This study focuses on the effect of V-doping on the ferromagnetism（FM） of 6H-SiC powder.The X-ray diffraction results indicate that V is inserted into the 6H-SiC lattice.The Raman spectra reveal that with a V concen...This study focuses on the effect of V-doping on the ferromagnetism（FM） of 6H-SiC powder.The X-ray diffraction results indicate that V is inserted into the 6H-SiC lattice.The Raman spectra reveal that with a V concentration of 25 ppm,the crystalline quality and carrier concentration of 6H-SiC are hardly varied.It is found that after the V-doping process,the saturation magnetization（Ms） and the vacancy concentration of 6H-SiC are both increased.From these results,it is deduced that the effect of V might contribute mainly to the increase of vacancy concentration,thus resulting in the increase of Ms of V-doped 6H-SiC.展开更多
Undoped and V-doped 6H-SiC single crystals have been grown by the physical vapor transport method.The V concentration is determined to be 3.76×10^17 at/cm^3 and 6.14×10^17 at/cm^3 by secondary ion mass spect...Undoped and V-doped 6H-SiC single crystals have been grown by the physical vapor transport method.The V concentration is determined to be 3.76×10^17 at/cm^3 and 6.14×10^17 at/cm^3 by secondary ion mass spectrometry for low V-doped and high V-doped SiC samples,respectively.The undoped 6H-SiC shows diamagnetism,while the V-doped 6H-SiC exhibits weak ferromagnetism.The lower V-doped sample shows stronger ferromagnetism compared to that of the higher V-doped sample.However,the structural characterization indicates that the lower V-doped SiC has a relative poor crystalline quality.It is found that both V dopants and defects are essential for introducing ferromagnetic exchange in V-doped SiC single crystals.展开更多
A novel V-doped CeO_(2)-supported alkali-activated-steel-slag-based catalyst(V-CeO_(2)/AC)for photocatalytic decomposition of water to hydrogen was prepared via co-impregnation method.The chemical composition,mineral ...A novel V-doped CeO_(2)-supported alkali-activated-steel-slag-based catalyst(V-CeO_(2)/AC)for photocatalytic decomposition of water to hydrogen was prepared via co-impregnation method.The chemical composition,mineral phase,morphology,and optical performances of the synthesized catalyst samples were characterized by XRF,XRD,SEM,UV-Vis DRS,and so on.XRD and SEM results show that calcium silicate hydrate(Ca1.5SiO3.5·xH2O)mineral phase is formed in the carrier sample,and the prepared catalyst specimens are made up of approximately 50 nm particles.After 6 hours of xenon lamp irradiation,the catalyst supported on V-doped 8wt%CeO_(2) exhibits the highest photocatalytic hydrogen production activity(8292μmol/g),which is attributed to the interaction between the V-doped CeO_(2) active components and FeO existed in catalyst carrier.A possible photocatalytic decomposition of water for hydrogen production mechanism over the V-8CeO_(2)/AC catalyst was proposed.展开更多
Li-rich Mn-based oxides(LRMOs)hold great promise as next-generation cathode materials for high-energy Li-ion batteries because of their low cost and high capacity.Nevertheless,the practical application of LRMOs is imp...Li-rich Mn-based oxides(LRMOs)hold great promise as next-generation cathode materials for high-energy Li-ion batteries because of their low cost and high capacity.Nevertheless,the practical application of LRMOs is impeded by their low initial Coulombic efficiency and rapid voltage decay.Herein,a V-doped layered-spinel coherent layer is constructed on the surface of a Co-free LRMO through a simple treatment with NH_(4)VO_(3).The layered-spinel coherent layer with 3D ion channels enhanced Li+diffusion efficiency,mitigates surface-inter-face reactions and suppresses irreversible oxygen release.Notably,V-doping significantly reduces the Bader charge of oxygen atoms,thereby impeding excessive oxidation of oxygen ions and further enhancing the stability of O-redox.The modified LRMO exhibites a remarkable initial Coulombic efficiency of 91.6%,signifi-cantly surpassing that of the original LRMO(74.4%).Furthermore,the treated sample showes an impressive capacity retention rate of 91.9%after 200 cycles,accompanied by a voltage decay of merely 0.47 mV per cycle.The proposed treatment approach is straightforward and significantly improves the initial Coulombic efficiency,voltage stability,and capacity stability of LRMO cathode materials,thus holding considerable promise for the development of high-energy Li-ion batteries.展开更多
