With the rapid development of electric vehicles,hybrid electric vehicles and smart grids,people's demand for large-scale energy storage devices is increasingly intense.As a new type of secondary battery,potassium ...With the rapid development of electric vehicles,hybrid electric vehicles and smart grids,people's demand for large-scale energy storage devices is increasingly intense.As a new type of secondary battery,potassium ion battery is promising to replace the lithium-ion battery in the field of large-scale energy storage by virtue of its low price and environmental friendliness.At present,the research on the anode materials of potassium ion batteries mainly focuses on carbon materials and the design of various nanostructured metal-based materials.Problems such as poor rate performance and inferior cycle life caused by electrode structure comminution during charge and discharge have not been solved.Quantum dots/nanodots materials are a new type of nanomaterials that can effectively improve the utilization of electrode materials and reduce production costs.In addition,quantum dots/nanodots materials can enhance the electrode reaction kinetics,reduce the stress generated in cycling,and effectively alleviate the agglomeration and crushing of electrode materials.In this review,we will systematically introduce the synthesis methods,K+storage properties and K+storage mechanisms of carbon quantum dots and carbon-based transition metal compound quantum dots composites.This review will have significant references for potassium ion battery researchers.展开更多
Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic ...Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion(Na^(+))radius hinder the practical application of SIBs,Here,we successfully prepared SnS_(2-x)Se_(x)nanodots embedded within N-doped carbon nanofibers(CNF)for use as electrode materials of SIBs,The introduction Se provided abundant anionic defect sites for Na+storage and enlarged the interlayer spacing of SnS_(2).In addition,the ultraifne nanodot structure reduces the volume expansion of SnS_(2-x)Se_(x)and shortens the ion transport path.As an anode of SIBs,SnS_(2-x)Se_(x)/CNF demonstrates remarkable reversible capacity(719 mAh g^(-1)at 0.5 A g^(-1)),along with rapid charging ability(completing a charge in just 127 s).Meanwhile,the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg^(-1)at a high-power output of 5526 W kg^(-1).This study presents an effective strategy for fabricating highperformance sulphide-based anode materials for SIBs,offering broad prospects for application.展开更多
Developing bifunctional electrocatalysts with enhanced efficiency for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)remains a significant challenge.Herein,we constructed S-doped ultra-fine RuO...Developing bifunctional electrocatalysts with enhanced efficiency for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)remains a significant challenge.Herein,we constructed S-doped ultra-fine RuO_(2) nanodots that were uniformly dispersed on carbon nanotubes.The incorporation of S effectively induces local rearrangement of the electronic structure of RuO_(2),thereby enhancing the dispersion of RuO_(2) as active sites and optimizing the adsorption free energy of H^(∗)intermediate.As ex-pected,the as-synthesized S-RuO_(2)/CNT delivers remarkable HER activity in all pH electrolytes,achieving lower overpotentials of 136,159,and 396 mV at 100 mA cm^(-2) in acidic,neutral,and basic solutions,respectively.Moreover,a unitary S-RuO_(2)/CNT electrolytic cell requires only a lower voltage(1.476 V)to achieve a current density of 10 mA cm^(-2) in 1.0 mol/L KOH.This ingenious work represents a significant breakthrough in the rational design of bifunctional electrocatalysts,enabling remarkable performance in electrochemical water electrolysis.展开更多
Development of highly active and stable non-noble electrocatalysts with well-defined nanostructures is crucial for efficient hydrogen evolution reaction(HER). Herein, a novel three-dimensional(3D) selfsupported electr...Development of highly active and stable non-noble electrocatalysts with well-defined nanostructures is crucial for efficient hydrogen evolution reaction(HER). Herein, a novel three-dimensional(3D) selfsupported electrode consists of vanadium nitride(VN) nanodots and Co nanoparticles co-embedded and highly active single Co atoms anchored in N-doped carbon nanotubes supported on carbon cloth(VN-Co@CoSAs-NCNTs/CC) is fabricated via a one-step in situ nanoconfined pyrolysis strategy, which shows remarkable enhanced HER electrocatalytic activity in acidic medium. During pyrolysis, the formed VN nanodots induce the generation of atomic Co Nxsites in NCNTs, contributing to superior electrocatalytic activity. Experimental and density functional theory(DFT) calculation results reveal that the electrode has multiple accessible active sites, fast reaction kinetics, low charge/mass transfer resistances,high conductivity, as well as downshifted d-band center with a thermodynamically favorable hydrogen adsorption free energy(△G_(H·)), all of which greatly boost the HER performance. As a result, the VNCo@CoSAs-NCNTs/CC electrode displays superb catalytic performance toward HER with a low overpotential of 29 mV at 10 mA cm^(-2) in acidic medium, which could maintain for at least 60 h of stable performance. This work opens a facile avenue to explore low-cost, high performance, but inexpensive metals/nitrogen-doped carbon composite electrocatalysts for HER.展开更多
