Synthetic Metals最新文献

Nitrated benzothiadiazole (BT) is the promising acceptor units in constructing D-A-D electrochromic polymers, but its researches in the electrochromic field was very limited so far. In this work, four kinds of nitrated polymer precursors (Th-NO₂-BT, EDOT-NO₂-BT, Th-2NO₂-BT, and EDOT-2NO₂-BT) were synthesized by Stille coupling reaction with EDOT and thiophene units as the end groups (electron donor units) and mono-nitrated benzothiadiazole and di-nitrated benzothiadiazole as the core groups (electron acceptor units). The chemical structure and optical properties of the precursor were investigated by means of ¹H NMR, UV–vis absorption and fluorescence spectra; the corresponding mono-nitrated polymer films were obtained in CH₂Cl₂-Bu₄NPF₆ system by electrochemical deposition method. The optical band gap of di-nitrated polymer precursor is obviously larger than the corresponding mono-nitrated polymer precursor (both ultraviolet and fluorescence spectra are obviously blue-shifted), accompanied with the obvious increased initial oxidation potential. Due to the fluorescence quenching effect of -NO₂ group, their absolute quantum yields are all very low (0.0006–0.015). The spectroelectrochemistry and electrochromic kinetics of mono-nitrated polymer films (P(Th-NO₂-BT) and P(EDOT-NO₂-BT)) were studied. It was found that P(EDOT-NO₂-BT) can show better electrochromic performance than P(Th-NO₂-BT), with dark green in the neutral state and more obvious electrochromic performance in the near-infrared region (optical contrast: 38.4 %, coloration efficiency: 129.1 cm²/C, and fast response time: 1.4 s). This systematically study about the effects of nitro substitution effect on the properties of D-A electrochromic polymers, which will further expand the selection of the new acceptor units and the application prospect of nitrated electrochromic materials.

In this study, a surface acoustic wave (SAW) resonator coated with graphene/polypyrrole hybrid nanocomposite films decorated with silver nanoparticles (AgNPs-G/PPy) is proposed for detecting ammonia (NH₃) in parts-per-billion concentrations. The AgNPs-G/PPy hybrid nanocomposite film was synthesized via in situ chemical oxidative polymerization. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction were used to characterize the AgNPs-G/PPy hybrid nanocomposite film, confirming its successful synthesis and identifying a wrinkled multilayered structure. The AgNPs-G/PPy hybrid nanocomposite film was spin-coated onto the surface of a stress-compensated temperature-cut quartz SAW resonator having an operating frequency of 98.5 MHz to create an NH₃ gas sensor. NH₃ adsorption by the AgNPs-G/PPy hybrid nanocomposite film modulated the acoustic wave velocity, and the corresponding frequency shift served as a sensing signal. The synergistic interaction between the three constituent materials (AgNPs, graphene, and polypyrrole) enhanced the sensitivity, selectivity, and response speed of the sensor for NH₃ detection. At room temperature, the proposed sensor exhibited a positive frequency shift of 568 Hz when exposed to 50 ppb of NH₃ gas and a rapid response time of less than 60 s. In addition, the SAW sensor exhibited excellent selectivity.

In recent years, the synthesis of new gas-sensitive materials for resistive humidity sensors has attracted significant interest. In the present paper, nickel-containing metal-polymer nanocomposites were obtained by thermolysis of nickel itaconate (I) and its complexes with 2,2′-dipyridyl (II), 1,10-phenanthroline (III) and 4′-phenyl-2,2′:6′,2''-terpyridine (IV). The formed nanocomposites were characterized by FTIR, elemental analysis, EDX, SEM, TEM and XRD studies. The most common particle sizes are 28, 12.8, 10.7 and 12.3 nm for the thermolysis products of compounds I–IV respectively. The manufactured sensor samples have good sensitivity to air relative humidity (RH) of 3.24 %/%RH, 4.72 %/%RH, 2.18 %/%RH and 4.37 %/%RH for thermolysis products of compounds I–IV with the polymer binder polyacrylamide, respectively. The average initial resistance of the sensors is 4.54, 15.33, 20.8 and 35.75 MΩ, respectively. Due to the high porosity and moisture absorption of the film, the maximum sensitivity was about 0.003 MΩ/%RH, which indicates a fairly effective behavior of the film with respect to humidity. The response times were 27, 25, 33, 30 s, and the recovery time 47, 44, 51, 49 s, respectively, and repeating the experiment resulted in 87–92 % reproducible results. The fabricated sensors have great potential for use as a humidity sensing element in sensors that can be used for humidity monitoring.

