Redox Self-Equilibration in Molecular Vanadium Oxide Mixtures Enables Multi-Electron Storage.

Polyoxometalates (POMs) are ideal components for reversible multi-electron storage in energy technologies. To-date, most redox-applications employ only single, individual POM species, which limits the number of electrons that can be stored within a given potential window. Here, we report that spontaneous redox self-equilibration during cluster synthesis leads to the formation of two structurally related polyoxovanadates which subsequently aggregate into co-crystals.

Coupled reaction equilibria enable the light-driven formation of metal-functionalized molecular vanadium oxides.

The introduction of metal sites into molecular metal oxides, so-called polyoxometalates, is key for tuning their structure and reactivity. The complex mechanisms which govern metal-functionalization of polyoxometalates are still poorly understood. Here, we report a coupled set of light-dependent and light-independent reaction equilibria controlling the mono- and di-metal-functionalization of a prototype molecular vanadium oxide cluster.

Mechanistic insights into template-driven polyoxovanadate self-assembly: the role of internal and external templates.

The self-assembly of molecular metal oxides, polyoxometalates (POMs), can be controlled using internal or, more rarely, external templates. Here, we explore how the interplay between internal templates (halides, oxoanions) and organic external templates (protonated cyclene species) affect the self-assembly of a model polyoxovanadate cluster, [VOX] (X = Cl, Br, NO). A combination of crystallographic analyses, spectroscopic studies and as well as solid-state V NMR spectroscopy provide critical insights into the initial formation of an intermediate vanadate species formed during the process.

Cation-controlled capture of polyoxovanadate-based organic-inorganic 1D architectures.

Metal cations are used to control the selective crystallization of organic-inorganic supramolecular polymers. Two complementary monomers, a dodecanuclear vanadate [VO(NO)] and the organic macrocycle cyclen assemble into hybrid host-guest aggregates. In the presence of Ba or La, supramolecular polymerization and crystallization is driven by a complex interplay of cyclene protonation, hydrogen-bonding and electrostatics.

The Diverse Landscape of Negative Polarity Items: On the Use of German NPIs as Experimental Diagnostics.

The goal of this study is to provide better empirical insight into the licensing conditions of a large set of NPIs in German so that they can be used as reliable diagnostics in future research on negation-related phenomena. Experiment 1 tests the acceptability of 60 NPIs under semantic operators that are expected to license superstrong, strong, weak, and nonveridicality-licensed NPIs, respectively: antimorphic (not), anti-additive (no), downward entailing (hardly), nonveridical (maybe, question). Controls were positive assertions.

About defect phenomena in ZnO nanocrystals.

ZnO nanocrystals are receiving renewed attraction due to their multifunctional properties. Selective enhancement and tuning of their optical and electrical properties are essential for achieving novel devices with accurate sensing and conducting capabilities. The nature and type of intrinsic defects that occur in ZnO influence these properties.

Hybrid Gold Nanoparticle-Polyoxovanadate Matrices: A Novel Surface Enhanced Raman/Surface Enhanced Infrared Spectroscopy Substrate.

Bare gold nanoparticles were embedded into an iron-polyoxovanadate matrix and used to enhance both the infrared and Raman signatures of a model analyte. A detailed characterization of the matrix-embedded nanoparticles revealed that they retained a plasmon resonance at 564 nm. The enhancement of vibrational signatures of the model analyte crystal violet using bare and embedded gold nanoparticles was compared for both surface enhanced infrared (SEIRA) spectroscopy and surface enhanced Raman spectroscopy (SERS) yielding enhancement factors of 2.

Hybrid Analytical Platform Based on Field-Asymmetric Ion Mobility Spectrometry, Infrared Sensing, and Luminescence-Based Oxygen Sensing for Exhaled Breath Analysis.

The reliable online analysis of volatile compounds in exhaled breath remains a challenge, as a plethora of molecules occur in different concentration ranges (i.e., ppt to %) and need to be detected against an extremely complex background matrix.