Fabricating low-strain and fast-charging silicon-carbon composite anodes is highly desired but remains a huge challenge for lithium-ion batteries.Herein,we report a unique silicon-carbon composite fabricated by unifor...Fabricating low-strain and fast-charging silicon-carbon composite anodes is highly desired but remains a huge challenge for lithium-ion batteries.Herein,we report a unique silicon-carbon composite fabricated by uniformly dis-persing amorphous Si nanodots(SiNDs)in carbon nanospheres(SiNDs/C)that are welded on the wall of the macroporous carbon framework(MPCF)by vertical graphene(VG),labeled as MPCF@VG@SiNDs/C.The high dispersity and amor-phous features of ultrasmall SiNDs(~0.7 nm),the flexible and directed electron/Li+transport channels of VG,and the MPCF impart the MPCF@VG@SiNDs/C more lithium storage sites,rapid Li+transport path,and unique low-strain property during Li+storage.Consequently,the MPCF@VG@SiNDs/C exhibits high cycle stability(1301.4 mAh g^(-1) at 1 A g^(-1) after 1000 cycles without apparent decay)and high rate capacity(910.3 mAh g^(-1),20 A g^(-1))in half cells based on industrial electrode standards.The assembled pouch full cell delivers a high energy density(1694.0 Wh L^(-1);602.8 Wh kg^(-1))and an excellent fast-charging capability(498.5 Wh kg^(-1),charging for 16.8 min at 3 C).This study opens new possibilities for preparing advanced silicon-carbon com-posite anodes for practical applications.展开更多
In past decades,Ni-based catalytic materials and electrodes have been intensively explored as low-cost hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts for water splitting.With increasing de...In past decades,Ni-based catalytic materials and electrodes have been intensively explored as low-cost hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts for water splitting.With increasing demands for Ni worldwide,simplifying the fabrication process,increasing Ni recycling,and reducing waste are tangible sustainability goals.Here,binder-free,heteroatom-free,and recyclable Ni-based bifunctional catalytic electrodes were fabricated via a one-step quick electrodeposition method.Typically,active Ni nanodot(NiND)clusters are electrodeposited on Ni foam(NF)in Ni(NO3)2 acetonitrile solution.After drying in air,NiO/NiND composites are obtained,leading to a binder-free and heteroatom-free NiO/NiNDs@NF catalytic electrode.The electrode shows high efficiency and long-term stability for catalyzing hydrogen and oxygen evolution reactions at low overpotentials(10ηHER= 119 mV and 50ηOER=360 mV)and can promote water catalysis at 1.70 V@ 10mA cm-2.More importantly,the recovery of raw materials(NF and Ni(NO3)2)is quite easy because of the solubility of NiO/NiNDs composites in acid solution for recycling the electrodes.Additionally,a large-sized(S^70 cm2)NiO/NiNDs@NF catalytic electrode with high durability has also been constructed.This method provides a simple and fast technology to construct high-performance,low-cost,and environmentally friendly Ni-based bifunctional electrocatalytic electrodes for water splitting.展开更多
Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-...Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-products.However,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic efficiency.Herein,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon architecture.Owing to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption capacity.As a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH solution.Moreover,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) solution.The microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.展开更多
Carbon nanodots(CDs) based fluorescent nanoprobes have recently drawn much attention in chemo-/bio-sensing and bioimaging.However,it is still challenging to integrate the colorimetric and fluorometric dual readouts in...Carbon nanodots(CDs) based fluorescent nanoprobes have recently drawn much attention in chemo-/bio-sensing and bioimaging.However,it is still challenging to integrate the colorimetric and fluorometric dual readouts into a single CD.Herein,novel hybrid CDs(HCDs) are prepared by a simple microwave-assisted reaction of citric acid(CA),branched polyethyleneimine(BPEI) and potassium thiocyanate(KSCN).As-prepared HCDs show extraordinary properties,including excitation-dependent emission,satisfactory fluorescence quantum yield(46.8%),excellent biocompatibility and optical stability.Significantly,the fluorescence intensity at 450 nm exhibits linear correlation over the Fe^(3+)concentration from 1 mmol/L to 150 mmol/L with a detection limit(LOD) of 52 nmol/L.Meanwhile,the solution color changes from colorless to orange,and the absorbance at 460 nm increased linearly with Fe^(3+)concentration ranging from 0.02 mmol/L to 5 mmol/L(LOD:3.4 mmol/L).All the evidence illustrates that the HCDs can be conditioned for specific Fe^(3+)sensing with colorimetric and fluorometric dual readouts,which has also been verified with paper-based microchips.The possible mechanism is attributed to the specific interactions between surface functional groups on the HCDs and Fe^(3+).Additionally,the HCDs are successfully applied in sensing Fe^(3+)in wastewater and living cells,demonstrating its potential applications in future environment monitoring and disease diagnosis.展开更多
For bone regenerative engineering,it is a promising method to form skeletal tissues differentiating from human bone morrow mesenchyme stem cells(hBMSCs).However,it is still a critical challenge to efficiently control ...For bone regenerative engineering,it is a promising method to form skeletal tissues differentiating from human bone morrow mesenchyme stem cells(hBMSCs).However,it is still a critical challenge to efficiently control ostogenesis and clearly reveal the influence factor.To this end,the fluorescent gold nanodots(Au NDs) with highly negative charges as osteogenic induction reagent are successfully synthesized,which display better than commercial osteogenic induction medium through the investigations of ALP activity(2.5 folds) and cytoskeleton staining(1.5 folds).Two kinds of oligopeptides with different bio-structures(cysteine,Cys and glutathione,GSH) are selected for providing surficial charges on Au NDs.It is revealed that Au-Cys with more negative charges(-51 mV) play better role than Au-GSH(-19 mV) in osteogenic differentiation,when both of them have same size(~2 nm),sphere shape and show similar cell uptake amount.To explore deeply,osteogenesis related signaling pathways are monitored,revealing that the enhancement of osteogenic differentiation was through autophagy signaling pathway triggered by Au-Cys.And the promotion of highly negative charges in osteogenic diffe rentiation was further proved via sliver nanodots(Ag NDs,Ag-Cys and Ag-GSH) and carbon nanodots(CDs,Cys-CDs and GSH-CDs).This work indicates part of insights during hBMSCs differentiation and provides a novel strategy in osteogenic differentiation process.展开更多
