Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical ...Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical properties has yet to be explored.In this study,we report on the fabrication of intrinsically super-strong fluorescent silk by feeding Bombyx mori silkworm carbon nanodots(CNDs).The CNDs were incorporated into silk fibroin,hindering the conformation transformation,confining crystallization,and inducing orientation of mesophase.The resultant silk exhibited super-strong mechanical properties with breaking strength of 521.9±82.7 MPa and breaking elongation of 19.2±4.3%,improvements of 55.1%and 53.6%,respectively,in comparison with regular silk.The CNDs-reinforced silk displayed intrinsic blue fluorescence when exposed to 405 nm laser and exhibited no cytotoxic effect on cells,suggesting that multi-functional silks would be potentially useful in bioimaging and other applications.展开更多
Transition metal chalcogenides represent a class of the most promising alternative electrode materials for high-performance lithium-ion batteries （LIBs） owing to their high theoretical capacities. However, they suff...Transition metal chalcogenides represent a class of the most promising alternative electrode materials for high-performance lithium-ion batteries （LIBs） owing to their high theoretical capacities. However, they suffer from large volume expansion, particle agglomeration, and low conductivity during charge/discharge processes, leading to unsatisfactory energy storage performance. In order to address these issues, we rationally designed three-dimensional （3D） hybrid composites consisting of ZnSe nanodots uniformly confined within a N-doped porous carbon network （ZnSe ND@N-PC） obtained via a convenient pyrolysis process. When used as anodes for LIBs, the composites exhibited outstanding electrochemical performance, with a high reversible capacity （1,134 mA.h.g-1 at a current density of 600 mA.g-1 after 500 cycles） and excellent rate capability （696 and 474 mA.h.g-1 at current densities of 6.4 and 12.8 A.g-1, respectively）. The significantly improved lithium storage performance can be attributed to the 3D architecture of the hybrid composites, which not only mitigated the internal mechanical stress induced by the volume change and formed a 3D conductive network during cycling, but also provided a large reactive area and reduced the lithium diffusion distance. The strategy reported here may open a new avenue for the design of other multi functional composites towards high-performance energy storage devices.展开更多
Bismuth oxides are important battery materials owing to their ability to electrochemically react and alloy with Li,which results in a high capacity level,which substantially exceeds that of graphite anodes.However,thi...Bismuth oxides are important battery materials owing to their ability to electrochemically react and alloy with Li,which results in a high capacity level,which substantially exceeds that of graphite anodes.However,this high Li-storage capability is often compromised by the poor electrochemical cyclability and rate capability of bismuth oxides.To address these challenges,in this study,we design a hybrid architecture composed of reduced graphene oxide （rGO） nanosheets decorated with ultrafine Bi2O2.33 nanodots （denoted as Bi2O2.33/rGO）,based on the selective and controlled hydrolysis of a Bi precursor on graphene oxide and subsequent crystallization via solvothermal treatment.Because of its high conductivity,large accessible area,and inherent flexibility,the Bi2O2.33/rGO hybrid exhibits stable and robust Li storage （346 mA＆#183;h＆#183;g-1 over 600 cycles at 10 C）,significantly outperforming previously reported Bi-based materials.This superb performance indicates that decorating rGO nanosheets with ultrafine nanodots may introduce new possibilities for the development of stable and robust metal-oxide electrodes.展开更多
The electrocatalytic CO_(2)reduction reaction(CO_(2)RR)is regarded as a promising route for renewable energy conversion and storage,but its development is limited by the high overpotential and low stability and select...The electrocatalytic CO_(2)reduction reaction(CO_(2)RR)is regarded as a promising route for renewable energy conversion and storage,but its development is limited by the high overpotential and low stability and selectivity of electrocatalysts.Moreover,it is complicated to accurately adjust the nanostructure of electrocatalysts,which impacts repeatability.Herein,we propose the rational design and controlled preparation of ultrafine Ag nanodots decorated fish-scale-like Zn nanoleaves(Ag-NDs/Zn-NLs)for highly selective electrocatalytic CO_(2)reduction.The Ag-NDs/Zn-NLs can be in-situ grown on copper foil with simple electrodeposition and replacement reactions.Benefiting from the coordination and synergistic effect of Zn and Ag species,the reconstruction of Zn surface and the agglomeration of Ag-NDs are efficiently prevented,bringing high activity and durable electrocatalytic stability for CO_(2)-to-CO conversion.The Faradaic efficiency for CO production reaches 85.2%at a moderate applied potential of-1.0 V vs.reversible hydrogen electrode(RHE).This study provides a promising approach for controlling the catalytic activity and selectivity of CO_(2)RR through the structural adjustment and decoration of transition metal based nanocatalysts.展开更多