The conductive ink research area has attracted much interest from researchers. The possibility of fabricating flexible and simple electronic devices offers many advantages for electronic devices, such as energy storage, wearable devices, and smart devices. Graphene conductive ink has gained much attention from scientists owing to its excellent electrical, optical, and mechanical properties. Numerous scientists have reported the modification of graphene properties to meet the demand for the application. Among the presented graphene synthesis methods, the electrochemical exfoliation process is simple, low-cost, and environmentally friendly. Moreover, the electrochemical exfoliation approach can be conducted in a water solution, thus decreasing production costs and making it environmentally safe. This review article presents the progress in the electrochemical exfoliation of graphene to produce graphene-conductive ink. Progress on graphene conductive ink and its hybrid is also presented. In particular, the potential application of graphene in energy storage, sensors, and other possible applications is summarized in the last part.

A highly sensitive and selective E-DNA biosensor was fabricated on a gold substrate using a reduced graphene oxide/polypyrrole/gold nanoparticle/oligonucleotide (RGO/PPy/Au*NPs/Apt) nanocomposite electrode to detect the nucleocapsid protein of SARS-CoV-2 in the patient blood plasma. The modified electrode was characterized by physicochemical techniques such as Fourier transform-infra red (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS) analyses, Brunauer-Emmett-Teller (BET), and Barrett-Joyner-Halenda (BJH) analyses. Moreover, electrochemical analyses were employed to study the electrochemical performance of the electrodes including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave voltammetry (SWV). Computational investigations of N protein bindings such as hydrogen bonding, Van der Waals binding, and Gibbs binding energies of the N-protein, and aptamer were studied by Molecular Dynamics Simulations (MDS). The unique synergistic effect of RGO, PPy, and the well-known effect of Au nanoparticles makes the DNA probe immobilized on the gold electrode surface. After optimizing the systems, the E-DNA biosensor exhibited a fast SWV response, higher sensitivity (33.77 μA.nM⁻¹.cm⁻²) and selectivity, high efficiency, good storage stability, and acceptable repeatability for monitoring DNA. The results of real samples based on SWV indicated the correct functioning of the aptasensor in the presence of the SARS-CoV-2 virus. The limit of detection was 3.16×10⁻¹⁷ M and the limit of quantitation was 1.42×10⁻¹⁶ M. The MDS results indicated the stable dynamic folding of the aptamer for beneficial binding. The results indicated that the RGO/PPy/Au*NPs/Apt biosensor is promising for detecting of SARS-CoV-2 virus.

This study employed time-of-flight secondary ion mass spectrometry (TOF-SIMS) to investigate degradation pathways at the nanoscale, utilizing its capacity for in-depth chemical and structural analysis through various methods, including depth profiling and 3D analysis. A key focus is the matrix effect in ToF-SIMS, which alters secondary ion yields based on the sample matrix composition, influencing species identification and quantification. We show that this effect can be used to enhance the resolution of ToF-SIMS beyond its traditional limits, allowing for detailed imaging of the degradation process. Our findings indicate that the initial formation of PbI₂ phases, a crucial step in the degradation pathway triggered by environmental factors, can be traced and visualized. By investigating the sputtering yields and secondary ion formation, we reveal the nonlinear sputtering regimes present in MAPI, contributing to our understanding of the mechanisms driving perovskite degradation. The application of this enhanced analytical technique paves the way for improved degradation studies.

Lithium-sulfur batteries (LSBs) are one of the representatives of a new generation of high-performance batteries, due to their large theoretical specific discharge capacity, high energy density and low cost et al. However, shuttle effect and slow conversion kinetics of polysulfides (LiPSs) hinder the performance of LSBs. In order to mitigate shuttle effect, metal-organic frameworks are introduced. Carbon nanotubes (CNTs) is used as composite cathode, due to their high electrical conductivity. V-MOF/CNTs-derived hexagonal VC/CNTs nanosheets are successfully synthesized and used as the sulfur host. VC/CNTs nanosheet with mesoporous structure can provide a lot of active sites. VC nanosheets are uniformly distributed and interconnected with CNTs to form a conductive network structure. VC/CNTs has excellent chemical adsorption and catalytic properties on polysulfides, which can improve the redox reaction kinetics and the adsorption capability. Due to the synergistic effects, S/VC/CNTs has an excellent cycling stability. S/VC/CNTs shows a significant initial specific capacity of 1370 mAh g⁻¹ at 0.1 C. Capacity decay rate per cycle is about 0.037 % After 500 cycles at 0.5 C, the Coulomb efficiency is nearly to 100 %. The results show that the introduction of VC/CNTs composites with special hexagonal structure can accelerate the catalytic electrochemical reaction, and the dissolution and diffusion of polysulfides are well controlled.

