[020]-oriented tin sulfide nanobelts with a length/thickness ratio of 100 have been synthesized by a facile hydrothermal method without any surfactants, and the nanobelts have shown good strain-accommodating propertie...[020]-oriented tin sulfide nanobelts with a length/thickness ratio of 100 have been synthesized by a facile hydrothermal method without any surfactants, and the nanobelts have shown good strain-accommodating properties as well as good electrochemical performance as the anode for Li-ion batteries. The formation of the nanobelts results from a precipitation-dissolution-transformation mechanism, and the [020] oriented growth can be ascribed to the {010} facet family having the lowest atomic density. In particular, SnS shows clear Li-Sn alloying/de-alloying reversible reactions in the potential range 0.1-1.0 V. Based on galvanostatic measurements and electrochemical impedance spectroscopy, SnS nanobelts have shown impressive rate performance. The post-cycled SnS nanobelts were completely transformed into metallic tin, and preserved the one-dimensional structure due to their flexibility which accommodates the large volumetric expansion.展开更多
The controlled synthesis of gold nanocrystals has been the subject of intensive studies for decades because the properties and functions of gold nanomaterials are highly dependent on their particle size, shape, and di...The controlled synthesis of gold nanocrystals has been the subject of intensive studies for decades because the properties and functions of gold nanomaterials are highly dependent on their particle size, shape, and dimensionality. Especially, anisotropic gold nanocrystals, such as nanowires, nanobelts, nanoplates and nanosheets, have attracted much attention due to their striking properties and promising applications in electronics, catalysis, photonics, sensing and biomedicine. In this review, we will summarize the recent developments of one- dimensional （1D） and two-dimensional （2D） gold nanostructures. Various kinds of synthetic methods for preparation of these 1D and 2D gold nanocrystals will be described. Moreover, we will also briefly introduce the properties and potential applications of these 1D and 2D gold nanocrystals.展开更多
t Molecular dynamics （MD） simulations are carried out to characterize the mechanical and thermal responses of [011^-1]-oriented ZnO nanobelts with lateral dimensions of 21.22A × 18.95 A, 31.02A× 29.42 A, a...t Molecular dynamics （MD） simulations are carried out to characterize the mechanical and thermal responses of [011^-1]-oriented ZnO nanobelts with lateral dimensions of 21.22A × 18.95 A, 31.02A× 29.42 A, and40.81A ×39.89A over the temperature range of 300-1000 K. The Young＇s modulus and thermal conductivity of the nanobelts are evaluated. Significant surface effects on properties due to the highsurface-to-volume ratios of the nanobelts are observed. For the mechanical response, surface-stress-induced internal stress plays an important role. For the thermal response, surface scattering of phonons dominates. Calculations show that the Young＇s modulus is higher than the corresponding value for bulk ZnO and decreases by -33% as the lateral dimensions increase from 21.22 A × 18.95A to 40.81 A × 39.89A. The thermal conductivity is one order of magnitude lower than the corresponding value for bulk ZnO single crystal and decreases with wire size. Specifically, the conductivity of the 21.22 A × 18.95 A belt is approximately （31-18）% lower than that of the 40.81 A × 39.89 A belt over the temperature range analyzed. A significant dependence of properties on temperature is also observed, with the Young＇s modulus decreasing on average by 12% and the conductivity decreasing by 50% as temperature increases from 300 K to 1000 K.展开更多