V-doped TiO2 nanoparticles（NPs） as dye adsorbents are synthesized by the co-precipitation method and characterized by X-ray powder diffraction, transmission electron microscope, N2 adsorption at 77 K, and X-ray phot...V-doped TiO2 nanoparticles（NPs） as dye adsorbents are synthesized by the co-precipitation method and characterized by X-ray powder diffraction, transmission electron microscope, N2 adsorption at 77 K, and X-ray photoelectron spectroscopy. The adsorption of methylene blue（MB） on the V-doped TiO2 NPs is studied in detail by varying the calcination temperature and V doping amount of the adsorbent, adsorbate concentration, adsorbent dosage, agitation rate, reaction temperature, and p H. The comparison of dye adsorption on V-doped TiO2 and parent TiO2 demonstrates that the adsorptive activity of TiO2 can be improved by V doping. The enhanced adsorptive performance can be attributed to the tremendous changes in texture, structure, and surface morphology of adsorbent. The adsorption kinetic analysis shows that the adsorption follows the pseudo-second order kinetics. The apparent activation energy for adsorption is calculated by Arrhenius formula to be 37.6 k J·mol-1, indicating that the adsorption is controlled by both of the diffusion and interfacial adsorption steps. The adsorption data are analyzed using Langmuir and Freundlich isotherms and the results indicate that the Langmuir model provides better correlation of the experimental data. The results conclusively show that the adsorption of MB is a spontaneous behavior and endothermic reaction with the ΔH value of 17.60 k J·mol-1.展开更多
Piezoelectric micromachined ultrasonic transducers(p-MUTs)have been extensively utilized in medical imaging,range-finding,gesture recognition,and so on.However,the piezoelectric layer is dominated by the toxic Pb(Zr,T...Piezoelectric micromachined ultrasonic transducers(p-MUTs)have been extensively utilized in medical imaging,range-finding,gesture recognition,and so on.However,the piezoelectric layer is dominated by the toxic Pb(Zr,Ti)O_(3),other materials possess inferior piezoelectric coefficients,and the traditional clamped diaphragm restricts the p-MUT response.In this work,lead-free ZnO films are doped by the vanadium nanostructures and are implemented to beam-island structure membranes,which are aimed to achieve non-toxic and high-performance p-MUTs.Firstly,the doping mechanism of ZnO is analyzed and the p-MUT structure is designed.Secondly,simulation based on the finite element method is conducted to evaluate the dynamic displacement of p-MUTs,after which prototypes are fabricated by the standard micromachined process.The effects of key fabrication parameters including O2 flow rates,sputtering targets,and annealing temperatures on V-doped ZnO films are investigated in detail.By using atomic force microscopy(AFM)and X-ray diffraction(XRD),the surface morphology and crystal structure of the films are analyzed respectively.Moreover,the piezoelectric properties are measured by piezo response force microscopy(PFM).The results indicate a piezoelectric coefficient as high as 194.5 pm/V,which is superior to most doped ZnO films.Finally,an experimental testing system is established to examine the p-MUT performance.Compared with the clamped diaphragm,the beam-island structure can acquire better electromechanical coupling and achieve range-finding successfully.This work provides a fine application prospect for enhancing the performance of lead-free p-MUTs.展开更多
Cobalt phosphide (CoP) is considered to be a potential candidate in the field of electrocatalysis due to its low-cost, abundant resources and high electrochemical stability. However, there is a great space for further...Cobalt phosphide (CoP) is considered to be a potential candidate in the field of electrocatalysis due to its low-cost, abundant resources and high electrochemical stability. However, there is a great space for further improvement of its electrocatalytic performance since its charge transfer rate and catalytic activity have not reached a satisfactory level. Herein, we design and fabricate a three dimensional urchins like V-doped CoP with different amounts of V-doping on nickel foam electrode. The V-doped CoP/NF electrode with optimized amounts of V-doping (10%) exhibits outstanding hydrogen evolution reaction (HER) performance under universal-pH conditions and preeminent oxygen evolution reaction (OER) performance in alkaline media. Notably, the assembled water-splitting cell displays a cell voltage of only 1.53 V at 10 mA·cm−2 and has excellent durability, much better than many reported related bifunctional catalysts. The experiment results and theoretical analysis revealed that vanadium atoms replace cobalt atoms in CoP lattice. Vanadium doping can not only raise the density of electronic states near the Fermi level enhancing the conductivity of the catalyst, but can also optimize the free energy of hydrogen and oxygen-containing intermediates adsorption over CoP, thus promoting its catalytic activity. Moreover, the unique nanostructure of the catalyst provides the various shortened channels for charge transfer and reactant/electrolyte diffusion, which accelerates the electrocatalytic process. Also, the in situ growth strategy can improve the conductivity and stability of the catalyst.展开更多