Shape-induced phase transition of vortex domain structures （VDSs） in BaTiO3 （BT） nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method. Our calculation indicat...Shape-induced phase transition of vortex domain structures （VDSs） in BaTiO3 （BT） nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method. Our calculation indicates the tetragonal VDS missing in cubic BT nanodots can be induced by varying the shape of a nanodot from cube to platelet. Interestingly, a novel VDS is found in BT nanoplatelets in our simulations. Further investigation shows that it is a result of compromise between the ground state and the symmetry of the shape of the nanodot. Furthermore, based on the novel VDS, routes of controlling VDSs governed by homogeneous electric field and uniform stress are discussed. In particular, our results show the possibility of designing multi-states devices based on a single VDS. ~ 2017 The Authors. Published by Elsevier Ltd on behalf of The Chinese Society of Theoretical and Applied Mechanics.展开更多
Biomass-based carbon nanodots(CNDs) are becoming promising fluorescent materials due to their superior optical properties and excellent biocompatibility. However, most fluorescent CNDs are prepared under high temperat...Biomass-based carbon nanodots(CNDs) are becoming promising fluorescent materials due to their superior optical properties and excellent biocompatibility. However, most fluorescent CNDs are prepared under high temperatures with artificial chemicals as precursors. In this work, multicolor biomass-based CNDs have been prepared by employing natural biomass as precursors through an ultrasonic-assisted method at room temperature. The multicolor biomass-based CNDs can be prepared within 10 min, and cavitation produced by ultrasound in solution contributes to the polymerization of biomolecules into nanodots. The emission of the CNDs covers from blue to red region, with emission peaks centered at 410 nm, 520 nm and 670 nm, and the corresponding photoluminescence quantum yields of the CNDs are 11%, 12% and28%, respectively. Furthermore, bacterial imaging by using the biomass-based CNDs as fluorescent imaging agent has been demonstrated. This work provides a convenient ultrasonic-assisted way for fabrication multicolor and eco-friendly biomass CNDs, demonstrating their application in bacterial imaging.展开更多
ZrO_2 nanodots are successfully prepared on LaAlO_3（LAO）（100） substrates by photo-assisted metal-organic chemical vapor deposition（MOCVD）. It is indicated that the sizes and densities of ZrO_2 nanodots are contr...ZrO_2 nanodots are successfully prepared on LaAlO_3（LAO）（100） substrates by photo-assisted metal-organic chemical vapor deposition（MOCVD）. It is indicated that the sizes and densities of ZrO_2 nanodots are controllable by modulating the growth temperature, oxygen partial pressure, and growth time. Meanwhile, the microwires are observed on the surfaces of substrates. It is found that there is an obvious competitive relationship between the nanodots and the microwires. In a growth temperature range from 500℃ to 660℃, the microwires turn longest and widest at 600℃, but in contrast, the nanodots grow into the smallest diameter at 600℃. This phenomenon could be illustrated by the energy barrier, decomposition rate of Zr（tmhd）_4, and mobility of atoms. In addition, growth time or oxygen partial pressure also affects the competitive relationship between the nanodots and the microwires. With increasing oxygen partial pressure from 451 Pa to 75_2 Pa,the microwires gradually grow larger while the nanodots become smaller. To further achieve the controllable growth, the coarsening effect of ZrO_2 is modified by varying the growth time, and the experimental results show that the coarsening effect of microwires is higher than that of nanodots by increasing the growth time to quickly minimize ZrO_2 energy density.展开更多
Large scale tungsten nanowires and tungsten nanodots are prepared in a controllable way. The preparation is based on mechanisms of chemical vapor transportation and phase transformation during the reduction of ammoniu...Large scale tungsten nanowires and tungsten nanodots are prepared in a controllable way. The preparation is based on mechanisms of chemical vapor transportation and phase transformation during the reduction of ammonium metatungstate （AMT） in H2. The AMT is first encapsulated into the hollow core of nanostructured carbon with hollow macroporous core/mesoporous shell （NC-HMC/MS） and forms nanorods, which are the precursors of both tungsten nanowires and tungsten nanodots. Just by controlling H2 flow rate and heating rate in the reduction process, the AMT nanorods could turn into nanowires （under low rate condition） or nanodots （under high rate condition）. Besides, via heat treatment at 1200 ℃, the as-obtained nano-sized tungsten could convert into W2C nanorods or WC nanodots respectively. Furthermore, the diameter of the as-obtained tungsten or tungsten carbide is confined within 50 nm by the NC-HMC/MS, and no agglomeration appears in the obtained nanomaterials.展开更多
WC nanorods or WC nanodots are prepared via an easy,shape-controllable and large-scale preparation technique.Results reveal that each of the WC nanorods and WC nanodots has a peroxidase-like activity.Besides,the perox...WC nanorods or WC nanodots are prepared via an easy,shape-controllable and large-scale preparation technique.Results reveal that each of the WC nanorods and WC nanodots has a peroxidase-like activity.Besides,the peroxidase-like activity of WC is the first time to be demonstrated.The catalytic efficiency of WC nanorods is much higher than that of WC nanodots and chemical condition range of WC can be wider than that of WC,which indicates that WC is likely to be used as artificial mimetic peroxidase or in-situ amplified colorimetric immunoassay.展开更多
