Cu2-xSe Nanoparticles Research Articles

Structural and Optical Characterization of Copper Selenide (Cu2-XSe) Nanoparticles

The stoichiometric Cu2Se and non-stoichiometric Cu1.98Se nanoparticles were prepared by a simple chemical method at room temperature The X-ray diffraction patterns revealed the formation of single phase nanostructured Cu2Se and Cu1.98Se particles with cubic lattice for different deposition conditions and the particle size is 17.45 nm, 26.85 nm respectively for Cu2Se and Cu2-xSe. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of single phase Cu2Se and Cu1.98Se nanoparticles, with characteristic vibrational modes of Cu and Se ions. Scanning electron microscopy (SEM) studies revealed that the Cu2Se particle surface is found to be textured with grains of irregular shapes while for Cu1.98Se, a mesh like structure which is loosely packed than Cu2Se is observed. This distinction may be due to variations in Cu content as seen from EDAX analysis. UV-Vis Studies specify blue shift from the bulk copper selenide as observed from the absorption shoulders occurs at 281 nm for Cu2Se and 276 nm for Cu1.98Se samples. The Optical band gap obtained for Cu2Se and Cu2-xSe nanoparticles are 4.41 eV and 4.52 eV respectively.

Reduced graphene oxide coated Cu2−xSe nanoparticles for targeted chemo-photothermal therapy

Recently, copper chalcogenide semiconductors have been reported as new near-infrared (NIR) photothermal agents. However, it is difficult to modify them with recognition molecules, and their photothermal conversion efficiencies are relatively low, making it difficult to achieve the targeted photothermal ablation of cancer cells with a high efficiency. In this study, reduced graphene oxide (rGO) was first coated on the surface of Cu2-xSe nanoparticles (NPs) to provide abundant functional groups for the next modification and to increase the photothermal conversion efficiency. Then, doxorubicin (DOX) was loaded and folic acid (FA) molecules were covalently linked onto the surface of Cu2−xSe/rGO nanocomposites. The formed DOX@Cu2−xSe@rGO-FA nanocomposites were successfully used as chemo-photothermal agents for the targeted killing of cancer cells by utilizing the recognition ability of FA, chemotherapy effect of DOX and photothermal effects of rGO and Cu2−xSe NPs. Under the 980-nm NIR laser irradiation, the nanocomposites showed significantly enhanced chemo-photothermal therapy effect, which can be potentially applied in the nanomedicine field.

Vacancy engineering of Cu2-xSe nanoparticles with tunable LSPR and magnetism for dual-modal imaging guided photothermal therapy of cancer.

The vacancies in the semiconductor nanocrystals not only induce unique properties, but also provide spaces for engineering them with multifunctions by the introduction of other elements. Herein, the vacancy of Cu2-xSe nanoparticles was tuned by doping with magnetic ferric ions (Fe3+) at room temperature, and the position and intensity of the near-infrared localized surface plasmon resonance (LSPR) in the resultant nanostructure can be finely controlled by altering the feeding amount of Fe3+ ions. The results of the density-functional theory (DFT) calculations show that both doping and replacement reactions are favourable. Owing to its tunable near-infrared absorption and magnetic property, the obtained hybrid nanostructure was demonstrated to be a novel nanotheranostic agent for effective deep-tissue photoacoustic imaging, magnetic resonance imaging, and photothermal therapy of cancer.

Determination of L-Cysteine Based on Energy Transfer between Cu2-xSe Nanoparticles and Rhodamine B

Abstract The fluorescence of Rhodamine B (RhB) could be quenched by the manner of photo-induced electron transfer with Cu2-xSe nanoparticles as the energy receptor and RhB as the energy donor. However, L-cysteine (L-Cys) was capable of recovering the fluorescence of Rhodamine B, and the recovered fluorescence intensity was proportional to the concentrations of L-Cys. Based on that, a novel method for detecting L-Cys was established. After mixing L-Cys and RhB pretreated by Cu2-xSe nanoparticles at pH 4.6 and 30 °C for 2 min, a linear relationship was obtained between the fluorescence intensity of RhB at 575 nm and the concentrations of L-Cys in the range of 2.5 × 10−7−1.1 × 10−6 M. This method was used for the determination of L-cys with a detection limit (3σ/k) of 5.5 × 10−8 M. The common amino acids presented little interference for the detection of L-Cys.