Molybdenum phosphide(MoP),owing to its abundant reserve and high theoretical capacity,is regarded as a promising anode material for potassium-ion batteries.However,it still suffers from the problems of acute volume ex...Molybdenum phosphide(MoP),owing to its abundant reserve and high theoretical capacity,is regarded as a promising anode material for potassium-ion batteries.However,it still suffers from the problems of acute volume expansion and weak diffusion kinetics.This study reports a simple method to synthesize a composite of molybdenum phosphide and porous carbon(MoP@PC)through simple mixing and annealing treatment.In the MoP@PC,lots of MoP nanodots with an average diameter of about 4 nm uniformly embedded in the petal-like porous carbon.The MoP@PC shows reversible capacities of 330 mAh g^(-1) at100 mA g^(-1) after 100 cycles,and ultra-long cycling stability with a capacity of 240 mAh g^(-1) after 1000 cycles at 1 A g^(-1) and 161 mAh g^(-1) after 1000 cycles at 5 A g^(-1).The structure of MoP@PC after charging-discharging cycles is also investigated by high resolution transmission electron microscope(HRTEM)and the result shows that MoP can still maintain the nanodot morphology without any agglomeration after 1000 cycles at 5 A g^(-1).The storage mechanism of potassium ions was studied as well,which reveals that MoP and potassium ion have a conversion reaction.展开更多
High-density ferroelectric BiFeO_(3)(BFO)nanodot arrays were developed through template-assisted tailoring of epitaxial thin films.By combining piezoresponse force microscopy(PFM)and Kelvin probe force microscopy(KPFM...High-density ferroelectric BiFeO_(3)(BFO)nanodot arrays were developed through template-assisted tailoring of epitaxial thin films.By combining piezoresponse force microscopy(PFM)and Kelvin probe force microscopy(KPFM)imaging techniques,we found that oxygen vacancies in nanodot arrays can be transported in the presence of an electric field.Besides triple-center domains,quadruple-center domains with different vertical polarizations were also identified.This was confirmed by combining the measurements of the domain switching and polarization vector distribution.The competition between the accumulation of mobile charges,such as oxygen vacancies,on the interface and the geometric constraints of nanodots led to the formation of these topological domain states.These abnormal multi-center topological defect states pave the way for improving the storage density of ferroelectric memory devices.展开更多
Ultrashort pulsed laser-induced periodic surface structures(LIPSS)can be generated on difFerent kinds of materials,which are widely utilized for modifying surface properties such as wettability,adhesion,and tribologic...Ultrashort pulsed laser-induced periodic surface structures(LIPSS)can be generated on difFerent kinds of materials,which are widely utilized for modifying surface properties such as wettability,adhesion,and tribological,as well as optical performances.Previous studies have focused mainly on one-dimensional LIPSS(i.e.,line structure)generation.In this study,a picosecond pulsed laser was used to irradiate stainless-steel surfaces for generating two-dimensional LIPSS,namely nanodot structures,by cross-scanning the laser beam for a different number of times.The obtained nanodot structures were found to be super hydrophilic just after laser irradiation,but turned to be hydrophobic after exposure in air for a few days.By cross・scanning the laser beam for the same number of times,local LIPSS rewriting was realized.This study showed the possibility of improving the homogeneity of the surface properties of steel materials through laser-induced nanodot structuring.展开更多
Multiferroic nanodots can be harnessed to aid the development of the next generation of nonvolatile data storage and multi-functional devices. In this paper, we review the computational aspects of multiferroic nanodot...Multiferroic nanodots can be harnessed to aid the development of the next generation of nonvolatile data storage and multi-functional devices. In this paper, we review the computational aspects of multiferroic nanodot materials and designs that hold promise for the future memory technology. Conception, methodology, and sys- tematical studies are discussed, followed by some up-to-date experimental progress towards the ultimate limits. At the end of this paper, we outline some challenges remaining in multiferroic research, and how the first principles based approach can be employed as an important tool providing critical information to understand the emergent phenomena in multiferroics.展开更多
Near-infrared （NIR） fluorescent metal nanodots may have significant advantages in biological detection and bioimaging. Herein, we introduce tunable near-infrared fluorescent gold nanodots （AuNDs） protected by bran...Near-infrared （NIR） fluorescent metal nanodots may have significant advantages in biological detection and bioimaging. Herein, we introduce tunable near-infrared fluorescent gold nanodots （AuNDs） protected by branched polyethylenimine （PEI） modified by surface segmental attachment of sulfhydryl groups （PEI-SH）, abbreviated as PEI-SH-AuNDs, for simultaneous gene delivery and cell imaging. The modified PEI endows the resultant PEI-SH-AuNDs with the following excellent advantages. Sulfhydryl groups of PEI-SH anchor to the surface of AuNDs, and such polycations with amine groups give PEI-SH-AuNDs remarkable stability. The cationic polymer PEI-SH with positive charges enables PEI-SH-AuNDs to perform gene delivery, and the gene transfection efficiency can reach 22.8%. Moreover, the fluorescence of PEI-SH-AuNDs is tunable from visible red light （wavelength 609 nm） to NIR light （wavelength 811 run） via an increase in the size of AuNDs. PEI-SH-AuNDs yielded gene transfection efficiency similar to that of commercial PEI, but showed much lower cytotoxicity and much greater red-shift fluorescence. With excellent photoluminescent properties, such multifunctional fluorescent PEI-SH-AuNDs hold promise in applications to bioimaging and as ideal fluorescent probes for tracking gene transfection behavior.展开更多