Lithium sulfur battery(LSB) is widely considered as a next-generation battery system due to its high theoretical energy density of 2567 Wh kg-1.However,several inherent issues obstruct the business application of LSB....Lithium sulfur battery(LSB) is widely considered as a next-generation battery system due to its high theoretical energy density of 2567 Wh kg-1.However,several inherent issues obstruct the business application of LSB.To address these issues,we assemble core-shell structure Fe_(3)O_(4)@C nanodots with 5 nm diameter as a valid sulfur host via a convenient organic pyrolysis treatment followed by calcination.The nanosized Fe3O4 particles could expose more chemisorption sites and inhibit the polysulfides shuttle.Moreover,the carbon layer could not only increase the conductivity but also ensure structural integrity during cyclic process.Furthermore,the mesoporous channels around Fe_(3)O_(4)@C could supply sufficient space to load sulfur and physically restrict the shuttle of polysulfides.Thus,the resultant S/Fe_(3)O_(4)@C cathode shows a highly initial capacity of 1089 mAh g^(-1) at 0.2 C,even retains 655 mAh g^(-1) over 200 cycles at 1 C.展开更多
In this study, an enzymatic electrode for glucose biosensing and bioanode of glucose/air biofuel cell has been fabricated by immobilizing poly (methylene green) (polyMG) for electrocatalytic NADH oxidation and NAD+-de...In this study, an enzymatic electrode for glucose biosensing and bioanode of glucose/air biofuel cell has been fabricated by immobilizing poly (methylene green) (polyMG) for electrocatalytic NADH oxidation and NAD+-dependent glucose dehydrogenase (GDH) for oxidizing glucose on carbon nanodots (CNDs). The polyMG-CNDscomposites obtained by electro-polymerization of dye MG molecules adsorbed on CNDs display excellent electrocatalytic activity toward NADH electro-oxidation at a low overpotential of ca. -0.10 V (vs. Ag/AgCl) and the integrated enzymatic electrode shows fast response to glucose electrooxidation. Using the fabricated GDH-based enzymatic electrode, a glucose biosensor was constructed and exhibits a wide linear dynamic range from 0 to 8 mM, a low detection limit of 0.02 μM (S/N = 3), and fast response time (ca. 4 s) under the optimized conditions. The developed glucose biosensor was used to detect glucose content in human blood with satisfactory results. The fabricated GDH-based enzymatic electrode was also employed as bioanode to assembly a glucose/air biofuel cell with the laccase-CNDs/GC as the biocathode. The maximum power density delivered by the assembled glucose/air biofuel cell reaches 3.1 μW·cm-2 at a cell voltage of 0.22 V in real sample fruit juice. The present study demonstrates that potential applications of GDH-based CNDs electrode in analytical and biomedical measurements.展开更多
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
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
Artificial photosynthesis has gained increasing interest as a promising solution to the worldwide energy and environmental issues. A crucial requirement for realizing a sustainable system for artificial photosynthesis...Artificial photosynthesis has gained increasing interest as a promising solution to the worldwide energy and environmental issues. A crucial requirement for realizing a sustainable system for artificial photosynthesis is to explore low cost, highly-efficient and stable photoactive materials. Carbon nanodots(CNDs) have attracted considerable attention owing to their low cost, tunable chemistry and unique light-harvesting capability. Previous review articles have highlighted the photocatalytic and photoelectrocatalytic applications of CNDs and CNDs-based composite photocatalysts. However, the control of the separation and transfer processes of photogenerated electron/hole pairs in CNDs has not been reviewed.This review summarizes the recent progress in the design of CNDs as new light-harvesting materials and highlights their applications in photocatalytic hydrogen production, CO2 photoreduction and environmental remediation. Strategies that have been employed to modulate the separation and transfer kinetics of photogenerated charge carriers in CNDs are discussed in detail. The challenges and new directions in this emerging area of research are also proposed.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
基金financial support from the Doctoral Foundation of Henan University of Engineering(No.D2022025)National Natural Science Foundation of China(No.U2004162)+1 种基金National Natural Science Foundation of China(No.52302138)Key Project for Science and Technology Development of Henan Province(No.232102320221)。
文摘With the rapid development of electric vehicles,hybrid electric vehicles and smart grids,people's demand for large-scale energy storage devices is increasingly intense.As a new type of secondary battery,potassium ion battery is promising to replace the lithium-ion battery in the field of large-scale energy storage by virtue of its low price and environmental friendliness.At present,the research on the anode materials of potassium ion batteries mainly focuses on carbon materials and the design of various nanostructured metal-based materials.Problems such as poor rate performance and inferior cycle life caused by electrode structure comminution during charge and discharge have not been solved.Quantum dots/nanodots materials are a new type of nanomaterials that can effectively improve the utilization of electrode materials and reduce production costs.In addition,quantum dots/nanodots materials can enhance the electrode reaction kinetics,reduce the stress generated in cycling,and effectively alleviate the agglomeration and crushing of electrode materials.In this review,we will systematically introduce the synthesis methods,K+storage properties and K+storage mechanisms of carbon quantum dots and carbon-based transition metal compound quantum dots composites.This review will have significant references for potassium ion battery researchers.
