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Full-Text Articles in Engineering

Using The Inelastic Background In Hard X-Ray Photoelectron Spectroscopy For A Depth-Resolved Analysis Of The Cds / Cu(In,Ga)Se < Inf > 2 < / Inf > Interface, Dirk Hauschild, Ralph Steininger, Dimitrios Hariskos, Wolfram Witte, Sven Tougaard, Clemens Heske, Lothar Weinhardt Dec 2021

Using The Inelastic Background In Hard X-Ray Photoelectron Spectroscopy For A Depth-Resolved Analysis Of The Cds / Cu(In,Ga)Se < Inf > 2 < / Inf > Interface, Dirk Hauschild, Ralph Steininger, Dimitrios Hariskos, Wolfram Witte, Sven Tougaard, Clemens Heske, Lothar Weinhardt

Chemistry and Biochemistry Faculty Research

The inelastic background of hard x-ray photoelectron spectroscopy data is analyzed to paint a depth-resolved picture of the CdS/Cu(In,Ga)Se2 (CdS/CIGSe) layer structure. The CdS/CIGSe interface is the central component in next-generation chalcopyrite thin-film photovoltaic devices. By analyzing both, the (unscattered) core-level peaks and the inelastic background, and by varying the excitation photon energy from 2.1 up to 14 keV, we can derive photoemission information over a broad range of electron kinetic energies and, hence, sampling depths. With this complementary information, the CdS film thickness of a CdS/CIGSe interface can be accurately determined as a function of the CdS deposition time. …


Coupling Methylammonium And Formamidinium Cations With Halide Anions: Hybrid Orbitals, Hydrogen Bonding, And The Role Of Dynamics, Chinnathambi Kamal, Dirk Hauschild, Linsey Seitz, Ralph Steininger, Wanli Yang, Clemens Heske, Lothar Weinhardt, Michael Odelius Nov 2021

Coupling Methylammonium And Formamidinium Cations With Halide Anions: Hybrid Orbitals, Hydrogen Bonding, And The Role Of Dynamics, Chinnathambi Kamal, Dirk Hauschild, Linsey Seitz, Ralph Steininger, Wanli Yang, Clemens Heske, Lothar Weinhardt, Michael Odelius

Chemistry and Biochemistry Faculty Research

The electronic structures of four precursors for organic-inorganic hybrid perovskites, namely, methylammonium chloride and iodide, as well as formamidinium bromide and iodide, are investigated by X-ray emission (XE) spectroscopy at the carbon and nitrogen K-edges. The XE spectra are analyzed based on density functional theory calculations. We simulate the XE spectra at the Kohn-Sham level for ground-state geometries and carry out detailed analyses of the molecular orbitals and the electronic density of states to give a thorough understanding of the spectra. Major parts of the spectra can be described by the model of the corresponding isolated organic cation, whereas high-emission …


Aerobic Copper-Promoted Oxidative Dehydrosulfurative Carbon-Oxygen Cross-Coupling Of 3,4-Dihydropyrimidine-1: H -2-Thiones With Alcohols, Jihong Lee, Yujeong Kwon, Dong-Chan Lee, Jeong Hun Sohn Nov 2021

Aerobic Copper-Promoted Oxidative Dehydrosulfurative Carbon-Oxygen Cross-Coupling Of 3,4-Dihydropyrimidine-1: H -2-Thiones With Alcohols, Jihong Lee, Yujeong Kwon, Dong-Chan Lee, Jeong Hun Sohn

Chemistry and Biochemistry Faculty Research

An aerobic Cu-promoted oxidative dehydrosulfurative carbon-oxygen cross-coupling of 3,4-dihydropyrimidin-1H-2-thiones (DHPMs) with both aliphatic and aromatic alcohols is described. Together with the ready availability of DHPMs and both alcohols, the method furnishes facile access to biologically valuable 2-alkoxypyrimidines with rapid diversification.