The fabrication of bit-patterned media （BPM） is crucial for new types of hard disk drives. The development of methods for the production of BPM is progressing rapidly. Conventional lithography reaches the limit rega...The fabrication of bit-patterned media （BPM） is crucial for new types of hard disk drives. The development of methods for the production of BPM is progressing rapidly. Conventional lithography reaches the limit regarding lateral resolution, and new routes are needed. In this study, we mainly focus on the dependence of the size and shape of magnetic nanodots on the Ar＋-ion etching duration, using silica dots as masks. Two-dimensional （2D） arrays of magnetic nanostructures are created using silica-filled diblock-copolymer micelles as templates. After the self-assembly of the micelles into 2D hexagonal arrays, the polymer shell is removed, and the SiO2 cores are utilized to transform the morphology into a （Co/Pt）2-multilayer via ion etching under normal incidence. The number of preparation steps is kept as low as possible to simplify the formation of the nanostructure arrays. High-resolution in situ grazing-incidence small-angle X-ray scattering （GISAXS） investigations are performed during the Ar＋-ion etching to monitor and control the fabrication process. The in situ investigation provides information on how the etching conditions can be improved for further ex situ experiments. The GISAXS patterns are compared with simulations. We observe that the dots change in shape from cylindrical to conical during the etching process. The magnetic behavior is studied by utilizing the magneto-optic Kerr effect. The Co/Pt dots exhibit different magnetic behaviors depending on their size, interparticle distance, and etching time. They show ferromagnetism with an easy axis of magnetization perpendicular to the film. A systematic dependence of the coercivitv on the dot size is observed.展开更多
It remains a great challenge to explore the facile way to fabricate multi-component nanoparticles in theranostic nanomedicine. Herein, an albumin nanoreactor templated synthesis of theranostic Gd203/CuS hybrid nanodo...It remains a great challenge to explore the facile way to fabricate multi-component nanoparticles in theranostic nanomedicine. Herein, an albumin nanoreactor templated synthesis of theranostic Gd203/CuS hybrid nanodots （NDs） has been developed for multimodal imaging guided photothermal tumor ablation. Gd2O3/CuS NDs are found to possess particle size of 4.4 ± 1.1nm, enhanced longitudinal relaxivity, effective photothermal conversion of 45.5%, as well as remarkable near-infrared fluorescence （NIRF） from Cy7.5-conjugated on albumin corona. The Gd203/CuS NDs further exhibited good photostability, en- hanced cellular uptake, and preferable tumor accumulation. Thus, the Gd203/CuS NDs generate remarkable NIRF imag- ing and Tl-weighted magnetic resonance （MR） imaging, and simultaneously result in effective photothermal tumor ab- lation upon irradiation. The albumin nanoreactor provides a facile and general strategy to synthesize multifunctional nanoparticles for cancer theranostics.展开更多
The electronic and transport properties of embedded boron nitride（BN） nanodot superlattices of armchair graphene nanoribbons are studied by first-principles calculations.The band structure of the graphene superlatti...The electronic and transport properties of embedded boron nitride（BN） nanodot superlattices of armchair graphene nanoribbons are studied by first-principles calculations.The band structure of the graphene superlattice strongly depends on the geometric shape and size of the BN nanodot,as well as the concentration of nanodots.The conduction bands and valence bands near the Fermi level are nearly symmetric,which is induced by electron-hole symmetry.When B and N atoms in the graphene superlattices with a triangular BN nanodot are exchanged,the valance bands and conduction bands are inverted with respect to the Fermi level due to electron-hole symmetry.In addition,the hybridization ofπorbitals from C and redundant B atoms or N atoms leads to a localized band appearing near the Fermi level.Our results also show a series of resonant peaks appearing in the conductance.This strongly depends on the distance of the two BN nanodots and on the shape of the BN nanodot. Controlling these parameters might allow the modulation of the electronic response of the systems.展开更多
Purpose: For post-mastectomy radiation therapy, skin dose must be accurately estimated to assess skin reactions, such as: erythema, desquamation, and necrosis. Even with advanced algorithms, planning systems do not al...Purpose: For post-mastectomy radiation therapy, skin dose must be accurately estimated to assess skin reactions, such as: erythema, desquamation, and necrosis. Even with advanced algorithms, planning systems do not always provide accurate dosimetry for target volumes distal to skin. Methods and Materials: In this study, a female anthropomorphic (ART) phantom and the newest generation of optically stimulated luminescence dosimeters (OSLD) (nanoDots, Landauer Inc.) were deployed to measure chest wall dose distribution. Since actual dose to patients’ lung and heart cannot be measured using in-vivo dosimetry, film was also used to verify the dose distribution to the left lung and heart. The treatment planning was performed using tolerance limits of 95% to 107% of prescription dose. The ART phantom was irradiated according to 3 three-dimensional (3D) conformal radiotherapy plans for 200 cGy dose per fraction using 6 MV medial and lateral tangential photon beams. The dose distribution provided by treatment planning was studied using nanoDots and film. Results: Results show that the largest surface dose difference between nanoDots measurement and prescribed dose for medial and lateral tangential beams, are 3.8% and 9.8%, respectively. This difference may be due to higher effective point of measurement and angular dependence of the nanoDots. The maximum differences in measured dose compared with prescribed dose, using film for heart and the left lung, were 6.2% and 7.5% respectively. Conclusions: Both nanoDots and film provided reasonable estimation of dose distribution in post-mastectomy radiation therapy.展开更多