Ambient Aqueous Synthesis of Ultrasmall PEGylated Cu2-x Se Nanoparticles as a Multifunctional Theranostic Agent for Multimodal Imaging Guided Photothermal Therapy of Cancer.

Ultrasmall PEGylated Cu2-x Se nanoparticles with strong near-infrared absorption have been prepared by an ambient aqueous method. The resultant water-soluble and biocompatible nanoparticles are demonstrated to be a novel nanotheranostic agent for effective deep-tissue photoacoustic imaging, computed tomography imaging, single-photon emission computed tomography imaging, and photothermal therapy of cancer.

Catalytic chemiluminescent detection of cholesterol in serum with Cu2-x Se semiconductor nanoparticles.

It is very important to be able to accurately and rapidly measure the cholesterol level in the human body, as cholesterol is associated with various diseases, such as Alzheimer's disease. In this work, a novel method of detecting cholesterol using chemiluminescence (CL) based on a newly prepared semiconductor catalyst, Cu2-x Se nanoparticles (Cu2-x Se NPs), was developed. It was found that the Cu2-x Se NPs strongly enhanced the CL signal by producing a large number of reactive oxygen species (ROS) in the luminol-Cu2-x Se NPs system. Based on the UV-vis-NIR absorption spectra, zeta potential, CL spectrum, and an investigation of the ROS, a possible mechanism for the CL was proposed. This CL-based method was successfully applied to determine cholesterol. It was found that the enhanced CL was proportional to the concentration of cholesterol over the range of 82 nM to 1.96μM with a detection limit of 0.062 nM, and that added cholesterol was successfully detected in human serum with a mean recovery of 97%.

Ratiometry, Wavelength, and Intensity: Triple Signal Readout for Colorimetric Sensing of Mercury Ions by Plasmonic Cu2-xSe Nanoparticles

In this study, we have reported a new colorimetric platform for sensitive and selective sensing of Hg2+ using near-infrared (NIR) plasmonic Cu2-xSe nanoparticles (NPs) as reporters. Because of ultrahigh affinity between Hg2+ and Se2–, the added Hg2+ can react with Cu2-xSe NPs and exchange their Cu+/Cu2+, yielding a HgSe layer around the host NPs. Accordingly, the absorption profiles of the Cu2-xSe NPs are modulated substantially: The absorbance at 400–600 nm is increased, and the NIR localized surface plasmon resonance dramatically decreases with a more than 150 nm bathochromic shift. Thus, the system possesses triple signal responses, namely, ratiometry, wavelength, and intensity, to the analytes simultaneously. Such uniquely multiple signal output not only provides more choices for the quantification, but also enhances the reliability in the analyte detection. By rationally choosing poly(allylamine hydrochloride) as the NP template, Hg2+ ions can be determined as ranging from 0–800 nM. The detection lim...

Synthesis of Plasmonic Cu2-x Se@ZnS Core@Shell Nanoparticles.

We report the synthesis of plasmonic Cu2-x Se@ZnS core@shell nanoparticles (NPs). We used a shell growth approach, starting from Cu2-x Se NPs that have been shown before to exhibit a localized surface plasmon resonance (LSPR). By careful synthesis planning we avoided cation exchange reactions and received core@shell nanoparticles that, after oxidation under air, exhibit a strong LSPR in the NIR. Interestingly, the crystalline, closed ZnS shell that we grew with variable thickness still allowed a slow oxidation of the core under ambient conditions, while the core was effectively protected from reduction, even in the presence of reducing agents such as borane tert-butyamine complex and diisobutylaluminum hydride, giving rise to a stable particle LSPR, also under strongly reducing conditions.