GaN ultraviolet （UV） photodetectors （PDs） have attracted tremendous attention due to their chemical stability in harsh environments. Although Schottky- contacted GaN-based UV PDs have been implemented with better ...GaN ultraviolet （UV） photodetectors （PDs） have attracted tremendous attention due to their chemical stability in harsh environments. Although Schottky- contacted GaN-based UV PDs have been implemented with better performance than that of ohmic contacts, it remains unknown how the barrier height at local Schottky contacts controls the sensors＇ performance. In this work, the piezotronic effect was employed to tune the Schottky barrier height （SBH） at local contacts and hence enhance the performances of Schottky-contacted metal-semiconductor- metal （MSM） structured GaN nanobelt （NB）-based PDs. In general, the response level of the PDs was obviously enhanced by the piezotronic effect when applying a strain on devices. The responsivity of the PD was increased by 18%, and the sensitivity was enhanced by from 22% to 31%, when illuminated by a 325 nm laser with light intensity ranging from 12 to 2 W/cm2. Carefully studying the mechanism using band structure diagrams reveals that the observed enhancement of the PD performance resulted from the change in SBH caused by external strain as well as light intensity. Using piezotronic effects thus provides a practical way to enhance the performance of PDs made not only of GaN, but also other wurtzite and zinc blende family materials.展开更多
Here, we report the direct hydrothermal synthesis of 1 D-based Zn2GeO4：Mn2＋ persistent luminescent nanobelts （ZGO：Mn PLNBs）. The ZGO：Mn PLNBs exhibit rapid growth rate, and nanobelts can be obtained after 30 rai...Here, we report the direct hydrothermal synthesis of 1 D-based Zn2GeO4：Mn2＋ persistent luminescent nanobelts （ZGO：Mn PLNBs）. The ZGO：Mn PLNBs exhibit rapid growth rate, and nanobelts can be obtained after 30 rain of hydrothermal treatment. The persistent luminescence performance can be fine-turned upon prolonging the hydrothermal time. Furthermore, the doping ratio of Mn2＋ exhibits influence on the persistent luminescence properties of ZGO：Mn PLNBs, and 2% doping of Mn2＋ shows superior persistent luminescence with decay time of longer than 20min. The developed 1D-based ZGO：Mn PLNBs can be simply prepared with the hydrothermal method and show tunable morphology and persistent luminescence. We believe that this solid-state-reaction-free chemical approach avoids the current key drawback in regard to PLNMs development, and thus will promote the broad use of these unique nanostructured PLNMs in developing optical device for imaging.展开更多
Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the d...Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the design and synthesis of size- and thickness-tunable two-dimensional （2-D） MnO2 nanosheets on highly conductive one-dimensional （l-D） backbone arrays has been developed via a facile, one-step enhanced chemical bath deposition （ECBD） method at a low temperature （-50 ℃）. Inclusion of an oxidizing agent, BrO3-, in the solution was crucial in controlling the heterogeneous nucleation and growth of the nanosheets, and in inducing the formation of the tailored and uniformly arranged nanosheet arrays. We fabricated supercapacitor devices based on 3-D MnO2 nanosheets with conductive Sb-doped SnO2 nanobelts as the backbone. They achieved a specific capacitance of 162 F·g-1 at an extremely high current density of 20 A·g% and good cycling stability that shows a capacitance retention of -92% of its initial value, along with a coulombic efficiency of almost 100% after 5,000 cycles in an aqueous solution of I M Na2SO4. The results were attributed to the unique hierarchical structures, which provided a short diffusion path of electrolyte ions by means of the 2-D sheets and direct electrical connections to the current collector by 1-D arrays as well as the prevention of aggregation by virtue of the well-aligned 3-D structure.展开更多
By a novel controlled combustion synthesis method, a large number of nanostructured ZnO whiskers with different morphologies, such as tetra-needles, long-leg tetra-needles and multi-needles, are prepared without any a...By a novel controlled combustion synthesis method, a large number of nanostructured ZnO whiskers with different morphologies, such as tetra-needles, long-leg tetra-needles and multi-needles, are prepared without any additive in open air at high temperature. The morphologies and crystalline structures of the as-prepared ZnO nanostructured whiskers are investigated by SEM and XRD. The possible growth mechanism on the nanostructured ZnO whiskers is proposed. The experimental results indicate that the dielectric constants and losses of the nanostructured ZnO whiskers are very low, demonstrating that the nanostructured ZnO whiskers are low-loss materials for microwave absorption in X-band. However, obvious microwave absorption in nanostructured ZnO whiskers is observed. The quasi-microantenna model may be attributed to the microwave absorption of the ZnO whiskers.展开更多
