As one of the emerging two-dimensional lead halide materials,lead iodide(PbI_(2))nanosheets have proven to possess strong application potential in the fields of high-energy radiation detection and highly efficient per...As one of the emerging two-dimensional lead halide materials,lead iodide(PbI_(2))nanosheets have proven to possess strong application potential in the fields of high-energy radiation detection and highly efficient perovskite solar cells.However,the underlying photophysical properties such as hot-exciton-related carrier dynamics remain unclear for PbI_(2)nanosheets.Here,we report the exciton dynamics of a single PbI_(2)nanoflake prepared by an aqueous solution method.Through a three-dimensional(3D)diffusion model,we obtain the exciton annihilation radius and diffusion coefficient of a single PbI_(2)nanoflake under nonresonant and resonant excitation conditions of band-edge exciton state.As initial exciton densities increase,we find the carrier recombination mechanism for a single PbI_(2)nanoflake gradually changes from exciton-exciton annihilation to free-carrier recombination.Finally,we reveal the room-temperature circular polarization of a single PbI_(2)nanoflake is due to free-carrier recombination with a band-edge exciton dissociation time of~120 fs under the resonant excitation condition.展开更多
A binder-free Ni3S2 electrode was prepared directly on a graphene-coated Ni foam （G/Ni） substrate through surface sulfiding of substrate using thiourea as the sulfur source in this work. The Ni3S2 showed a flower-li...A binder-free Ni3S2 electrode was prepared directly on a graphene-coated Ni foam （G/Ni） substrate through surface sulfiding of substrate using thiourea as the sulfur source in this work. The Ni3S2 showed a flower-like morphology and was uniformly distributed on the G/Ni surface. The flower-like Ni3S2 was composed of cross-arrayed nanoflakes with a diameter and a thickness of 1-2 μm and -50 nm, re- spectively. The free space in the flowers and the thin feature of Ni3S2 buffered the volume changes and relieved mechanical strain during re- peated cycling. The intimate contact with the Ni substrate and the fixing effect of graphene maintained the structural stability of the Ni3S2 electrode during cycling. The G/Ni-supported Ni3S2 maintained a reversible capacity of 250 mAh·g^-1 after 100 cycles at 50 mA·g^-1, demon- strating the good cycling stability as a result of the unique microstructure of this electrode material.展开更多
Dendrite growth and thermal runaway induce serious safety hazards,impeding the practical applications of lithium metal batteries(LMBs).Although extensive advances have been attained in terms of LMB safety,most work on...Dendrite growth and thermal runaway induce serious safety hazards,impeding the practical applications of lithium metal batteries(LMBs).Although extensive advances have been attained in terms of LMB safety,most work only focus on a single aspect at a time.This paper reports a multifunctional separator coated by Mg(OH)2 nanoflakes with various excellent properties including electrolyte wettability,ionic conductivity,Li+ transference number,puncture strength,thermal stability and flame retardance.When used in LMBs,the Mg(OH)2 nanoflake coatings enable uniform Li+ distributing,which makes it homogeneous to deposit lithium,realizing effective dendrite suppression and less volume expansion.Meanwhile,Mg(OH)2 coatings can ensure LMBs are in normal conditions without thermal runaway until 140 ℃.A part of lithium can be converted into Li+ ions by Mg(OH)2 during repeated charge/discharge cycles,not only reducing the risk of separator damage and consequent short circuit,but also replenishing the capacity loss of LMBs.The Mg(OH)2 nanoflakes can coat on all kinds of commercial separators to improve their performances,which offers a facile but effective strategy for fabricating multifunctional separators and a comprehensive insight into enhancing LMB safety.展开更多
Oxygen vacancy plays vital roles in regulating the electronic and charge distribution of the oxygen deficient materials.Herein,abundant oxygen vacancies are created during assembling the two-dimensional(2D)ultra-thin ...Oxygen vacancy plays vital roles in regulating the electronic and charge distribution of the oxygen deficient materials.Herein,abundant oxygen vacancies are created during assembling the two-dimensional(2D)ultra-thin Bi_(2)MoO_(6) nanoflakes into three dimensional(3D)Bi_(2)MoO_(6) nanospheres,resulting in significantly improved performance for photocatalytical conversion of CO_(2) into liquid hydrocarbons.The increased performance is contributed by two primary sites,namely the abundant oxygen vacancy and the exposed molybdenum(Mo)atom induced by oxygen-migration,as revealed by the theoretical calculation.The oxygen vacancy(Ov)and uncovered Mo atom serving as dual binding sites for trapping CO_(2) molecules render the synchronous fixation-reduction process,resulting in the decline of activation energy for CO_(2) reduction from 2.15 eV on bulk Bi_(2)MoO_(6) to 1.42 eV on Ov-rich Bi_(2)MoO_(6).Such a striking decrease in the activation energy induces the efficient selective generation of liquid hydrocarbons,especially the methanol(C_(2)H_(5) OH)and ethanol(CH_(3) OH).The yields of CH_(3) OH and C_(2)H_(5) OH over the optimal Ov-Bi_(2)MoO_(6) is high up to 106.5 and 10.3μmol g^(-1) respectively,greatly outperforming that on the Bulk-Bi_(2)MoO_(6).展开更多
