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Superfast, Porous and Organic Solvent Sensitive Actuator Based on EVOH Nanofibrous Membrane and PS Microspheres
摘要： Despite much progress in solvent-sensitive actuators, most of the actuators are sensitive to water, ethanol or acetone with low responsive speed and small curvature. Herein, a simple approach was introduced to fabricate a new solvent-sensitive bilayer actuator consisting of poly(vinyl alcohol-co-ethylene) (EVOH) nanofibrous membrane and polystyrene (PS) microspheres. The actuator showed superfast and multi-stimulus responsive ability to organic vapors of toluene, chloroform, THF and acetone. With solvents stimulation, the difference in swelling degree between the EVOH layer and PS microspheres layer contributed to the asymmetric expansions or contractions of two layers, therefore resulting in the mechanical deformation of the actuator. The flexible and porous EVOH nanofibrous membrane, as well as the spherical PS could improve the response rate and deformation scale. This bilayer actuator could bend quickly into a multi-coil with the curvature of 21.02 cm-1 within 0.15 s in response to toluene vapor, and the bending-unbending process could repeat more than 150 times when the deformation degree was controlled by cross-linking PS microspheres with divinylbenzene (DVB). This study will provide an important insight for the development of new solvent-sensitive devices and applications in volatile organic compounds detecting.
关键词： PS microspheres,EVOH nanofibrous membrane,multi-stimulus responsive,organic vapors,solvent-sensitive actuators
更新于2025-09-09 09:28:46
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Optimization of the liquid–liquid interfacial precipitation method for the synthesis of $$\hbox {C}_{60}$$C60 nanotubes
摘要： Tubular fullerene nanowhiskers called ‘fullerene nanotubes’ are composed of C60 fullerene molecules (C60 NTs) are synthesized at room temperature using the liquid–liquid interfacial precipitation method in the pyridine and isopropyl alcohol (IPA) system. The growth control of fullerene nanotubes is important for their chemical and physical properties as well as for their future applications. In the present study, we investigated the effect of light, water, solvent ratio and temperature on the synthesis of C60 nanotubes. A marked development in the yield of C60 NTs was achieved using dehydrated solvents, a solution with a volume ratio of 1:9 for pyridine: IPA, a growth temperature equal to 5?C and by illuminating the C60-pyridine solution with ultraviolet light (wavelength 302 nm) for 102 h. The synthesized fullerene nanotubes were characterized by different analytical techniques including Raman and Fourier transform infrared spectroscopy, optical microscopy, focussed ion beam scanning electron microscopy and transmission electron microscopy.
关键词： solution growth,liquid–liquid interfacial precipitation method,light,temperature,solvent,Fullerene nanotubes
更新于2025-09-09 09:28:46
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Ultrafast THz photophysics of solvent engineered triple-cation halide perovskites
摘要： Solution processed thin film organic-inorganic perovskites are key to the large scale manufacturing of next generation wafer scale solar cell devices. The high efficiency of the hybrid perovskite solar cells is derived mainly from the large carrier mobility and the charge dynamics of films, which heavily depend on the type of solvent used for the material preparation. Here, we investigate the nature of conduction and charge carrier dynamics of mixed organic-inorganic cations [methylammonium (MA), formamidinium (FA), and cesium (Cs)] along with the mixed halides [iodine (I) and bromine (Br)] perovskite material [Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3] synthesized in different solvents using optical pump terahertz probe (OPTP) spectroscopy. Our findings reveal that carrier mobilities and diffusion lengths strongly depend on the type of solvent used for the preparation of the mixed cation perovskite film. The mixed cation perovskite film prepared using dimethylformamide/dimethylsulfoxide solvent shows greater mobility and diffusion length compared to γ-butyrolactone solvent. Our findings provide valuable insights to improve the charge carrier transport in mixed cation perovskites through solvent engineering.
关键词： charge carrier dynamics,OPTP spectroscopy,diffusion length,perovskites,carrier mobility,solvent engineering
更新于2025-09-09 09:28:46
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[Springer Theses] The Electronic Transitions of Molecular Oxygen || Temperature Effects on the Lifetime of O2(a1Δg)
摘要： The non-radiative deactivation of O2(a1(cid:2)g) and O2(b1(cid:3) + g) by solvent molecules has been a topic of intense and extensive research for almost half a century. The seminal interest derived in part from an unusually large effect of solvent and solvent deuteration on the lifetime of O2(a1(cid:2)g). The lifetime of O2(a1(cid:2)g), τ (cid:2), varies by 5 orders of magnitude in different solvents, and differences between H/D-isotopologues of the same solvent often exceed a factor of 20. The early reports on the subject were based on indirect probe-based measurements of τ (cid:2). Therefore, the interpretations were often misguided and afforded considerable controversy. With the advent of fast near-IR sensitive detectors in the late 1970s, it became possible to detect O2(a1(cid:2)g) phosphorescence with time-resolution. This facilitated the recording of an increasingly accurate set of data, which in turn, led to the development of ever more sophisticated theories. This effort culminated in the 1990’s with the development of an empirical model of electronic-to-vibrational (e-to-v) energy transfer. This model, which by now is widely accepted, focusses on the solvent as a “vibrational energy sink” that accept the excitation energy of O2(a1(cid:2)g) and O2(b1(cid:3) + g). In particular, the model accounts nicely for H/D solvent isotope effects on τ (cid:2) that are signi?cantly different from those observed on τ (cid:3). Nevertheless, as we shall see in the present chapter, it still has some important limitations.
