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Nanoscale Horizons Jan 2024High-performance semiconductor materials and devices are needed to supply the growing energy and computing demand. Organic semiconductors (OSCs) are attractive options...
High-performance semiconductor materials and devices are needed to supply the growing energy and computing demand. Organic semiconductors (OSCs) are attractive options for opto-electronic devices, due to their low cost, extensive tunability, easy fabrication, and flexibility. Semiconducting single-walled carbon nanotubes (s-SWCNTs) have been extensively studied due to their high carrier mobility, stability and opto-electronic tunability. Although molecular charge transfer doping affords widely tunable carrier density and conductivity in s-SWCNTs (and OSCs in general), a pervasive challenge for such systems is reliable measurement of charge carrier density and mobility. In this work we demonstrate a direct quantification of charge carrier density, and by extension carrier mobility, in chemically doped s-SWCNTs by a nuclear magnetic resonance approach. The experimental results are verified by a phase-space filling doping model, and we suggest this approach should be broadly applicable for OSCs. Our results show that hole mobility in doped s-SWCNT networks increases with increasing charge carrier density, a finding that is contrary to that expected for mobility limited by ionized impurity scattering. We discuss the implications of this important finding for additional tunability and applicability of s-SWCNT and OSC devices.
PubMed: 38044846
DOI: 10.1039/d3nh00480e -
Sensors (Basel, Switzerland) Mar 2024With the development of civilisation, the awareness of the impact of versatile aerosol particles on human health and the environment is growing. New advanced materials...
With the development of civilisation, the awareness of the impact of versatile aerosol particles on human health and the environment is growing. New advanced materials and techniques are needed to purify the air to reduce this impact. This brings the necessity of fast and low-cost devices to evaluate the air quality from particulate and gaseous impurities, especially in a place where gas chromatography (GC) techniques are unavailable. Small portable and low-cost systems may work separately or be incorporated into devices responsible for air-cleaning processes, such as filters, smoke adsorbers, or plasma air cleaners. Given the above, this study proposes utilising a self-assembled low-cost system to evaluate air quality, which can be used in many outdoor and indoor applications. ESP32 boards with the wireless communication protocol ESP-NOW were used as the framework of the system. The concentration of aerosol particles was measured using Alphasense sensors. The concentrations of the following gases were measured: NO, SO, O, CO, CO, and HS. The system was used to evaluate the quality of air containing tobacco smoke after passing through an actual DBD plasma reactor where the purification occurred. A high amount of reduction in aerosol particles and a reduction in the SO concentration were detected. An increase in the NO concentration was seen as an undesirable effect. The aerosol particle measurements were compared with those using a professional device (GRIMM, Hamburg, Germany), which showed the same trends in aerosol particle behaviour. The obtained results are auspicious and are a step towards producing a low-cost, efficient system for evaluating air quality as well as indoor and outdoor conditions.
PubMed: 38544031
DOI: 10.3390/s24061769 -
Crystal Growth & Design Feb 2024Highly reflective assemblies of purine, pteridine, and flavin crystals are used in the coloration and visual systems of many different animals. However, structure...
Highly reflective assemblies of purine, pteridine, and flavin crystals are used in the coloration and visual systems of many different animals. However, structure determination of biogenic crystals by single-crystal XRD is challenging due to the submicrometer size and beam sensitivity of the crystals, and powder XRD is inhibited due to the small volumes of powders, crystalline impurity phases, and significant preferred orientation. Consequently, the crystal structures of many biogenic materials remain unknown. Herein, we demonstrate that the 3D electron diffraction (3D ED) technique provides a powerful alternative approach, reporting the successful structure determination of biogenic guanine crystals (from spider integument, fish scales, and scallop eyes) from 3D ED data confirmed by analysis of powder XRD data. The results show that all biogenic guanine crystals studied are the previously known β-polymorph. This study highlights the considerable potential of 3D ED for elucidating the structures of biogenic molecular crystals in the nanometer-to-micrometer size range. This opens up an important opportunity in the development of organic biomineralization, for which structural knowledge is critical for understanding the optical functions of biogenic materials and their possible applications as sustainable, biocompatible optical materials.
PubMed: 38344673
DOI: 10.1021/acs.cgd.3c01290 -
Chemico-biological Interactions Sep 2023Lung toxicity of carbon nanotubes (CNTs) is matter of concern since very long time. However, their mechanism of toxicity is still not yet well defined. In this work, the...
