- 标题
- 摘要
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- 实验方案
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Improved breakdown strength of Poly(vinylidene Fluoride)-based composites by using all ball-milled hexagonal boron nitride sheets without centrifugation
摘要： Hexagonal boron nitride (h-BN) is an ideal candidate to endow ferroelectric polymers with high energy density ((cid:1)(cid:2)) due to its intrinsic high breakdown strength ((cid:3)(cid:4)) of 800 kV/mm. Generally, it is believed that only boron nitride nanosheets (BNNSs) could remarkably improve (cid:3)(cid:4) of composite. Nevertheless, low-yield and time-consuming preparation procedures of BNNSs greatly limits the application of h-BN. To overcome this challenge, in this study, all ball-milled h-BN (B-BN) sheets were entirely used to enhance (cid:3)(cid:4) of poly(vinylidene fluoride) (PVDF) without any further centrifugation. (cid:3)(cid:4) of composites increased as ball-milling time increases at filler content of 8 wt%. Remarkably, PVDF with h-BN ball-milled for 16 h (B16-BN) possesses an impressive (cid:3)(cid:4) value of 506.8 kV/mm, which is 2.86 times that of neat PVDF (272.4 kV/mm) and even 1.33 times higher than that of PVDF/h-BN composites (380.6 kV/mm). (cid:3)(cid:4) of PVDF/B16-BN composites is close to that of PVDF/OH-BNNSs composites at same filler content, suggesting that the centrifugation is not a necessary procedure. Besides, improved dielectric loss, calculated (cid:1)(cid:2), mechanical properties and in-plane thermal conductivity can also be achieved for PVDF/B16-BN composites. These improved properties of PVDF/B16-BN composites indicate that the employment of B16-BN can avoid the weakness of low-yield and time-consuming preparation procedure of BNNSs and broaden its applications in the field of energy storage. Finally, the improved dispersion of OH-BN as well as synergy effect (f) on (cid:3)(cid:4) between OH-BN and OH-BNNSs were discussed to better understand these improved properties of PVDF/B16-BN composites.
关键词： Breakdown strength,No centrifugation,Synergy effect,Hexagonal boron nitride
更新于2025-09-19 17:13:59
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Single-Walled boron nitride nanotubes interaction with nickel, titanium, palladium, and gold metal atoms- A first-principles study
摘要： Ab initio calculations based on density functional theory was carried out to study the electronic properties of (3,3), (4,2), (5,2) and (6,0) boron nitride nanotubes when interacting with nickel, titanium, palladium and gold metal atoms. These interactions occurred via adsorption, intercalation, nitrogen substitutional doping and boron substitutional doping. The wide band gaps intrinsic to the pristine boron nitride nanotubes were successfully tuned upon interaction with the metal atoms irrespective of the type of interactions. However, for most of the interactions that occurred via intercalation and nitrogen substitutional doping, the boron nitride nanotube was found to possess semi-metallic properties. More states were added in the density of states upon interaction in which the d orbital of the transition metal atoms was found to be the major contributor to the increase in density of states.
关键词： Transition metals,Fermi energy,Density functional theory,Band gap,Boron nitride nanotubes
更新于2025-09-19 17:13:59
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Localized Nanoresonator Mode in Plasmonic Microcavities
摘要： Submicron-thick hexagonal boron nitride crystals embedded in noble metals form planar Fabry-Perot half-microcavities. Depositing Au nanoparticles on top of these microcavities forms previously unidentified angle- and polarization-sensitive nanoresonator modes that are tightly laterally confined by the nanoparticle. Comparing dark-field scattering with reflection spectroscopies shows plasmonic and Fabry-Perot-like enhancements magnify subtle interference contributions, which lead to unexpected redshifts in the dark-field spectra, explained by the presence of these new modes.
