Publications by authors named "Elen K"

Monoclinic vanadium dioxide (VO (M)) is a promising material for various applications ranging from sensing to signature management and smart windows. Most applications rely on its reversible structural phase transition to rutile VO (VO (R)), which is accompanied by a metal-to-insulator transition. Bottom-up hydrothermal synthesis has proven to yield high quality monoclinic VO but requires toxic and highly reactive reducing agents that cannot be used outside of a research lab.

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This work introduces a polymeric backbone eutectogel (P-ETG) hybrid solid-state electrolyte with an -isopropylacrylamide (NIPAM) backbone for high-energy lithium-ion batteries (LIBs). The NIPAM-based P-ETG is (electro)chemically compatible with commercially relevant positive electrode materials such as the nickel-rich layered oxide LiNiMnCoO (NMC622). The chemical compatibility was demonstrated through (physico)chemical characterization methods.

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Quasi-spherical undoped ZnO and Al-doped ZnO nanoparticles with different aluminum content, ranging from 0.5 to 5 at% of Al with respect to Zn, were synthesized. These nanoparticles were evaluated as photocatalysts in the photodegradation of the Rhodamine B (RhB) dye aqueous solution under UV-visible light irradiation.

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This study reports the low temperature and low pressure conversion (up to 160 °C, = 3.5 bar) of CO and H to CO using plasmonic Au/TiO nanocatalysts and mildly concentrated artificial sunlight as the sole energy source (up to 13.9 kW·m = 13.

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The recent cost-driven transition from silver- to copper-based inks for printing on flexible substrates is connected with new key challenges. Given the high oxidation sensitivity of copper inks before, during, and after the curing process, the conductivity and thereby the device performance can be affected. Strategies to limit or even avoid this drawback include the development of metal organic decomposition (MOD) inks with selected "protective" ligands.

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Methane, which has a high energy storage density and is safely stored and transported in our existing infrastructure, can be produced through conversion of the undesired energy carrier H with CO. Methane production with standard transition-metal catalysts requires high-temperature activation (300-500 °C). Alternatively, semiconductor metal oxide photocatalysts can be used, but they require high-intensity UV light.

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Fast and scalable low-temperature deposition of microscale metallic features is of utmost importance for the development of future flexible smart applications including sensors, wireless communication, and wearables. Recently, a new class of metal-organic decomposition (MOD) copper inks was developed, consisting of self-reducing copper formate containing amine complexes. From these novel inks, copper metal features with outstanding electrical conductivity (±10 S cm) are deposited at a temperature of 150 °C or less, which is well below the reduction temperature of orthorhombic α-copper formate (around 225 °C).

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Silver nanowire networks have demonstrated significant potential as semi-transparent electrodes for various applications. However, for their widespread utilisation in devices, upscaled coating technologies such as screen-printing need to be explored and related to this, the formulation of suitable inks is indispensable. This work contributes to this effort by the synthesis of Ag-NW based formulations.

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A combined experimental and first-principles study is performed to study the origin of conductivity in ZnO:Al nanoparticles synthesized under controlled conditions via a reflux route using benzylamine as a solvent. The experimental characterization of the samples by Raman, nuclear magnetic resonance (NMR) and conductivity measurements indicates that upon annealing in nitrogen, the Al atoms at interstitial positions migrate to the substitutional positions, creating at the same time Zn interstitials. We provide evidence for the fact that the formed complex of Al and Zn corresponds to the origin of the Knight shifted peak (KS) we observe in Al NMR.

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By ultrasonic spray deposition of precursors, conformal deposition on 3D surfaces of tungsten oxide (WO₃) negative electrode and amorphous lithium lanthanum titanium oxide (LLT) solid-electrolyte has been achieved as well as an all-solid-state half-cell. Electrochemical activity was achieved of the WO₃ layers, annealed at temperatures of 500 °C. Galvanostatic measurements show a volumetric capacity (415 mAh·cm) of the deposited electrode material.

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The identification, fine-tuning, and process optimization of appropriate hole transporting layers (HTLs) for organic solar cells is indispensable for the production of efficient and sustainable functional devices. In this study, the optimization of a solution-processed molybdenum oxide (MoOx) layer fabricated from a combustion precursor is carried out via the introduction of zirconium and tin additives. The evaluation of the output characteristics of both organic photovoltaic (OPV) and organic light emitting diode (OLED) devices demonstrates the beneficial influence upon the addition of the Zr and Sn ions compared to the generic MoOx precursor.

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Integration of electronic circuit components onto flexible materials such as plastic foils, paper and textiles is a key challenge for the development of future smart applications. Therefore, conductive metal features need to be deposited on temperature sensitive substrates in a fast and straightforward way. The feasibility of these emerging (nano-) electronic technologies depends on the availability of well-designed deposition techniques and on novel functional metal inks.

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In this paper a 2(8-4) fractional factorial design of experiments is applied to identify the important parameters that affect the average diameter of ZnO rods, synthesized by means of a hydrothermal procedure. A water-based Zn(2+) precursor is used for the formation of one-dimensional ZnO particles, without the presence of an organic additive. Results indicate that, at the investigated levels, four of the parameters have a significant effect on the mean diameter.

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The effect of structural factors on the stability of duplexes formed by DNA minor groove binders conjugated with oligonucleotide mono- or diphosphoramidates of the general formula Oligo-MGBm (where Oligo is an oligonucleotide; m = 1 or 2; MGB is -L(Py)2R, L(Py)4R, -L(Im)4R, or -L(Py)4NH(CH2)3CO(Py)4R; Py is a 4-aminopyrrol-2-carboxylic acid residue, L is a gamma-aminobutyric acid or an epsilon-aminocaproic acid residue, R = OEt, NH(CH2)6NEt2, or NH(CH2)6N+Me3) was studied by the method of thermal denaturation. The mode of binder interaction with minor groove depends on the conjugate structure; it may be of the parallel head to head type for bisphosphoramidates and of the antiparallel head to tail type for monophosphoramidates of a hair-pin structure. The effects of the duplexes with parallel orientation (bisphosphoramidates, MGB is L(Py)4R, m = 2) and those of the hairpin structure with the antiparallel orientation (monophosphoramidates, MGB is L(Py)4(CH2)3CO(Py)4R, m = 1) on Tm values were close.

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