Synthesis of In2Se3 and Cu2-xSe Micro- and Nanoparticles with Microwave-Assisted Solvothermal and Aqueous Redox Reactions for the Preparation and Stabilization of Printable Precursors for a CuInSe2 Solar Cell Absorber Layer

Micro- and nanoparticles were synthesized and stabilized in order to process a copper indium diselenide (CISe) solar cell absorber layer. A microwave assisted solvothermal reaction for In2Se3 particles was performed, finding that smaller particles could be obtained in shorter times and at lower temperatures than with a conventional autoclave based solvothermal synthesis. In a second route In2Se3 and Cu2-xSe nanoparticles have been synthesized via aqueous redox reactions and been Zeta potential-stabilized to acquire a nanoparticulate ink. This ink was drop cast in ambient atmosphere and annealed in N2-atmosphere leading to the formation of CISe at lower temperatures than with state-of-the-art processing routes.

Synergetic catalytic effect of Cu2-xSe nanoparticles and reduced graphene oxide coembedded in electrospun nanofibers for the reduction of a typical refractory organic compound.

A new heterogeneous catalytic composite composed of nonstoichiometric Cu2-xSe nanoparticles (NPs) with high copper deficiency and graphene oxide (GO) is prepared by coembedding in electrospun nanofibers of a poly(vinylpyrrolidone) (PVP) support, wherein GO in the nanofibers is converted into reduced GO (rGO) via heat treatment. The as-prepared composite Cu2-xSe/rGO/PVP nanofibers have demonstrated superior catalytic activity toward the reduction of a refractory organic compound by taking 4-nitrophenol (4-NP) as an example. In the presence of NaBH4, the Cu2-xSe/rGO/PVP nanofibers display a synergetic effect between Cu2-xSe and rGO in PVP nanofibers compared to their independent components or corresponding nanofibers. Furthermore, the Cu2-xSe/rGO/PVP nanofibers exhibit a favorable water-stable property via heat treatment to solidify the hydrophilic PVP matrix, which makes the composite display good reusability, stability in aqueous solution, and separability from a water medium. This work not only presents a direct, convenient, and effective approach to doping semiconductor nanomaterials into polymer nanofibers but also provides fundamental routes for further investigations about the synergetic effect between different materials based on the platform of electrospun nanofibers.

Dialkyldiselenophosphinato-metal complexes – a new class of single source precursors for deposition of metal selenide thin films and nanoparticles

We report here a new synthetic approach for convenient and high yield synthesis of dialkyldiselenophosphinato-metal complexes. A number of diphenyldiselenophosphinato-metal as well as diisopropyldiselenophosphinato-metal complexes have been synthesized and used as precursors for deposition of semiconductor thin films and nanoparticles. Cubic Cu2-xSe and tetragonal CuInSe2 thin films have been deposited by AACVD at 400, 450 and 500 °C whereas cubic PbSe and tetragonal CZTSe thin films have been deposited through doctor blade method followed by annealing. SEM investigations revealed significant differences in morphology of the films deposited at different temperatures. Preparation of Cu2-xSe and In2Se3 nanoparticles using diisopropyldiselenophosphinato-metal precursors has been carried out by colloidal method in HDA/TOP system. Cu2-xSe nanoparticles (grown at 250 °C) and In2Se3 nanoparticles (grown at 270 °C) have a mean diameter of 5.0 ± 1.2 nm and 13 ± 2.5 nm, respectively.

Ultrafast Optical Mapping of Nonlinear Plasmon Dynamics in Cu2–xSe Nanoparticles

We report on the experimental investigation and theoretical modeling of the ultrafast nonlinear optical response exhibited by Cu2–xSe nanoparticles in a broad range of wavelengths, from the red to the near-infrared, under excitation with intense femtosecond-laser pulses. The ultrafast dynamics of the localized plasmon resonance of the system is mapped by pump–probe differential transmission measurements. Deviations from theoretical predictions based on standard two-temperature model (TTM) are revealed in the subpicosecond time-scale where the nonlinear phenomenon is more pronounced. The key-role played by nonthermalized carriers is investigated in detail on the basis of an extended TTM.