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An in situ inward etching strategy for constructing a p-p heterojunction Cu2S/Cu2-xSe material based on brass as an effective counter electrode for quantum dot sensitized solar cells
摘要： Composite counter electrode Cu2S/Cu2-xSe nanosheets based on brass are fabricated by an in situ inward etching method using Cu(OH)2 nanotubes as a template. Due to superior electrocatalytic activity towards the polysulfide electrolyte, the quantum dot-sensitized solar cells constructed with Cu2S/Cu2-xSe counter electrodes deliver a considerable power conversion efficiency of 6.10% under 1 sun illumination, which is a 22% enhancement compared to that of Cu2S/brass (5.00%). According to the results of BET testing, solid-state J-V measurements and transient photocurrent measurements, the enhanced electrocatalytic activity is attributed to two aspects: one is the larger surface active area, which provides more active sites for the electrolyte, and the other is the formation of a p-p heterojunction for more effective electron transfer in the counter electrode. In addition, the band energy structure of the Cu2S/Cu2-xSe heterojunction is further investigated to understand the behavior of interfacial electron transfer. Finally, the outstanding electrochemical catalytic activity and stability of the Cu2S/Cu2-xSe counter electrode are proved by electrochemical impedance spectroscopy, Tafel polarization and cyclic voltammetry results for symmetric dummy cells, demonstrating that the Cu2S/Cu2-xSe composite is a desirable material as a counter electrode for quantum dot sensitized solar cells.
关键词： Cu2S/Cu2-xSe CE,Electrochemical catalytic activity,QDSCs,p-p heterojunction,Stability
更新于2025-09-11 14:15:04
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Investigations of the electron paramagnetic resonance parameters and defect structures for Cu2+ ions in BeO crystal with trigonally distorted tetrahedral symmetry
摘要： The electron paramagnetic resonance(EPR) parameters (g factors gi and hyperfine structure constants Ai, where i=x, z) for Cu2+ ions embedded in beryllium oxide (BeO) crystal at Be2+ sites with C3v local symmetry have been calculated by the complete diagonalization method (CDM) and high-order perturbation theory method (PTM). The calculated results from the two methods are in reasonable agreement with the observed data available. The defect structural data of the trigonal Cu2+ center in beryllium oxide are determined from the calculations and analyses.The calculated results show that the Be2+ ions are replaced by Cu2+ ions in BeO crystal and the ligands undergo outward movement.
关键词： Electron paramagnetic resonance (EPR),Crystal - and ligand- field theory,Defect structure,BeO:Cu2+
更新于2025-09-10 09:29:36
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Cu2-xS loaded diatom nanocomposites as novel photocatalysts for efficient photocatalytic degradation of organic pollutants
摘要： Diatom frustules with hierarchical structures have been widely investigated in many fields due to their unique optical features, excellent mechanical resistance and extraordinarily intricate pore patterns. Herein, Cu2-xS modified diatomite has been successfully fabricated for the first time via a mild method at room temperature. The Cu2-xS nanoparticles with diameters of 50–100 nm were uniformly distributed on the diatomite. The as-prepared Cu2-xS-diatomite (Cu2-xS-DE) exhibits excellent photocatalytic degradation efficiencies for MB and MO, which reach to 99.1% and 96.9% respectively in 40 min under the irradiation of UV–vis light with 20 mg photocatalyst. The degradation mechanism of the organic pollutant over the Cu2-xS-DE/H2O2 reaction system was also proposed. This work provides an effective strategy to design and prepare of the diatom-based nanomaterials with efficient photocatalytic degradation activity, which is of great value for the environmental applications.
关键词： Diatom,Cu2-xS,Photocatalyst,Organic pollutant,Degradation
更新于2025-09-10 09:29:36
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A ratiometric fluorescent and colorimetric dual-signal sensing platform based on N-doped carbon dots for selective and sensitive detection of copper(II) and pyrophosphate ion
摘要： A simple ratiometric fluorescent and colorimetric dual-signal sensing system for Cu2+ and pyrophosphate ion (PPi) detection is established based on N-doped carbon dots (N-CDs) which are synthesized via one-step hydrothermal approach. In the strategy, 2,3-diaminophenazine (oxOPD), the oxidation product of o-phenylenediamine (OPD), can be adsorbed on the surface of N-CDs through electrostatic interaction, which efficiently quenches the fluorescence of N-CDs, meanwhile, oxOPD provides a new emission peak at 553 nm. In virtue of the selective oxidative and chromogenic reaction of OPD with Cu2+, a dual-readout sensing system for Cu2+ is achieved. In addition, the redox and chromogenic reaction among them can be inhibited by PPi, which protects effectively the fluorescence of N-CDs from quenching. This sensing system exhibits good selectivity and sensitivity toward Cu2+ and PPi over other analytes with a low detection limit of 23 nM and 0.7 μM, respectively. Furthermore, the proposed sensing system displays a prospective application for quantitative assay of Cu2+ and PPi in practical samples.