Manganese-based binary transition metal oxides(BTMO)emerge as a highly followed cathode for aqueous zinc-ion batteries(AZIBs)in recent years because of the relatively stable structure and exceptional energy density.No...Manganese-based binary transition metal oxides(BTMO)emerge as a highly followed cathode for aqueous zinc-ion batteries(AZIBs)in recent years because of the relatively stable structure and exceptional energy density.Nonetheless,the problems of slow electrochemical reaction kinetics and low intrinsic conductivity have limited their development.Herein,V was introduced into pomegranate-like CoMn_(2)O_(4) to form V doped CoMn_(2)O_(4)(V-CMO)with lauxriant oxygen vancancies via a straightforward solvothermal method,followed by a calcination treatment.DFT calculations demonstrate that oxygen vacancies improve the intrinsic conductivity of V-CMO and reduce Zn^(2+) diffusion energy barrier.Simultaneously,the unique pomegranate-like morphology with abundant pores and the void space promotes the exposure of electrochemical active sites and reduces the volume strain of electrode during cycling,which can further improve the long-term cycling and rate performance of V-CMO cathode.Consequently,V-CMO cathode shows a high specific capacity(306.6 mAh g^(-1) at 0.1 A g^(-1) after 200 cycles)and outstanding cycling stability(98.6 mAh g^(-1) at 1 A g^(-1) after 2000 cycles with a decay of 0.05%per cycle).Furthermore,the assembled flexible ZIBs based on V-CMO exhibit outstanding mechanical stability and excellent electrochemical properties at different deformations.This work sheds some new light on designing spinel-type Mn-based cathode for high-performance ZIBs.展开更多
Vanadium doped nanoporous Ti0.9Sn0.1O2 thin film has been prepared on an alumina substrate by sol-gel method with Pluronic P123 as the organic template, and humidity sensing properties of it has been investigated. It ...Vanadium doped nanoporous Ti0.9Sn0.1O2 thin film has been prepared on an alumina substrate by sol-gel method with Pluronic P123 as the organic template, and humidity sensing properties of it has been investigated. It is found that V-doped nanoporous Ti0.9Sn0.1O2 thin film shows good humidity sensing properties, and impendence of it de- creases more than four orders of magnitude in the relative humidity （RH） range of 11%--95% at 25 ℃. The response and recovery time of this sensor are about 13 and 17 s, respectively. High sensitivity, narrow hysteresis loop, rapid response and recovery, prominent stability and good repeatability are obtained. A possible mechanism is sug- gested to explain the humidity sensitive properties.展开更多
Epitaxy growth and accurate doping of wafer-scale two-dimensional(2D)semiconductor single crystals are two crucial issues to break the scaling limitation of transistors.Despite remarkable progresses have been realized...Epitaxy growth and accurate doping of wafer-scale two-dimensional(2D)semiconductor single crystals are two crucial issues to break the scaling limitation of transistors.Despite remarkable progresses have been realized in preparing large-area 2D n-type semiconductor single crystals,the epitaxy growth of wafer-scale p-type semiconductor single crystals have yet to be realized.Here an in-situ hole doping strategy is proposed to control the domain orientation and modulate the electronic property of monolayer MoS_(2),which enable the achievement of centimeter-sized ptype semiconductor single crystals.The introduction of hole dopants(e.g.,V_(2)O_(5),NH_(4)VO_(3),and VCl_(3))contributes to the parallel steps formation on sapphire surfaces to induce the unidirectional monolayer MoS_(2) domains nucleation.Meanwhile,the electronic property of monolayer MoS_(2) is also changed from n-type semiconducting to p-type.Benefiting from the different doping abilities of V_(2)O_(5),NH_(4)VO_(3),and VCl_(3),the V doping concentrations can be regulated within a large range from 0.36 to 12.60 at%,which delivers an excellent hole mobility(17.6 cm^(2)·V^(–1)·s^(–1)).This work provides a new avenue for synthesizing wafer-scale 2D p-type semiconductor single crystals,which will enrich the device functions and extend Moore’s law.展开更多
