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Growth and Self-Assembly of Silicon–Silicon Carbide Nanoparticles into Hybrid Worm-Like Nanostructures at the Silicon Wafer Surface
摘要： This work describes the growth of silicon–silicon carbide nanoparticles (Si–SiC) and their self-assembly into worm-like 1D hybrid nanostructures at the interface of graphene oxide/silicon wafer (GO/Si) under Ar atmosphere at 1000 °C. Depending on GO film thickness, spread silicon nanoparticles apparently develop on GO layers, or GO-embedded Si–SiC nanoparticles self-assembled into some-micrometers-long worm-like nanowires. It was found that the nanoarrays show that carbon–silicon-based nanowires (CSNW) are standing on the Si wafer. It was assumed that Si nanoparticles originated from melted Si at the Si wafer surface and GO-induced nucleation. Additionally, a mechanism for the formation of CSNW is proposed.
关键词： nanoparticles,thermal reduction,silicon carbide,graphene oxide,self-assembly,silicon,nanowires
更新于2025-09-23 15:23:52
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Efficient photo-Fenton activity in mesoporous MIL-100(Fe) decorated with ZnO nanosphere for pollutants degradation
摘要： Metal-organic frameworks (MOFs) have received significant interest as a promising photocatalyst for environmental remediation due to its high surface area and porous nature. The small pores (<2 nm) in microporous MOFs help the adsorption of small molecules but limits diffusion and accessing of bigger molecules from MOF cavities, thus preventing their applications in some situation. The aim of this work is to fabricate mesoporous MOF composite with larger pore sizes (>2 nm) and open pore cavities that can provide right pathways for ingoing and outgoing of molecules during catalysis. Herein, we successfully report stable mesoporous MIL-100(Fe) loaded with ZnO NS by an in situ self-assembly method. The prepared samples were characterized by Brunauer–Emmett–Teller (BET) and N2 adsorption-desorption isotherm to study their surface area and porosity. The catalytic performance of mesoporous MIL-100(Fe) was approximately 2-3 order of magnitude more than that of microporous MIL-100(Fe). Such higher catalytic activity in mesoporous MIL-100(Fe) can be ascribed to its mesocellular structure which can improve the molecular diffusion and accessibility inside MOF channels. The charge separation efficiency and photo-Fenton activity of mesoporous MIL-100(Fe) can further be increased by introduction of certain amount of ZnO NS and H2O2. Moreover, the as synthesized sample shows higher photo-Fenton degradation efficiency at lower pH value with certain amount of H2O2. Lastly, the possible catalytic mechanism has been tentatively proposed. This study not only used for the pollutants degradation but also provide useful platform for the application of mesoporous MOFs as an efficient photo-Fenton activity to various other fields.
关键词： Metal-organic framework,ZnO,MIL-100(Fe),self-assembly,photo-Fenton,mesoporous
更新于2025-09-23 15:23:52
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Size and dimension dependent surface-enhanced Raman scattering properties of well-defined Ag nanocubes
摘要： Understanding the role of the morphology and particle–particle interactions on the plasmonic properties is of significant importance for the development of nanomaterials with excellent optical properties. However, the preparation of precisely defined nanomaterials with sizes that span a large range and their controllable self-assembly still remain a great challenge. Here, a multistep seed-mediated method has been established for preparing uniform Ag nanocubes over a broad size range from nanoscale (50 nm) to microscale (1400 nm) and with different hierarchical nanostructures range from “zero-dimension” (“0D”) to “three-dimension” (“3D”). The influence of the size and the interactions between the Ag nanocubes on their surface-enhanced Raman scattering (SERS) properties have been systematically and quantitatively investigated. It is demonstrated through experiments and finite-difference time-domain (FDTD) calculations that the SERS activity is dependent on the matching of the nanocube size to the excitation wavelength. The optimal combinations are 80, 110 and 130 nm nanocubes with respect to 532, 638 and 785 nm excitation wavelength, respectively. Furthermore, the Raman enhancement of the Ag nanocube hierarchical nanostructures increases rapidly from “0D” to “3D”, due to the extra increase of the hot spots that is attributed to the out-of-plane plasmonic coupling realized in the “3D” hierarchical nanostructures. This work clearly illustrates the quantitative role of the size and dimension of Ag nanocubes on their SERS properties and provides fundamental information for the design of advanced nanomaterials with higher SERS sensitivity.