The paper reports the fabrication of Zn-doped TiO_2 nanotubes(Zn-TONT)/ZnO nanoflakes heterostructure for the first time,which shows improved performance as a photoanode in dye-sensitized solar cell(DSSC).The layered ...The paper reports the fabrication of Zn-doped TiO_2 nanotubes(Zn-TONT)/ZnO nanoflakes heterostructure for the first time,which shows improved performance as a photoanode in dye-sensitized solar cell(DSSC).The layered structure of this novel nanoporous structure has been analyzed unambiguously by Rutherford backscattering spectroscopy,scanning electron microscopy,and X-ray diffractometer.The cell using the heterostructure as photoanode manifests an enhancement of about an order in the magnitude of the short circuit current and a seven-fold increase in efficiency,over pure TiO_2 photoanodes.Characterizations further reveal that the Zn-TONT is preferentially oriented in [001] direction and there is a Ti metal-depleted interface layer which leads to better band alignment in DSSC.展开更多
SnS2 nanoflakes were successfully synthesized via a simple hydrothermal process. The as-prepared SnS2 samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, nitrogen adsorption-de...SnS2 nanoflakes were successfully synthesized via a simple hydrothermal process. The as-prepared SnS2 samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, nitrogen adsorption-desorption isotherms, and UV-vis diffuse reflectance spectroscopy（DRS）. The photocatalytic activities of the as-prepared SnS2 nanoflakes under visible light irradiation（λ〉420 nm） were evaluated by the degradation of rhodamine B（Rh B）. The effect of hydrothermal temperatures on the photocatalytic efficiency of as-prepared SnS2 nanoflakes was investigated. The experimental result showed that SnS2 nanoflakes synthesized at the temprature of 160 o had higher photocatalytic efficiency and good photocatalytic stability.展开更多
When focusing YAG laser pulses at 266nm into a heat-pipe oven containing PbI2 molecules vapor,four red line emissions at 626.0,619.8,613.7 and 621.8nm are observed.The photodissociation mechanism of PbI_(2) molecules ...When focusing YAG laser pulses at 266nm into a heat-pipe oven containing PbI2 molecules vapor,four red line emissions at 626.0,619.8,613.7 and 621.8nm are observed.The photodissociation mechanism of PbI_(2) molecules and the possible generation channels of these four line emissions are given.Moreover,the dependence of the emission at 626.0nm on incident laser energy and heat-pipe temperature is measured.The experimental observation is well supported by the photodissociation mechanism proposed by us.展开更多
The triple cation mixed perovskites(Cs FAMA)are known as one of the most efficient candidates for perovskite solar cells(PSCs).It is found that the power conversion efficiency(PCE)of triple-cation based devices would ...The triple cation mixed perovskites(Cs FAMA)are known as one of the most efficient candidates for perovskite solar cells(PSCs).It is found that the power conversion efficiency(PCE)of triple-cation based devices would increase with the test time extending,and the maximum efficiency is normally obtained after several days aging storage.Here,the relationship between enhanced device performance,excess PbI_(2)and its evolution in triple cation perovskite films of initial days was systematically explored.The Cs FAMA-PSCs are prepared by two-step methods under two environmental conditions,including in the glove box and the ambient air(30%humidity).After 7 days testing,the maximum PCE of PSCs under two conditions dramatically increased 12.4%and 12.2%,reached 21.68%and 21.89%,respectively.At initial days,the XRD peak intensities of perovskite phase gradually decreased and those corresponding to PbI_(2)increased.Along with time-resolved photoluminescence(TRPL)and kelvin probe force microscopy(KPFM),it was found that the defects were passivated with the evolution of PbI_(2).This work reveals the excess PbI_(2)and its evolution in perovskite film,which can further supplement the understanding of PbI_(2)defect passivation.展开更多