Dynamically engineering the optical and electrical properties in two-dimensional(2D)materials is of great signifcance for designing the related functions and applications.The introduction of foreign-atoms has previous...Dynamically engineering the optical and electrical properties in two-dimensional(2D)materials is of great signifcance for designing the related functions and applications.The introduction of foreign-atoms has previously been proven to be a feasible way to tune the band structure and related properties of 3D materials;however,this approach still remains to be explored in 2D materials.Here,we systematically demonstrate the growth of vanadium-doped molybdenum disulfde(V-doped MoS_(2))monolayers via an alkali metal-assisted chemical vapor deposition method.Scanning transmission electron microscopy demonstrated that V atoms substituted the Mo atoms and became uniformly distributed in the MoS_(2)monolayers.This was also confrmed by Raman and X-ray photoelectron spectroscopy.Power-dependent photoluminescence spectra clearly revealed the enhanced B-exciton emission characteristics in the V-doped MoS_(2)monolayers(with low doping concentration).Most importantly,through temperature-dependent study,we observed efcient valley scattering of the B-exciton,greatly enhancing its emission intensity.Carrier transport experiments indicated that typical p-type conduction gradually arisen and was enhanced with increasing V composition in the V-doped MoS_(2),where a clear n-type behavior transited frst to ambipolar and then to lightly p-type charge carrier transport.In addition,visible to infrared wide-band photodetectors based on V-doped MoS_(2)monolayers(with low doping concentration)were demonstrated.The V-doped MoS_(2)monolayers with distinct B-exciton emission,enhanced p-type conduction and broad spectral response can provide new platforms for probing new physics and ofer novel materials for optoelectronic applications.展开更多
基金Project supported by the Innovation Programs of the Chinese Academy of Sciences (Grant No. KJCX2-EW-W10)
文摘This study focuses on the effect of V-doping on the ferromagnetism（FM） of 6H-SiC powder.The X-ray diffraction results indicate that V is inserted into the 6H-SiC lattice.The Raman spectra reveal that with a V concentration of 25 ppm,the crystalline quality and carrier concentration of 6H-SiC are hardly varied.It is found that after the V-doping process,the saturation magnetization（Ms） and the vacancy concentration of 6H-SiC are both increased.From these results,it is deduced that the effect of V might contribute mainly to the increase of vacancy concentration,thus resulting in the increase of Ms of V-doped 6H-SiC.
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 51002176)the Innovation Programs of the Chinese Academy of Sciences (Grant No. KJCX2-EW-W10)
文摘Undoped and V-doped 6H-SiC single crystals have been grown by the physical vapor transport method.The V concentration is determined to be 3.76×10^17 at/cm^3 and 6.14×10^17 at/cm^3 by secondary ion mass spectrometry for low V-doped and high V-doped SiC samples,respectively.The undoped 6H-SiC shows diamagnetism,while the V-doped 6H-SiC exhibits weak ferromagnetism.The lower V-doped sample shows stronger ferromagnetism compared to that of the higher V-doped sample.However,the structural characterization indicates that the lower V-doped SiC has a relative poor crystalline quality.It is found that both V dopants and defects are essential for introducing ferromagnetic exchange in V-doped SiC single crystals.
基金Funded by the National Natural Science Foundation of China(No.51372197)the Basic Research Plan of Natural Science of Shaanxi Province(No.2020JQ-754)+4 种基金the Key Innovation Team of Shaanxi Province(No.2014KCT-04)the Special Project of Shaanxi Province(No.19JK0490)the Construction and Promotion of Highlevel Achievements in Material Science and Engineering Discipline of Xi’an University of Science and Technology(No.2040519061)the Study on Preparation and Properties of New Solid-wastebased Cementitious Materials(No.6000190120)the Xi’an University of Science and Technology Doctoral Start-up Project(No.2018QDJ011)。
文摘A novel V-doped CeO_(2)-supported alkali-activated-steel-slag-based catalyst(V-CeO_(2)/AC)for photocatalytic decomposition of water to hydrogen was prepared via co-impregnation method.The chemical composition,mineral phase,morphology,and optical performances of the synthesized catalyst samples were characterized by XRF,XRD,SEM,UV-Vis DRS,and so on.XRD and SEM results show that calcium silicate hydrate(Ca1.5SiO3.5·xH2O)mineral phase is formed in the carrier sample,and the prepared catalyst specimens are made up of approximately 50 nm particles.After 6 hours of xenon lamp irradiation,the catalyst supported on V-doped 8wt%CeO_(2) exhibits the highest photocatalytic hydrogen production activity(8292μmol/g),which is attributed to the interaction between the V-doped CeO_(2) active components and FeO existed in catalyst carrier.A possible photocatalytic decomposition of water for hydrogen production mechanism over the V-8CeO_(2)/AC catalyst was proposed.