关键词： Silver nanocubes,Self-assembly,Surface-enhanced Raman scattering,Seed-mediated method
更新于2025-09-23 15:23:52
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CsxWO3 nanosheet-coated cotton fabric with multiple functions: UV/NIR shielding and full-spectrum-responsive self-cleaning
摘要： Utilizing fewer functional materials to achieve multifunctional fabrics via facile approaches have been confronting worldwide scientists with an enormous challenge. In this study, a novel multifunctional cotton fabric, combining UV/NIR shielding and full-spectrum-responsive self-cleaning, has been fabricated via self-assembly of CsxWO3 nanosheets based on electrostatic interaction assisted by Poly (diallyldimethylammonium chloride) (PDDA) in aqueous solution. The microstructure of CsxWO3 nanosheets and their self-assembly coating on cotton fabric were characterized and investigated. The functional properties of the CsxWO3-coated cotton fabric, including UV/NIR shielding and photocatalytic self-cleaning were evaluated. The results indicate that the CsxWO3-coated cotton fabric exhibits superb UV/NIR and heat shielding performance with 15.8 °C and 5.9 °C lower than no coverage and coverage by none-treated cotton fabric, respectively. Moreover, the well-coated cotton fabric demonstrates photocatalytic self-cleaning property responsive to the light ranging from UV, Vis to NIR, especially exhibits highly efficient self-cleaning under the respective irritation of full-spectrum, UV and Vis light (color faded completely within 10 h). In summary, the CsxWO3-coated fabrics can achieve multi-functions of UV shielding, heat insulation and self-cleaning by means of a single functional nanomaterial and promise of huge applications in functional textiles.
关键词： full-spectrum self-cleaning,self-assembly coating,UV/NIR shielding,CsxWO3 nanosheets,functional cotton fabric
更新于2025-09-23 15:23:52
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Fundamental and Practical Limits of Achieving Artificial Magnetism and Effective Optical Medium by Using Self-Assembly of Metallic Colloidal Clusters
摘要： The self-assembly of metallic colloidal clusters (so called plasmonic metamolecules) has been viewed as a versatile, but highly effective approach for the materialization of the metamaterials exhibiting artificial magnetism at optical frequencies (including visible and near infrared (NIR) regimes). Indeed, several proofs of concepts of plasmonic metamolecules have been successfully demonstrated in both theoretical and experimental ways. Nevertheless, this self-assembly strategy has barely been used and still remains an underutilized method. For example, the self-assembly and optical utilization of the plasmonic metamolecules have been limited to the discrete unit of the structure; the materialization of effective optical medium made of plasmonic metamolecules is highly challenging. In this work, we theoretically exploited the practical limits of self-assembly technology for the fabrication of optical magnetic metamaterials.
关键词： colloids,magnetism,self-assembly,plasmonic metamolecules
更新于2025-09-23 15:23:52
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Optically active polyaniline film based on cellulose nanocrystals
摘要： Chiral transfer from cellulose nanocrystals (CNCs) chiral nematic liquid crystal to polyaniline (PANI) is successfully achieved through co-assembly method for the first time, affording the PANI film based on CNCs optical activity. Meanwhile, the CNCs/PANI composite film displays notable Cotton effect ascribed to the polaron band transitions of PANI in circular dichroism (CD) spectrum. Hydrogen bond and electrostatic attraction favor the combination of two molecular chains in the mixed aqueous suspension and will lead to the chiral assembly of the PANI in the host chiral nematic film. However, the CD signal disappears when cholesteric phase collapse by acid protonation, and which demonstrates the chiral nematic ordering of the CNCs is essential to the chiral transfer. With the assistance of CNCs, PANI chains form a helically stacked structure. Thus, the optical activity of PANI originates from its long range organization.
关键词： co-assembly,chiral transfer,polaron transition,optical activity,Cotton effect
更新于2025-09-23 15:23:52
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A Lesson from Nature: Biomimetic Self-assembling Phthalocyanines for High-efficient Photothermal Therapy within the Biological Transparent Window
摘要： Development of facile but high-efficient small organic molecule based photothermal therapy (PTT) in the in vivo transparent window (800-900 nm) has been regarded as a minimally invasive and most promising strategy for potential clinical cancer treatment. Phthalocyanine (Pc) molecules with remarkable photophysical and photochemical properties as well as high extinction coefficients in the near-infrared region are highly desirable for PTT, but as far satisfying single-component Pc-based PTT within the in vivo transparent window (800-900 nm) has very rarely been reported. Herein, inspired by the self-assembly algorithm of natural bacteriochlorophylls (BChl's) c, d, and e, biomimetic self-assembling tetrahexanoyl Pc Bio-ZnPc with outstanding light-harvesting capacity was demonstrated to exhibit excellent PTT efficacy evidenced by both in vitro and in vivo results, within the biological transparent window.
