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Non-enzymatic glucose sensors based on metal structures produced by laser-induced deposition from solution
摘要： The conditions for synthesis of conductive copper and nickel microstructures using laser-induced deposition technique were determined and electrocatalytic activity of these materials towards D-glucose was investigated. It was found out that formation of these conductive electrodes upon laser irradiation occurs only in solutions containing OH- coordinating ligands. Coordination via other functional groups (including carboxyl and amino) does not lead to synthesis of conductive structures. Topology and composition of copper and nickel deposits were observed using scanning electron microscopy and EDX analysis, respectively. The electrochemical properties of the synthesized structures were studied using cyclic voltamperometry and amperometry. The studied materials display linear dependencies of the Faraday current vs. concentration between 2 μM and 1.1 mM for nickel and 0.25 mM and 3 mM for copper.
关键词： Cyclic voltammetry,Nickel,Copper,Laser-induced deposition,Electrochemical sensors
更新于2025-09-12 10:27:22
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Synthesis, characterization, optical properties, computational characterizations, QTAIM analysis and cyclic voltammetry of new organic dyes for dye-sensitized solar cells
摘要： In recent years, dye-sensitized solar cells (DSSCs) have regarded as potential solar cells for the next generation of photovoltaic technologies. Many organic compounds are explored and used in DSSCs to produce low-cost devices and improve the cell efficiency. In this work, three new heterocyclic purple dyes are synthesized from the reaction of 3-nitropyrazolo[1,5-a]pyridine with various arylacetonitriles for dye-sensitized solar cells (DSSCs), exhibiting high molar extinction coefficients and a broad absorption range led to the good photovoltaic performance of 6.95e7.18%. Physical spectral, analytical data and optical properties are established the structures of the new dyes. The optimized geometries and relevant frontier orbitals of the dyes are obtained by density functional theory (DFT) at the level of B3LYP/6-311 + G(d,p). Electrostatic potential maps and electron density maps of the dyes were also obtained by atoms in molecules (AIM) analysis. Cyclic voltammetry measurement was performed to evaluate the electrochemical properties of the dyes and reversible oxidation waves were observed for them.
关键词： Dye-sensitized solar cells,DFT,3-Nitropyrazolo[1,5-a]pyridine,AIM,Cyclic voltammetry,Purple dyes
更新于2025-09-12 10:27:22
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Electronic properties of oxidized cyclometalated diiridium complexes: Spin delocalization controlled by the mutual position of the iridium centres
摘要： Four cyclometalated diiridium complexes, with IrCp*Cl (Cp* = η5-C5Me5?) termini bridged by 1,4- and 1,3-bis(p-tolylimino-ethyl)benzene (1, 2), or 1,4- and 1,3-bis(2-pyridyl)benzene (3, 4), were prepared and characterized by nuclear magnetic resonance (NMR) spectroscopy and single-crystal X-ray diffraction (complexes 1, 2 and 4). The two iridium centres in complexes 1 and 3 are thus bound at the central benzene ring in the para-position (trans-Ir2), while those in complexes 2 and 4 in the meta-position (cis-Ir2). Cyclic voltammograms of all four complexes show two consecutive one-electron oxidations. The potential difference between the two anodic steps in 1 and 3 is distinctly larger compared to 2 and 4. The visible - near-infrared (NIR) - short-wave infrared (SWIR) absorption spectra of trans-Ir2 monocations 1+ and 3+ are markedly different from those of cis-Ir2 monocations 2+ and 4+. Notably, strong near-infrared electronic absorption appears only in the spectra of 1+ and 3+ while 2+ and 4+ absorb only weakly in the NIR-SWIR region. Combined DFT and TD-DFT calculations have revealed that (a) 1+ and 3+ (the diiridium-benzene trans-isomers) display HOSO and LUSO evenly delocalized over both molecule halves, and (b) their electronic absorptions in the NIR-SWIR region are attributed to mixed metal-to-ligand and ligand-to-ligand charge transfers (MLCT and LLCT). In contrast, cis-isomers 2+ and 4+ do not feature this stabilizing π-delocalization but a localized mixed-valence state showing a weak IVCT absorption in the SWIR region.