Aqueous zinc-ion batteries(ZIBs) have been considered as one of the most promising electrochemical devices for large-scale energy storage system owing to their low cost and high safety. Herein, Na2V6O16·2.14H2O n...Aqueous zinc-ion batteries(ZIBs) have been considered as one of the most promising electrochemical devices for large-scale energy storage system owing to their low cost and high safety. Herein, Na2V6O16·2.14H2O nanobelts are synthesized and applied as cathode material for ZIBs. The sample displays a high capacity of 466 m Ahg^-1 at 100 mAg^-1 and stable cycling performance with a capacity retention of 90% over 20 0 0 cycles at the 20 Ag^-1. Moreover, Na2V6O16·2.14H2O presents a capable rate ability and a high energy density of 312 Wh kg^-1 at a specific power of 70 Wkg^-1. The superior electrochemical performance is attributed to the large interlayer spacing and outstanding structure stability, which promise the highly reversible intercalation and extraction of zinc ion. The electrochemical kinetics and zinc ion storage mechanism are also investigated. This work demonstrates that nanoscale electrode materials with large interlayer spacing can effectively enhance the electrochemical performance of aqueous ZIBs, which can be extended to other metal ion batteries, such as magnesium ion batteries and aluminum ion batteries.展开更多
Sodium-ion batteries(SIBs)are an attractive battery system because of similar characteristics to lithium-ion batteries(LIBs)and large Na element abundance.Nevertheless,exploring stable,high-capacity and high-rate anod...Sodium-ion batteries(SIBs)are an attractive battery system because of similar characteristics to lithium-ion batteries(LIBs)and large Na element abundance.Nevertheless,exploring stable,high-capacity and high-rate anode materials for SIBs is still challenging now.Herein,diethylenetriamine(DETA)molecular template derived ultrathin N-doped carbon(NC)layer decorated CoSe_(2)nanobelts(CoSe_(2)/NC)are prepared by solvothermal reaction followed by calcination process.The CoSe_(2)/NC exhibits large potential as an anode for SIBs.Experiments and theoretical calculations reveal that the in situ formed conductive ultrathin NC layer can not only relieve the volume change of CoSe_(2)but also accelerate electron and ion transport.In addition,the nanobelt structure of CoSe_(2)/NC with abundant exposed active sites can obviously accelerate the electrochemical kinetics.Under the synergistic effect of special nanobelt structure and NC layer,the rate as well as cycling performances of CoSe_(2)/NC are obviously improved.A superior capacity retention of 94.8%is achieved at 2 A·g^(-1)after 2000 cycles.When using Na3V2(PO4)3 cathodes,the pouch full batteries can work steadily at 0.5 C,verifying the application ability.CoSe_(2)/NC anodes also exhibit impressive performances in LIBs and potassium-ion batteries(PIBs).展开更多
Oriented nanobelts of manganese oxide have been firstly and successfully prepared by a microemulsion technique under controlled circumstances. The samples were characterized by X-ray diffraction (XRD), transmission el...Oriented nanobelts of manganese oxide have been firstly and successfully prepared by a microemulsion technique under controlled circumstances. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM). Influences of sodium chloride and annealed temperature on the synthesis of Mn3O4 nanobelts were investigated. It was found that NaCI is the key factor to synthesize oriented Mn3O4 nanobelts and 827 K is optimum temperature to produce fine nanobelts. Oriented growth mechanism of Mn3O4 nanobelts was discussed.展开更多
基金Acknowledgements This work was supported by the State Key Project of Fundamental Research for Nanoscience and Nano- technology （Nos. 2011CB932401 and 2011CBA00500）, and the National Natural Science Foundation of China （Nos. 20921001 and 21051001）. We are grateful to Associate Professor Jiaping Wang and lab assistant Fei Zhao in the Tsinghua-Foxconn Nanocenter for their generous help in the fabrication of batteries.
