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One-pot synthesis of 3D Cu <sub/>2</sub> S–MoS <sub/>2</sub> nanocomposites by an ionic liquid-assisted strategy with high photocatalytic activity
摘要： Novel 3D Cu2S–MoS2(x : y) nanocomposites with different proportions of Cu2S (x) and MoS2 (y) are synthesized successfully by a one-step hydrothermal method with the assistance of the ionic liquid [BMIM]SCN. The characterization results show that the nanocomposites are self-assembled from nanosheets of Cu2S and MoS2, they display nanoflower morphology and a typical mesoporous structure. The fabrication mechanism of the nanocomposites is investigated using time-dependent experiments, which indicate the key role of the ionic liquid (IL) in the synthesis process. Furthermore, TAA is used as a sulfur source instead of the IL to form a Cu2S–MoS2 nanocomposite, with the aim of further investigating the effects of the IL on the morphology of the composite. Photodegradation of MB under visible light irradiation experiments were used as probe reactions to evaluate the photocatalytic performance of the as-prepared samples. All the nanocomposites show better catalytic activity than Cu2S and MoS2 monomers. Among the different Cu2S–MoS2(x : y) nanocomposites, the Cu2S–MoS2(1 : 1) composite exhibits the most excellent photocatalytic performance and cycling stability.
关键词： Cu2S–MoS2 nanocomposites,hydrothermal synthesis,photocatalytic activity,ionic liquid,methylene blue degradation
更新于2025-11-14 17:04:02
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Percolation Effects in Electrolytically-Gated WS <sub/>2</sub> /Graphene Nano:Nano Composites
摘要： Mixed networks of conducting and non-conducting nanoparticles show promise in a range of applications where fast charge transport is important. While the dependence of network conductivity on the conductive mass fraction (Mf) is well understood, little is known about the Mf-dependence of mobility and carrier density. This is particularly important as the addition of graphene might lead to increases in the mobility of semiconducting nanosheet-network transistors. Here, we use electrolytic gating to investigate the transport properties of spray-coated composite networks of graphene and WS2 nanosheets. As the graphene Mf is increased, we find both conductivity and carrier density to increase in line with percolation theory with percolation thresholds (~8 vol%) and exponents (~2.5) consistent with previous reporting. Perhaps surprisingly, we find the mobility increases modestly from ~0.1 cm2/Vs (for a WS2 network) to ~0.3 cm2/Vs (for a graphene network) which we attribute to the similarity between WS2-WS2 and graphene-graphene junction resistances. In addition, we find both the transistor on- and off-currents to scale with Mf according to percolation theory, changing sharply at the percolation threshold. Through fitting, we show that only the current in the WS2 network changes significantly upon gating. As a result, the on-off ratio falls sharply at the percolation threshold from ~104 to ~2 at higher Mf. Reflecting on these results, we conclude that the addition of graphene to a semiconducting network is not a viable strategy to improve transistor performance as it reduces the on:off ratio far more than it improves the mobility.
关键词： graphene,ionic liquid,thin film transistor,WS2,carrier density,composite,mobility,Printed electronics
更新于2025-10-22 19:40:53
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Hydrophilic Poly(vinylidene Fluoride) Film with Enhanced Inner Channels for Both Water- and Ionic Liquid-Driven Ion-Exchange Polymer Metal Composite Actuators
摘要： This study presents a novel and facile strategy to fabricate a hydrophilic poly(vinylidene fluoride) (PVDF) electrolyte film with enhanced inner channels for a high-performance and cost-effective ion-exchange polymer metal composite (IPMC) actuator. The resultant PVDF composite film is composed of hierarchical micro/nanoscale structures: well-defined polymer grains with a diameter of ～20 μm and much finer particles with a diameter of ～390 nm, producing three-dimensional interconnected, hierarchical inner channels to facilitate ion migration of the electrolyte matrix film has a high porosity of 15.8% and yields a high water uptake of 44.2% and an ionic liquid (IL, [EMIm]·[BF4]) uptake of 38.1% to make both water-driven and IL-driven IPMC actuators because of the introduction of polar polyvinyl pyrrolidone. Compared to the conventional PVDF/IL-based IPMC, both water-driven and IL-driven PVDF-based IPMCs exhibit high ion migration rates, thus effectively improving the actuation frequency and producing remarkably higher levels of actuation force and displacement. Specifically, the force outputs are increased by 13.4 and 3.0 folds, and the displacement outputs are increased by 2.2 and 1.9 folds. Using an identical electrolyte matrix, water-driven IPMC exhibits stronger electromechanical performance, benefiting to make IPMC actuator with high levels of force and power outputs, whereas IL-driven IPMC exhibits a more stable electromechanical performance, benefiting to make long lifetime IPMC actuator in air. Thus, the resultant IPMCs are promising in the design of artificial muscles with tunable electromechanical performance for flexible actuators or displacement/vibration sensors at low cost.