基金financially supported by the National Natural Science Foundation of China(22278348)Natural Science Foundation of Xinjiang Autonomous Region(2022D01D05)+1 种基金National guidance for local projects of Xinjiang Autonomous Region(ZYYD2025JD09)Tianshan Leading technology talents Program of Xinjiang Autonomous Region。
文摘Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion(Na^(+))radius hinder the practical application of SIBs,Here,we successfully prepared SnS_(2-x)Se_(x)nanodots embedded within N-doped carbon nanofibers(CNF)for use as electrode materials of SIBs,The introduction Se provided abundant anionic defect sites for Na+storage and enlarged the interlayer spacing of SnS_(2).In addition,the ultraifne nanodot structure reduces the volume expansion of SnS_(2-x)Se_(x)and shortens the ion transport path.As an anode of SIBs,SnS_(2-x)Se_(x)/CNF demonstrates remarkable reversible capacity(719 mAh g^(-1)at 0.5 A g^(-1)),along with rapid charging ability(completing a charge in just 127 s).Meanwhile,the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg^(-1)at a high-power output of 5526 W kg^(-1).This study presents an effective strategy for fabricating highperformance sulphide-based anode materials for SIBs,offering broad prospects for application.
基金financially supported by the Joint Fund of Science and Technology R&D Plan of Henan Province(No.232301420003)。
文摘Developing bifunctional electrocatalysts with enhanced efficiency for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)remains a significant challenge.Herein,we constructed S-doped ultra-fine RuO_(2) nanodots that were uniformly dispersed on carbon nanotubes.The incorporation of S effectively induces local rearrangement of the electronic structure of RuO_(2),thereby enhancing the dispersion of RuO_(2) as active sites and optimizing the adsorption free energy of H^(∗)intermediate.As ex-pected,the as-synthesized S-RuO_(2)/CNT delivers remarkable HER activity in all pH electrolytes,achieving lower overpotentials of 136,159,and 396 mV at 100 mA cm^(-2) in acidic,neutral,and basic solutions,respectively.Moreover,a unitary S-RuO_(2)/CNT electrolytic cell requires only a lower voltage(1.476 V)to achieve a current density of 10 mA cm^(-2) in 1.0 mol/L KOH.This ingenious work represents a significant breakthrough in the rational design of bifunctional electrocatalysts,enabling remarkable performance in electrochemical water electrolysis.
基金supported by grants from the National Natural Science Foundation of China (21971129, 21961022, 21661023,21802076, and 21962013)the 111 Project (D20033)+2 种基金the Natural Science Foundation of Inner Mongolia Autonomous Region of China (2018BS05007)the Program of Higher-level Talents of IMU (21300-5195109)the Cooperation Project of State Key Laboratory of Baiyun Obo Rare Earth Resource Researches and Comprehensive Utilization (2017Z1950)。
文摘Development of highly active and stable non-noble electrocatalysts with well-defined nanostructures is crucial for efficient hydrogen evolution reaction(HER). Herein, a novel three-dimensional(3D) selfsupported electrode consists of vanadium nitride(VN) nanodots and Co nanoparticles co-embedded and highly active single Co atoms anchored in N-doped carbon nanotubes supported on carbon cloth(VN-Co@CoSAs-NCNTs/CC) is fabricated via a one-step in situ nanoconfined pyrolysis strategy, which shows remarkable enhanced HER electrocatalytic activity in acidic medium. During pyrolysis, the formed VN nanodots induce the generation of atomic Co Nxsites in NCNTs, contributing to superior electrocatalytic activity. Experimental and density functional theory(DFT) calculation results reveal that the electrode has multiple accessible active sites, fast reaction kinetics, low charge/mass transfer resistances,high conductivity, as well as downshifted d-band center with a thermodynamically favorable hydrogen adsorption free energy(△G_(H·)), all of which greatly boost the HER performance. As a result, the VNCo@CoSAs-NCNTs/CC electrode displays superb catalytic performance toward HER with a low overpotential of 29 mV at 10 mA cm^(-2) in acidic medium, which could maintain for at least 60 h of stable performance. This work opens a facile avenue to explore low-cost, high performance, but inexpensive metals/nitrogen-doped carbon composite electrocatalysts for HER.