Porous anodic alumina （PAA） hosts with ZnO nanoparticles loaded in were prepared by immersing PAA films in an aqueous solution of zinc acetate and then annealing at high temperatures. Highly ordered ZnO nanodot arra...Porous anodic alumina （PAA） hosts with ZnO nanoparticles loaded in were prepared by immersing PAA films in an aqueous solution of zinc acetate and then annealing at high temperatures. Highly ordered ZnO nanodot arrays were produced using the method in combination of PAA template with RF magnetron sputtering deposition. The photoluminescence of the ZnO/PAA composite and the highly ordered ZnO nanodot arrays were investigated by means of a fluorescent spectrometer. The ZnO/PAA composite exhibits intense and broad photoluminescence spectra with the peak position at around 485 nm. The ZnO nanodot arrays have a strong UV light emissive peak at about 380 nm and a wide light emissive peak at 460 nm-610 nm at the room temperature.展开更多
Self-assembled Ge nanodots with areal number density up to 2.33× 1010 cm-2 and aspect ratio larger than 0.12 are prepared by ion beam sputtering deposition. The dot density, a function of deposition rate and Ge c...Self-assembled Ge nanodots with areal number density up to 2.33× 1010 cm-2 and aspect ratio larger than 0.12 are prepared by ion beam sputtering deposition. The dot density, a function of deposition rate and Ge coverage, is observed to be limited mainly by the transformation from two-dimensional precursors to three-dimensional islands, and to be associated with the adatom behaviors of attachment and detachment from the islands. An unusual increasing temperature dependence of nanodot density is also revealed when a high ion energy is employed in sputtering deposition, and is shown to be related to the breaking down of the superstrained wetting layer. This result is attributed to the interaction between energetic atoms and the growth surface, which mediates the island nucleation.展开更多
Magnetic Co nanodots embedded in the porous anodic alumina films(AAFs)on silicon substrate can be used as the magnetic recording material with high area recording density.For this purpose,pure aluminum films were depo...Magnetic Co nanodots embedded in the porous anodic alumina films(AAFs)on silicon substrate can be used as the magnetic recording material with high area recording density.For this purpose,pure aluminum films were deposited on Si substrate with the Electron Cyclotron Resonance(ECR)plasma sputtering technique,and AAFs with vertical nano holes were synthesized with the two-step anodization process in oxalic acid.Finally magnetic material Co was deposited into the nano holes with electrochemical method.The results showed that polycrystalline ECR-Al films are homogenous and fit for the synthesis of AAFs with uniform distributed nano holes when ion sheath formed in front of the substrate surface.The diameters of AAF nano holes were in the range from 30 to 70 nm,and the hole pitches were approximately 100 nm,the AAF on silicon substrate was about 100 nm thick after two-step anodization.Magnetic Co nanodots filled into the nano holes of AAF exhibited both fcc and hcp structures.展开更多
Light-emitting electrochemical cells(LECs)can be fabricated with cost-efficient printing and coating methods,but a current drawback is that the LEC emitter is commonly either a rare-metal complex or an expensive-to-sy...Light-emitting electrochemical cells(LECs)can be fabricated with cost-efficient printing and coating methods,but a current drawback is that the LEC emitter is commonly either a rare-metal complex or an expensive-to-synthesize conjugated polymer.Here,we address this issue through the pioneering employment of metal-free and facile-to-synthesize carbon nanodots(CNDs)as the emitter in functional LEC devices.Circular-shaped(average diameter=4.4 nm)and hydrophilic CNDs,which exhibit narrow cyan photoluminescence(peak=485 nm,full width at half maximum=30 nm)with a high quantum yield of 77%in dilute ethanol solution,were synthesized with a catalyst-free,one-step solvothermal process using low-cost and benign phloroglucinol as the sole starting material.The propensity of the planar CNDs to form emission-quenching aggregates in the solid state was inhibited by the inclusion of a compatible 2,7-bis(diphenylphosphoryl)-9,9’-spirobifluorene host compound,and we demonstrate that such pristine host-guest CND-LECs turn on to a peak luminance of 118 cd·m^(−2)within 5 s during constant current-density driving at 77 mA·cm^(−2).展开更多
Laser-induced forward transfer(LIFT)is a direct-writing technique capable of depositing a single dot smaller than the laser wavelength at small shot energy through the laser-induced dot transfer(LIDT)technique.To depo...Laser-induced forward transfer(LIFT)is a direct-writing technique capable of depositing a single dot smaller than the laser wavelength at small shot energy through the laser-induced dot transfer(LIDT)technique.To deposit a single nanodot in a single shot of laser irradiation,a liquid nanodrop is transferred from donor to receiver and finally solidified via a solid–liquid–solid(SLS)process.In conventional LIDT experiments,multi-shots with step scanning have been used to form array structures.However,interference laser processing can achieve an arrayed process and generate a periodic structure in a single shot.In this study,a femtosecond laser interference pattern was first applied to LIDT,and an array of nanodots was successfully deposited in a single shot,producing the following unit structures:a single dot,adjoining dots,and stacking dots.The diameter of the smallest nanodot was 355 nm,and the narrowest gap between two adjoining nanodots was 17.2 nm.The LIDT technique produces high-purity,catalyst-free that do not require post-cleaning or alignment processes.Given these significant advantages,LIDT can expand the usability of nanodots in a wide range of fields.展开更多
基金sponsored by the National Key Research and Development Program of China(2016YFA0201700,2016YFA0201702)the Fundamental Research Funds for the Central Universities(2232019A3-06,2232019D3-02)+2 种基金the National Key Research and Development Program of China(2018YFC1105800)the National Natural Science Foundation of China(21674018,51903045)the Shanghai Belt and Road Joint Laboratory of Advanced Fiber and Low-Dimension Materials(18520750400).