The rational design and synthesis of two-dimensional(2D) nanoflake ensemble-based materials have garnered great attention owing to the properties of the components of these materials, such as high mechanical flexibili...The rational design and synthesis of two-dimensional(2D) nanoflake ensemble-based materials have garnered great attention owing to the properties of the components of these materials, such as high mechanical flexibility, high specific surface area, numerous active sites,chemical stability, and superior electrical and thermal conductivity. These properties render the 2D ensembles great choices as alternative electrode materials for electrochemical energy storage systems. More recently,recognition of the numerous advantages of these 2D ensemble structures has led to the realization that the performance of certain devices could be significantly enhanced by utilizing three-dimensional(3D) architectures that can furnish an increased number of active sites. The present review summarizes the recent progress in 2D ensemble-based materials for energy storage applications,including supercapacitors, lithium-ion batteries, and sodium-ion batteries. Further, perspectives relating to the challenges and opportunities in this promising research area are discussed.展开更多
As an important neurotransmitter,the detection of dopamine(DA)is of great significance for the diagnosis and treatment of neurological diseases.In this study,WO_(3)-SnO_(2)nanoflake arrays were synthesized on fluorine...As an important neurotransmitter,the detection of dopamine(DA)is of great significance for the diagnosis and treatment of neurological diseases.In this study,WO_(3)-SnO_(2)nanoflake arrays were synthesized on fluorine-doped tin oxide(FTO)by hydrothermal synthesis and pulse electrodeposition,revealing significant surface-enhanced Raman scattering(SERS)activity with an enhancement factor(EF)reaching 4.79×10^(7).The obvious EF was mainly ascribed to the charge transfer between WO_(3)-SnO_(2)and methylene blue(MB)based on chemical mechanism(CM)and the molecular resonance effect.With the competitive adsorption of DA and absorbed MB,we prepared a SERS and electrochemical(EC)dual-mode detection platform of DA based on the WO_(3)-SnO_(2)nanoflake arrays.The linear range(LR)was 5.00-1.75×10^(3)nmol/L,and the detection limits(LODs)were as low as 1.50 and 0.80 nmol/L by SERS and EC respectively.Besides,the developed detection platform can shield the interference of many neurotransmitters similar to DA,showing good selectivity and excellent stability.In general,the SERS-EC dual-mode detection platform can be well applied to the detection of DA in cell lysate,demonstrating great potential in diagnosis of neurodegenerative diseases.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.62175088,61927814,21773087,21603083&21903035)China Postdoctoral Science Foundation(Grant No.2016M590259).
文摘As one of the emerging two-dimensional lead halide materials,lead iodide(PbI_(2))nanosheets have proven to possess strong application potential in the fields of high-energy radiation detection and highly efficient perovskite solar cells.However,the underlying photophysical properties such as hot-exciton-related carrier dynamics remain unclear for PbI_(2)nanosheets.Here,we report the exciton dynamics of a single PbI_(2)nanoflake prepared by an aqueous solution method.Through a three-dimensional(3D)diffusion model,we obtain the exciton annihilation radius and diffusion coefficient of a single PbI_(2)nanoflake under nonresonant and resonant excitation conditions of band-edge exciton state.As initial exciton densities increase,we find the carrier recombination mechanism for a single PbI_(2)nanoflake gradually changes from exciton-exciton annihilation to free-carrier recombination.Finally,we reveal the room-temperature circular polarization of a single PbI_(2)nanoflake is due to free-carrier recombination with a band-edge exciton dissociation time of~120 fs under the resonant excitation condition.
基金financially supported by the Scientific and Technological Project of State Grid Corporation of China
文摘A binder-free Ni3S2 electrode was prepared directly on a graphene-coated Ni foam （G/Ni） substrate through surface sulfiding of substrate using thiourea as the sulfur source in this work. The Ni3S2 showed a flower-like morphology and was uniformly distributed on the G/Ni surface. The flower-like Ni3S2 was composed of cross-arrayed nanoflakes with a diameter and a thickness of 1-2 μm and -50 nm, re- spectively. The free space in the flowers and the thin feature of Ni3S2 buffered the volume changes and relieved mechanical strain during re- peated cycling. The intimate contact with the Ni substrate and the fixing effect of graphene maintained the structural stability of the Ni3S2 electrode during cycling. The G/Ni-supported Ni3S2 maintained a reversible capacity of 250 mAh·g^-1 after 100 cycles at 50 mA·g^-1, demon- strating the good cycling stability as a result of the unique microstructure of this electrode material.