关键词： photothermal therapy,phthalocyanine,biological transparent window,self-assembly,biomimetics
更新于2025-09-23 15:23:52
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The Belle II silicon vertex detector: Assembly and initial results
摘要： The "chip-on-sensor" concept of this detector minimizes the distance of the signal propagation from the double-sided silicon detector strips to the readout chips and thus reduces noise from strip capacitance. One half of the detector is built, the second half is being assembled at the time of writing. Prototypes have been tested in several test beams as well as in the so-called Phase 2 setup inside the detector structure. First results from a commissioning run of the Belle-II prototype SVD detector are presented. The measured signal-to-noise and timing performance are found to be according to design specifications.
关键词： Silicon vertex detector,First results,Assembly
更新于2025-09-23 15:23:52
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Voltage Stimulated Anion Binding of Metallo-Porphyrin Induced Crystalline 2D Nanoflakes
摘要： Voltage stimulated redox active materials received significant attention in the field of organic electronics and sensor technology. Consequently, such stimuli responsive materials triggered the formation of crystalline nanostructures facilitates the design of efficient smart devices hitherto unknown. Thus, we reported free base and metallo- tetratolylporphyrin linked ferrocene derivatives (H2TTP-Fc and ZnTTP-Fc) undergo distinct proton/anion binding mechanism in CHCl3 during bulk electrolysis at applied voltage of 1.4 V followed by nanospheres and crystalline 2D nanoflakes formation via MVD approach. Cyclic voltammetry and UV-Vis absorption studies of H2TTP-Fc and ZnTTP-Fc revealed the cation (H+)/anion (Cl-) binding affinity towards free ‘N’ atoms and Zn leads [H4TTP-Fc]+Cl- and H+[(Cl)ZnTTP-Fc]- thereby improvement in current and charge generation compared to initial state. SEM and TEM images revealed the nanospheres and 2D nanoflakes with average diameter of 50 – 200 nm and 0.2 - 1 μm. x-ray diffraction analysis suggest that protonated H2TTP-Fc aggregates exhibit amorphous nature, while H+[(Cl)ZnTTP-Fc]- revealed crystalline nature from layer-by-layer arrangement of nanoflakes assisted by π-π stacking and ion-dipole interactions. Hence, voltage responsive anion binding of metallo-porphyrins unique observation offer remarkable design of smart organic materials for sensors and biological applications.
关键词： anion binding,crystalline nanoflakes,metallo-porphyrin,self-assembly,bulk electrolysis
更新于2025-09-23 15:23:52
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An infrared IgG immunoassay based on the use of a nanocomposite consisting of silica coated Fe3O4 superparticles
摘要： A reliable, rapid and ultrasensitive immunoassay is described for determination of immunoglobulin G (IgG). It is making use of biofunctional magnetite (Fe3O4) superparticles coated with SiO2 and serving as an infrared (IR) probe. The unique IR fingerprint signals originating from the transverse and longitudinal phonon modes, respectively, of the asymmetric stretching of the Si–O–Si bridges display a satisfactory resistance to optical interference from the environment. The adoption of Fe3O4 superparticles instead of Fe3O4 nanoparticles as the magnetic core warrants a controllable structure and a strong magnetic response. This facilitates the efficient purification of the probes and the alleviation of the interfacial resistance between the liquid-solid interfaces by using a magnet. The gold-coated substrate was used to immobilize goat-anti-human IgG. The analyte (human IgG) was incubated with the IR probes, and then captured by the substrate immobilized antibody with the assistance of an external magnetic field. The integral area of the IR absorption band between 1250 cm?1 – 900 cm?1 was chosen for quantitative assay. The limit of detection is 95 fM, which is two orders of magnitude better than that without the magnetic field. The assay time was shortened from 2 h to 1 min. High selectivity, specificity, and long-term stability of the immunoassay were achieved. The performance of the assay when analyzing blood samples confirmed the practicability of the method.
关键词： Molecular vibration,IR spectroscopy,Core-shell,Sandwich immunoassay,Self-assembly,Protein,Blood,Superparamagnetism,Magnetic beads
更新于2025-09-23 15:23:52