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Multifunctional Ag@NaGdF4:Yb3+, Er3+ core-shell nanocomposites for dual-mode imaging and photothermal therapy
摘要： Multifunctional core-shell nanostructure, which can be applied on bio-imaging and photothermal therapy (PTT), has attracted tremendous interest in recent years. Here, Ag@NaGdF4:Yb3+, Er3+ core-shell nanostructure incorporating luminescent, magnetic and photothermal conversion properties was prepared via a simple method. The as-prepared nanocomposites (NCs) exhibit uniform core-shell sphere morphology, green up-conversion luminescence (UCL), good paramagnetic and photothermal conversion behaviors. The luminescence resonance energy transfer (LRET) between Ag nanoparticles (NPs) and NaGdF4:Yb3+, Er3+ NPs were researched. The cytotoxicity test on HeLa cells using methyl thiazolyltetrazolium (MTT) assay shows good biocompatibility of the core-shell NCs. Moreover, in vitro computed tomography (CT) and UCL imaging studies and in vitro PTT of living assay suggest that the core-shell NCs can be used as theranostic nanoagents for dual-mode imaging guided PTT for tumor.
关键词： Dual-mode imaging,Core-shell structure,Multifunctional nanocomposites,Photothermal therapy
更新于2025-09-19 17:15:36
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Core–shell structured poly(vinylidene fluoride)- <i>grafted</i> -BaTiO <sub/>3</sub> nanocomposites prepared <i>via</i> reversible addition–fragmentation chain transfer (RAFT) polymerization of VDF for high energy storage capacitors
摘要： Core–shell structured poly(vinylidene fluoride)-grafted-barium titanate (PVDF-g-BaTiO3) nanocomposites were prepared by surface-initiated reversible addition–fragmentation chain transfer (RAFT) polymerization of VDF from the surface of functionalized BaTiO3 nanoparticles. The ceramic fillers were first surface-modified with xanthate functions to further allow the RAFT grafting of VDF. A series of structured core shells were synthesized by tuning the feed [initiator functionalized nanoparticles]0 : [monomer]0 ratio, varying from 3 to 5, 10 and 20 wt%. Fourier transform infrared spectroscopy (FTIR), high resolution magic angle spinning (HRMAS) NMR and thermogravimetric analysis (TGA) confirmed the successful surface functionalization of the ceramic filler and the grafting of the PVDF shell onto the surface of the BaTiO3 cores. Transmission electron microscopy results revealed that BaTiO3 nanoparticles are covered by thin shells of PVDF, with thickness varying from 2.2 to 5.1 nm, forming a core–shell structure. HRMAS 19F indicated a grafting of 39–50 units of VDF. X-ray diffraction measurements together with FTIR measurements revealed that PVDF was present in the α form. Thermal properties also indicated that the addition of a small amount of the BaTiO3 filler to the PVDF matrix increased the melting temperature from 168 °C for neat PVDF to 173 °C for PVDF-g-BaTiO3 (20 wt%) and decreased the crystallinity of PVDF from 47% to 21%.
关键词： Nanocomposites,Core-Shell Structure,BaTiO3,PVDF,RAFT Polymerization,Polymer Chemistry,Dielectric Materials
更新于2025-09-19 17:15:36
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N-Doped K3Ti5NbO14@TiO2 Core-Shell Structure for Enhanced Visible-Light-Driven Photocatalytic Activity in Environmental Remediation
摘要： A novel N-doped K3Ti5NbO14@TiO2 (NTNT) core-shell heterojunction photocatalyst was synthesized by firstly mixing titanium isopropoxide and K3Ti5NbO14 nanobelt, and then calcinating at 500 °C in air using urea as the nitrogen source. The samples were analyzed by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and X-ray photoelectron spectroscopic (XPS) spectra. Anatase TiO2 nanoparticles were closely deposited on the surface of K3Ti5NbO14 nanobelt to form a nanoscale heterojunction structure favorable for the separation of photogenerated charge carriers. Meanwhile, the nitrogen atoms were mainly doped in the crystal lattices of TiO2, resulting in the increased light harvesting ability to visible light region. The photocatalytic performance was evaluated by the degradation of methylene blue (MB) under visible light irradiation. The enhanced photocatalytic activity of NTNT was ascribed to the combined effects of morphology engineering, N doping and the formation of heterojunction. A possible photocatalytic mechanism was proposed based on the experimental results.