基金Natural Science Research(Department of Education)Project of Higher Education Institutions in Guangdong Province(Grant No.2018KQNCX063)Applied Basic Research Fund of Guangdong Province(Grant No.2024B1515020071)+1 种基金National Natural Science Foundation of China(Grant Nos.52371217 and 52150410411)Guangdong Provincial Science and Technology Plan Project(Grant No.2023A0505020009)。
文摘Li-rich Mn-based oxides(LRMOs)hold great promise as next-generation cathode materials for high-energy Li-ion batteries because of their low cost and high capacity.Nevertheless,the practical application of LRMOs is impeded by their low initial Coulombic efficiency and rapid voltage decay.Herein,a V-doped layered-spinel coherent layer is constructed on the surface of a Co-free LRMO through a simple treatment with NH_(4)VO_(3).The layered-spinel coherent layer with 3D ion channels enhanced Li+diffusion efficiency,mitigates surface-inter-face reactions and suppresses irreversible oxygen release.Notably,V-doping significantly reduces the Bader charge of oxygen atoms,thereby impeding excessive oxidation of oxygen ions and further enhancing the stability of O-redox.The modified LRMO exhibites a remarkable initial Coulombic efficiency of 91.6%,signifi-cantly surpassing that of the original LRMO(74.4%).Furthermore,the treated sample showes an impressive capacity retention rate of 91.9%after 200 cycles,accompanied by a voltage decay of merely 0.47 mV per cycle.The proposed treatment approach is straightforward and significantly improves the initial Coulombic efficiency,voltage stability,and capacity stability of LRMO cathode materials,thus holding considerable promise for the development of high-energy Li-ion batteries.
基金financially supported by the NNSFC(Nos.21003021,21173044,21473096)the Science and Technology Project of the Education Office of Fujian Province(JA12017)+3 种基金National Basic Research Program of China(973 Program,No.2012CB722607)the Science and Technology Project of Fujian Province(Nos.2007J0359,2006F5030,CE0015)the Ningde Normal University projects on serving the western coast to the TW strait(No.2010H103)the Project of Fujian Province Communications Department(No.201323)
文摘V-doped TiO2 nanoparticles（NPs） as dye adsorbents are synthesized by the co-precipitation method and characterized by X-ray powder diffraction, transmission electron microscope, N2 adsorption at 77 K, and X-ray photoelectron spectroscopy. The adsorption of methylene blue（MB） on the V-doped TiO2 NPs is studied in detail by varying the calcination temperature and V doping amount of the adsorbent, adsorbate concentration, adsorbent dosage, agitation rate, reaction temperature, and p H. The comparison of dye adsorption on V-doped TiO2 and parent TiO2 demonstrates that the adsorptive activity of TiO2 can be improved by V doping. The enhanced adsorptive performance can be attributed to the tremendous changes in texture, structure, and surface morphology of adsorbent. The adsorption kinetic analysis shows that the adsorption follows the pseudo-second order kinetics. The apparent activation energy for adsorption is calculated by Arrhenius formula to be 37.6 k J·mol-1, indicating that the adsorption is controlled by both of the diffusion and interfacial adsorption steps. The adsorption data are analyzed using Langmuir and Freundlich isotherms and the results indicate that the Langmuir model provides better correlation of the experimental data. The results conclusively show that the adsorption of MB is a spontaneous behavior and endothermic reaction with the ΔH value of 17.60 k J·mol-1.
基金supported by the National Natural Science Foundation of China(Grant No.52205602&52075455).