Lung toxicity of carbon nanotubes (CNTs) is matter of concern since very long time. However, their mechanism of toxicity is still not yet well defined. In this work, the role of structural defects as organic stressors of CNTs able to trigger their potential toxicity is investigated. Four commercial CNTs, with different carbon purity grade, are morphologically characterized by transmission electron microscopy (TEM) and the relative amount of structural defects are estimated through Raman spectroscopy, by measuring the intensity ratio D/G (I/I). The oxidative potential of CNTs is evaluated with cytochrome-C assay and reactive oxygen species (ROS) detection. Data show that CNTs with larger amounts of structural defects (higher I/I ratio) induce an increased ROS generation and consequent cytotoxicity and cellular damage, shown by TEM images of CNTs-cells interaction. Raman analyses of cells exposed to CNTs point out that the spectra of the CNTs inside the cells show no differences with respect of the signal recorded for cell-free CNTs, evidencing their biopersistence in lung cells. Raman spectra cannot provide direct indication of the existence of metals as impurity. It follows that the intensity ratio I/I can be taken as a predictive marker of the toxicity of a given CNT.
Topics: Nanotubes, Carbon; Spectrum Analysis, Raman; Microscopy, Electron, Transmission; Humans; Cell Line; Lung; Animals
PubMed: 37353135
DOI: 10.1016/j.cbi.2023.110613 -
Inorganic Chemistry Sep 2023Metal-organic frameworks (MOFs) have attracted extensive attention in methane (CH) purification and storage. Specially, multinuclear cluster-based MOFs usually have...
Metal-organic frameworks (MOFs) have attracted extensive attention in methane (CH) purification and storage. Specially, multinuclear cluster-based MOFs usually have prominent performance because of large cluster size and abundant open metal sites. However, compared to diverse combinations of organic linkers, one MOF with two or more multinuclear clusters is difficult to achieve. In this paper, we demonstrate a mixed multinuclear cluster strategy, which successfully led to three new heterometallic MOFs (SNNU-328-330) with the same common HTATB [2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine] tritopic linker and six types of multinuclear clusters ([YCd(COO)(μ-HO)], [YCd(COO)], [In(COO)(μ-OH)], [InEu(COO)(μ-OH)(μ-O)], [Y(COO)(μ-OH)] and [YCd(COO)(μ-HO)(μ-OH)]). Three MOF adsorbents all show great potentials to remove the impurities (CO and C-hydrocarbons) in natural gas and show prominent high-pressure methane storage capacity. Among them, the ideal adsorbed solution theory separation ratios of equimolar CH/CH, CH/CH, CH/CH, and CO/CH at 298 K for SNNU-328 reach to 29.7-16.0, 19.1-8.2, 33.2-10.3, and 74.3-8.5, which have surpassed many famous MOF adsorbents. Dynamic breakthrough experiments conducted at 273 and 298 K showed that SNNU-330 can separate CH from CH/CH, CH/CH, CH/CH, and CO/CH mixtures with the breakthrough interval times of about 48.2, 17.9, 37.2, and 17.1 min g (273 K, 1 bar, / = 50/50, 2 mL min), respectively. Remarkably, SNNU-329 exhibits extremely high methane storage performance at 298 K with the total uptake and working capacity of 192 cm cm (95 bar) and 171 cm cm (65 bar) due to the synergistic effects of high surface area, suitable pore sizes, and multiple open metal sites.
PubMed: 37656912
DOI: 10.1021/acs.inorgchem.3c02347 -
Dalton Transactions (Cambridge, England... Apr 2024Hybrid methylammonium (MA) lead halide perovskites have emerged as materials exhibiting excellent photovoltaic performance related to their rich structural and dynamic...
Hybrid methylammonium (MA) lead halide perovskites have emerged as materials exhibiting excellent photovoltaic performance related to their rich structural and dynamic properties. Here, we use multifrequency (X-, Q-, and W-band) electron paramagnetic resonance (EPR) spectroscopy of Mn impurities in MAPbCl to probe the structural and dynamic properties of both the organic and inorganic sublattices of this compound. The temperature dependent continuous-wave (CW) EPR experiments reveal a sudden change of the Mn spin Hamiltonian parameters at the phase transition to the ordered orthorhombic phase indicating its first-order character and significant slowing down of the MA cation reorientation. Pulsed EPR experiments are employed to measure the temperature dependences of the spin-lattice relaxation and decoherence times of the Mn ions in the orthorhombic phase of MAPbCl revealing a coupling between the spin center and vibrations of the inorganic framework. Low-temperature electron spin echo envelope modulation (ESEEM) experiments of the protonated and deuterated MAPbCl analogues show the presence of quantum rotational tunneling of the ammonium groups, allowing to accurately probe their rotational energy landscape.