文摘Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical properties has yet to be explored.In this study,we report on the fabrication of intrinsically super-strong fluorescent silk by feeding Bombyx mori silkworm carbon nanodots(CNDs).The CNDs were incorporated into silk fibroin,hindering the conformation transformation,confining crystallization,and inducing orientation of mesophase.The resultant silk exhibited super-strong mechanical properties with breaking strength of 521.9±82.7 MPa and breaking elongation of 19.2±4.3%,improvements of 55.1%and 53.6%,respectively,in comparison with regular silk.The CNDs-reinforced silk displayed intrinsic blue fluorescence when exposed to 405 nm laser and exhibited no cytotoxic effect on cells,suggesting that multi-functional silks would be potentially useful in bioimaging and other applications.
文摘Transition metal chalcogenides represent a class of the most promising alternative electrode materials for high-performance lithium-ion batteries （LIBs） owing to their high theoretical capacities. However, they suffer from large volume expansion, particle agglomeration, and low conductivity during charge/discharge processes, leading to unsatisfactory energy storage performance. In order to address these issues, we rationally designed three-dimensional （3D） hybrid composites consisting of ZnSe nanodots uniformly confined within a N-doped porous carbon network （ZnSe ND@N-PC） obtained via a convenient pyrolysis process. When used as anodes for LIBs, the composites exhibited outstanding electrochemical performance, with a high reversible capacity （1,134 mA.h.g-1 at a current density of 600 mA.g-1 after 500 cycles） and excellent rate capability （696 and 474 mA.h.g-1 at current densities of 6.4 and 12.8 A.g-1, respectively）. The significantly improved lithium storage performance can be attributed to the 3D architecture of the hybrid composites, which not only mitigated the internal mechanical stress induced by the volume change and formed a 3D conductive network during cycling, but also provided a large reactive area and reduced the lithium diffusion distance. The strategy reported here may open a new avenue for the design of other multi functional composites towards high-performance energy storage devices.
基金We acknowledge the financial support of the National Natural Science Foundation of China （Nos. 51672182 and 51302181）, the Natural Science Foundation of Jiangsu Province （No. BK20151219）, and the Priority Academic Program Development of Jiangsu Higher Education Institutions （PAPD）.
文摘Bismuth oxides are important battery materials owing to their ability to electrochemically react and alloy with Li,which results in a high capacity level,which substantially exceeds that of graphite anodes.However,this high Li-storage capability is often compromised by the poor electrochemical cyclability and rate capability of bismuth oxides.To address these challenges,in this study,we design a hybrid architecture composed of reduced graphene oxide （rGO） nanosheets decorated with ultrafine Bi2O2.33 nanodots （denoted as Bi2O2.33/rGO）,based on the selective and controlled hydrolysis of a Bi precursor on graphene oxide and subsequent crystallization via solvothermal treatment.Because of its high conductivity,large accessible area,and inherent flexibility,the Bi2O2.33/rGO hybrid exhibits stable and robust Li storage （346 mA＆#183;h＆#183;g-1 over 600 cycles at 10 C）,significantly outperforming previously reported Bi-based materials.This superb performance indicates that decorating rGO nanosheets with ultrafine nanodots may introduce new possibilities for the development of stable and robust metal-oxide electrodes.
基金The authors are grateful to the supports by the National Key Research and Development Program of China(No.2017YFA0208200)the National Natural Science Foundation of China(Nos.22022505 and 21872069)+3 种基金the Fundamental Research Funds for the Central Universities(Nos.020514380266,020514380272,and 020514380274)the Scientific and Technological Innovation Special Fund for Carbon Peak and Carbon Neutrality of Jiangsu Province(No.BK20220008)the Nanjing International Collaboration Research Program(No.202201007 and 2022SX00000955)the Suzhou Gusu Leading Talent Program of Science and Technology Innovation and Entrepreneurship in Wujiang District(No.ZXL2021273).
文摘The electrocatalytic CO_(2)reduction reaction(CO_(2)RR)is regarded as a promising route for renewable energy conversion and storage,but its development is limited by the high overpotential and low stability and selectivity of electrocatalysts.Moreover,it is complicated to accurately adjust the nanostructure of electrocatalysts,which impacts repeatability.Herein,we propose the rational design and controlled preparation of ultrafine Ag nanodots decorated fish-scale-like Zn nanoleaves(Ag-NDs/Zn-NLs)for highly selective electrocatalytic CO_(2)reduction.The Ag-NDs/Zn-NLs can be in-situ grown on copper foil with simple electrodeposition and replacement reactions.Benefiting from the coordination and synergistic effect of Zn and Ag species,the reconstruction of Zn surface and the agglomeration of Ag-NDs are efficiently prevented,bringing high activity and durable electrocatalytic stability for CO_(2)-to-CO conversion.The Faradaic efficiency for CO production reaches 85.2%at a moderate applied potential of-1.0 V vs.reversible hydrogen electrode(RHE).This study provides a promising approach for controlling the catalytic activity and selectivity of CO_(2)RR through the structural adjustment and decoration of transition metal based nanocatalysts.
