@article{41991, author = {{Kunze, Christian and Valtiner, Markus and Michels, Rolf and Huber, Klaus and Grundmeier, Guido}}, issn = {{1463-9076}}, journal = {{Physical Chemistry Chemical Physics}}, keywords = {{Physical and Theoretical Chemistry, General Physics and Astronomy}}, number = {{28}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Self-localization of polyacrylic acid molecules on polar ZnO(0001)–Zn surfaces}}}, doi = {{10.1039/c1cp20913b}}, volume = {{13}}, year = {{2011}}, } @article{41989, author = {{Cravillon, Janosch and Schröder, Christian A. and Nayuk, Roman and Gummel, Jeremie and Huber, Klaus and Wiebcke, Michael}}, issn = {{0044-8249}}, journal = {{Angewandte Chemie}}, keywords = {{General Medicine}}, number = {{35}}, pages = {{8217--8221}}, publisher = {{Wiley}}, title = {{{Fast Nucleation and Growth of ZIF-8 Nanocrystals Monitored by Time-Resolved In Situ Small-Angle and Wide-Angle X-Ray Scattering}}}, doi = {{10.1002/ange.201102071}}, volume = {{123}}, year = {{2011}}, } @article{41986, author = {{Seuring, Jan and Bayer, Frank M. and Huber, Klaus and Agarwal, Seema}}, issn = {{0024-9297}}, journal = {{Macromolecules}}, keywords = {{Materials Chemistry, Inorganic Chemistry, Polymers and Plastics, Organic Chemistry}}, number = {{1}}, pages = {{374--384}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Upper Critical Solution Temperature of Poly(N-acryloyl glycinamide) in Water: A Concealed Property}}}, doi = {{10.1021/ma202059t}}, volume = {{45}}, year = {{2011}}, } @article{41988, author = {{Bayer, Frank M. and Tang, Mingxue and Michels, Rolf and Schmidt, Claudia and Huber, Klaus}}, issn = {{0743-7463}}, journal = {{Langmuir}}, keywords = {{Electrochemistry, Spectroscopy, Surfaces and Interfaces, Condensed Matter Physics, General Materials Science}}, number = {{21}}, pages = {{12851--12858}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Molecular Recognition with 2,4-Diaminotriazine-Functionalized Colloids}}}, doi = {{10.1021/la202685e}}, volume = {{27}}, year = {{2011}}, } @article{25965, abstract = {{Nanoporous ZnO powders with high surface-to-mass ratios (SMR) between 15 and 70 m2 g−1 are synthesized, structurally characterized, and studied by time-resolved photoluminescence (PL). A strong dependence of the recombination dynamics and spectral width on SMR is observed at T = 10 K, and pronounced disorder-induced effects are found in the temperature dependence. Both the thermally induced shift of the PL maximum and the spectrally integrated PL intensity are interpreted by appropriate theoretical models. This consistent quantitative analysis of the experimental data yields a characteristic energy of 15 meV for the disorder scale in the nanoporous ZnO sample with an intermediate SMR.}}, author = {{Chernikov, Alexej and Horst, Swantje and Waitz, Thomas and Tiemann, Michael and Chatterjee, Sangam}}, issn = {{1932-7447}}, journal = {{The Journal of Physical Chemistry C}}, pages = {{1375--1379}}, title = {{{Photoluminescence Properties of Ordered Mesoporous ZnO}}}, doi = {{10.1021/jp104293e}}, year = {{2011}}, } @inproceedings{4312, abstract = {{The intensity dependence of optically-induced injection currents in semiconductor quantum wells is investigated numerically. Oscillatory behavior of the electron charge current transients as function of intensity and time is predicted and explained.}}, author = {{Pochwala, Michal and Duc, Huynh Thanh and Förstner, Jens and Meier, Torsten}}, booktitle = {{CLEO:2011 - Laser Applications to Photonic Applications}}, isbn = {{9781557529107}}, issn = {{2160-8989 }}, keywords = {{tet_topic_qw}}, location = {{Baltimore, Maryland (USA)}}, publisher = {{Optical Society of America}}, title = {{{Intensity dependence of optically-induced injection currents in semiconductor quantum wells}}}, doi = {{10.1364/qels.2011.qmk4}}, year = {{2011}}, } @inproceedings{4043, abstract = {{We present numerical results of the mutual coupling between photonic crystal cavities and semiconductor quantum dots. Normal mode splitting between a single cavity mode and a single quantum dot is shown under weak excitation, while under strong excitation Q‐factor dependent side bands appear, according to the AC‐Stark effect. Coupled photonic crystals, aligned parallel but displaced under a 30°‐angle for efficient coupling, show line splittings of all eigenmodes, if a single eigenmode is resonantly coupled to a single quantum dot. The mutual coupling of N resonant quantum dots to a single cavity mode results in a N−−√ scaling of the splitting, known from quantum optics, but corrected by the field amplitude fraction for not collocated quantum dots.