关键词： Mixed-valence State,Cyclometalated Isomers,Cyclic Voltammetry,Diiridium Complex,Spectroelectrochemistry
更新于2025-09-12 10:27:22
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Optical Voltammetry of Polymer-Encapsulated Single-Walled Carbon Nanotubes
摘要： The semiconducting single-walled carbon nanotube (SWCNT), noncovalently wrapped by a polymeric monolayer, is a nanoscale semiconductor?electrolyte interface under investigation for sensing, photonics, and photovoltaic applications. SWCNT complexes are routinely observed to sensitize various electrochemical/redox phenomena, even in the absence of an external ?eld. While the photoluminescence response to gate voltage depends on the redox potential of the functionalized nanotube, analogous optical voltammetry of carbon nanotubes could be conducted in suspension without applying voltage but by varying the solution conditions as well as the chemistry of the encapsulating polymer. Steady-state photoluminescence, absorbance, and in situ measurements of O2/H2O reactivity show correlation with the pH/pKa-dependent reactivity of π-rich coatings. The nanotube emission responses suggest that the presence of photogenerated potential may explain the observed coating electrochemical reactivity. This work ?nds that electronic and chemical interactions of the nanotube with the encapsulating polymer may play a critical role in applications that depend on radiative recombination, such as optical sensing.
关键词： redox phenomena,optical voltammetry,single-walled carbon nanotubes,photoluminescence,polymer encapsulation
更新于2025-09-12 10:27:22
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Electrodeposition of photovoltaic thin films from ionic liquids in ambient atmosphere: Gallium from a chloroaluminate ionic liquid
摘要： At present time, semiconductive thin films used in photovoltaic cells can be successfully electrodeposited using ionic liquids in lab scale. However, scaling-up of this technology is hazardous due to the complexity involved to conduct electrodeposition in inert gas atmosphere. This paper reports on a novel approach for electrodeposition of gallium from a chloroaluminate ionic liquid composed of anhydrous aluminum chloride (AlCl3) and 1-ethyl-3-methylimidazolium chloride (EMIC) in ambient atmosphere, after protection with a non water-absorbable hydrocarbon layer. Cyclic voltammetry (CV) measurements were undertaken to characterize the electrodissolution and electrodeposition behavior of Ga. Potentiostatic electrodeposition experiments were conducted to deposit functional Ga layers on Pt, nickel, and mild steel substrates. SEM/EDX investigations revealed that Ga deposits have inhomogeneous microstructure developed through the progressive nucleation-growth mechanism that has been controlled by diffusion of Ga cations.
关键词： Ionic liquids,Semiconductors,Photovoltaic cells,Cyclic voltammetry,Electrodeposition,Gallium
更新于2025-09-12 10:27:22
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Electron Transfer Kinetics at Graphene Quantum Dot Assembly Electrodes
摘要： Electrochemical performance of nanostructured carbon electrodes was evaluated using cyclic voltammetry and a simple simulation model. The electrodes were prepared from soluble precursors by anodic electrodeposition of two sizes of graphene quantum dot assemblies (HBC and CQD) onto conductive support. Experimental and simulated voltammograms enabled the extraction of the following electrode parameters: conductivity of the electrodes (a combination of ionic and electronic contributions), density of available electrodes states at different potentials and tunneling rate constant (Marcus-Gerischer model) for interfacial charge transfer to ferrocene/ferrocenium (Fc/Fc+) couple. The parameters indicate that HBC and CQD have significant density of electronic states at potentials more positive than –0.5 V vs Ag/Ag+. Enabled by these large densities, the electron transfer rates at the Fc/Fc+ thermodynamic potential are several orders of magnitude slower than those commonly observed on other carbon electrodes. This study is expected to accelerate the discovery of improved synthetic carbon electrodes by providing fast screening methodology of their electrochemical behavior.
关键词： cyclic voltammetry,kinetics,interface,electrode,electron transfer,graphene quantum dots
更新于2025-09-12 10:27:22
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Highly Selective and Sensitive Sensing of Toxic Mercury Ions Utilizing Carbon Quantum Dot-Modified Glassy Carbon Electrode
摘要： In this paper, a novel synthesis of 1 nm sized metal-free carbon quantum dots (CQDs) and their electrochemical application vis-à-vis mercury (Hg) sensing have been demonstrated. The characterization of synthesized CQDs was done by FT-IR, HR-TEM, XRD and UV–Vis analysis. Furthermore, the CQD-modified electrode shows an excellent sensing ability toward deleterious Hg ion even when 600-fold of excess of interfering ions such as Cu2+, Pb2+, Cd2+, Na+, K+, Mg2+, Ba2+, Bi2+, Fe2+, Zn2+ and Hg2+ are present. A wide linearity range (0.5–300 nM) and the lowest limit of detection (2.5 nM) are exhibited by the proposed sensor with potential scanning from ? 0.7 to + 0.7 V vs Ag/AgCl at a scan rate of 20 mV. In addition, the CQD-modified electrode displays an outstanding recovery results toward Hg in various real water samples. This study promotes new possibilities of designing various electrochemical sensors based on CQD nanocomposite.
