresponding compounds Pd4 Pd5 respectively, while loadings 5% compound Pd6. The characterization new was achieved by FT-IR for functional group...
The π-conjugated organic molecules 3,4,9,10-perylene-tetracarboxylic dianhydride, 1,4,5,8-naphthalene-tetracarboxylic and 1,8-naphthalene-dicarboxylic anhydride were investigated via gas phase bulk ultraviolet photoemission spectroscopy compared to density functional theory calculations. Values for final state effects such as intermolecular polarization determined the differing features in spectra interpreted a consequence of interactions thin films. Additionally, highest occupied molecular...
n doping of the molecular organic semiconductor perylene-3,4,9,10-tetracarboxylic–dianhydride (PTCDA) is often achieved by use alkali metals as dopants. This process commonly performed in two steps. In first dopant evaporated onto surface PTCDA film. As it has been believed that shows an inhomogeneous diffusion profile through layer with most accumulated few layers, a subsequent annealing step order to reach homogeneous distribution whole layer. this paper experimental results concerning...
n -type doping of the molecular organic semiconductor perylene-3,4,9,10-tetracarboxylicdianhydride (PTCDA) by sodium, potassium, and cesium was carried out. The chemical properties processes were investigated means x-ray photoemission infrared absorption spectroscopy. Simultaneously evolution occupied electronic states around transport gap monitored ultraviolet It found that ratio depends on ionization energy alkali metal, in particular if compared with highest orbital formed alkali-PTCDA...
In order to clarify the doping behavior of different alkali metals in perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), Fourier transform infrared spectra PTCDA thin films doped with sodium, potassium, and cesium were measured compared. Furthermore vibrational properties calculated using density-functional theory these frequencies assigned experimental IR modes films.
Donor-acceptor (D-A) structured molecules are essential components of organic electronics. The respective molecular structures these and their synthesis primarily determined by the intended area application. Typically, D-A promote charge separation transport in photovoltaics or field-effect transistors. showing a larger twist angle between D A units are, e.g., for development high internal quantum efficiency light-emitting diodes. prototypical molecule this type is DCzDCN...
The interaction between zinc-tetraphenylporphyrin (ZnTPP) and fullerenes (C60 C60F48) are studied using ultraviolet photoelectron spectroscopy (UPS) scanning tunneling microscopy (STM). Low temperature STM reveals highly ordered ZnTPP monolayers on Au(111). In contrast to C60, a submonolayer coverage of C60F48 results in long-range disorder the underlying single layer distortion individual molecules. This is induced by substantial charge transfer at organic-organic interface, revealed...
Time-resolved two-photon photoemission of the doping process perylene-tetracarboxylicdianhydride (PTCDA) thin films with sodium gives insight into dynamics hot electrons in this system. Interaction Na results a charge transfer from to PTCDA and increases lifetime optically excited electrons. A similar increase can be observed for ultrathin layers on Ag(111). Both are discussed one-electron picture, treated ``classical'' theory, many-electron picture as commonly considered strongly correlated systems.
Dithienylated phenothiazines (DTPTs) with different functional groups attached to the central nitrogen atom are presented as a class of versatile metal-free chromophores for design dye-sensitized solar cells (DSSCs) and organic light-emitting diodes (OLEDs). The electronic characteristics spin-coated thin films on polycrystalline gold were studied using photoelectron spectroscopy assisted by theoretical calculations, scanning force microscopy, UV/Vis spectroscopy. Complementary fluorescence...
Ultrathin films of tetracyanoethylene (TCNE) on Co(100) were investigated by means spin-integrated and spin-resolved photoemission spectroscopy ((sp-)UPS), X-ray (XPS), near edge absorption fine-structure (NEXAFS), magnetic circular dichroism (XMCD). We found a coverage-dependent modulation the interface dipole switching between metallic resistive spin filtering at triggered two distinct adsorption geometries TCNE. The strongest hybridization structure modifications are low coverage with...
Abstract The highest occupied molecular orbital (HOMO) of the pi‐conjugated organic molecule 3,4,9,10‐perylenetetracarboxylic dianhydride (PTCDA) was investigated via bulk and gas phase ultraviolet photoemission spectroscopy. As a result absence various linewidth broadening effects which occur in case condensed matter, measurements on single molecules allow an estimate contributions these to total linewidth. Distinctive peaks resulting from vibrational excitations can be recognized thus...
Spin-flip inelastic tunneling spectroscopy (SF-IETS) at low temperatures allows the electrical characterization of surface magnetism, particularly for molecule/substrate systems which can be interesting molecular spintronics. Here, SF-IETS was used to explore competing character intramolecular superexchange interactions on a device-compatible metallic substrate. For this purpose, multinuclear metallacrown system CuFe4, [Cu(ii)(DMF)2Cl2[12-MCFe(III)N(Shi)-4](DMF)4·2DMF], Au(111) and its...
Spin-flip inelastic tunneling spectroscopy (SF-IETS) is an outstanding technique to investigate elementary spin excitation of adsorbed atoms, molecules, and their assemblies on surfaces. The analysis the measured spectra provides access interactions within systems coupling with substrate electrons. Here, we use SF-IETS in combination different perturbative electron transport model simulations explore processes Cu(II)[12-MCCu(II)N(Shi)-4] metallacrown molecule (CuCu4), containing five...
Donor-acceptor (D-A) structured molecules are essential components in organic electronics. The respective molecular structure of these and their synthesis primarily determined by the intended area application. Typically, D-A promote charge separation transport photovoltaics (OPV) or field-effect transistors (OFET). showing a larger twist angle between D A units are, e.g., extremely important for development high internal quantum efficiency light-emitting diodes (OLEDs). prototypical molecule...