文摘[020]-oriented tin sulfide nanobelts with a length/thickness ratio of 100 have been synthesized by a facile hydrothermal method without any surfactants, and the nanobelts have shown good strain-accommodating properties as well as good electrochemical performance as the anode for Li-ion batteries. The formation of the nanobelts results from a precipitation-dissolution-transformation mechanism, and the [020] oriented growth can be ascribed to the {010} facet family having the lowest atomic density. In particular, SnS shows clear Li-Sn alloying/de-alloying reversible reactions in the potential range 0.1-1.0 V. Based on galvanostatic measurements and electrochemical impedance spectroscopy, SnS nanobelts have shown impressive rate performance. The post-cycled SnS nanobelts were completely transformed into metallic tin, and preserved the one-dimensional structure due to their flexibility which accommodates the large volumetric expansion.
文摘The controlled synthesis of gold nanocrystals has been the subject of intensive studies for decades because the properties and functions of gold nanomaterials are highly dependent on their particle size, shape, and dimensionality. Especially, anisotropic gold nanocrystals, such as nanowires, nanobelts, nanoplates and nanosheets, have attracted much attention due to their striking properties and promising applications in electronics, catalysis, photonics, sensing and biomedicine. In this review, we will summarize the recent developments of one- dimensional （1D） and two-dimensional （2D） gold nanostructures. Various kinds of synthetic methods for preparation of these 1D and 2D gold nanocrystals will be described. Moreover, we will also briefly introduce the properties and potential applications of these 1D and 2D gold nanocrystals.
基金The project supported by the US National Science Foundation through CAREER grant no. CMS9984298the National Natural Science Foundation of China (10528205)
文摘t Molecular dynamics （MD） simulations are carried out to characterize the mechanical and thermal responses of [011^-1]-oriented ZnO nanobelts with lateral dimensions of 21.22A × 18.95 A, 31.02A× 29.42 A, and40.81A ×39.89A over the temperature range of 300-1000 K. The Young＇s modulus and thermal conductivity of the nanobelts are evaluated. Significant surface effects on properties due to the highsurface-to-volume ratios of the nanobelts are observed. For the mechanical response, surface-stress-induced internal stress plays an important role. For the thermal response, surface scattering of phonons dominates. Calculations show that the Young＇s modulus is higher than the corresponding value for bulk ZnO and decreases by -33% as the lateral dimensions increase from 21.22 A × 18.95A to 40.81 A × 39.89A. The thermal conductivity is one order of magnitude lower than the corresponding value for bulk ZnO single crystal and decreases with wire size. Specifically, the conductivity of the 21.22 A × 18.95 A belt is approximately （31-18）% lower than that of the 40.81 A × 39.89 A belt over the temperature range analyzed. A significant dependence of properties on temperature is also observed, with the Young＇s modulus decreasing on average by 12% and the conductivity decreasing by 50% as temperature increases from 300 K to 1000 K.
基金Acknowledgements This research was supported by National Science Foundation （NSF）, Multidisciplinary University Research Initiative （MURI） Airforce, Basic Energy Sciences （BES） Department of Energy （DOE） （No. DE- FG02-07ER46394） and the Knowledge Innovation Program of the Chinese Academy of Sciences （Grant No. KJCX2-YW-M13）.