文摘Piezoelectric micromachined ultrasonic transducers(p-MUTs)have been extensively utilized in medical imaging,range-finding,gesture recognition,and so on.However,the piezoelectric layer is dominated by the toxic Pb(Zr,Ti)O_(3),other materials possess inferior piezoelectric coefficients,and the traditional clamped diaphragm restricts the p-MUT response.In this work,lead-free ZnO films are doped by the vanadium nanostructures and are implemented to beam-island structure membranes,which are aimed to achieve non-toxic and high-performance p-MUTs.Firstly,the doping mechanism of ZnO is analyzed and the p-MUT structure is designed.Secondly,simulation based on the finite element method is conducted to evaluate the dynamic displacement of p-MUTs,after which prototypes are fabricated by the standard micromachined process.The effects of key fabrication parameters including O2 flow rates,sputtering targets,and annealing temperatures on V-doped ZnO films are investigated in detail.By using atomic force microscopy(AFM)and X-ray diffraction(XRD),the surface morphology and crystal structure of the films are analyzed respectively.Moreover,the piezoelectric properties are measured by piezo response force microscopy(PFM).The results indicate a piezoelectric coefficient as high as 194.5 pm/V,which is superior to most doped ZnO films.Finally,an experimental testing system is established to examine the p-MUT performance.Compared with the clamped diaphragm,the beam-island structure can acquire better electromechanical coupling and achieve range-finding successfully.This work provides a fine application prospect for enhancing the performance of lead-free p-MUTs.
基金The work reported here was supported by the National Natural Science Foundation of China(No.52072196)We acknowledge the National Supercomputing Center in Shenzhen,P.R.China for their computations assistance.
文摘Cobalt phosphide (CoP) is considered to be a potential candidate in the field of electrocatalysis due to its low-cost, abundant resources and high electrochemical stability. However, there is a great space for further improvement of its electrocatalytic performance since its charge transfer rate and catalytic activity have not reached a satisfactory level. Herein, we design and fabricate a three dimensional urchins like V-doped CoP with different amounts of V-doping on nickel foam electrode. The V-doped CoP/NF electrode with optimized amounts of V-doping (10%) exhibits outstanding hydrogen evolution reaction (HER) performance under universal-pH conditions and preeminent oxygen evolution reaction (OER) performance in alkaline media. Notably, the assembled water-splitting cell displays a cell voltage of only 1.53 V at 10 mA·cm−2 and has excellent durability, much better than many reported related bifunctional catalysts. The experiment results and theoretical analysis revealed that vanadium atoms replace cobalt atoms in CoP lattice. Vanadium doping can not only raise the density of electronic states near the Fermi level enhancing the conductivity of the catalyst, but can also optimize the free energy of hydrogen and oxygen-containing intermediates adsorption over CoP, thus promoting its catalytic activity. Moreover, the unique nanostructure of the catalyst provides the various shortened channels for charge transfer and reactant/electrolyte diffusion, which accelerates the electrocatalytic process. Also, the in situ growth strategy can improve the conductivity and stability of the catalyst.
基金supported by the National Natural Science Foundation of China(Nos.52072034 and 52372173).
文摘Manganese-based binary transition metal oxides(BTMO)emerge as a highly followed cathode for aqueous zinc-ion batteries(AZIBs)in recent years because of the relatively stable structure and exceptional energy density.Nonetheless,the problems of slow electrochemical reaction kinetics and low intrinsic conductivity have limited their development.Herein,V was introduced into pomegranate-like CoMn_(2)O_(4) to form V doped CoMn_(2)O_(4)(V-CMO)with lauxriant oxygen vancancies via a straightforward solvothermal method,followed by a calcination treatment.DFT calculations demonstrate that oxygen vacancies improve the intrinsic conductivity of V-CMO and reduce Zn^(2+) diffusion energy barrier.Simultaneously,the unique pomegranate-like morphology with abundant pores and the void space promotes the exposure of electrochemical active sites and reduces the volume strain of electrode during cycling,which can further improve the long-term cycling and rate performance of V-CMO cathode.Consequently,V-CMO cathode shows a high specific capacity(306.6 mAh g^(-1) at 0.1 A g^(-1) after 200 cycles)and outstanding cycling stability(98.6 mAh g^(-1) at 1 A g^(-1) after 2000 cycles with a decay of 0.05%per cycle).Furthermore,the assembled flexible ZIBs based on V-CMO exhibit outstanding mechanical stability and excellent electrochemical properties at different deformations.This work sheds some new light on designing spinel-type Mn-based cathode for high-performance ZIBs.