关键词： N-doped carbon dots,ratiometric fluorescence,PPi,colorimetric detection,Cu2+
更新于2025-09-10 09:29:36
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Multipurpose sensing applications of biocompatible radish-derived carbon dots as Cu2+ and acetic acid vapor sensors
摘要： A recent trend in the preparation of carbon dots, an optically unique nanomaterials, revolves around the use of readily-available, low-cost natural resources as precursors and their multipurpose applications. In this work, a hydrothermal method for preparing biocompatible carbon dots from radish was developed. The carbon dots were then tested for sensing of Cu2+ and acetic acid vapor. The carbon dots exhibited blue emission under UV illumination with, a quantum yield of 15%. The fluorescence emission was selectively quenched when Cu2+ ions were added, giving a detection limit of 0.16 μM. A paper-based fluorescent sensor was fabricated and shown to sense Cu2+ with a limit of detection of 6.8 μM. The carbon dots were able to determine the Cu2+ concentration in real water samples, with excellent recovery and reliability. The carbon dots were also used as the sensing material in an optical electronic nose, and tested for real-time detection of acetic acid vapor. Using principal component analysis, different ratios of acetic acid to methanol in solution were successfully identified with a detection limit of 15.5%. The acetic acid concentration in a real vinegar sample was also accurately determined. Our results demonstrated that label-free carbon dots derived from readily available radish can be simply used as versatile probes, giving them potential uses in multipurpose sensing applications.
关键词： Radish,Hydrothermal,Carbon dots,Vapor sensor,Cu2+ sensor
更新于2025-09-09 09:28:46
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Novel fluorescent probes for relay detection copper/citrate ion and application in cell imaging
摘要： Two novel fluorescent probes L1 and L2 displayed sequential detection of Cu2+ ion and citrate anions (CA) with high selectivity and sensitivity in DMSO/H2O solution (v/v=1/1, 0.01 M, Tris-HCl buffer, pH 7.20). The detection limits of probes L1 and L2 were 2.14×10-8 and 2.70×10-8 M for Cu2+ ion, respectively, which were much lower than drinking water permission concentrations by the United States Environmental Protection Agency (U.S. EPA) and World Health Organization (WHO). Moreover, the probe L1 could be apply for monitoring Cu2+ and CA in living cells.
关键词： Cu2+,Cells imaging.,Successive fluorescent detection,Citrate anions
更新于2025-09-09 09:28:46
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Transformation of the Anion Sublattice in the Cation-Exchange Synthesis of Au <sub/>2</sub> S from Cu <sub/>2-x</sub> S Nanocrystals
摘要： Cation exchange is a versatile post-synthetic technique that has been exploited in the synthesis of metastable nanocrystals through preservation of the anion sublattice. Here we report on the mechanistic details of the synthesis of metastable Au2S via cation exchange with Cu2-xS nanocrystals. This conversion requires a transformation of the anion sublattice, from hcp in Cu2-xS to bcc Au2S accompanied by an expansion of the unit cell. The ligand environment plays a key role in the driving force of the reaction as the presence of oleylamine allows the conversion to proceed at room temperature while the addition of trioctylphosphine hinders the reaction. By employing transmission electron microscopy (TEM) on faceted nanocrystals and partial cation exchange of nanocrystals, it was demonstrated that the reaction proceeds in a highly directional manner through the pyramidal facets. Since cation exchange produces high quality nanocrystals as seen through XRD and TEM, UV-Vis and Raman spectroscopy were used to characterize the optoelectronic properties of the metastable Au2S nanocrsytals. A Tauc plot analysis revealed a band gap of 2.6 eV, while two intrinsic Raman modes were identified at 265 cm-1 and 329 cm-1. Density functional theory (DFT) calculations of structures, energy bands, optical spectra, and phonon spectra were performed and combined with the experimental data to provide additional insights into the characterization of Au2S nanocrystals.