基金All authors acknowledge fund support from Guangdong Basic and Applied Basic Research Foundation(2020A1515110762)National Natural Science Foundation of China(52172084).
文摘Fabricating low-strain and fast-charging silicon-carbon composite anodes is highly desired but remains a huge challenge for lithium-ion batteries.Herein,we report a unique silicon-carbon composite fabricated by uniformly dis-persing amorphous Si nanodots(SiNDs)in carbon nanospheres(SiNDs/C)that are welded on the wall of the macroporous carbon framework(MPCF)by vertical graphene(VG),labeled as MPCF@VG@SiNDs/C.The high dispersity and amor-phous features of ultrasmall SiNDs(~0.7 nm),the flexible and directed electron/Li+transport channels of VG,and the MPCF impart the MPCF@VG@SiNDs/C more lithium storage sites,rapid Li+transport path,and unique low-strain property during Li+storage.Consequently,the MPCF@VG@SiNDs/C exhibits high cycle stability(1301.4 mAh g^(-1) at 1 A g^(-1) after 1000 cycles without apparent decay)and high rate capacity(910.3 mAh g^(-1),20 A g^(-1))in half cells based on industrial electrode standards.The assembled pouch full cell delivers a high energy density(1694.0 Wh L^(-1);602.8 Wh kg^(-1))and an excellent fast-charging capability(498.5 Wh kg^(-1),charging for 16.8 min at 3 C).This study opens new possibilities for preparing advanced silicon-carbon com-posite anodes for practical applications.
基金the China and Germany Postdoctoral Exchange Program for this research in Helmholtz-Zentrum Berlin für Materialien und Energiethe Postdoctoral Science Foundation of China (2017M610324)NSFC (21704040)
文摘In past decades,Ni-based catalytic materials and electrodes have been intensively explored as low-cost hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts for water splitting.With increasing demands for Ni worldwide,simplifying the fabrication process,increasing Ni recycling,and reducing waste are tangible sustainability goals.Here,binder-free,heteroatom-free,and recyclable Ni-based bifunctional catalytic electrodes were fabricated via a one-step quick electrodeposition method.Typically,active Ni nanodot(NiND)clusters are electrodeposited on Ni foam(NF)in Ni(NO3)2 acetonitrile solution.After drying in air,NiO/NiND composites are obtained,leading to a binder-free and heteroatom-free NiO/NiNDs@NF catalytic electrode.The electrode shows high efficiency and long-term stability for catalyzing hydrogen and oxygen evolution reactions at low overpotentials(10ηHER= 119 mV and 50ηOER=360 mV)and can promote water catalysis at 1.70 V@ 10mA cm-2.More importantly,the recovery of raw materials(NF and Ni(NO3)2)is quite easy because of the solubility of NiO/NiNDs composites in acid solution for recycling the electrodes.Additionally,a large-sized(S^70 cm2)NiO/NiNDs@NF catalytic electrode with high durability has also been constructed.This method provides a simple and fast technology to construct high-performance,low-cost,and environmentally friendly Ni-based bifunctional electrocatalytic electrodes for water splitting.
基金supported by the National Natural Science Foundation of China(22025801)and(22208190)National Postdoctoral Program for Innovative Talents(BX2021146)Shuimu Tsinghua Scholar Program(2021SM055).
文摘Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-products.However,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic efficiency.Herein,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon architecture.Owing to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption capacity.As a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH solution.Moreover,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) solution.The microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.
基金Financial support for this work came from the Project of Henan Provincial Medical Science and Technology Research Plan (No.SBGJ202002086)Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instruments (No.2020B1212060077)Natural Science Foundation of China (Nos.81901808,81701752, 81601470)。
文摘Carbon nanodots(CDs) based fluorescent nanoprobes have recently drawn much attention in chemo-/bio-sensing and bioimaging.However,it is still challenging to integrate the colorimetric and fluorometric dual readouts into a single CD.Herein,novel hybrid CDs(HCDs) are prepared by a simple microwave-assisted reaction of citric acid(CA),branched polyethyleneimine(BPEI) and potassium thiocyanate(KSCN).As-prepared HCDs show extraordinary properties,including excitation-dependent emission,satisfactory fluorescence quantum yield(46.8%),excellent biocompatibility and optical stability.Significantly,the fluorescence intensity at 450 nm exhibits linear correlation over the Fe^(3+)concentration from 1 mmol/L to 150 mmol/L with a detection limit(LOD) of 52 nmol/L.Meanwhile,the solution color changes from colorless to orange,and the absorbance at 460 nm increased linearly with Fe^(3+)concentration ranging from 0.02 mmol/L to 5 mmol/L(LOD:3.4 mmol/L).All the evidence illustrates that the HCDs can be conditioned for specific Fe^(3+)sensing with colorimetric and fluorometric dual readouts,which has also been verified with paper-based microchips.The possible mechanism is attributed to the specific interactions between surface functional groups on the HCDs and Fe^(3+).Additionally,the HCDs are successfully applied in sensing Fe^(3+)in wastewater and living cells,demonstrating its potential applications in future environment monitoring and disease diagnosis.