关键词： ionic exchange polymer metal composite (IPMC),ionic liquid (IL),poly(vinylidene fluoride) (PVDF),inner channel,electromechanical response,polyvinyl pyrrolidone (PVP)
更新于2025-09-23 15:23:52
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Formation of zirconia precursor nanoplates mediated by ionic liquid and transformation to monoclinic ZrO <sub/>2</sub> nanostructures
摘要： The [Zr(OH)5]– imidazolium complex was used to synthesize a zirconia precursor with plate-like nanostructure hydrolyzed under strong acid conditions, which was characterized by means of powder X-ray diffraction, thermogravimetric-differential scanning calorimetry, Fourier transform infrared spectroscopy, Raman spectroscopy, elemental analysis, inductively coupled plasma and electronic differential system. The zirconia precursor can be transformed to monoclinic ZrO2 by annealing at a temperature above 400 °C. With the increasing of the curing temperature, it tended to give rise to porous ZrO2 nanostructures.
关键词： Zirconia precursor,Zirconium oxide,Anion exchange reaction,Nanoplate,Ionic liquid
更新于2025-09-23 15:22:29
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Electric-Field Control of Dirac Two-Dimensional Electron Gas in PbTe/CdTe Heterostructures
摘要： Two-dimensional electron gases (2DEGs) confined to quantum wells trigger rich emergent phenomena and serve as a host for high-speed electronics. 2DEG in PbTe/CdTe heterostructure was predicted to be Dirac electrons and confirmed by recent experiments. Here, we demonstrate the manipulation of electrical transport properties of this 2DEG with extremely high mobility and unique electron structure by ionic liquid-gating. The extreme capacitance of carrier modulation enables to tune the band structure. With a change of the gate voltage, the Fermi level moves to the conduction band and crosses the Dirac Point, leading to the shift of quantum oscillation. Our results may offer new insight toward electronic application with on-demand properties.
关键词： Fermi surface,molecular beam epitaxy,ionic liquid gating,quantum oscillation,two-dimensional electron gas
更新于2025-09-23 15:22:29
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Photostable soft materials with tunable emission
摘要： Herein we present a synthesis of ionic liquid imidazole-based cations with appended sulfone as terminals. These structures are investigated by RMN (2D), XDR, FTIR and Raman; and show high yield; purity; melting point < 95 °C associated with thermal stability up to 239 °C; chemical stability in water and common organic solvents; and highlighted white light emission. We employed the IL as building blocks in coordination chemistry with ions Gd3+, Eu3+, and Tb3+ to elaborate translucent, luminescent and photostable soft materials. Coordination compounds were characterized by vibrational spectroscopy (FTIR/Raman), UV-vis and photoluminescence spectroscopy. Gd3+, Eu3+, Tb3+(IL)3(H2O)3 complexes display great lifetime >1.6 ms, quantum efficiency > 77%, narrow linewidth, a high degree of color purity and tunable emission. These excellent photophysical properties, associated with soft materials processability, make these materials potentially applicable in the development of luminescent films as OLEDs. We provide data for a detailed study of photoluminescence based on the theories developed by Malta-Judd-Ofelt.
关键词： europium,gadolinium,terbium,ionic liquid
更新于2025-09-23 15:22:29
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Boronic ester-based dynamic covalent ionic liquid gels for self-healable, recyclable and malleable optical devices
摘要： Dynamic covalent ionic liquid (IL) gels have been proved to be promising materials for soft optical devices which possess the advantages of other dynamic gels but avoid shrinking. The focal length of the planoconvex lens made from the gels is tunable and the prism from them shows an excellent beam splitting property. Damaged devices could be re-covered via self-healing or re-molding.