文摘GaN ultraviolet （UV） photodetectors （PDs） have attracted tremendous attention due to their chemical stability in harsh environments. Although Schottky- contacted GaN-based UV PDs have been implemented with better performance than that of ohmic contacts, it remains unknown how the barrier height at local Schottky contacts controls the sensors＇ performance. In this work, the piezotronic effect was employed to tune the Schottky barrier height （SBH） at local contacts and hence enhance the performances of Schottky-contacted metal-semiconductor- metal （MSM） structured GaN nanobelt （NB）-based PDs. In general, the response level of the PDs was obviously enhanced by the piezotronic effect when applying a strain on devices. The responsivity of the PD was increased by 18%, and the sensitivity was enhanced by from 22% to 31%, when illuminated by a 325 nm laser with light intensity ranging from 12 to 2 W/cm2. Carefully studying the mechanism using band structure diagrams reveals that the observed enhancement of the PD performance resulted from the change in SBH caused by external strain as well as light intensity. Using piezotronic effects thus provides a practical way to enhance the performance of PDs made not only of GaN, but also other wurtzite and zinc blende family materials.
基金supported by the National Key R&D Program of China (No. 2017YFA0208000)National Natural Science Foundation of China (No. 21675120)+2 种基金Ten Thousand Talents Program for Young Talents, Start-up Research Fund for Prof. Q. Yuan (No. 531107050973)State Key Laboratory of Chemo/Bio-Sensing and Chemometrics at Hunan University(No. 734106172)Open Funding Project of the State Key Laboratory of Biochemical Engineering (No. 4102010299)
文摘Here, we report the direct hydrothermal synthesis of 1 D-based Zn2GeO4：Mn2＋ persistent luminescent nanobelts （ZGO：Mn PLNBs）. The ZGO：Mn PLNBs exhibit rapid growth rate, and nanobelts can be obtained after 30 rain of hydrothermal treatment. The persistent luminescence performance can be fine-turned upon prolonging the hydrothermal time. Furthermore, the doping ratio of Mn2＋ exhibits influence on the persistent luminescence properties of ZGO：Mn PLNBs, and 2% doping of Mn2＋ shows superior persistent luminescence with decay time of longer than 20min. The developed 1D-based ZGO：Mn PLNBs can be simply prepared with the hydrothermal method and show tunable morphology and persistent luminescence. We believe that this solid-state-reaction-free chemical approach avoids the current key drawback in regard to PLNMs development, and thus will promote the broad use of these unique nanostructured PLNMs in developing optical device for imaging.
文摘Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the design and synthesis of size- and thickness-tunable two-dimensional （2-D） MnO2 nanosheets on highly conductive one-dimensional （l-D） backbone arrays has been developed via a facile, one-step enhanced chemical bath deposition （ECBD） method at a low temperature （-50 ℃）. Inclusion of an oxidizing agent, BrO3-, in the solution was crucial in controlling the heterogeneous nucleation and growth of the nanosheets, and in inducing the formation of the tailored and uniformly arranged nanosheet arrays. We fabricated supercapacitor devices based on 3-D MnO2 nanosheets with conductive Sb-doped SnO2 nanobelts as the backbone. They achieved a specific capacitance of 162 F·g-1 at an extremely high current density of 20 A·g% and good cycling stability that shows a capacitance retention of -92% of its initial value, along with a coulombic efficiency of almost 100% after 5,000 cycles in an aqueous solution of I M Na2SO4. The results were attributed to the unique hierarchical structures, which provided a short diffusion path of electrolyte ions by means of the 2-D sheets and direct electrical connections to the current collector by 1-D arrays as well as the prevention of aggregation by virtue of the well-aligned 3-D structure.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50572010 and 10672020, the National Defense Founds under Grant Nos 51420205BQ0154, A2220061080）, and the National Key Basic Research Programme of China under Grant No 5131803.
文摘By a novel controlled combustion synthesis method, a large number of nanostructured ZnO whiskers with different morphologies, such as tetra-needles, long-leg tetra-needles and multi-needles, are prepared without any additive in open air at high temperature. The morphologies and crystalline structures of the as-prepared ZnO nanostructured whiskers are investigated by SEM and XRD. The possible growth mechanism on the nanostructured ZnO whiskers is proposed. The experimental results indicate that the dielectric constants and losses of the nanostructured ZnO whiskers are very low, demonstrating that the nanostructured ZnO whiskers are low-loss materials for microwave absorption in X-band. However, obvious microwave absorption in nanostructured ZnO whiskers is observed. The quasi-microantenna model may be attributed to the microwave absorption of the ZnO whiskers.