We report the synthesis of polyaniline/magnetite nanocomposites (PMNCs) via in situ chemical oxidation polymerization of aniline with magnetite nanoparticles (MNPs) at 5, 12, and 25 wt%. The objective was to evaluate how the MNPs’ proportion affects the electrical, magnetic, and structural properties, which were investigated using XRD, EDXRF, TEM, EIS, ESR spectroscopy, Mössbauer spectroscopy, and VSM. EDXRF confirmed the formation of MNPs, while XRD revealed the crystalline nature of MNPs and the semicrystalline structure of PANI, with a decrease crystallinity index as the MNPs percentage increased. TEM showed PANI encapsulating MNPs with average diameters of 9.7 ± 2, 9.9 ± 2, and 13.1 ± 3 nm for PMNC25, PMNC12, and PMNC5, respectively. Conductivity values of PANI, PMNC25, PMNC12 and PMNC5 were 7.96 ×10⁻⁴, 1.38 ×10⁻⁴, 2.19 ×10⁻⁴ and 2.31 ×10⁻⁴ S/cm, respectively. ESR indicated cationic radicals responsible for conductivity. Saturation magnetization (Ms) for MNPs, PMNC25, PMNC12 and PMNC5 were 93.4, 24.6, 11.8 and 5.6 emu/g, respectively, with superparamagnetic behavior observed. Our findings show that incorporating MNPs into the PANI matrix modulates electrical conductivity and magnetic properties while maintaining the nanocomposite’s structure, highlighting the multifunctional potential of these composites.

Graphitic carbon nitride (g-C₃N₄) has been widely used to improve photoelectrochemical (PEC) activity owing to its outstanding photoresponse and strength. In this study, g-C₃N₄ hollow tubes decorated with SnO₂ quantum dots were prepared by combining hydrothermal and post-annealing approaches. In particular, different characterization techniques such as Fourier transform infrared, photoluminescence, ultraviolet–visible, and X-ray photoelectron spectroscopies were employed to investigate the electrical and optical behaviors of the samples. The prepared samples exhibited considerable photoresponse and excellent PEC performance, producing hydrogen. Furthermore, the heterostructures among SnO₂ and g-C₃N₄ encouraged carrier separation, improving the PEC ability. In addition, the applied voltage showed numerous effects on generating charge carriers for the anodes in a 0.1 M sodium hydroxide electrolyte. Therefore, the proposed approach is simple and effective and can be used to enhance the performance of the PEC activity.

Metal-organic frameworks (MOFs) have garnered considerable interest for supercapacitors as electrode materials. Although MOFs possess large pore sizes and high specific surface areas, most MOFs face major challenges due to their inferior stability and low electronic conductivity. In this study, we synthesized Ni-MOF/MWCNT nanocomposite using a mixed-ligand approach through hydrothermal method to provide more redox reaction sites, facilitate ion diffusion, increase the stability, and electronic conductivity of the electrode. Benzoic acid (BA) has partially replaced Benzene-1,3,5-tricarboxylic acid (BTC). BTC has been used to shape Ni-MOF nanosheets into flower-like microspheres, which can reduce the electron/ion diffusion path. The introduction of BA and combination of MWCNT and Ni-MOF result in high electric conductivity. Furthermore, the combination of two organic ligands, and the synergistic effect of MWCNTs and Ni-based MOFs lead to excellent electrochemical performance. The prepared Ni-MOF/MWCNT nanocomposite shows an outstanding capacitance of 900 F g⁻¹ at 0.5 A g⁻¹ and excellent cycling stability with 82 % capacity etention over 1000 cycles. This study presents an innovative strategy for enhancing energy storage performance.