PubMed: 38587489
DOI: 10.1039/d4dt00116h -
Se Pu = Chinese Journal of... Dec 2023The complex matrix of soil samples and low extraction efficiency of aniline compounds limit many methods developed for detecting aniline and benzidine compounds in soil....
The complex matrix of soil samples and low extraction efficiency of aniline compounds limit many methods developed for detecting aniline and benzidine compounds in soil. In this study, a rapid and sensitive method based on gas chromatography-mass spectrometry was developed for the simultaneous determination of 14 aniline and benzidine compounds in soil. The collected soil samples were sealed with 5% sodium sulfite solution and refrigerated to inhibit the oxidation of the target compounds for up to 7 d. The extraction efficiencies of accelerated solvent extraction and oscillating dispersion extraction were compared, and the recovery of accelerated solvent extraction was found to be unsuitable. Hence, three-phase oscillating dispersion extraction was adopted. A certain amount of alkaline aqueous solution was added to the test system during extraction to improve the extraction efficiency because aniline and benzidine compounds are weakly alkaline substances. When the pH of the extracted water phase was greater than 12, relatively good recoveries were obtained. Next, a mixed solvent of ethyl acetate-methylene chloride (1∶4, v/v) was added to extract the target compounds via oscillation for 20 min. The solid phase was discarded via centrifugation, and the aqueous and organic phases were transferred to a liquid separation funnel for further separation. Finally, the organic phase was retained. This pretreatment process prevents the co-extraction of acidic compounds or other impurities, thereby enhancing the purification ability of the method. Solid phase extraction (SPE) is generally recommended for soil extraction and purification. A preliminary test showed that compared with other columns, the Florisil SPE column could better retain the target substances and exhibited higher elution efficiency. After purification, the organic phase was concentrated to 1 mL using a nitrogen blower. The analytes were analyzed by gas chromatography-mass spectrometry using a capillary column (DB-35MS, 30 m×0.25 mm×0.25 μm). The temperature program was optimized to separate the target compounds at the baseline. Specifically, the initial oven temperature was set to 60 ℃, held for 2 min, increased to 130 ℃ at a rate of 5 ℃/min, increased to 300 ℃ at a rate of 30 ℃/min, and held for 4 min. The injector and ion source temperatures were 250 and 300 ℃, respectively. Aniline-d and acenaphthene-d were used as the internal standards for quantification. The effects of antioxidant addition, extraction solvent type, salting out, and other factors on extraction efficiency were investigated. The results showed that the method performed well under the optimized experimental conditions when actual soils were used as real sample matrices. The accuracy and precision of the proposed method were verified. A total of 14 aniline and benzidine compounds demonstrated good linearities in the range of 0.5-100 mg/L. The method detection limits (MDLs) ranged from 0.02 to 0.07 mg/kg, and the limits of quantification (LOQs) ranged from 0.08 to 0.28 mg/kg. The target compounds were spiked at contents of 1 and 10 mg/kg. The spiked recoveries of the 14 targets in actual soils were 62.9%-101%, and the relative standard deviations (RSDs) of six precision tests were 3.8%-10.3%. The proposed method effectively inhibited the oxidation of aniline and benzidine compounds during extraction, and the target compounds exhibited high recoveries and good stabilities in the presence of three phases. Moreover, the operating procedure was simple and easy to implement. The proposed method was applied to the soil collected from an industrial enterprise in Jiangsu province that was suspected to be contaminated with aniline, and two aniline compounds were detected. The developed method requires a small sample size, and the preservation step is simple and effective. In addition, it can be applied to various types of actual soils. The method meets the requirements of current soil pollution risk control standards for aniline and benzidine compounds in soils.
PubMed: 38093543
DOI: 10.3724/SP.J.1123.2023.01002 -
Nanomaterials (Basel, Switzerland) Feb 2024Metal-organic frameworks (MOFs) are hybrid materials that are being explored as active electrode materials in energy storage devices, such as rechargeable batteries and...