关键词： XRD,Raman spectroscopy,UV-Vis,trioctylphosphine,nanocrystals,TEM,Cation exchange,DFT,Cu2-xS,anion sublattice transformation,Au2S,oleylamine
更新于2025-09-09 09:28:46
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Total Aqueous Synthesis of Au@Cu <sub/>2?</sub><i> <sub/>x</sub></i> S Core–Shell Nanoparticles for In Vitro and In Vivo SERS/PA Imaging‐Guided Photothermal Cancer Therapy
摘要： Both accurate tumor navigation and nanostructures with high photothermal (PT) conversion efficiency are important but remain challenging to achieve in current biomedical applications. This study reports an anion exchange-based facile and green approach for synthesizing Au@Cu2?xS core–shell nanoparticles (NPs) in an aqueous system. In addition to the PT effect of the suggested NPs, the surface-enhanced Raman scattering (SERS) is also significantly improved due to the tailored localized surface plasmon resonance coupling between the Au metal core and the Cu2?xS semiconductor shell. Using an epitaxial strategy, Au@Cu2O NPs are first obtained by the in situ reduction of cupric hydroxide on a cresyl violet acetate-coated Au core; then, Au@Cu2?xS NPs are obtained via anion exchange between the S2? and Cu2O shell. Both the Cu/S atomic ratio and the Cu2?xS shell thickness can be adjusted conveniently. Hence, the ideal integration of the plasmonic Au core and Cu2?xS shell into a single unit is conducive not only to highly efficient PT conversion but also to the construction of a SERS-based navigator. This new type of SERS-guided NP, with enhanced photoacoustic signals, is an important candidate for both accurate tumor navigation and nondestructive PT treatment guided in vivo by two modes of optical imaging.
关键词： navigation treatment,photothermal therapy (PTT),Au@Cu2?xS core–shell nanoparticles (NPs),plasmonic enhancement,surface-enhanced Raman scattering (SERS)
更新于2025-09-09 09:28:46
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Enzyme-free multicolor biosensor based on Cu2+-modified carbon nitride nanosheets and gold nanobipyramids for sensitive detection of neuron specific enolase
摘要： In this work, we have synthesized Cu2+-modified carbon nitride nanosheets (Cu2+-C3N4) as peroxidase mimic catalytic substance, which is more active than the horseradish peroxidase enzyme in extreme environments. Gold nanobipyramid (Au NBP) is a good chromogenic substrate for multicolor display because the longitudinal plasmon bands of AuNRs can be easily tuned by adjusting their aspect ratios and used as an excellent indicator for colorimetric detection of immunoassays. The generation of TMB2+ from sandwich complex (peroxidase-like catalysis) efficiently etches Au NPBs to produce multicolor variations from brown to olive, green, blue, purple, purple, red, pink, and colorless in presence of varied concentrations of neuron specific enolase (NSE). The experimental results show that the colorimetric detection ranging from 312.5 to 20,000 pM with a detection limit of 92.8 pM, which is higher than other multicolor based sensors. The Cu2+-C3N4 nanosheets and Au NBPs based colorimetric visual (naked eye) semi-quantitative method as a potential platform towards the detection of important biomolecules in clinical and therapeutic applications. The proposed method is simple, low-cost and enzyme-free to detect NSE for the first time.
关键词： Gold nanobipyramids,Cu2+-C3N4 nanosheets,Mimic enzyme activity,Neuron specific enolase,Biosensor
更新于2025-09-04 15:30:14
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Water-dispersible Copper Sulfide Nanocrystals via Ligand Exchange of 1-dodecanethiol
摘要： In colloidal Cu2-xS nanocrystal synthesis, thiols are often used as organic ligands and sulfur source, as they yield high-quality nanocrystals. However, thiol ligands on Cu2-xS nanocrystals are difficult to exchange, limiting the applications of these nanocrystals in photovoltaics, biomedical sensing and photocatalysis. Here, we present an effective and facile procedure to exchange native 1-dodecanethiol on Cu2-xS nanocrystals by 3-mercaptopropionic acid, 11-mercaptoundecanoic acid, and S2- in formamide under inert atmosphere. The product hydrophilic Cu2-xS nanocrystals have excellent colloidal stability in formamide. Furthermore, the size, shape and optical properties of the nanocrystals are not significantly affected by the ligand exchange. Water-dispersible Cu2-xS nanocrystals are easily obtained by precipitation of the nanocrystals capped by S2-, 3-mercaptopropionate or 11-mercaptoundecanoate from formamide, followed by redispersion in water. Interestingly, the ligand exchange rates for Cu2-xS nanocrystals capped with 1-dodecanethiol are observed to depend on the preparation method, being much slower for Cu2-xS nanocrystals prepared through heating-up than through hot-injection synthesis protocols. XPS studies reveal that the differences in the ligand exchange rates are due to the surface chemistry of the Cu2-xS nanocrystals, where the nanocrystals prepared via hot-injection synthesis have a less dense ligand layer due to the presence of trioctylphosphine oxide during synthesis. A model is proposed that explains the observed differences in the ligand exchange rates. The facile ligand exchange procedures reported here enable the use of high-quality colloidal Cu2-xS nanocrystals prepared in the presence of 1-dodecanethiol in various applications.
关键词： thiol ligands,surface chemistry,ligand exchange,colloidal Cu2-xS nanocrystals,water-dispersible
更新于2025-09-04 15:30:14