}}, author = {{Declair, S. and Song, X. and Meier, Torsten and Förstner, Jens}}, booktitle = {{THE FOURTH INTERNATIONAL WORKSHOP 2011}}, keywords = {{tet_topic_phc, tet_topic_qd}}, location = {{Bad Honnef}}, number = {{123}}, pages = {{123--125}}, publisher = {{AIP}}, title = {{{Simulation of Mutual Coupling of Photonic Crystal Cavity Modes and Semiconductor Quantum Dots}}}, doi = {{10.1063/1.3644232}}, volume = {{1398}}, year = {{2011}}, } @article{44059, abstract = {{A novel adaptive wavelet based method is presented that allows us to compute eigenvalues and eigenvectors of the electronic Schrödinger equation. Our method outperforms direct discretization methods with equidistant grid spacings, in particular, for problems that involve several length scales. As an application we present numerical evaluations of the energetically lowest exciton states for ordered and disordered semiconductor quantum wires.}}, author = {{Meier, Torsten and Mollet, Christian and Kunoth, Angela}}, journal = {{AIP Conference Proceedings}}, number = {{1}}, pages = {{156--158}}, publisher = {{American Institute of Physics}}, title = {{{Wavelet‐Based Adaptive Computations of the Excitonic Eigenstates of Disordered Semiconductor Quantum Wires}}}, doi = {{10.1063/1.3644243}}, volume = {{1398}}, year = {{2011}}, } @inproceedings{4048, abstract = {{We present an ab-initio method for calculating nonlinear and nonlocal optical effects in metallic slabs with sub-wavelength thickness. We find a strong localization of the second-harmonic current at the metal-vacuum interface.}}, author = {{Wand, Mathias and Schindlmayr, Arno and Meier, Torsten and Förstner, Jens}}, booktitle = {{CLEO:2011 - Laser Applications to Photonic Applications }}, isbn = {{978-1-4577-1223-4}}, issn = {{2160-8989}}, keywords = {{tet_topic_shg}}, location = {{Baltimore, Maryland, United States}}, publisher = {{Optical Society of America}}, title = {{{Theoretical approach to the ultrafast nonlinear optical response of metal slabs}}}, doi = {{10.1364/CLEO_AT.2011.JTuI59}}, year = {{2011}}, } @article{25962, abstract = {{We report the correlation of the aging of Pd-doped SnO2 methane sensors with the change of the oxidation state of Pd. Mesoporous SnO2 doped with palladium species was prepared and exposed to different gas mixtures at high temperature (600 °C) to simulate long term usage. After each exposure step a fraction of the sample was cooled down to “freeze” the current oxidation state of Pd which was then analyzed by X-ray Absorption Near-Edge Spectroscopy (XANES) using the 'white line' (i.e. the absorption peak corresponding to the transition from the 2p3/2 core level to unoccupied 4 d states) intensity of the L(III) edge as a probe for the oxidation state. The Pd oxidation state correlates with the response of the resistive SnO2 sensor to methane gas, as determined by measuring the gas response to different concentrations of methane. Samples treated with 5000 ppm methane in air show a significant reduction of Pd(II) to Pd(0), depending clearly on the carrier gas (synthetic air, pure nitrogen) and on the temperature (600 °C vs. 300 °C).}}, author = {{Wagner, T. and Bauer, M. and Sauerwald, T. and Kohl, C.