基金supported by the Natural Science Project from Science and Technology Department of Henan Province (172102410034)National Natural Science Foundation of China (NSFC-U1604120)。
文摘Dendrite growth and thermal runaway induce serious safety hazards,impeding the practical applications of lithium metal batteries(LMBs).Although extensive advances have been attained in terms of LMB safety,most work only focus on a single aspect at a time.This paper reports a multifunctional separator coated by Mg(OH)2 nanoflakes with various excellent properties including electrolyte wettability,ionic conductivity,Li+ transference number,puncture strength,thermal stability and flame retardance.When used in LMBs,the Mg(OH)2 nanoflake coatings enable uniform Li+ distributing,which makes it homogeneous to deposit lithium,realizing effective dendrite suppression and less volume expansion.Meanwhile,Mg(OH)2 coatings can ensure LMBs are in normal conditions without thermal runaway until 140 ℃.A part of lithium can be converted into Li+ ions by Mg(OH)2 during repeated charge/discharge cycles,not only reducing the risk of separator damage and consequent short circuit,but also replenishing the capacity loss of LMBs.The Mg(OH)2 nanoflakes can coat on all kinds of commercial separators to improve their performances,which offers a facile but effective strategy for fabricating multifunctional separators and a comprehensive insight into enhancing LMB safety.
基金financially supported by the National Natural Science Foundation of China(Grants 52072165,52070092,51662031)。
文摘Oxygen vacancy plays vital roles in regulating the electronic and charge distribution of the oxygen deficient materials.Herein,abundant oxygen vacancies are created during assembling the two-dimensional(2D)ultra-thin Bi_(2)MoO_(6) nanoflakes into three dimensional(3D)Bi_(2)MoO_(6) nanospheres,resulting in significantly improved performance for photocatalytical conversion of CO_(2) into liquid hydrocarbons.The increased performance is contributed by two primary sites,namely the abundant oxygen vacancy and the exposed molybdenum(Mo)atom induced by oxygen-migration,as revealed by the theoretical calculation.The oxygen vacancy(Ov)and uncovered Mo atom serving as dual binding sites for trapping CO_(2) molecules render the synchronous fixation-reduction process,resulting in the decline of activation energy for CO_(2) reduction from 2.15 eV on bulk Bi_(2)MoO_(6) to 1.42 eV on Ov-rich Bi_(2)MoO_(6).Such a striking decrease in the activation energy induces the efficient selective generation of liquid hydrocarbons,especially the methanol(C_(2)H_(5) OH)and ethanol(CH_(3) OH).The yields of CH_(3) OH and C_(2)H_(5) OH over the optimal Ov-Bi_(2)MoO_(6) is high up to 106.5 and 10.3μmol g^(-1) respectively,greatly outperforming that on the Bulk-Bi_(2)MoO_(6).
基金UGC-DAE CSR,Indore,for funding through a collaborative project and SAIF IIT Bombay for the help with SEMsupported by the Michigan Space Grant Consortium+1 种基金by Hope CollegeDAE-BRNS for funding the preliminary works
文摘The paper reports the fabrication of Zn-doped TiO_2 nanotubes(Zn-TONT)/ZnO nanoflakes heterostructure for the first time,which shows improved performance as a photoanode in dye-sensitized solar cell(DSSC).The layered structure of this novel nanoporous structure has been analyzed unambiguously by Rutherford backscattering spectroscopy,scanning electron microscopy,and X-ray diffractometer.The cell using the heterostructure as photoanode manifests an enhancement of about an order in the magnitude of the short circuit current and a seven-fold increase in efficiency,over pure TiO_2 photoanodes.Characterizations further reveal that the Zn-TONT is preferentially oriented in [001] direction and there is a Ti metal-depleted interface layer which leads to better band alignment in DSSC.
基金Funded by the National Natural Science Foundation of China(No.U1304520)the Education Department of Henan Province(2013GGJS-185)
文摘SnS2 nanoflakes were successfully synthesized via a simple hydrothermal process. The as-prepared SnS2 samples were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, nitrogen adsorption-desorption isotherms, and UV-vis diffuse reflectance spectroscopy（DRS）. The photocatalytic activities of the as-prepared SnS2 nanoflakes under visible light irradiation（λ〉420 nm） were evaluated by the degradation of rhodamine B（Rh B）. The effect of hydrothermal temperatures on the photocatalytic efficiency of as-prepared SnS2 nanoflakes was investigated. The experimental result showed that SnS2 nanoflakes synthesized at the temprature of 160 o had higher photocatalytic efficiency and good photocatalytic stability.
基金Supported by the National Natural Science Foundation of China for Distinguished Young Scholars(19825110)National High Technology 410 Project.