文摘Vanadium doped nanoporous Ti0.9Sn0.1O2 thin film has been prepared on an alumina substrate by sol-gel method with Pluronic P123 as the organic template, and humidity sensing properties of it has been investigated. It is found that V-doped nanoporous Ti0.9Sn0.1O2 thin film shows good humidity sensing properties, and impendence of it de- creases more than four orders of magnitude in the relative humidity （RH） range of 11%--95% at 25 ℃. The response and recovery time of this sensor are about 13 and 17 s, respectively. High sensitivity, narrow hysteresis loop, rapid response and recovery, prominent stability and good repeatability are obtained. A possible mechanism is sug- gested to explain the humidity sensitive properties.
基金supported by the National Natural Science Foundation of China(Nos.U24A2055 and 92164103)the National Key R&D Program of China(No.2021YFA1200800)+2 种基金the Natural Science Foundation of Hubei Province(No.2024AFA052)the Natural Science Foundation of Wuhan or Wuhan Science and Technology Bureau(No.2023010201010067)the Fundamental Research Funds for the Central Universities(No.2042023kf0187).
文摘Epitaxy growth and accurate doping of wafer-scale two-dimensional(2D)semiconductor single crystals are two crucial issues to break the scaling limitation of transistors.Despite remarkable progresses have been realized in preparing large-area 2D n-type semiconductor single crystals,the epitaxy growth of wafer-scale p-type semiconductor single crystals have yet to be realized.Here an in-situ hole doping strategy is proposed to control the domain orientation and modulate the electronic property of monolayer MoS_(2),which enable the achievement of centimeter-sized ptype semiconductor single crystals.The introduction of hole dopants(e.g.,V_(2)O_(5),NH_(4)VO_(3),and VCl_(3))contributes to the parallel steps formation on sapphire surfaces to induce the unidirectional monolayer MoS_(2) domains nucleation.Meanwhile,the electronic property of monolayer MoS_(2) is also changed from n-type semiconducting to p-type.Benefiting from the different doping abilities of V_(2)O_(5),NH_(4)VO_(3),and VCl_(3),the V doping concentrations can be regulated within a large range from 0.36 to 12.60 at%,which delivers an excellent hole mobility(17.6 cm^(2)·V^(–1)·s^(–1)).This work provides a new avenue for synthesizing wafer-scale 2D p-type semiconductor single crystals,which will enrich the device functions and extend Moore’s law.
基金supported by the National Key R&D Program of China(No.2022YFA1204300)the National Natural Science Foundation of China(Grant Nos.62104066,52372146,U22A20138,52221001 and 62090035)+2 种基金the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2020WNLOKF016)the Science and Technology Innovation Program of Hunan Province(Nos.2021RC3061 and 2020RC2028)the National Postdoctoral Program for Innovative Talents(No.BX2021094).
文摘Dynamically engineering the optical and electrical properties in two-dimensional(2D)materials is of great signifcance for designing the related functions and applications.The introduction of foreign-atoms has previously been proven to be a feasible way to tune the band structure and related properties of 3D materials;however,this approach still remains to be explored in 2D materials.Here,we systematically demonstrate the growth of vanadium-doped molybdenum disulfde(V-doped MoS_(2))monolayers via an alkali metal-assisted chemical vapor deposition method.Scanning transmission electron microscopy demonstrated that V atoms substituted the Mo atoms and became uniformly distributed in the MoS_(2)monolayers.This was also confrmed by Raman and X-ray photoelectron spectroscopy.Power-dependent photoluminescence spectra clearly revealed the enhanced B-exciton emission characteristics in the V-doped MoS_(2)monolayers(with low doping concentration).Most importantly,through temperature-dependent study,we observed efcient valley scattering of the B-exciton,greatly enhancing its emission intensity.Carrier transport experiments indicated that typical p-type conduction gradually arisen and was enhanced with increasing V composition in the V-doped MoS_(2),where a clear n-type behavior transited frst to ambipolar and then to lightly p-type charge carrier transport.In addition,visible to infrared wide-band photodetectors based on V-doped MoS_(2)monolayers(with low doping concentration)were demonstrated.The V-doped MoS_(2)monolayers with distinct B-exciton emission,enhanced p-type conduction and broad spectral response can provide new platforms for probing new physics and ofer novel materials for optoelectronic applications.
