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Sequential Growth of High Quality Sub-10 nm Core-Shell Nanocrystals: Understanding the Nucleation and Growth Process Using Dynamic Light Scattering
摘要： Monodisperse sub-10 nm core-shell nanocrystals have been extensively studied owing to their important applications in catalysis, bioimaging, nanomedicine and so on. In this work, an amorphous shell component-crystallization strategy has been proposed to prepare high quality sub-10 nm NaYF4:Yb/Er@NaGdF4 core-shell nanocrystals successfully via a sequential growth process. Dynamic light scattering technique has been used to investigate the secondary nucleation and growth process of forming the core-shell nanocrystals. The size and morphologies evolution of the core-shell nanocrystals reveal that the secondary nucleation of the shell component is unavoidable after hot-injecting of the shell precursor at high temperature, which followed by dissolution and re-crystallization process (an Ostwald Ripening process) to partially produce the core-shell nanocrystals. The present study demonstrates that the size of seed nanocrystals and the injection temperature of the shell component precursor play a vital role in formation of core-shell nanostructures completely. This work will provide an alternative strategy for precisely controllable fabrication of sub-10nm core-shell nanostructures for various applications.
关键词： Seed-mediated growth,Monodisperse,Core-shell nanoparticles,Dynamic light scattering
更新于2025-09-04 15:30:14
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Electrochemical Effects of Depositing Iridium Oxide Nanoparticles onto Conductive Woven and Nonwoven Flexible Substrates
摘要： This Article reports methods to deposit iridium oxide nanoparticles (IrOx NPs) onto ?exible materials for charge storage and the stable charge?discharge mechanism. In this work, IrOx NPs were electrodeposited onto commercially available ?exible surfaces of both knit and nonwoven cotton and nonwoven carbon-based (carbon nanotubes and graphene) textile substrates. Carbon-coated cotton materials were fabricated by reducing graphene oxide on fabric. Flexible electrode materials were fabricated by either reducing graphene oxide on cotton fabric or binding carbon nanotubes/graphene into a free-standing platform. The IrOx NPs were then electrodeposited onto ?exible platform samples by applying a positive potential to the fabric. After deposition, the resultant speci?c capacitance of the materials increased within the range from 192% to 2747% and was stable for over 1000 charge and discharge cycles.
关键词： ?exible materials,iridium oxide nanoparticles,?exible substrates,electrodeposition
更新于2025-09-04 15:30:14
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Er3+-to-Yb3+ and Pr3+-to-Yb3+ energy transfer for highly efficient near-infrared cryogenic optical temperature sensing
摘要： Here, the very high thermal sensing capability of Er3+,Yb3+ doped LaF3 nanoparticles, where Er3+-to-Yb3+ energy transfer is used, are reported. Also Pr3+,Yb3+ doped LaF3 nanoparticles, with Pr3+-to-Yb3+ energy transfer, showed temperature sensing in the same temperature regime, but with lower performance. The investigated Er3+,Yb3+ doped LaF3 nanoparticles show a remarkably high relative sensitivity Sr up to 6.6092 %K-1 (at 15K) in the near-infrared (NIR), in the cryogenic (15 – 105K) temperature region opening a whole new thermometric system suitable for advanced applications in the very low temperature ranges. Up to date reports on NIR cryogenic sensors are very scarce.
关键词： near-infrared,Pr3+-to-Yb3+ energy transfer,Er3+-to-Yb3+ energy transfer,LaF3 nanoparticles,cryogenic temperature sensing
更新于2025-09-04 15:30:14
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Iono-Fluorochromic Nanoparticles Derived from Octa-Pyrene-Modified Polyhedral Oligomeric Silsesquioxanes (POSS) Organic Frameworks for Fluoride Ion Detection
摘要： Three octa-pyrene modified POSS molecules POSS-(C0-Py)8, POSS-(C1-Py)8 and POSS-(C3-Py)8 were successfully prepared by condensation reactions between pyrene carboxylic acid and amino-substituted POSS in good yields, and they were structurally characterized by various spectroscopic methods. All those three POSS molecules could form stable supramolecular hydrogen-bonded organic framework (HOF) structures via amide linkages. Among of them, POSS-(C1-Py)8 displayed the purest excimer emission due to the efficient stacking of pyrene residues in their HOF structures, which was further developed to a highly efficient green-emissive iono-fluorochromic sensor for F- ion. This ratiometric fluorescence sensor displayed the unique selectivity to the F- ion with a detection limit of lower than 5 × 10-5 M and rapid detection within 10 minutes, and it almost did not respond to anions such as Cl-, Br-, I-, AcO-, NO3-, and HPO42- ions. A comparative experiment using ion chromatography method to measure the concentration of the F- ion was conducted, revealing that our iono-fluorochromic sensor had better selectivity and higher anti-interference ability than the traditional chromatography method particularly in the presence of interfering anions. In contrast to the common F- ion fluorescence sensors, which rely on the turn-on or turn-off of the fluorescence, and other traditional chromatography techniques, this type of F- iono-fluorochromic sensors would make it attractive and convenient for fast and reliable detection of F- ion.