Modifications Of The Cztse/Mo Back-Contact Interface By Plasma Treatments, Wenjin Chen, Teoman Taskesen, David Nowak, Ulf Mikolajczak, Mohamed H. Sayed, Devendra Pareek, Jorg Ohland, Thomas Schnabel, Erik Ahlswede, Dirk Hauschild, Lothar Weinhardt, Clemens Heske, Jurgen Parisi, Levent Gutay Aug 2019

Modifications Of The Cztse/Mo Back-Contact Interface By Plasma Treatments, Wenjin Chen, Teoman Taskesen, David Nowak, Ulf Mikolajczak, Mohamed H. Sayed, Devendra Pareek, Jorg Ohland, Thomas Schnabel, Erik Ahlswede, Dirk Hauschild, Lothar Weinhardt, Clemens Heske, Jurgen Parisi, Levent Gutay

Chemistry and Biochemistry Faculty Research

Molybdenum (Mo) is the most commonly used back-contact material for copper zinc tin selenide (CZTSe)-based thin-film solar cells. For most fabrication methods, an interfacial molybdenum diselenide (MoSe2) layer with an uncontrolled thickness is formed, ranging from a few tens of nm up to ≈1 μm. In order to improve the control of the back-contact interface in CZTSe solar cells, the formation of a MoSe2 layer with a homogeneous and defined thickness is necessary. In this study, we use plasma treatments on the as-grown Mo surface prior to the CZTSe absorber formation, which consists of the deposition of stacked metallic layers …


Phosphine Oxide Containing Poly(Pyridinium Salt)S As Fire Retardant Materials, Maksudul M. Alam, Bidyut Biswas, Alexi K. Nedeltchev, Haesook Han, Asanga D. Ranasinghe, Pradip K. Bhowmik, Kisholoy Goswami Jul 2019

Phosphine Oxide Containing Poly(Pyridinium Salt)S As Fire Retardant Materials, Maksudul M. Alam, Bidyut Biswas, Alexi K. Nedeltchev, Haesook Han, Asanga D. Ranasinghe, Pradip K. Bhowmik, Kisholoy Goswami

Chemistry and Biochemistry Faculty Research

Six new rugged, high-temperature tolerant phosphine oxide-containing poly(4,4′-(p-phenylene)-bis(2,6-diphenylpyridinium)) polymers P-1, P-2, P-3, P-4, P-5, and P-6 are synthesized, characterized, and evaluated. Synthesis results in high yield and purity, as confirmed by elemental, proton (1H), and carbon 13 (13C) nuclear magnetic resonance (NMR) spectra analyses ... See full text for complete abstract.


Copper Complexation By Dissolved Organic Matter In Arid Soils: A Voltametric Study, Spencer M. Steinberg, Vernon F. Hodge Nov 2018

Copper Complexation By Dissolved Organic Matter In Arid Soils: A Voltametric Study, Spencer M. Steinberg, Vernon F. Hodge

Chemistry and Biochemistry Faculty Research

A voltammetric method was used to estimate the complexing capacity of water extracts from both desert soils sampled at the root zone of creosote and salt cedar plants, and in soils from interspace or background regions where no vegetative influence was apparent. The copper complexing capacity of water extracts of these desert soils was influenced by contact time and pH. In soils from the root zones of creosote and salt cedar plant, copper complexation capacities at pH 8 were from 5 µM to 60 µM after five min contact periods, while 18 h contact periods yielded copper complexation capacities of …


Yttrium And Hydrogen Superstructure And Correlation Of Lattice Expansion And Proton Conductivity In The Bazr0.9y0.1o2.95 Proton Conductor, A. Braun, A. Ovalle, V. Pomjakushin, A. Cervellino, S. Erat, Wayne C. Stolte, T. Graule Jan 2009

Yttrium And Hydrogen Superstructure And Correlation Of Lattice Expansion And Proton Conductivity In The Bazr0.9y0.1o2.95 Proton Conductor, A. Braun, A. Ovalle, V. Pomjakushin, A. Cervellino, S. Erat, Wayne C. Stolte, T. Graule

Chemistry and Biochemistry Faculty Research

Bragg reflections in Y-resonant x-ray diffractograms of BaZr0.9Y0.1O2.95 (BZY10) reveal that Y is organized in a superstructure. Comparison with neutron diffraction superstructure reflections in protonated/deuterated BZY10 suggests that both superstructures are linked, and that protons move in the landscape imposed by the Y. The thermal lattice expansion decreases abruptly for protonated BZY10 at T≥648±20 K, coinciding with the onset of lateral proton diffusion and suggesting a correlation of structural changes and proton conductivity. The chemical shift in the Y L1-shell x-ray absorption spectra reveals a reduction from Y3+ toward Y2+ upon …