基金supported by the National Natural Science Foundation of China (Nos. 51772193 , 51702063)Nature Science Fund of Liaoning Province (No. 20180550200)+1 种基金China Postdoctoral Science Foundation(2018M630340)Project of Science and Technology Plan Shenyang (No. 17-231-1-18)
文摘Aqueous zinc-ion batteries(ZIBs) have been considered as one of the most promising electrochemical devices for large-scale energy storage system owing to their low cost and high safety. Herein, Na2V6O16·2.14H2O nanobelts are synthesized and applied as cathode material for ZIBs. The sample displays a high capacity of 466 m Ahg^-1 at 100 mAg^-1 and stable cycling performance with a capacity retention of 90% over 20 0 0 cycles at the 20 Ag^-1. Moreover, Na2V6O16·2.14H2O presents a capable rate ability and a high energy density of 312 Wh kg^-1 at a specific power of 70 Wkg^-1. The superior electrochemical performance is attributed to the large interlayer spacing and outstanding structure stability, which promise the highly reversible intercalation and extraction of zinc ion. The electrochemical kinetics and zinc ion storage mechanism are also investigated. This work demonstrates that nanoscale electrode materials with large interlayer spacing can effectively enhance the electrochemical performance of aqueous ZIBs, which can be extended to other metal ion batteries, such as magnesium ion batteries and aluminum ion batteries.
基金supported by the National Natural Science Foundation of China(Nos.U21A2077 and 51972198)the State Key Program of National Natural Science of China(No.62133007)+3 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2021ZD05,ZR2020JQ19,ZR2022JQ08 and ZR2023QB169)Taishan Scholars Program of Shandong Province(Nos.tsqn201812002,ts20190908 and tsqn202211028)Shenzhen Fundamental Research Program(No.JCYJ20190807093405503)China Postdoctoral Science Foundation(No.2022M721913).
文摘Sodium-ion batteries(SIBs)are an attractive battery system because of similar characteristics to lithium-ion batteries(LIBs)and large Na element abundance.Nevertheless,exploring stable,high-capacity and high-rate anode materials for SIBs is still challenging now.Herein,diethylenetriamine(DETA)molecular template derived ultrathin N-doped carbon(NC)layer decorated CoSe_(2)nanobelts(CoSe_(2)/NC)are prepared by solvothermal reaction followed by calcination process.The CoSe_(2)/NC exhibits large potential as an anode for SIBs.Experiments and theoretical calculations reveal that the in situ formed conductive ultrathin NC layer can not only relieve the volume change of CoSe_(2)but also accelerate electron and ion transport.In addition,the nanobelt structure of CoSe_(2)/NC with abundant exposed active sites can obviously accelerate the electrochemical kinetics.Under the synergistic effect of special nanobelt structure and NC layer,the rate as well as cycling performances of CoSe_(2)/NC are obviously improved.A superior capacity retention of 94.8%is achieved at 2 A·g^(-1)after 2000 cycles.When using Na3V2(PO4)3 cathodes,the pouch full batteries can work steadily at 0.5 C,verifying the application ability.CoSe_(2)/NC anodes also exhibit impressive performances in LIBs and potassium-ion batteries(PIBs).
基金support from the National Natural Science Foundation of China under grant No.550071028Program of Science and Technology Bureau of Qingdao under grant No.03-2-IR-18
文摘Oriented nanobelts of manganese oxide have been firstly and successfully prepared by a microemulsion technique under controlled circumstances. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM). Influences of sodium chloride and annealed temperature on the synthesis of Mn3O4 nanobelts were investigated. It was found that NaCI is the key factor to synthesize oriented Mn3O4 nanobelts and 827 K is optimum temperature to produce fine nanobelts. Oriented growth mechanism of Mn3O4 nanobelts was discussed.