The Prosody of -exclamatives and -questions in German: Speech Act Differences, Information Structure, and Sex of Speaker.

The prosody of non-assertive speech acts other than questions is rather underexplored. Very little is known about the role of information structure in non-assertive speech acts in general. The present study presents two production experiments examining the prosody of string-identical verb-second (experiment 1) and verb-final (experiment 2) -exclamatives and -questions in German in relation to their status as different speech acts, in relation to their sensitivity to information structure, and in relation to speaker sex.

Superbat: battery-like supercapacitor utilized by graphene foam and zinc oxide (ZnO) electrodes induced by structural defects.

The current work presents a hybrid type of energy storage device composed of both graphene foam and zinc oxide electrodes, which exhibits both the electrochemical performance of a supercapacitor with a relatively higher power density, and a battery with a relatively higher energy density as compared to each individual component as single devices. Te hybrid's improved performance was correlated to the defective structure of the electrodes. To enhance the electrochemical performance of supercapacitors, it is necessary to have a well-defined mass, shape, and surface area of electrode materials.

Synergetic effects of Fe doped spinel LiTiO nanoparticles on reduced graphene oxide for high surface electrode hybrid supercapacitors.

In this work, reduced graphene oxide (rGO) based electrode materials were developed to achieve a hybrid supercapacitor (SC) function. Therefore, several synthesis methods were developed to prepare a cost effective and environmentally friendly rGO. Additionally, to maintain the high surface area, spinel lithium titanate (sLTO) nanoparticles (NPs) were synthesized and deposited on the rGO surface to inhibit the restacking of the rGO layers on graphite.

High-Capacitance Hybrid Supercapacitor Based on Multi-Colored Fluorescent Carbon-Dots.

Multi-colored, water soluble fluorescent carbon nanodots (C-Dots) with quantum yield changing from 4.6 to 18.3% were synthesized in multi-gram using dated cola beverage through a simple thermal synthesis method and implemented as conductive and ion donating supercapacitor component.

Charge transfer and surface defect healing within ZnO nanoparticle decorated graphene hybrid materials.

To harness the unique properties of graphene and ZnO nanoparticles (NPs) for novel applications, the development of graphene-ZnO nanoparticle hybrid materials has attracted great attention and is the subject of ongoing research. For this contribution, graphene-oxide-ZnO (GO-ZnO) and thiol-functionalized reduced graphene oxide-ZnO (TrGO-ZnO) nanohybrid materials were prepared by novel self-assembly processes. Based on electron paramagnetic resonance (EPR) and photoluminescence (PL) investigations on bare ZnO NPs, GO-ZnO and TrGO-ZnO hybrid materials, we found that several physical phenomena were occurring when ZnO NPs were hybridized with GO and TrGO.

A microwave molecular solution based approach towards high-κ-tantalum(V)oxide nanoparticles: synthesis, dielectric properties and electron paramagnetic resonance spectroscopic studies of their defect chemistry.

Stable dispersions of tantalum oxide nanoparticles are accessible from solutions of tantalum(V) complexes with a mixed malonato and alkanolato ligand sphere in ethoxyethanol by microwave processing. The malonato ligand is cleaved during decomposition and acetic acid or acetic acid esters are formed as derived from in situ spectroscopic studies. The solubility of the tantalum precursor and the obtained particle size therefrom depend strongly on the type of alkanolato ligand moiety.

Controlling the exciton energy of zinc oxide (ZnO) quantum dots by changing the confinement conditions.

ZnO nanoparticles were synthesized by solid state and hydrolysis methods based on the conventional precipitation. In situ growth of ZnO nanoparticles were monitored by photoluminescence spectroscopy (PL). By the help of electron paramagnetic resonance (EPR) technique, detailed analysis of intrinsic defect structure of ZnO was given with respect to mean particle size.