基金supported by the National Nature Science Foundation of China(Nos.51861145311,22005338)Science Foundation of China University of Petroleum,Beijing(No.2462017YJRC027)Open Project of State Key Laboratory of Superhard Materials(Jilin University 201802)。
文摘For bone regenerative engineering,it is a promising method to form skeletal tissues differentiating from human bone morrow mesenchyme stem cells(hBMSCs).However,it is still a critical challenge to efficiently control ostogenesis and clearly reveal the influence factor.To this end,the fluorescent gold nanodots(Au NDs) with highly negative charges as osteogenic induction reagent are successfully synthesized,which display better than commercial osteogenic induction medium through the investigations of ALP activity(2.5 folds) and cytoskeleton staining(1.5 folds).Two kinds of oligopeptides with different bio-structures(cysteine,Cys and glutathione,GSH) are selected for providing surficial charges on Au NDs.It is revealed that Au-Cys with more negative charges(-51 mV) play better role than Au-GSH(-19 mV) in osteogenic differentiation,when both of them have same size(~2 nm),sphere shape and show similar cell uptake amount.To explore deeply,osteogenesis related signaling pathways are monitored,revealing that the enhancement of osteogenic differentiation was through autophagy signaling pathway triggered by Au-Cys.And the promotion of highly negative charges in osteogenic diffe rentiation was further proved via sliver nanodots(Ag NDs,Ag-Cys and Ag-GSH) and carbon nanodots(CDs,Cys-CDs and GSH-CDs).This work indicates part of insights during hBMSCs differentiation and provides a novel strategy in osteogenic differentiation process.
文摘Shape-induced phase transition of vortex domain structures （VDSs） in BaTiO3 （BT） nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method. Our calculation indicates the tetragonal VDS missing in cubic BT nanodots can be induced by varying the shape of a nanodot from cube to platelet. Interestingly, a novel VDS is found in BT nanoplatelets in our simulations. Further investigation shows that it is a result of compromise between the ground state and the symmetry of the shape of the nanodot. Furthermore, based on the novel VDS, routes of controlling VDSs governed by homogeneous electric field and uniform stress are discussed. In particular, our results show the possibility of designing multi-states devices based on a single VDS. ~ 2017 The Authors. Published by Elsevier Ltd on behalf of The Chinese Society of Theoretical and Applied Mechanics.
基金supported by the National Natural Science Foundation of China (Nos.11904326,62075198)China Postdoctoral Science Foundation (Nos.2019TQ0287,2019M662510)。
文摘Biomass-based carbon nanodots(CNDs) are becoming promising fluorescent materials due to their superior optical properties and excellent biocompatibility. However, most fluorescent CNDs are prepared under high temperatures with artificial chemicals as precursors. In this work, multicolor biomass-based CNDs have been prepared by employing natural biomass as precursors through an ultrasonic-assisted method at room temperature. The multicolor biomass-based CNDs can be prepared within 10 min, and cavitation produced by ultrasound in solution contributes to the polymerization of biomolecules into nanodots. The emission of the CNDs covers from blue to red region, with emission peaks centered at 410 nm, 520 nm and 670 nm, and the corresponding photoluminescence quantum yields of the CNDs are 11%, 12% and28%, respectively. Furthermore, bacterial imaging by using the biomass-based CNDs as fluorescent imaging agent has been demonstrated. This work provides a convenient ultrasonic-assisted way for fabrication multicolor and eco-friendly biomass CNDs, demonstrating their application in bacterial imaging.
基金Project supported by the National Natural Science Foundation of China(Grant No.51002063)the International Science and Technology Cooperation Program of Science and Technology Bureau of Changchun City,China(Grant No.12ZX68)
文摘ZrO_2 nanodots are successfully prepared on LaAlO_3（LAO）（100） substrates by photo-assisted metal-organic chemical vapor deposition（MOCVD）. It is indicated that the sizes and densities of ZrO_2 nanodots are controllable by modulating the growth temperature, oxygen partial pressure, and growth time. Meanwhile, the microwires are observed on the surfaces of substrates. It is found that there is an obvious competitive relationship between the nanodots and the microwires. In a growth temperature range from 500℃ to 660℃, the microwires turn longest and widest at 600℃, but in contrast, the nanodots grow into the smallest diameter at 600℃. This phenomenon could be illustrated by the energy barrier, decomposition rate of Zr（tmhd）_4, and mobility of atoms. In addition, growth time or oxygen partial pressure also affects the competitive relationship between the nanodots and the microwires. With increasing oxygen partial pressure from 451 Pa to 75_2 Pa,the microwires gradually grow larger while the nanodots become smaller. To further achieve the controllable growth, the coarsening effect of ZrO_2 is modified by varying the growth time, and the experimental results show that the coarsening effect of microwires is higher than that of nanodots by increasing the growth time to quickly minimize ZrO_2 energy density.