关键词： malleable optical devices,recyclable,Boronic ester,dynamic covalent ionic liquid gels,self-healable
更新于2025-09-23 15:21:21
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The role of ionic liquid breakdown in the electrochemical metallization of VO <sub/>2</sub> : An NMR study of gating mechanisms and VO <sub/>2</sub> reduction
摘要： Metallization of initially insulating VO2 via ionic liquid electrolytes, otherwise known as electrolyte gating, has recently been a topic of much interest for possible applications such as Mott transistors and memory devices. It is clear that the metallization takes place electrochemically and, in particular, there has previously been extensive evidence for the removal of small amounts of oxygen during ionic liquid gating. Hydrogen intercalation has also been proposed, but the source of the hydrogen has remained unclear. In this work, solid-state magic angle spinning NMR spectroscopy (1H, 2H, 17O and 51V) is used to investigate the thermal metal-insulator transition in VO2, before progressing to catalytically hydrogenated VO2 and electrochemically metallized VO2. In these experiments electrochemical metallization of bulk VO2 particles is shown to be associated with intercalation of hydrogen, the degree of which can be measured with quantitative 1H NMR spectroscopy. Possible sources of the hydrogen are explored, and by using a selectively deuterated ionic liquid, it is revealed that the hydrogenation is due to deprotonation of the ionic liquid; specifically, for the commonly used dialkyl-imidazolium based ionic liquids, it is the “carbene” proton which is responsible. Increasing the temperature of the electrochemistry is shown to increase the degree of hydrogenation, forming first a less hydrogenated metallic orthorhombic phase then a more hydrogenated insulating Curie-Weiss paramagnetic orthorhombic phase, both of which were also observed for catalytically hydrogenated VO2. The NMR results are supported by magnetic susceptibility measurements, which corroborate the degree of Pauli and Curie-Weiss paramagnetism. Finally, NMR spectroscopy is used to identify the presence of hydrogen in an electrolyte gated thin film of VO2, suggesting that electrolyte breakdown, proton intercalation and reactions with decomposition products within the electrolyte should not be ignored when interpreting the electronic and structural changes observed in electrochemical gating experiments.
关键词： metal-insulator transition,hydrogen intercalation,VO2,NMR spectroscopy,electrolyte gating,ionic liquid
更新于2025-09-23 15:21:21
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Dynamic Interplay between Transport and Reaction Kinetics of Luminophores on the Operation of AC-driven Electrochemiluminescence Devices
摘要： Electrochemiluminescence (ECL) involves light emission accompanied by a series of electrochemical processes on luminophores, which has been recently exploited in a new light-emitting device platform, referred to as the ECL device (ECLD). Here, we investigate the influence of the transport of the ECL luminophores and their reaction kinetics on the emission properties of AC-voltage-driven ECLDs. A model based on the diffusion and reaction rate equations is developed to predict the operational frequency (f)-dependent luminance properties of the ECLD. It is found that more frequent generation of the redox precursors with a shorter time interval enhances their probability of encountering each other, and therefore, the luminance of the device increases with increasing f initially. The luminance at a higher f, however, is suppressed eventually due to the decreased rate of the electrode reactions. Using the model, the influence of diffusion and reaction rates on the performance of an ECLD is analyzed separately and systematically. The results provide insight on the operation of this emerging class of light-emitting device platform.
关键词： electrochemiluminescence,ionic transition metal complex,reaction kinetics,mass transport,ionic liquid,light-emitting device
更新于2025-09-23 15:21:01
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Solvation of quantum dots in 1-alkyl-1-methylpyrrolidinium ionic liquids: toward stably luminescent composites
摘要： CdTe nanoparticles capped with a cationic thiolate ligand were stably dispersed in ionic liquids, 1-alkyl-1-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)amides with an alkyl group of n-propyl, butyl and octyl-chain, and in an ionic plastic crystal, 1-ethyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide. Dispersion behavior of CdTe nanoparticles in these ionic media was evaluated, in which the solvation of nanoparticles by the ionic components was particularly interested. The ionic media showed alkyl-chain length-dependent solvation behavior, which was suggested by the thermal analysis of nanocomposites. The longer alkyl-chains led to the greater decrease in the thermal melting enthalpy of ionic media with the introduction of nanoparticles. The ionic liquid with an octyl-chain, which is considered to form a thicker solvation layer, afforded better emission durability of CdTe nanoparticles compared to the ionic liquid with a shorter alkyl chain.
关键词： ionic liquid,photoluminescence,semiconductor,nanoparticles,solvation
更新于2025-09-23 15:21:01