基金supported by the National Natural Science Foundation of China(Grant Nos.51974114,51672075 and 21908049)Natural Science Foundation of Hunan Province(Grant No.2020JJ4175)the Fundamental Research Funds for the Central Universities。
文摘Molybdenum phosphide(MoP),owing to its abundant reserve and high theoretical capacity,is regarded as a promising anode material for potassium-ion batteries.However,it still suffers from the problems of acute volume expansion and weak diffusion kinetics.This study reports a simple method to synthesize a composite of molybdenum phosphide and porous carbon(MoP@PC)through simple mixing and annealing treatment.In the MoP@PC,lots of MoP nanodots with an average diameter of about 4 nm uniformly embedded in the petal-like porous carbon.The MoP@PC shows reversible capacities of 330 mAh g^(-1) at100 mA g^(-1) after 100 cycles,and ultra-long cycling stability with a capacity of 240 mAh g^(-1) after 1000 cycles at 1 A g^(-1) and 161 mAh g^(-1) after 1000 cycles at 5 A g^(-1).The structure of MoP@PC after charging-discharging cycles is also investigated by high resolution transmission electron microscope(HRTEM)and the result shows that MoP can still maintain the nanodot morphology without any agglomeration after 1000 cycles at 5 A g^(-1).The storage mechanism of potassium ions was studied as well,which reveals that MoP and potassium ion have a conversion reaction.
基金supported by the Natural Science Foundation of Huai’an(Grant No.HAB202150)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.22KJD140002)Jiangsu Students’Platform for Innovation and Entrepreneurship Training Program(Grant No.202311049095Y).
文摘High-density ferroelectric BiFeO_(3)(BFO)nanodot arrays were developed through template-assisted tailoring of epitaxial thin films.By combining piezoresponse force microscopy(PFM)and Kelvin probe force microscopy(KPFM)imaging techniques,we found that oxygen vacancies in nanodot arrays can be transported in the presence of an electric field.Besides triple-center domains,quadruple-center domains with different vertical polarizations were also identified.This was confirmed by combining the measurements of the domain switching and polarization vector distribution.The competition between the accumulation of mobile charges,such as oxygen vacancies,on the interface and the geometric constraints of nanodots led to the formation of these topological domain states.These abnormal multi-center topological defect states pave the way for improving the storage density of ferroelectric memory devices.
文摘Ultrashort pulsed laser-induced periodic surface structures(LIPSS)can be generated on difFerent kinds of materials,which are widely utilized for modifying surface properties such as wettability,adhesion,and tribological,as well as optical performances.Previous studies have focused mainly on one-dimensional LIPSS(i.e.,line structure)generation.In this study,a picosecond pulsed laser was used to irradiate stainless-steel surfaces for generating two-dimensional LIPSS,namely nanodot structures,by cross-scanning the laser beam for a different number of times.The obtained nanodot structures were found to be super hydrophilic just after laser irradiation,but turned to be hydrophobic after exposure in air for a few days.By cross・scanning the laser beam for the same number of times,local LIPSS rewriting was realized.This study showed the possibility of improving the homogeneity of the surface properties of steel materials through laser-induced nanodot structuring.
基金supported by the Eastern Scholar Program from the Shanghai Municipal Education Commissionthe National Natural Science Foundation of China (Grant No. 11274222)the Shanghai Supercomputer Center, and the Shanghai Shuguang Program (Grant No. 12SG34)
文摘Multiferroic nanodots can be harnessed to aid the development of the next generation of nonvolatile data storage and multi-functional devices. In this paper, we review the computational aspects of multiferroic nanodot materials and designs that hold promise for the future memory technology. Conception, methodology, and sys- tematical studies are discussed, followed by some up-to-date experimental progress towards the ultimate limits. At the end of this paper, we outline some challenges remaining in multiferroic research, and how the first principles based approach can be employed as an important tool providing critical information to understand the emergent phenomena in multiferroics.
基金This work was supported by the National Natural Science Foundation of China （Nos. 51503085, 51373061 and 21304090）, Science Foundation of China University of Petroleum, Beijing （No. 2462017YJRC027）, open project of state key laboratory of supramolecular structure and materials （No. sklssm201724） and Graduate Innovation Fund of Jilin University （Project 2016112）.
文摘Near-infrared （NIR） fluorescent metal nanodots may have significant advantages in biological detection and bioimaging. Herein, we introduce tunable near-infrared fluorescent gold nanodots （AuNDs） protected by branched polyethylenimine （PEI） modified by surface segmental attachment of sulfhydryl groups （PEI-SH）, abbreviated as PEI-SH-AuNDs, for simultaneous gene delivery and cell imaging. The modified PEI endows the resultant PEI-SH-AuNDs with the following excellent advantages. Sulfhydryl groups of PEI-SH anchor to the surface of AuNDs, and such polycations with amine groups give PEI-SH-AuNDs remarkable stability. The cationic polymer PEI-SH with positive charges enables PEI-SH-AuNDs to perform gene delivery, and the gene transfection efficiency can reach 22.8%. Moreover, the fluorescence of PEI-SH-AuNDs is tunable from visible red light （wavelength 609 nm） to NIR light （wavelength 811 run） via an increase in the size of AuNDs. PEI-SH-AuNDs yielded gene transfection efficiency similar to that of commercial PEI, but showed much lower cytotoxicity and much greater red-shift fluorescence. With excellent photoluminescent properties, such multifunctional fluorescent PEI-SH-AuNDs hold promise in applications to bioimaging and as ideal fluorescent probes for tracking gene transfection behavior.