关键词： dark-field scattering,plasmonic microcavities,nanoresonator mode,Au nanoparticles,hexagonal boron nitride
更新于2025-09-19 17:13:59
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Hexagonal Boron Nitride Phononic Crystal Waveguides
摘要： Hexagonal boron nitride (h-BN), one of the hallmark van der Waals (vdW) layered crystals with an ensemble of attractive physical properties, is playing increasingly important roles in exploring two-dimensional (2D) electronics, photonics, mechanics, and emerging quantum engineering. Here we report on the demonstration of h-BN phononic crystal waveguides with designed pass and stop bands in the radio frequency (RF) range, and controllable wave propagation and transmission, by harnessing arrays of coupled h-BN nanomechanical resonators with engineerable coupling strength. Experimental measurements validate that these phononic crystal waveguides confine and support 15 to 24 megahertz (MHz) wave propagation over hundreds of micrometers. Analogous to solid-state crystal lattices, phononic bandgaps and dispersive behaviors have been observed and systematically investigated in the h-BN phononic waveguides. Guiding and manipulating acoustic waves on such additively integratable h-BN platform may facilitate multiphysical coupling and information transduction, and open up new opportunities for coherent on-chip signal processing and communication via emerging h-BN photonic and phononic devices.
关键词： integrated phononics,phononic crystal waveguide,nanoelectromechanical systems (NEMS),acoustic wave,Hexagonal boron nitride (h-BN),radio frequency
更新于2025-09-19 17:13:59
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Plasmonically enabled two-dimensional material-based optoelectronic devices
摘要： Two-dimensional (2D) materials, such as graphene, transition metal dichalcogenides, black phosphorus and hexagonal boron nitride, have been intensively investigated as building blocks for optoelectronic devices in the past few years. Very recently, significant efforts have been devoted to the improvement of the optoelectronic performances of 2D materials, which are restricted by their intrinsically low light absorption due to the ultrathin thickness. Making use of the plasmonic effects of metal nanostructures as well as intrinsic plasmon excitation in graphene has been shown to be one of the promising strategies. In this minireview, recent progresses in 2D material-based optoelectronics enabled by the plasmonic effects are highlighted. A perspective on more possibilities in plasmon-assisted 2D material-based optoelectronic applications will also be provided.
关键词： Transition metal dichalcogenides,Plasmonic effects,Two-dimensional materials,Black phosphorus,Hexagonal boron nitride,Graphene,Optoelectronic devices
更新于2025-09-19 17:13:59
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Boron nitride/sulfonated polythiophene composite electro-catalyst as the TCO and Pt-free counter electrode for dye-sensitized solar cells: 21% at dim light
摘要： Boron nitride (BN) is newly introduced as a non-metal electro-catalyst for the counter electrode of a dye-sensitized solar cell (DSSC). By applying a conductive binder of sulfonated poly(thiophene-3-[2-(2-methoxyethoxy)ethoxy]-2,5-diyl) (s-PT), the BN/s-PT composite film was successfully wrapped around each carbon fiber (CF) in the flexible carbon cloth (CC) substrate via a low-cost drop-coating method. Each CF in CC provided a one-dimensional electron transfer core, and the wrapped BN/s-PT composite film functioned as the mesoporous electro-catalytic shell. Compared to pristine BN and pristine s-PT electrodes, the electrochemical and impedance performances of the BN/s-PT composite film were incredibly enhanced due to the synergetic effect of BN nanoparticle and s-PT binder; the former offered large active surface area and high intrinsic heterogeneous rate constant, the latter formed fast electron transfer matrices. With a proper BN weight percentage among BN/s-PT solutions, the best DSSC coupling with a BN/s-PT composite counter electrode exhibited a good cell efficiency (η) of 9.21% at 1 sun, showing a great potential to substitute the expensive platinum (8.11%). At the dim light environment (i.e., T5 fluorescent illumination), the DSSC reached attractive η’s of 21.02% (6000 lux), 19.52% (3000 lux), and 17.48% (1000 lux).
关键词： boron nitride,DSSC,dim light,sulfonated polythiophene,counter electrode
更新于2025-09-19 17:13:59
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Decoding the structure of interfaces and impurities in 2D materials by photoelectron holography
摘要： The properties of atomically thin materials essentially depend on their structures, including impurities, defects and interfaces with underlying substrates. Thus, the detailed structural information is relevant for creation of 2D materials with desired properties. Here, we explore the capabilities of photoelectron diffraction and holography for structural analysis of atomically thin layers using as examples such systems as h-BN, graphene, and modified graphene with boron impurities. We show that for planar 2D crystals with commensurate interface to the substrate, it is possible to visualize the interface and impurities with high spatial resolution, and to distinguish possible non-equivalent structural units. Our approach applied to B-doped graphene on Ni(1 1 1) and Co(0 0 0 1) surfaces has allowed to reveal asymmetry of boron concentrations in the two carbon sublattices and established its dependence on the applied synthesis procedure and chosen substrate. The obtained results suggest that such approach can be widely applied for studies of various 2D systems, where the structures of interfaces and defects are of remarkable importance.