关键词： electronic-to-vibrational energy transfer,solvent molecules,temperature effects,O2(a1(cid:2)g),non-radiative deactivation
更新于2025-09-04 15:30:14
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Steady State and Time-Resolved Fluorescence Study of 7,8-Benzoquinoline: Reinvestigation of Excited State Protonation
摘要： Steady state and time resolved spectral properties of 7,8-benzoquinoline (7,8-BQ) have been reinvestigated in a series of organic solvents of different proticity, polarity and wide range of pH. The salient features of this work are the effect of hydrogen bonding in protonation reaction which is explored through its behaviour in water and strong hydrogen bond donating solvent (trifluoroethanol). Quantum yield and rates (radiative, non-radiative and excited state protonation) have been calculated and discussed. Irreversible diffusion controlled excited state proton transfer in water and faster excited state protonation in trifluoroethanol is observed.
关键词： 7,8-benzoquinoline (Benzo[h]quinoline),protonation,trifluoroethanol,solvent,pH,hydrogen bonding
更新于2025-09-04 15:30:14
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Solvothermal Synthesis and Characterization of Flower-Like b-In2S3 Microparticles
摘要： Flower-like β-In2S3 particles have been successfully synthesized via solvothermal process by using acetylacetone-water solvent mixture. The products were characterized by X-ray diffraction, scanning electron microscopy, reflectance spectra. X-ray diffraction analysis confirms the formation of cubic β-In2S3. Microstructural investigation with SEM indicated that the particle size increases with increasing reaction time. The optical band gap determined from reflectance spectra was found to have values within the range of 2.34-2.49 eV.
关键词： Microstructure,Solvothermal synthesis,Optical properties,β-Indium sulphide,Acetylacetone-water solvent system
更新于2025-09-04 15:30:14
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Fabrication of Ag@AgCl with Enhanced Plasmonic Photocatalysis Performance via a Deep Eutectic Solvent
摘要： The plasmonic photocatalyst Ag@AgCl was successfully prepared through a facile solvothermal method via a deep eutectic solvent (DES), which is composed of choline chloride and urea. X-Ray diffraction, scanning electron microscopy, energy-dispersive X-ray, element-mapping, X-ray photoelectron spectroscopy, N2 absorption–desorption, and UV-vis diffuse reflectance techniques were adopted to analyse the performance of the plasmonic photocatalyst. Characterisation results indicated that the DES not only served as a solvent and Cl source, but also as a reductant. Meanwhile, the probable mechanism for the formation of Ag@AgCl is discussed, which revealed a visible light enhanced photocatalytic property for the degradation of benzidine. Furthermore, the photocatalyst showed no decrease in its catalytic activity even after five cycles of operation. Finally, a possible photocatalytic oxidation mechanism of Ag@AgCl is proposed.
关键词： solvothermal method,photocatalytic degradation,plasmonic photocatalyst,Ag@AgCl,deep eutectic solvent
更新于2025-09-04 15:30:14
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Investigation on crystallization of CH3NH3PbI3 perovskite and its intermediate phase from polar aprotic solvents
摘要： Perovskite films are usually fabricated by solution-processed method due to its low cost and ease of fabrication. The organic solvent plays multiple roles in growth of perovskites. Here, we investigate the growth of methylammonium lead iodide perovskite and its intermediate phase from micro-droplets containing with various solvents. Perovskite intermediate phase inclines to grow in the direction of its (020) plane from polar aprotic solvents at low temperature. At high temperature, the growth of perovskites depends on the structure of solvent molecules. The intermediate phase still grows from the solvents with short chain structure. It tends to form smooth films containing radial domains with dimension in tens of microns, which consist of nanocrystals due to annealing effects. However, perovskite grains grow directly from the solvents with ring structure. It tends to form smooth thin films by joining the large hexagonal perovskite crystals together. It provides a guidance to prepare high quality perovskite films for high performance optoelectronic devices.
关键词： micro-droplet,polar aprotic solvent,perovskite,crystallization
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Hangzhou, China (2018.8.13-2018.8.17)] 2018 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Precisely Lateral Alignment of Gold Nanorods Array via Hydrophilic-Hydrophobic Pattern
摘要： A simple strategy which combines the controlled solvent evaporation and hydrophilic-hydrophobic pattern to allow assembling gold nanorods (GNRs) on a flat substrate with arbitrary shapes in this work. Soft polydimethylsiloxane (PDMS) template as a pattern transfer stamp were utilized and transferred the structures onto the substrate successfully. By tuning the structures and sizes of templates, oriented large area lateral aligned GNRs arrays were fabricated as expected. Scan electron microscopy (SEM) images revealed that GNRs had been precisely placed as expected and the assembly is uniform.
关键词： hydrophilic-hydrophobic pattern,gold nanorods,self-assembly,solvent evaporation,micro-array
更新于2025-09-04 15:30:14
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A Two-Step Method for Stable and Impurity-Free Graphene Oxide Dispersion in Various Organic Solvents without a Stabilizer or Chemical Modification
摘要： The low stability of graphene oxide (GO) in organic solvents renders it unsuitable for several applications. Thus, an effective dispersion technique must be rapidly developed in order to allow the widespread use of GO. In this study, we successfully produced GO dispersions in various organic (including nonpolar) solvents without a stabilizer, chemical modification, or complex processing by a facile two-step method. In this technique, perfectly exfoliated single-layer GO was firstly prepared in water. Then, water was carefully replaced with each solvent. GO dispersed via this new method exhibited excellent long-term stability in organic solvents with a low impurity content. This is attributed to the release of interlayer water, which strongly links GO layers and causes aggregation in organic solvents, along with impurities trapped in interlayers during exfoliation. Additionally, a GO/polyvinyl chloride composite prepared using this new method showed better mechanical and electrical performances than prepared via the conventional method. The result obtained here will promote the widespread use of GO.
关键词： Organic solvent,polymer composite,Graphene oxide
更新于2025-09-04 15:30:14