关键词： visible-light photodegradation,core-shell structure,TiO2,K3Ti5NbO14 nanobelt
更新于2025-09-19 17:15:36
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<i>In situ</i> synthesis of n–n Bi <sub/>2</sub> MoO <sub/>6</sub> & Bi <sub/>2</sub> S <sub/>3</sub> heterojunctions for highly efficient photocatalytic removal of Cr( <scp>vi</scp> )
摘要： Exploiting novel photocatalysts with high efficiency and durability for reduction of hexavalent chromium (Cr(VI)) has gained attention from fundamental science and industrial research. In this work, we synthesized novel two-dimensional (2D) n–n Bi2MoO6 & Bi2S3 heterojunctions by a facile in situ anion exchange process for remarkably efficient removal of Cr(VI). Results show that Bi2MoO6 & Bi2S3 heterojunctions with core–shell structures are formed through the intimate contact of Bi2MoO6 core and Bi2S3 shell. The prepared Bi2MoO6 & Bi2S3 heterojunctions exhibit unprecedented photocatalytic activity for reduction of Cr(VI) under visible light irradiation. The optimized BMO-S1 heterojunction displays the highest reduction efficiency (kapp = 0.164 min?1) for Cr(VI) reduction. To the best of our knowledge, it is one of the highest reduction rate achieved among reported photocatalysts for Cr(VI) reduction under visible-light irradiation. Detailed studies show that strong selective adsorption for Cr(VI) enhances this unprecedented photocatalytic activity. Moreover, the intimate heterojunction between Bi2MoO6 core and Bi2S3 shell can efficiently deteriorate the charge carrier recombination and Bi2S3 content can boost visible light harvesting, thereby contributing to the remarkable photocatalytic catalytic activity, which were proven by PL, EIS and transient photocurrent responses. Characterization of Mott–Schottky plots and DRS prove that the Bi2MoO6 & Bi2S3 heterojunctions established a type-II band alignment with intimate contact, accounting for the efficient transfer and separation of photogenerated carriers. This work provides a simple route for facial synthesis of heterojunction photocatalysts for Cr(VI) reduction in industrial applications.
关键词： photocatalytic,visible light,Cr(VI) reduction,heterojunctions,Bi2S3,core-shell structure,Bi2MoO6
更新于2025-09-19 17:15:36
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Core-shell structure-induced high displacement response in piezoelectric ceramics: A theoretical design
摘要： In this work, a series of piezoelectric composites with core-shell structure are proposed to pursue high displacement response under a low applied electric field. The shell and core consist of piezoelectric and non-piezoelectric material, respectively. A finite element method (FEM) is introduced to simulate the distribution of local electric field and the displacement response. The results show that the largest piezoelectric displacement response of these core-shell structural composites reaches twenty-five times larger than that of pure piezoelectric ceramic under the applied electric field of 2 kV/mm, which can be explained by the fact that the local electric field inside the shell is enhanced up to dozens of times as large as the applied electric field. It is also suggested that the displacement response of piezoelectric composites can be heightened by adopting smaller shell volume fraction, or increasing the permittivity or decreasing the Young's modulus of the core.
关键词： Displacement response,Finite element method (FEM),Core-shell structure,Piezoelectric
更新于2025-09-19 17:15:36
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Plasmonic Ag@TiO <sub/>2</sub> Core-Shell Nanoparticles for Enhanced CO <sub/>2</sub> Photoconversion to CH <sub/>4</sub>
摘要： Ag@TiO2 nanoparticles (NPs) with Ag metal cores and TiO2 semiconductor shells were prepared with a hydrothermal method and their structure was characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The core-shell Ag-TiO2 NPs were deposited on a glass plate and employed as photocatalysts for CO2 conversion by irradiation of solar simulator (AM1.5) under CO2 atmosphere. Selective CH4 evolution by CO2 photoconversion was attained with the core-shell Ag@TiO2 NP photocatalyst. The CH4 evolution rate normalized by specific surface areas was ten times higher than those of reference TiO2 NPs and conventional TiO2 NPs with accompanying Ag deposits. The role of the Ag core was also demonstrated in photodecomposition of a dye by the core-shell Ag@TiO2 NPs. These results suggested the high photocatalytic activity of the core-shell Ag@TiO2 NPs was archived due to bandgap improvement of the TiO2 shell and increase of photon flux to the TiO2 shell by the plasmonic Ag core.
关键词： Photocatalytic CO2 Reduction,Surface Plasmonic Resonance,Ag@TiO2,Core-shell Structure,Light Scattering Effect
更新于2025-09-19 17:13:59
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Macroscopic Au@PANI Core/shell Nanoparticle Superlattice Monolayer Film with Dual-responsive Plasmonic Switches
摘要： The self-assembled gold nanoparticles superlattice displays unusual but distinctive features such as highly mechanical and free-standing performance, electrical conductivity and plasmonic properties, which were widely employed in various applications especially in biological diagnostics and optoelectronic devices. Two-dimensional (2D) superlattice monolayer film composed of a given metal nanostructure, it is rather challenging to tune either its plasmonic properties or its optical properties in a reversible way, and it is not reported. It is therefore of significant value to construct free-standing 2D superlattice monolayer film of gold nanoparticles with intelligent response and desired functions. Herein, we developed an easy and efficient approach to construct gold nanoparticles superlattice film with a dual-responsive plasmonic switch. In this system, gold nanoparticles were firstly coated by polyaniline (PANI), and then interracially self-assembled into monolayer film at the air-liquid interface. PANI shell plays two important roles in superlattice monolayer film. Firstly, PANI shell acts as a physical spacer to provide a steric hindrance to counteract the van der Waals (vdWs) attraction between densely packed nanoparticles (NPs), resulting in the formation of superlattice by adjusting the thickness of the PANI shell. Secondly, PANI shells provide superlattice film with multiple stimuli such as electrical potential and pH change, leading to reversible optical and plasmonic responsive. Superlattice monolayer film can show a vivid color change from olive green to pink, or from olive green to violet by the change of corresponding stimuli. And the localized surface plasmonic resonance (LSPR) of superlattice monolayer film can be reversibly modulated by changing both local pH and applying electric potential. Notably, a significant plasmonic shift of superlattice monolayer film can be achieved to 157 nm, when PANI shell with the thickness of 35 nm and gold nanorods as core were used. The superlattice monolayer film with dual-responsive plasmonic switches is promising for a range of potential applications in optoelectronic devices, plasmonic and colorimetric sensors, and Surface enhanced Raman scattering (SERS).
