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3D core-multishell piezoelectric nanogenerators
摘要： The thin film configuration presents obvious practical advantages over the 1D implementation in energy harvesting systems such as easily manufacturing and processing, and long-lasting and stable devices. However, ZnO-based piezoelectric nanogenerators (PENGs) generally rely on the exploitation of single-crystalline nanowires because of their self-orientation in the c-axis direction and ability to accommodate long deformations resulting in high piezoelectric performance. Herein, we show an innovative approach to produce PENGs by combining polycrystalline ZnO layers fabricated at room temperature by plasma-assisted deposition with supported small-molecule organic nanowires (ONWs) acting as 1D scaffolds. Such hybrid nanostructures present convoluted core-shell morphology, formed by a single-crystalline organic nanowire conformally surrounded by a poly-crystalline ZnO shell and combine the organic core mechanical properties with the ZnO layer piezoelectric response. In a step forward towards the integration of multiple functions within a single wire, we have also developed ONW-Au-ZnO nanoarchitectures including a gold shell acting as inner electrode achieving output piezo-voltages up to 170 mV. The synergistic combination of functionalities in the ONW-Au-ZnO devices promotes an enhanced performance generating piezo-currents one order of magnitude larger than the ONW-ZnO nanowires and superior to the thin film nanogenerators for equivalent and higher thicknesses.
关键词： piezoelectric nanogenerators,organic nanowires,ZnO,small-molecules,plasma deposition,core-shell nanowires
更新于2025-09-23 15:22:29
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Ultrasensitive detection of diclofenac in water samples by a novel surface-enhanced Raman scattering (SERS)-based immunochromatographic assay using AgMBA@SiO2-Ab as immunoprobe
摘要： In the last years, surface-enhanced Raman scattering based immunochromatographic assay (SERS-ICA) has been getting great attention and been applied for the detection of different target analytes. In this study, a novel SERS-ICA using AgMBA@SiO2-Ab as an immunoprobe has been developed for rapid, quantitative and ultrasensitive detection of a pharmaceutical diclofenac (DCF) residue in water samples. Ag, Ag@SiO2 and AgMBA@SiO2 nanoparticles (NPs) were synthesized and characterized. The immunoprobe was prepared by sandwiching the Raman reporter mercaptobenzoic acid (MBA) between the core-shell layers and immobilizing the monoclonal antibody (mAb) against DCF on the surface of the Ag@SiO2 NPs. Under optimal conditions, the sensitivity and limit of detection (LOD) of the SERS-ICA for DCF were found to be 9 pg mL-1 and 0.07 pg mL-1, respectively. The detection of the SERS-ICA for DCF was completed within 15 min. AgMBA@SiO2-Ab was stable within four months without significant loss of SERS intensity. The key to success of the SERS-ICA was the employment of the Ag@SiO2 NPs as the SERS substrate, which possessed gorgeous SERS enhancement capability, predominant biocompatibility and excellent stability. This SERS-ICA is potential as an ultrasensitive analytical method in point-of-care testing, clinical diagnosis, food inspecting and environmental monitoring.
关键词： Surface-enhanced Raman scattering (SERS),SERS-ICA,Diclofenac,Ag@SiO2 core-shell nanoparticles,Immunochromatographic assay (ICA)
更新于2025-09-23 15:22:29
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Conductive TiO2 nanorods via surface coating by antimony doped tin dioxide
摘要： Titanium dioxide (TiO2) has been widely used as the white pigment in paintings and coatings. It is of significance to endow TiO2 powders with the high conductivity to extend its application. In this research, rutile TiO2 nanorods were prepared as the substrate material. Further the surface coating by antimony doped tin dioxide (SbeSnO2) shell layers was achieved to obtain conductive TiO2 nanorods. The morphology and structure of TiO2@SbeSnO2 nanorods was mainly focused on to obtain high conductivity by optimizing the calcination temperature. When the temperature was properly applied at nearly 500 °C, the calcination led to the fusion and attachment of SbeSnO2 crystalline regions on the surface of TiO2 nanorods, forming a continuous intact coating layer and thus getting lower volume electrical resistivity of the composite nanopowder. However, after calcination at 600 °C or higher temperature, the integrity of SbeSnO2 shell layers would be destroyed, resulting in the increased electrical resistivity. The conductive TiO2 nanorods obtained at the optimized reaction condition showed a very low resistivity of 52 ± 1.6 Ω cm, in contrast to 105 Ω cm of the pure TiO2. The conductive TiO2 nanorods would be excellent candidate for antistatic or electromagnetic shielding applications in coatings.