关键词： doping,structure,photoelectron diffraction,graphene,hexagonal boron nitride,photoelectron holography
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Zhenjiang, China (2019.8.4-2019.8.8)] 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Femtosecond Laser-assisted Fabrication of Fluorescent Boron Nitride Quantum Dots
摘要： As a kind of heavy metal-free quantum dot, boron nitride quantum dots (BNQDs) have attracted great interest due to their unique optical properties. Although there many synthesis methods of BNQDs, most of them require complex or time-consuming procedures, which limits the application of BNQDs. Here, we present a facile synthesizing method of few-layer BNQDs, which is based on liquid-phase ultra-short laser pulse ablation and ultrasonic-assisted exfoliation methods. The fabricated BNQDs are systematically characterized by atomic force microscope, transmission electron microscope, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The products possess an average size of about 2.1 nm with few-layer thickness. Because of the abundant surface functional groups, the BNQDs show bright luminescence emission under UV light irradiation.
关键词： femtosecond laser pulse ablation,ultrasonic-assisted exfoliation,boron nitride quantum dots
更新于2025-09-16 10:30:52
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A novel electrochemiluminescence sensor based on resonance energy transfer system between nitrogen doped graphene quantum dots and boron nitride quantum dots for sensitive detection of folic acid
摘要： Electrochemiluminescence resonance energy transfer (ECL-RET) between quantum dots (QDs) was firstly proposed. In this work, boron nitride quantum dots (BNQDs) as the donor and nitrogen doped graphene quantum dots (NGQDs) as the acceptor were confirmed by the absorption spectrum, the emission spectrum and fluorescence spectrum. Based on the reaction between FA and the SO4?? in the ECL system of NGQDs/BNQDs/K2S2O8, the ECL sensing platform for FA was successfully constructed. Surprisingly, a stable and strong ECL signal was obtained based on the RET, which was used for signal-off detection of FA in the presence of coreactant K2S2O8. Notably, about 10-fold enhancement was observed compared with the absence of BNQDs. The proposed sensor showed wide linear ranges of 1.0 × 10?11 M to 1.0 × 10?4 M and a low detection limit of 5.13 × 10?12 M. Simultaneously, the sensor was successfully applied to detection of FA in human serum samples with excellent recoveries. Therefore, the NGQDs/BNQDs system provided a new perspective for development of novel ECL-RET sensors.
关键词： Folic acid,Nitrogen doped graphene quantum dots,Resonance energy transfer,Boron nitride quantum dots,Electrochemiluminescence
更新于2025-09-16 10:30:52
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Nd:YAG pulsed laser brazing of cBN to steel matrix with Zr modified Aga??Cua??Ti active brazing alloy
摘要： The study was to investigate the modifying effect of the active element Zr on the properties of mechanical alloyed (MA) AgCu28–4.5Ti brazing alloys, especially the joint performance of cubic boron nitride (cBN)/45 steel brazed with AgCu28–4.5Ti–4Zr active brazing alloy. The brazing process was carried out using an Nd:YAG pulsed laser device under a high purity argon atmosphere. The granularity distribution and composition analysis of the MA brazing alloys, microstructural examinations and phase analysis were performed using a laser granularity analyzer, scanning electron microscopy (SEM) equipped with energy dispersion spectrometry (EDS), and X–ray diffraction (XRD) techniques. The results indicate that the alloy particles are refined, sizes are uniform, and the formation of the hard-brittle phase is reduced owing to the addition of the active element Zr. The wettability of the brazing alloy containing Zr is enhanced. The reaction of the active element Zr with Ag or Cu inhibits the combination of Ti with Ag or Cu under rapid laser heating and cooling, and further promotes the generation of Ti-B and Ti-N compounds. The joining mechanism is derived from the formation of a continuous reaction layer between cBN and the brazed alloy, containing a sub-outer structure of TiB, TiB2, TiN, ZrB2, and an outer structure consisting of AgZr2, Cu10Zr7. This multi-layered structure, which is from cBN to 45 steel, realizes the metallurgy combination of the brazing alloy and cBN particles. The friction and wear tests indicate that the reliable connection of cBN to steel is realized.
关键词： Joint performance,Laser brazing,Active brazing alloy,Cubic boron nitride,Microstructure
更新于2025-09-16 10:30:52