-D. and Tiemann, Michael}}, issn = {{0040-6090}}, journal = {{Thin Solid Films}}, pages = {{909--912}}, title = {{{X-ray absorption near-edge spectroscopy investigation of the oxidation state of Pd species in nanoporous SnO2 gas sensors for methane detection}}}, doi = {{10.1016/j.tsf.2011.04.187}}, year = {{2011}}, } @article{25964, abstract = {{Capacitive sensors are the most commonly used devices for the detection of humidity because they are inexpensive and the detection mechanism is very specific for humidity. However, especially for industrial processes, there is a lack of dielectrics that are stable at high temperature (>200 °C) and under harsh conditions. We present a capacitive sensor based on mesoporous silica as the dielectric in a simple sensor design based on pressed silica pellets. Investigation of the structural stability of the porous silica under simulated operating conditions as well as the influence of the pellet production will be shown. Impedance measurements demonstrate the utility of the sensor at both low (90 °C) and high (up to 210 °C) operating temperatures.}}, author = {{Wagner, Thorsten and Krotzky, Sören and Weiß, Alexander and Sauerwald, Tilman and Kohl, Claus-Dieter and Roggenbuck, Jan and Tiemann, Michael}}, issn = {{1424-8220}}, journal = {{Sensors}}, pages = {{3135--3144}}, title = {{{A High Temperature Capacitive Humidity Sensor Based on Mesoporous Silica}}}, doi = {{10.3390/s110303135}}, year = {{2011}}, } @article{25963, abstract = {{We report the synthesis of mesoporous tin dioxide (SnO2) materials with well-defined particle morphology. The products consist of uniform spheres with a diameter of 5 μm. The spheres are hierarchically porous with two distinct pore modes of 5.0 nm and 52 nm, respectively. This special porosity is the result of a synthesis procedure which involves a ‘hard templating’ (nanocasting) process. The product forms an approximately homogeneous monolayer of spheres on a sensor substrate and shows promising response to methane gas with low cross-sensitivity to water. The structural properties and gas-sensing performance are compared with a mesoporous SnO2 material without defined morphology, prepared by a ‘soft templating’ procedure.}}, author = {{Smått, J.-H. and Lindén, M. and Wagner, T. and Kohl, C.-D. and Tiemann, Michael}}, issn = {{0925-4005}}, journal = {{Sensors and Actuators B: Chemical}}, pages = {{483--488}}, title = {{{Micrometer-sized nanoporous tin dioxide spheres for gas sensing}}}, doi = {{10.1016/j.snb.2010.12.051}}, year = {{2011}}, } @article{25961, abstract = {{Mesoporous In2O3, synthesized by a nanocasting procedure, is used as a resistive gas sensor for ozone in very low concentrations (from 20 ppb to 2.4 ppm) at room temperature. Its sensing performance is substantially increased by illumination with blue light (460 nm, 2.7 eV). For low ozone concentrations the sensor response increases with increasing humidity. However, higher humidity also results in the occurrence of a saturation of the response at lower ozone concentrations; this is rationalized by assuming a poisoning of surface active sites by hydroxyl groups.}}, author = {{Wagner, T. and Hennemann, J. and Kohl, C.-D. and Tiemann, Michael}}, issn = {{0040-6090}}, journal = {{Thin Solid Films}}, pages = {{918--921}}, title = {{{Photocatalytic ozone sensor based on mesoporous indium oxide: Influence of the relative humidity on the sensing performance}}}, doi = {{10.1016/j.tsf.2011.04.181}}, year = {{2011}}, } @article{43259, abstract = {{The extreme nonlinear terahertz response of initially unexcited intrinsic semiconductor nanostructures is studied theoretically by solving extended semiconductor Bloch equations numerically. The coupled dynamics of intraband acceleration and multiphoton interband transitions leads to high-harmonic generation up to several tens of the exciting terahertz frequency. It is shown that the actual cut-off frequency is determined by the band structure and not by the excitation strength.}}, author = {{Golde, D. and Kira, M. and Meier, Torsten and Koch, S.W.