关键词： Core-shell,Calcination,Titanium dioxide,Conductive
更新于2025-09-23 15:22:29
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Enhanced performance of porous silicone-based dielectric elastomeric composites by low filler content of Ag@SiO <sub/>2</sub> Core-Shell nanoparticles
摘要： In the present work, micropores and a low filler content of Ag@SiO2 nanoparticles (NPs) are synchronously introduced into polydimethylsiloxane (PDMS) film to obtain porous dielectric elastomeric composites. The morphology and dielectric and mechanical properties of the composites are investigated. The resulting composites possess high dielectric permittivity, low dielectric loss and low Young’s modulus, which is beneficial to the requirements of a dielectric elastomer actuator. This study provides an effective method to prepare high-performance PDMS-based dielectric porous dielectric elastomeric composites filled with low filler contents of Ag@SiO2 NPs.
关键词： core-shell particles,dielectric loss,Young’s modulus,dielectric permittivity,elastomer,Porous materials
更新于2025-09-23 15:22:29
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Manufacture of Magnesium Oxide Nanoparticles Coated with Silica Shells
摘要： MgO@SiO 2 core–shell nanoparticles were manufactured, and a synthetic protocol was developed to prepare MgO nanoparticles where the SiO2 shell thickness was less than 10 nm. The influence of synthesis parameters on the formation of MgO@SiO2 nanoparticles was studied. The fact of a SiO2 shell being formed on the MgO surface was established and the sizes of the thus-prepared MgO@SiO2 nanoparticles were determined by TEM and Fourier-transform IR spectroscopy.
关键词： metal oxide nanoparticles,magnesium oxide,silica shell,core–shell nanoparticles,tetraethoxysilane
更新于2025-09-23 15:21:21
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Design of Au@WO3 core?shell structured nanospheres for ppb-level NO2 sensing
摘要： As motivated by the driving force of the urgent demand for high-performance nitrogen dioxide (NO2) sensor, in this work, a novel structure of Au@WO3 core?shell nanospheres (CSNSs) was designed and successfully prepared for NO2 detection. The techniques of X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller measurement, and elemental mapping analysis were used for the characterizations of the obtained samples. The results demonstrated that Au nanoparticles with 25?50 nm in diameter were successfully encapsulated by WO3 shells with the thickness of 30?50 nm. The NO2 sensing performance of the Au@WO3 CSNSs as well as the pure WO3 nanospheres were systematically investigated. Compared with the pure WO3 nanospheres, Au@WO3 CNNSs exhibited overall enhanced NO2 sensing performances in terms of response, detection limit, and response/recovery times. At the optimal operating temperature of 100 °C, Au@WO3 CSNSs showed excellent NO2 selectivity and long-term stability. Notably, the excellent NO2 sensing performance of Au@WO3 CSNSs was slightly affected by humidity. The possible sensing mechanism of the enhanced NO2 sensing properties of the Au@WO3 CSNSs was discussed.
关键词： Au@WO3,Core?shell structure,Nanosphere,Gas sensor,NO2
更新于2025-09-23 15:21:21
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Single Nanocrystal Spectroscopy of Shortwave Infrared Emitters
摘要： Short-wave infrared (SWIR) emitters are at the center of ground-breaking applications in biomedical imaging, next-generation optoelectronic devices, and optical communications. Colloidal nanocrystals based on indium arsenide are some of the most promising SWIR emitters to date. However, the lack of single-particle spectroscopic methods accessible in the SWIR has prevented advances in both nanocrystal synthesis and fundamental characterization of emitters. Here, we demonstrate an implementation of a solution photon correlation Fourier spectroscopy (s-PCFS) experiment utilizing the SWIR sensitivity and time resolution of superconducting nanowire single-photon detectors to extract indium arsenide/cadmium selenide (InAs/CdSe) core/shell single-particle emission linewidths from colloidal nanocrystals emissive from 1.2 to 1.6 μm. We show that the average single InAs/CdSe nanocrystal ?uorescence linewidth is, remarkably, as narrow as 52 meV, similar to what has been observed in some of the most narrowband nanostructured emitters in the visible region. Additionally, the single nanocrystal ?uorescence linewidth increases with increasing shell thickness, suggesting exciton?phonon coupling as the dominant emission line-broadening mechanism in this system. The development of the SWIR s-PCFS technique has enabled measurements of spectral linewidths of colloidal SWIR-emissive NCs in solution and provides a platform to study the single NC spectral characteristics of SWIR emitters.