关键词： plasmonic switching,dual-responsive,superlattice,2D monolayer film,core shell structure
更新于2025-09-19 17:13:59
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Self‐assembled core‐shell structured organic nanofibers fabricated by single‐nozzle electrospinning for highly sensitive ammonia sensors
摘要： Electrospinning is a unique method to prepare 1-dimentional nanofiber for large-scale manufacturing. Here in, we demonstrated chemical sensors based on the semiconducting nanofibers with core-shell structure by simple single-nozzle electrospinning with the spontaneous phase separation. The core-shell structure nanofiber has large active sites which make it highly sensitive to chemical analytes. The thickness of the sensing shell can be tuned by controlling the mass ratio of core and shell components. As a demonstration, the nanofiber-based sensor exhibits high sensitivity to low-concentration ammonia (ppb level), as well as stability and reversibility. This unique fast single-nozzle electrospinning technique used to fabricate semiconducting nanofibers with core-shell structure provides a facile and designable process for the integration of multifunctional organic semiconducting layer into the organic electronic system.
关键词： nanofiber,chemical sensor,core-shell structure,electrospinning
更新于2025-09-19 17:13:59
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Enrichment and Identification of Metallothionein by Functionalized Nano-Magnetic Particles and Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry
摘要： As a low molecular weight protein with the ability of binding metal ions and high inducibility, metallothionein (MT) is often regarded as an important biomarker for assessment of heavy metal pollution in water environment. In the light of that the traditional process of enrichment and identification is time-consuming and complicated, we prepared a core-shell nanoparticle, gold-coated iron oxide nanoparticles (Fe3O4@Au NPs) herein. It possessed the advantages of fast response to magnetic fields and optical properties attributing to Fe3O4 and Au nanoparticles, respectively. The Fe3O4@Au nanoparticles could be used to enrich MT simply through Au–S interaction, and the purified proteins were determined by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The results showed that the Fe3O4@Au nanoparticles could directly enrich MT from complex solutions and the detection limit could be as low as 10 fg mL?1.
关键词： Core-shell structure,Mass spectrometry,Low-abundant,Metallothionein,Gold nanoparticles,Magnetic nanomaterials
更新于2025-09-19 17:13:59
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New Strategy to Achieve Laser Direct Writing of Polymers: Fabrication of the Color-Changing Microcapsule with Core-Shell Structure
摘要： This paper proposed an efficient and environmentally friendly strategy to prepare a new color-changing microcapsule with core-shell structure for laser direct writing of polymers, and only the physical melt blending of polymers was employed. The laser absorber (SnO2) and the easily carbonized polymer (PC) were designed as the “core” and the “shell” of the microcapsule, respectively. The microcapsules were in situ formed during melt blending. SEM, TEM, and EDS confirmed the successful preparation of SnO2/PC microcapsules with core-shell structure. Its average diameter was 2.2 μm, and the “shell” thickness was 0.21?0.24 μm. As expected, this SnO2/PC microcapsule endowed polymers with an outstanding performance of NIR laser direct writing. The Raman spectroscopy and XPS indicated that the color change ascribed to the polymer carbonization due to the instantaneous high temperature caused by the SnO2 absorption of NIR laser energy. Optical microscopy observed a thick carbonization layer of 234 μm. Moreover, Raman depth imaging revealed the carbonization distribution, confirming that the amorphous carbon produced by the carbonization of the PC “shell” is the key factor of SnO2/PC microcapsules to provide polymers an outstanding performance of laser direct writing. This color-changing microcapsule has no selectivity to polymers due to providing a black color source (the carbonization of PC) itself, ensuring the high contrast and precision of patterns or texts after laser direct writing for all general-purpose polymers. We believe that this novel strategy to achieve laser direct writing of polymers will have broad application prospects.
关键词： microcapsule,core-shell structure,carbonization,polymer,laser direct writing,near-infrared pulsed laser
更新于2025-09-16 10:30:52