}}, journal = {{physica status solidi (b)}}, number = {{4}}, pages = {{863--866}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Microscopic theory of the extremely nonlinear terahertz response of semiconductors}}}, doi = {{10.1002/pssb.201000840}}, volume = {{248}}, year = {{2011}}, } @inproceedings{44060, abstract = {{In recent years, single-walled carbon nanotubes (SWCNTs) have received widespread attention due to their perfect quasi-one-dimensional structure and unique physical properties, as well as their potential for applications. In the present work, we calculate the band structure of SWCNTs using an atomistic tight-binding model including spin-orbit interaction. We combine this approach with a many-particle calculation of the nonlinear optical response using multi-band semiconductor Bloch equations. We show that, for SWCNTs lacking inversion symmetry, the intrinsic spin-orbit interaction can give rise to single-color photoinduced charge and spin currents. In particular, we study the influence of excitonic effects on these photoinduced currents and draw the analogy to recent investigations on single-color injection of photocurrents in semiconductor quantum wells.}}, author = {{Meier, Torsten and Liu, Hong and Duc, Huynh Thanh and Schumache, Stefan}}, booktitle = {{75. Annual meeting of the DPG and combined DPG Spring meeting}}, issn = {{0420-0195}}, location = {{Dresden, Germany}}, number = {{1}}, title = {{{Photocurrents in semiconductor carbon nanotubes with spin-orbit interaction}}}, volume = {{46}}, year = {{2011}}, } @inproceedings{44062, abstract = {{Optical two-dimensional Fourier transform spectroscopy has been used to study the properties of semiconductor nanostructures in four-wave-mixing like experiments. Applying a phenomenological level model, we numerically and analytically analyze the main features of excitonic and biexcitonic contributions in a semiconductor quantum well by solving the optical Bloch equations. The method is extended to three-dimensional Fourier transform spectroscopy to investigate a recent experiment.}}, author = {{Meier, Torsten and Wiebeler, Christian and Reichelt, Matthias}}, booktitle = {{ 75. Annual meeting of the DPG and combined DPG Spring meeting }}, issn = {{0420-0195}}, location = {{Dresden, Germany}}, number = {{1}}, title = {{{Analysis of multidimensional Fourier transform spectroscopy for semiconductors with a phenomenological level model}}}, volume = {{46}}, year = {{2011}}, } @inproceedings{44061, abstract = {{If a two-level system is excited with an intense light field of several times the Rabi frequency, the well-known Mollow triplets appear in the emitted radiation spectrum. We show that the pattern of the emission spectrum can be changed by using appropriately shaped laser pulses. The effect is also observable for a more realistic description of a semiconductor system.}}, author = {{Meier, Torsten and Reichelt, Matthias and Walther, Andrea}}, booktitle = {{75. Annual meeting of the DPG and combined DPG Spring meeting}}, issn = {{0420-0195}}, location = {{ Dresden, Germany}}, number = {{1}}, title = {{{Extreme nonlinear optics in semiconductors with shaped laser pulses}}}, volume = {{46}}, year = {{2011}}, } @article{44962, author = {{Kohagen, M. and Brehm, Martin and Lingscheid, Y. and Giernoth, R. and Sangoro, J. and Kremer, F. and Naumov, S. and Iacob, C. and Kärger, J. and Valiullin, R. and Kirchner, B.}}, journal = {{J. Phys. Chem. B}}, pages = {{15280--15288}}, title = {{{How Hydrogen Bonds Influence the Mobility of Imidazolium-Based Ionic Liquids. A Combined Theoretical and Experimental Study of 1-n-Butyl-3-Methylimidazolium Bromide}}}, doi = {{10.1021/jp206974h}}, volume = {{115 (51)}}, year = {{2011}}, } @article{44959, author = {{Kohagen, M. and Brehm, Martin and Thar, J. and Zhao, W. and Müller-Plathe, F. and Kirchner, B.}}, journal = {{J. Phys. Chem. B}}, pages = {{693--702}}, title = {{{Performance of Quantum Chemically Derived Charges and Persistence of Ion Cages in Ionic Liquids. A Molecular Dynamics Simulations Study of 1-n-Butyl-3-Methylimidazolium Bromide}}}, doi = {{10.1021/jp109612k}}, volume = {{115 (4)}}, year = {{2011}}, } @article{44961, author = {{di Dio, P. J. and Brehm, Martin and Kirchner, B.}}, journal = {{J. Chem. Theory Comput.}}, pages = {{3035--3039}}, title = {{{Singular Value Decomposition for Analyzing Temperature- and Pressure-Dependent Radial Distribution Functions: Decomposition into Grund RDFs (GRDFs)}}}, doi = {{10.1021/ct2003385}}, volume = {{7 (10)}}, year = {{2011}}, }