关键词： Differential pulse voltammetry,Mercury,Cyclic voltammetry,Carbon quantum dots,Electrochemical Sensing
更新于2025-09-11 14:15:04
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Electrochemical Detection of 4-p-nitrophenol Based on TiO2NPs / RGO / AuNPs Composite Modified Glassy Carbon Electrode
摘要： A glassy carbon electrode modified with TiO2NPs/RGO/AuNPs was used as an electrochemical sensor to detect trace amounts of 4-p-nitrophenol (4-NP). The surface morphology of the composites was characterized by field-emission scanning electron microscopy (FE-SEM). The electrochemical characteristics of the composite electrode were analyzed by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS). The modified electrode exhibited outstanding electrochemical performance due to the large specific surface area and strong conductivity of composite material. The differential pulse voltammetry(DPV) and square wave voltammetry(SWV) were used for the trace detection of p-nitrophenol. The peak current of the two methods showed a high linear relationship with the 4-NP concentration. The detection range applied DPV method was 0.5-100μmol/L, the detection limit was 0.03μmol/L. When SWV was employed, detection range was from 0.5 to 100μmol/L, The detection limit was 0.08μmol/L. In this study, the electrochemical sensor had the advantage of large detection range, low detection limit, stable, simple and fast analysis. Based on these characteristics, the sensor can be considered as a potential sensor for the detection of 4-NP.
关键词： 4-NP,Square Wave Voltammetry,TiO2NPs,AuNPs,RGO,Differential Pulse Voltammetry
更新于2025-09-11 14:15:04
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Synthesis and characterization of vinazene end capped dipyrrolo[2,3-b:2′,3′-e]pyrazine-2,6(1H,5H)-dione small molecules as non-fullerene acceptors for bulk heterojunction organic solar cells
摘要： Two dipyrrolo[2,3-b:2',3'-e]pyrazine-2,6(1H,5H)-dione (PzDP)-based small molecules DPDV and DPEV with PzDP as the core building block and 4,5-dicyano-2-vinylimdazole (vinazene) as end-cap units were synthesized by Heck coupling reaction. The photophysical, electrochemical properties of DPDV and DPEV were investigated and applied as non-fullerene acceptors (NFAs) for solution-processed bulk heterojunction (BHJ) organic solar cells (OSCs). Theoretically evaluated optical and electrochemical properties were well matched with experimental values. Solution processed BHJOSCs employing poly[(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl)-alt-(3-fluoro-2-[(2-ethylhexy)carbonyl]thieno[3,4-b]thiophene-4,6-diyl)] (PTB7) as the donor polymer and DPDV/ DPEV as NFAs exhibited short-circuit current density (JSC) of 2.23/ 2.44 mA cm-2, open-circuit voltage (VOC) of 0.54/ 0.55 V, fill factor (FF) of 36.97/ 38.62 and power conversion efficiency (PCE) of 0.45/0.52%, respectively.
关键词： heterocycles,cyclic voltammetry,bulk heterojunction organic solar cells,non-fullerene acceptors materials,organic semiconductors
更新于2025-09-11 14:15:04
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Handbook of Graphene || Quantitative Real‐Time Evaluation of C/O Ratios and Stepwise Control of Deoxidization of Graphene Oxide Using Plasmonic‐Based Electrochemical Spectroscopy
摘要： Graphene oxide (GO) is composed of carbon and oxygen functional groups. It has been the subject of extensive research because these oxygen functional groups can be readily processed for various applications. A novel technique to deoxidize GO to reduced graphene oxide (rGO) sheets to enable the stepwise control of surface oxygen content and maximize the quality of carbon-based composites at low cost is needed. This chapter introduces new technology using the electrochemical (EC) technique of cyclic voltammetry to reduce GO, and shows that surface plasmon resonance (SPR) technology can be used to detect refractive index variations of dielectric materials near the metal surface while simultaneously using surface plasmon waves (SPWs) to detect the reduction of GO. It is important to understand the mechanisms of the atomic construction of GO surface oxygen-containing functional groups so that they can be developed in bulk for biosensor and optoelectronic applications. Directions for future research in the field of rGO film-based composites include increasing the stability of the electrodes, improving charge carrier mobility, tuning the dielectric layer and its optical band-gap properties, enhancing the binding interaction to improve the sensitivity of biosensors using the film, and modulating the SP resonance energy.
关键词： cyclic voltammetry (CV),reduced graphene oxide (rGO),Graphene oxide (GO),electrochemical surface plasmon resonance (EC-SPR)
更新于2025-09-11 14:15:04