关键词： fluoride ion detection,iono-fluorochromic,hydrogen-bonded organic frameworks,POSS,nanoparticles
更新于2025-09-04 15:30:14
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X-ray study of anisotropically shaped metal halide perovskite nanoparticles in tubular pores
摘要： Recently, we have reported that metal halide perovskite nanoparticles formed in nanoporous alumina and silicon thin films exhibit blue shifted photoluminescence due to spatial confinement, thus allowing for color tuning of the emission by varying the pore size. While perovskite nanoparticles grown in nanoporous alumina films have been integrated into LEDs, similar approaches have failed with silicon. Here, we report the results of investigating the structure of the alumina pore system and the perovskite crystallites forming within. We use two x-ray diffraction techniques, namely, small-angle x-ray scattering (SAXS) and high-energy microbeam wide-angle x-ray scattering (WAXS). SAXS reveals that the alumina pore system diffracts like regularly arranged tubes with the average diameter and nearest neighbor distance of 12 nm and 20 nm, respectively. High-energy microbeam WAXS shows that perovskite nanoparticles within the nanoporous alumina have a distinctly anisotropic shape with the average particle length along and perpendicular to the pore axis of 26 nm and 13 nm, respectively. In contrast, no shape anisotropy has been detected for nanoparticles inside the silicon pores in a previous study. This suggests that utilizing nanoporous alumina has a twofold advantage. First, the tubular alumina pores, spanning the entire insulating film, offer percolated paths for the perovskite to fill. Second, the elongation of the nanoparticles in the tubular alumina pores can be expected to aid device performance as the length of the nanoparticles approaches the active layer thickness (ca. 40 nm) of LEDs, while the small diameter of the crystallites accounts for the observed blue shifted emission.
关键词： LEDs,anisotropic shape,nanoporous alumina,SAXS,WAXS,nanoparticles,metal halide perovskite
更新于2025-09-04 15:30:14
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Structural basis for a naphthyl end-capped oligothiophene with embedded metallic nanoparticles for organic field-effect transistors
摘要： We report on the apparent structure of 5,500-bis(naphth-2-yl)-2,20:50,200-terthiophene (NaT3) in organic field-effect transistors (OFETs) with and without embedded silver nanoparticles. Using regular- and microbeam grazing incidence wide- and small-angle X-ray scattering, the device structure is characterized locally in the area with the embedded particles. The NaT3 thin film order is reduced and the found unit cell (a ? 25.7 A? , b ? 5.87 A? , c ? 8.03 A? , and b ? 98.9(cid:2)) differs significantly from the one reported in the bulk, but shows no significant change, when the particles corresponding to the crystal size are incorporated into the device structure. At the same time, the apparent thin film crystal sizes in OFETs are found to be similar with and without the embedded particles. In both cases, the carrier mobilities are of the order of 10(cid:3)4 cm2/(V s).
关键词： X-ray scattering,oligothiophene,organic field-effect transistors,silver nanoparticles,crystal structure
更新于2025-09-04 15:30:14
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Gold nanoparticles – an optical biosensor for RNA quantification for cancer and neurologic disorders diagnosis
摘要： The objective of this study is to develop a facile tool for the absolute detection and quantification of nucleic acid transcripts, using a gold nanoparticle-based optical biosensor. Topoisomerase 1 (TOP1) and tyrosyl DNA phosphodiesterase 2 (TDP2) were among the nucleic acid transcripts of choice due to their role as genomic instability biomarkers and their implication in various cancers and neurologic disorders. This opens the door to develop a simple tool that can be used for diagnosing and monitoring treatment response for such diseases, overcoming the requirements for high cost, time, and complexity of the existing technologies for the absolute quantification of transcripts of interest.