Metal-organic frameworks (MOFs) are hybrid materials that are being explored as active electrode materials in energy storage devices, such as rechargeable batteries and supercapacitors (SCs), due to their high surface area, controllable chemical composition, and periodic ordering. However, the facile and controlled synthesis of a pure MOF phase without impurities or without going through a complicated purification process (that also reduces the yield) are challenges that must be resolved for their potential industrial applications. Moreover, various oxide formations of the Ni during Ni-MOF synthesis also represent an issue that affects the purity and performance. To resolve these issues, we report the controlled synthesis of nickel-based metal-organic frameworks (NiMOFs) by optimizing different growth parameters during hydrothermal synthesis and by utilizing nickel chloride as metal salt and Hbdt as the organic ligand, in a ratio of 1:1 at 150 °C. Furthermore, the synthesis was optimized by introducing a magnetic stirring stage, and the reaction temperature varied across 100, 150, and 200 °C to achieve the optimized growth of the NiMOFs crystal. The rarely used Hbdt ligand for Ni-MOF synthesis and the introduction of the ultrasonication stage before putting it in the furnace led to the formation of a pure phase without impurities and oxide formation. The synthesized materials were further characterized by powder X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), and UV-vis spectroscopy. The SEM images exhibited the formation of nano NiMOFs having a rectangular prism shape. The average size was 126.25 nm, 176.0 nm, and 268.4 nm for the samples (1:1)s synthesized at 100 °C, 150 °C, and 200 °C, respectively. The electrochemical performances were examined in a three-electrode configuration, in a wide potential window from -0.4 V to 0.55 V, and an electrolyte concentration of 2M KOH was maintained for each measurement. The charge-discharge galvanostatic measurement results in specific capacitances of 606.62 F/g, 307.33 F/g, and 287.42 F/g at a current density of 1 A/g for the synthesized materials at 100 °C, 150 °C, and 200 °C, respectively.
PubMed: 38392725
DOI: 10.3390/nano14040353 -
Small (Weinheim An Der Bergstrasse,... Sep 2023Considering the significant application of acetylene (C H ) in the manufacturing and petrochemical industries, the selective capture of impurity carbon dioxide (CO ) is...
Considering the significant application of acetylene (C H ) in the manufacturing and petrochemical industries, the selective capture of impurity carbon dioxide (CO ) is a crucial task and an enduring challenge. Here, a flexible metal-organic framework (Zn-DPNA) accompanied by a conformation change of the Me NH ions in the framework is reported. The solvate-free framework provides a stepped adsorption isotherm and large hysteresis for C H , but type-I adsorption for CO . Owing to their uptakes difference before gate-opening pressure, Zn-DPNA demonstrated favorable inverse CO /C H separation. According to molecular simulation, the higher adsorption enthalpy of CO (43.1 kJ mol ) is due to strong electrostatic interactions with Me NH ions, which lock the hydrogen-bond network and narrow pores. Furthermore, the density contours and electrostatic potential verifies the middle of the cage in the large pore favors C H and repels CO , leading to the expansion of the narrow pore and further diffusion of C H . These results provide a new strategy that optimizes the desired dynamic behavior for one-step purification of C H .
PubMed: 37194973
DOI: 10.1002/smll.202302975 -
Journal of Pharmaceutical and... Sep 2024A long-term stability study using high performance liquid chromatography (HPLC) revealed an unidentified impurity in the bromhexine hydrochloride injection, which was...
A long-term stability study using high performance liquid chromatography (HPLC) revealed an unidentified impurity in the bromhexine hydrochloride injection, which was employed as a mucolytic agent. Investigations into stress degradation and elemental impurities revealed one of the elemental impurities Fe in this injection as the primary generator of these impurities. This impurity, named N-carboxymethyl bromhexine, was a product formed during drug-excipient interaction between bromhexine and tartaric acid with Fe. The structure of the impurity was identified through ultra-high-performance liquid chromatography with diode array detector (UHPLC-DAD), liquid chromatograph mass spectrometer (LC-MS). Further, the formation mechanism of the impurity was discussed. Overall, this study elucidates the cause, origin, and mechanism of an unknown impurity in bromhexine hydrochloride injection, providing a basis for quality control for bromhexine hydrochloride injections and drug products containing both amine and tartaric acid.
Topics: Bromhexine; Drug Contamination; Chromatography, High Pressure Liquid; Excipients; Tartrates; Mass Spectrometry; Drug Stability; Quality Control
PubMed: 38850847
DOI: 10.1016/j.jpba.2024.116256