关键词： nanocrystals,single-molecule spectroscopy,core/shell,indium arsenide,short-wave infrared
更新于2025-09-23 15:21:21
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Highly tunable multiple narrow emissions of dyed dielectric-metal core-shell resonators: towards efficient fluorescent labels
摘要： We report a potential efficient fluorescent label based on the dyed dielectric-metal core-shell resonators. By utilizing the near-field coupling between the dyes and the multipolar sharp cavity plasmon resonances, the dyed dielectric-metal core-shell resonators with diameter of 1.02 μm are demonstrated to be capable of supporting multiple spontaneous emission peaks with the linewidths as narrow as ~ 10 nm in visible range, and these reshaped fluorescent emissions are insensitive to the surrounding dielectric environment. Furthermore, these multiple narrow emission peaks show a precise tunability on the spectrum by simply separating a nanometric dielectric layer between the dielectric core and the metallic shell, which may provide an attractive spectral multiplexing strategy in the fields of cell biology and medical sciences.
关键词： spectral multiplexing,cavity plasmons,fluorescent label,dyed dielectric-metal core-shell resonators,quality factor
更新于2025-09-23 15:21:21
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Transparent Conductive Materials (Materials, Synthesis, Characterization, Applications) || Metal Nanowires
摘要： Metal nanowires are one-dimensional entities of metals of either single crystalline or polycrystalline nature [1]. Metal nanowires have attracted tremendous research attention since the last two decades, because of their important applications in plasmonics [2], electronics [3], electrocatalysis [4], and so on. In the past decade, researchers have attempted to coat metal nanowires on a transparent substrate as a transparent conductive ?lm (TCF) [5–7]. The visible light transparency and the conductivity of TCFs on the basis of metal nanowires have improved rapidly, being comparable with the performance of the state-of-the-art indium tin oxide (ITO) TCFs [8–10]. The recognition of the potential applications of metal nanowire TCFs stimulates research zeal for the synthesis of metal nanowires. So far, a range of metal nanowires have been synthesized, including Ag nanowires (AgNWs) [11], Au nanowires (AuNWs) [12], Cu nanowires (CuNWs) [13], and Pt nanowires [14]. Bicomponent metal nanowires, such as Cu@Ni [15], Ag@Au [16], Cu@Ag [17], Ag@Ni [18], and Cu@Pt [19] core@shell nanowires, have also been synthesized. These nanowires have been coated on a substrate to produce TCFs, and the performance has been characterized. At early stage of the research on metal nanowire TCFs, the transparency was lower than 80%, and the sheet resistance was as large as several kΩ to MΩ. Both experimental investigation and theoretical modeling have been extensively carried out to improve the performance of metal nanowire TCFs.
关键词： Core@shell nanowires,Transparent conductive films,Plasmonics,Electronics,Au nanowires,Metal nanowires,Ag nanowires,Cu nanowires,Electrocatalysis
更新于2025-09-23 15:21:21
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Preparation of composite Ag@Au core–shell nanoparticles and their linear and nonlinear optical properties
摘要： We herein report the preparation of composite Ag@Au core–shell nanoparticles (NPs) through galvanic replacement reaction and the investigations of linear and nonlinear optical properties. TEM micrographs envisage the formation of core–shell NPs. EDS elemental mapping images demonstrate the homogeneous distribution of the elements and their chemical composition. The powder XRD pattern confirms the formation of highly crystalline composite Ag@Au core–shell NPs. The UV–Vis absorption spectrum shows contribution of Ag and Au characteristic absorption bands and the slight red shift provides the strong evidence for coating of Au shell over the Ag core. Moreover, the linear optical parameters such as the extinction coefficient, reflectance, refractive index, conductivity, susceptibility and polarizability are studied. z-scan analysis reveals the enhanced nonlinear optical properties of the composite Ag@Au core–shell NPs with nonlinear refraction coefficient (n2) being ten times higher than that of Ag NPs and eight times increase in comparison with that of Au NPs.
关键词： Nonlinear optical properties,Ag@Au core–shell nanoparticles,z-scan technique,Galvanic replacement reaction,Linear optical properties
更新于2025-09-23 15:21:21