关键词： RNA extraction,genomic instability,tumor markers,gold aggregating gold,TDP2,TOP1,neurodegenerative diseases,magnetic nanoparticles
更新于2025-09-04 15:30:14
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Effect of Tin and Strontium Doping on the Photocatalytic Activity of Zinc Sulphide Nanoparticles for the Photocatalytic Degradation of Resorcinol under Solar and Ultra-Violet Light
摘要： Tin (Sn) and Strontium (Sr) doped Zinc Sulphide and pure Zinc Sulphide photocatalyst have been prepared by Sol-Gel method. The prepared photocatalyst have been characterised by Thermo gravimetric Differential Thermal Analysis, Scanning Electron Microscopy, Energy Dispersive X-ray, X-Ray Diffraction, ultra-violet visible spectroscopy and photoluminescence spectroscopy. Characterization Techniques have provided information of wurtzite hexagonal structure of Zinc Sulphide. The PL spectra have shown the blue shift of Zinc Sulphide after doping it with Tin and Strontium. Photocatalytic degradation study was done by the complete degradation of an organic pollutant Resorcinol in Sun light as well as in UV-light. The factors affecting the photocatalytic activity of photocatalyst viz. pH, catalyst loading and reuse of photocatalyst have been studied along with the photocatalytic degradation of Resorcinol. These external parameters have considerable influenced on the phtocatalytic activity of Zinc Sulphide.
关键词： Photocatalyst,Pollution,Sol-gel synthesis,Doping,Zinc sulphide nanoparticles,Photoluminescence
更新于2025-09-04 15:30:14
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Efficient synthesis of high solid content emulsions of AIE polymeric nanoparticles with tunable brightness and surface functionalization through miniemulsion polymerization
摘要： Efficient production and flexible surface functionalization are important developing directions for the synthesis of polymeric nanomaterials. In this work, aggregation-induced emission (AIE) polymeric nanoparticles (PNPs) were efficiently synthesized by encapsulating a model AIE luminogen, tetraphenylethylene (TPE), within a polymeric matrix via miniemulsion polymerization. The AIE PNPs with similar emission and particle properties were synthesized in a wide solid content range of 8–40 wt%. The particle size and photoluminescence intensity of AIE PNPs could be flexibly tuned by synthetic parameters including the surfactant content and TPE content. Furthermore, the surface carboxyl- and amino-functionalization of AIE PNPs were conveniently achieved through copolymerization of styrene and functional monomers methacrylic acid and 2-aminoethyl methacrylate hydrochloride, respectively, in miniemulsions. The surface functionalization extent could be facilely tuned by the content of functional monomers. This miniemulsion polymerization based technique could be a feasible and efficient method to prepare AIE PNPs with versatile surface functionalization, tunable brightness, and controllable particle properties for the applications in biodetection, bioimaging, etc.
关键词： high solid content,miniemulsion polymerization,Aggregation-induced emission,AIE polymeric nanoparticles,surface functionalization
更新于2025-09-04 15:30:14
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Dual?Wavelength Ratiometric Electrochemiluminescence Immunosensor for Cardiac Troponin I Detection
摘要： Ratiometric electrochemiluminescence (ECL) has attracted special focus in biological analysis field because it could eliminate the environmental interference to gain precise measurement. Herein, a dual?wavelength ratiometric ECL biosensor was designed for detection of cardiac troponin I (cTnI), where (4,4’?dicarboxylicacid?2,2’?bipyridyl) ruthenium(II) (Ru(dcbpy)3 2+) and Au nanoparticles loaded graphene oxide/polyethyleneimine (GPRu?Au) nanomaterial acts as an acceptor, and Au nanoparticles modified graphitic phase carbon nitride nanosheets composite (Au?CNN) acts as donor. Au?CNN shows high and steady ECL signal centered at 455 nm, which is well matched with the adsorption of GPRu?Au, thereby a high efficient electrochemiluminescent resonance energy transfer (ECL?RET) sensing platform is designed. AuNPs facilitate the immobilization of antibody on the nanomaterials through Au?N bond. The high surface area of graphene oxide/polyethyleneimine allows a large number of Ru(dcbpy)3 2+ to be loaded, which immensely amplify the ECL signal. This sensing platform exhibits outstanding analytical performance toward cTnI with a detection limit of 3.94 fg/mL (S/N=3). The high reliability, selectivity and sensitivity of this ratiometric ECL biosensor provides a versatile sensing platform for the bioanalysis.
关键词： carbon nitride nanosheets,ECL biosensor,graphene oxide,Ratiometric electrochemiluminescence,cardiac troponin I,Au nanoparticles
更新于2025-09-04 15:30:14