文摘The fabrication of bit-patterned media （BPM） is crucial for new types of hard disk drives. The development of methods for the production of BPM is progressing rapidly. Conventional lithography reaches the limit regarding lateral resolution, and new routes are needed. In this study, we mainly focus on the dependence of the size and shape of magnetic nanodots on the Ar＋-ion etching duration, using silica dots as masks. Two-dimensional （2D） arrays of magnetic nanostructures are created using silica-filled diblock-copolymer micelles as templates. After the self-assembly of the micelles into 2D hexagonal arrays, the polymer shell is removed, and the SiO2 cores are utilized to transform the morphology into a （Co/Pt）2-multilayer via ion etching under normal incidence. The number of preparation steps is kept as low as possible to simplify the formation of the nanostructure arrays. High-resolution in situ grazing-incidence small-angle X-ray scattering （GISAXS） investigations are performed during the Ar＋-ion etching to monitor and control the fabrication process. The in situ investigation provides information on how the etching conditions can be improved for further ex situ experiments. The GISAXS patterns are compared with simulations. We observe that the dots change in shape from cylindrical to conical during the etching process. The magnetic behavior is studied by utilizing the magneto-optic Kerr effect. The Co/Pt dots exhibit different magnetic behaviors depending on their size, interparticle distance, and etching time. They show ferromagnetism with an easy axis of magnetization perpendicular to the film. A systematic dependence of the coercivitv on the dot size is observed.
基金financially supported by the National Natural Science Foundation of China (31422021, 51473109, and 81501585)National Basic Research Program of China (2014CB931900)+5 种基金Natural Science Foundation of Jiangsu Province of China (BK20150348)Natural Science Foundation of the Jiangsu Higher Education Institutions of China (15KJB310019)China Postdoctoral Science Foundation (2015M570475 and 2016T90496)Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-PsychoDiseases, Open Fund of CAS Key Laboratory of Nano-Bio Interface (16NBI02)Jiangsu Undergraduates Innovation and Entrepreneurship Program (20150285075Y)
文摘It remains a great challenge to explore the facile way to fabricate multi-component nanoparticles in theranostic nanomedicine. Herein, an albumin nanoreactor templated synthesis of theranostic Gd203/CuS hybrid nanodots （NDs） has been developed for multimodal imaging guided photothermal tumor ablation. Gd2O3/CuS NDs are found to possess particle size of 4.4 ± 1.1nm, enhanced longitudinal relaxivity, effective photothermal conversion of 45.5%, as well as remarkable near-infrared fluorescence （NIRF） from Cy7.5-conjugated on albumin corona. The Gd203/CuS NDs further exhibited good photostability, en- hanced cellular uptake, and preferable tumor accumulation. Thus, the Gd203/CuS NDs generate remarkable NIRF imag- ing and Tl-weighted magnetic resonance （MR） imaging, and simultaneously result in effective photothermal tumor ab- lation upon irradiation. The albumin nanoreactor provides a facile and general strategy to synthesize multifunctional nanoparticles for cancer theranostics.
基金Project supported by the National Natural Science Foundation of China(No.10832005)
文摘The electronic and transport properties of embedded boron nitride（BN） nanodot superlattices of armchair graphene nanoribbons are studied by first-principles calculations.The band structure of the graphene superlattice strongly depends on the geometric shape and size of the BN nanodot,as well as the concentration of nanodots.The conduction bands and valence bands near the Fermi level are nearly symmetric,which is induced by electron-hole symmetry.When B and N atoms in the graphene superlattices with a triangular BN nanodot are exchanged,the valance bands and conduction bands are inverted with respect to the Fermi level due to electron-hole symmetry.In addition,the hybridization ofπorbitals from C and redundant B atoms or N atoms leads to a localized band appearing near the Fermi level.Our results also show a series of resonant peaks appearing in the conductance.This strongly depends on the distance of the two BN nanodots and on the shape of the BN nanodot. Controlling these parameters might allow the modulation of the electronic response of the systems.
文摘Purpose: For post-mastectomy radiation therapy, skin dose must be accurately estimated to assess skin reactions, such as: erythema, desquamation, and necrosis. Even with advanced algorithms, planning systems do not always provide accurate dosimetry for target volumes distal to skin. Methods and Materials: In this study, a female anthropomorphic (ART) phantom and the newest generation of optically stimulated luminescence dosimeters (OSLD) (nanoDots, Landauer Inc.) were deployed to measure chest wall dose distribution. Since actual dose to patients’ lung and heart cannot be measured using in-vivo dosimetry, film was also used to verify the dose distribution to the left lung and heart. The treatment planning was performed using tolerance limits of 95% to 107% of prescription dose. The ART phantom was irradiated according to 3 three-dimensional (3D) conformal radiotherapy plans for 200 cGy dose per fraction using 6 MV medial and lateral tangential photon beams. The dose distribution provided by treatment planning was studied using nanoDots and film. Results: Results show that the largest surface dose difference between nanoDots measurement and prescribed dose for medial and lateral tangential beams, are 3.8% and 9.8%, respectively. This difference may be due to higher effective point of measurement and angular dependence of the nanoDots. The maximum differences in measured dose compared with prescribed dose, using film for heart and the left lung, were 6.2% and 7.5% respectively. Conclusions: Both nanoDots and film provided reasonable estimation of dose distribution in post-mastectomy radiation therapy.