文摘Large scale tungsten nanowires and tungsten nanodots are prepared in a controllable way. The preparation is based on mechanisms of chemical vapor transportation and phase transformation during the reduction of ammonium metatungstate （AMT） in H2. The AMT is first encapsulated into the hollow core of nanostructured carbon with hollow macroporous core/mesoporous shell （NC-HMC/MS） and forms nanorods, which are the precursors of both tungsten nanowires and tungsten nanodots. Just by controlling H2 flow rate and heating rate in the reduction process, the AMT nanorods could turn into nanowires （under low rate condition） or nanodots （under high rate condition）. Besides, via heat treatment at 1200 ℃, the as-obtained nano-sized tungsten could convert into W2C nanorods or WC nanodots respectively. Furthermore, the diameter of the as-obtained tungsten or tungsten carbide is confined within 50 nm by the NC-HMC/MS, and no agglomeration appears in the obtained nanomaterials.
文摘WC nanorods or WC nanodots are prepared via an easy,shape-controllable and large-scale preparation technique.Results reveal that each of the WC nanorods and WC nanodots has a peroxidase-like activity.Besides,the peroxidase-like activity of WC is the first time to be demonstrated.The catalytic efficiency of WC nanorods is much higher than that of WC nanodots and chemical condition range of WC can be wider than that of WC,which indicates that WC is likely to be used as artificial mimetic peroxidase or in-situ amplified colorimetric immunoassay.
基金financially supported by the National Science Foundation of China(Nos.51772296,21878195,21805018 and 21805198)the Foundation for State Key Laboratory of Biochemical Engineering。
文摘Lithium sulfur battery(LSB) is widely considered as a next-generation battery system due to its high theoretical energy density of 2567 Wh kg-1.However,several inherent issues obstruct the business application of LSB.To address these issues,we assemble core-shell structure Fe_(3)O_(4)@C nanodots with 5 nm diameter as a valid sulfur host via a convenient organic pyrolysis treatment followed by calcination.The nanosized Fe3O4 particles could expose more chemisorption sites and inhibit the polysulfides shuttle.Moreover,the carbon layer could not only increase the conductivity but also ensure structural integrity during cyclic process.Furthermore,the mesoporous channels around Fe_(3)O_(4)@C could supply sufficient space to load sulfur and physically restrict the shuttle of polysulfides.Thus,the resultant S/Fe_(3)O_(4)@C cathode shows a highly initial capacity of 1089 mAh g^(-1) at 0.2 C,even retains 655 mAh g^(-1) over 200 cycles at 1 C.
文摘In this study, an enzymatic electrode for glucose biosensing and bioanode of glucose/air biofuel cell has been fabricated by immobilizing poly (methylene green) (polyMG) for electrocatalytic NADH oxidation and NAD+-dependent glucose dehydrogenase (GDH) for oxidizing glucose on carbon nanodots (CNDs). The polyMG-CNDscomposites obtained by electro-polymerization of dye MG molecules adsorbed on CNDs display excellent electrocatalytic activity toward NADH electro-oxidation at a low overpotential of ca. -0.10 V (vs. Ag/AgCl) and the integrated enzymatic electrode shows fast response to glucose electrooxidation. Using the fabricated GDH-based enzymatic electrode, a glucose biosensor was constructed and exhibits a wide linear dynamic range from 0 to 8 mM, a low detection limit of 0.02 μM (S/N = 3), and fast response time (ca. 4 s) under the optimized conditions. The developed glucose biosensor was used to detect glucose content in human blood with satisfactory results. The fabricated GDH-based enzymatic electrode was also employed as bioanode to assembly a glucose/air biofuel cell with the laccase-CNDs/GC as the biocathode. The maximum power density delivered by the assembled glucose/air biofuel cell reaches 3.1 μW·cm-2 at a cell voltage of 0.22 V in real sample fruit juice. The present study demonstrates that potential applications of GDH-based CNDs electrode in analytical and biomedical measurements.
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.
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financially supported by the National Natural Science Foundation of China(21703039)。
文摘Artificial photosynthesis has gained increasing interest as a promising solution to the worldwide energy and environmental issues. A crucial requirement for realizing a sustainable system for artificial photosynthesis is to explore low cost, highly-efficient and stable photoactive materials. Carbon nanodots(CNDs) have attracted considerable attention owing to their low cost, tunable chemistry and unique light-harvesting capability. Previous review articles have highlighted the photocatalytic and photoelectrocatalytic applications of CNDs and CNDs-based composite photocatalysts. However, the control of the separation and transfer processes of photogenerated electron/hole pairs in CNDs has not been reviewed.This review summarizes the recent progress in the design of CNDs as new light-harvesting materials and highlights their applications in photocatalytic hydrogen production, CO2 photoreduction and environmental remediation. Strategies that have been employed to modulate the separation and transfer kinetics of photogenerated charge carriers in CNDs are discussed in detail. The challenges and new directions in this emerging area of research are also proposed.
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.