基金Natural Science Foundation of Shandong Province Education Department (J04B01)
文摘Porous anodic alumina （PAA） hosts with ZnO nanoparticles loaded in were prepared by immersing PAA films in an aqueous solution of zinc acetate and then annealing at high temperatures. Highly ordered ZnO nanodot arrays were produced using the method in combination of PAA template with RF magnetron sputtering deposition. The photoluminescence of the ZnO/PAA composite and the highly ordered ZnO nanodot arrays were investigated by means of a fluorescent spectrometer. The ZnO/PAA composite exhibits intense and broad photoluminescence spectra with the peak position at around 485 nm. The ZnO nanodot arrays have a strong UV light emissive peak at about 380 nm and a wide light emissive peak at 460 nm-610 nm at the room temperature.
基金Project supported by the Joint Fund of National Natural Science Foundation of China and Yunnan Province, China (Grant No. U1037604)the Applied Basic Research Foundations of Yunnan Province, China (Grant No. 2009CD003)the Scientific Research Foundation of Yunnan University, China (Grant No. 2009E28Q)
文摘Self-assembled Ge nanodots with areal number density up to 2.33× 1010 cm-2 and aspect ratio larger than 0.12 are prepared by ion beam sputtering deposition. The dot density, a function of deposition rate and Ge coverage, is observed to be limited mainly by the transformation from two-dimensional precursors to three-dimensional islands, and to be associated with the adatom behaviors of attachment and detachment from the islands. An unusual increasing temperature dependence of nanodot density is also revealed when a high ion energy is employed in sputtering deposition, and is shown to be related to the breaking down of the superstrained wetting layer. This result is attributed to the interaction between energetic atoms and the growth surface, which mediates the island nucleation.
基金NSFC(90923027 and 51050110137)The Fundamental Research Funds for Central Universities
文摘Magnetic Co nanodots embedded in the porous anodic alumina films(AAFs)on silicon substrate can be used as the magnetic recording material with high area recording density.For this purpose,pure aluminum films were deposited on Si substrate with the Electron Cyclotron Resonance(ECR)plasma sputtering technique,and AAFs with vertical nano holes were synthesized with the two-step anodization process in oxalic acid.Finally magnetic material Co was deposited into the nano holes with electrochemical method.The results showed that polycrystalline ECR-Al films are homogenous and fit for the synthesis of AAFs with uniform distributed nano holes when ion sheath formed in front of the substrate surface.The diameters of AAF nano holes were in the range from 30 to 70 nm,and the hole pitches were approximately 100 nm,the AAF on silicon substrate was about 100 nm thick after two-step anodization.Magnetic Co nanodots filled into the nano holes of AAF exhibited both fcc and hcp structures.
基金support from J.C.Kempes Minnes Stipendiefond(No.SMK-1849.1)the Swedish Energy Agency(Nos.45419-1,46523-1,and 50779-1)+2 种基金the Swedish Research Council(Nos.2017-04380,2017-04862,2018-03937,and 2019-02345)the Swedish Foundation for Strategic Research,Stiftelsen Olle Engkvist Byggmästare(Nos.186-0637 and 193-0578)Bertil&Britt Svenssons stiftelse för belysningsteknik,the Swedish Foundation for International Cooperation in Research and Higher Education via an Initiation Grant for Internationalization(No.2019-8553)。
文摘Light-emitting electrochemical cells(LECs)can be fabricated with cost-efficient printing and coating methods,but a current drawback is that the LEC emitter is commonly either a rare-metal complex or an expensive-to-synthesize conjugated polymer.Here,we address this issue through the pioneering employment of metal-free and facile-to-synthesize carbon nanodots(CNDs)as the emitter in functional LEC devices.Circular-shaped(average diameter=4.4 nm)and hydrophilic CNDs,which exhibit narrow cyan photoluminescence(peak=485 nm,full width at half maximum=30 nm)with a high quantum yield of 77%in dilute ethanol solution,were synthesized with a catalyst-free,one-step solvothermal process using low-cost and benign phloroglucinol as the sole starting material.The propensity of the planar CNDs to form emission-quenching aggregates in the solid state was inhibited by the inclusion of a compatible 2,7-bis(diphenylphosphoryl)-9,9’-spirobifluorene host compound,and we demonstrate that such pristine host-guest CND-LECs turn on to a peak luminance of 118 cd·m^(−2)within 5 s during constant current-density driving at 77 mA·cm^(−2).
基金the Japan Society for the Promotion of Science(JSPS)through a Grant-in-Aid for Scientific Research(B)(No.16H038850)Amada Foundation for Metal Work Technology(AF-2018212).
文摘Laser-induced forward transfer(LIFT)is a direct-writing technique capable of depositing a single dot smaller than the laser wavelength at small shot energy through the laser-induced dot transfer(LIDT)technique.To deposit a single nanodot in a single shot of laser irradiation,a liquid nanodrop is transferred from donor to receiver and finally solidified via a solid–liquid–solid(SLS)process.In conventional LIDT experiments,multi-shots with step scanning have been used to form array structures.However,interference laser processing can achieve an arrayed process and generate a periodic structure in a single shot.In this study,a femtosecond laser interference pattern was first applied to LIDT,and an array of nanodots was successfully deposited in a single shot,producing the following unit structures:a single dot,adjoining dots,and stacking dots.The diameter of the smallest nanodot was 355 nm,and the narrowest gap between two adjoining nanodots was 17.2 nm.The LIDT technique produces high-purity,catalyst-free that do not require post-cleaning or alignment processes.Given these significant advantages,LIDT can expand the usability of nanodots in a wide range of fields.