文摘When focusing YAG laser pulses at 266nm into a heat-pipe oven containing PbI2 molecules vapor,four red line emissions at 626.0,619.8,613.7 and 621.8nm are observed.The photodissociation mechanism of PbI_(2) molecules and the possible generation channels of these four line emissions are given.Moreover,the dependence of the emission at 626.0nm on incident laser energy and heat-pipe temperature is measured.The experimental observation is well supported by the photodissociation mechanism proposed by us.
基金the financial support from the Young Scholars Development Fund of SWPU(201699010017)the Sichuan Science and Technology Program(2018JY0015)+1 种基金the National Nature Science Foundation of China(61774022)the 2020 Li Ka Shing Foundation Cross-Disciplinary Research Grant(2020LKSFG01A)。
文摘The triple cation mixed perovskites(Cs FAMA)are known as one of the most efficient candidates for perovskite solar cells(PSCs).It is found that the power conversion efficiency(PCE)of triple-cation based devices would increase with the test time extending,and the maximum efficiency is normally obtained after several days aging storage.Here,the relationship between enhanced device performance,excess PbI_(2)and its evolution in triple cation perovskite films of initial days was systematically explored.The Cs FAMA-PSCs are prepared by two-step methods under two environmental conditions,including in the glove box and the ambient air(30%humidity).After 7 days testing,the maximum PCE of PSCs under two conditions dramatically increased 12.4%and 12.2%,reached 21.68%and 21.89%,respectively.At initial days,the XRD peak intensities of perovskite phase gradually decreased and those corresponding to PbI_(2)increased.Along with time-resolved photoluminescence(TRPL)and kelvin probe force microscopy(KPFM),it was found that the defects were passivated with the evolution of PbI_(2).This work reveals the excess PbI_(2)and its evolution in perovskite film,which can further supplement the understanding of PbI_(2)defect passivation.
基金supported by the National Natural Science Foundation of China (21571157,U1604123,and 2187051489)Outstanding Young Talent Research Fund of Zhengzhou University (No.1521320001)+3 种基金the Young Outstanding Teachers of University in Henan Province (2016-130)Creative talents in the Education Department of Henan Province (19HASTIT039)the Open Project Foundation of Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) (2017-29),Nankai UniversityOpen Project Foundation of State Key Laboratory of Inorganic Synthesis and Preparation of Jilin University
文摘The rational design and synthesis of two-dimensional(2D) nanoflake ensemble-based materials have garnered great attention owing to the properties of the components of these materials, such as high mechanical flexibility, high specific surface area, numerous active sites,chemical stability, and superior electrical and thermal conductivity. These properties render the 2D ensembles great choices as alternative electrode materials for electrochemical energy storage systems. More recently,recognition of the numerous advantages of these 2D ensemble structures has led to the realization that the performance of certain devices could be significantly enhanced by utilizing three-dimensional(3D) architectures that can furnish an increased number of active sites. The present review summarizes the recent progress in 2D ensemble-based materials for energy storage applications,including supercapacitors, lithium-ion batteries, and sodium-ion batteries. Further, perspectives relating to the challenges and opportunities in this promising research area are discussed.
基金support from the National Natural Science Foundation of China(No.21827814 for Y.T.,No.21974049 for T.T.Z.)funded by Shanghai Rising-star Program(No.20QA1403300)Innovation Program of Shanghai Municipal Education Commission(No.201701070005E00020).
文摘As an important neurotransmitter,the detection of dopamine(DA)is of great significance for the diagnosis and treatment of neurological diseases.In this study,WO_(3)-SnO_(2)nanoflake arrays were synthesized on fluorine-doped tin oxide(FTO)by hydrothermal synthesis and pulse electrodeposition,revealing significant surface-enhanced Raman scattering(SERS)activity with an enhancement factor(EF)reaching 4.79×10^(7).The obvious EF was mainly ascribed to the charge transfer between WO_(3)-SnO_(2)and methylene blue(MB)based on chemical mechanism(CM)and the molecular resonance effect.With the competitive adsorption of DA and absorbed MB,we prepared a SERS and electrochemical(EC)dual-mode detection platform of DA based on the WO_(3)-SnO_(2)nanoflake arrays.The linear range(LR)was 5.00-1.75×10^(3)nmol/L,and the detection limits(LODs)were as low as 1.50 and 0.80 nmol/L by SERS and EC respectively.Besides,the developed detection platform can shield the interference of many neurotransmitters similar to DA,showing good selectivity and excellent stability.In general,the SERS-EC dual-mode detection platform can be well applied to the detection of DA in cell lysate,demonstrating great potential in diagnosis of neurodegenerative diseases.
基金supported by the Open Fund of the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University,PLN2021-17)the Science and Technology Project of Southwest Petroleum University(2021JBGS08)Sichuan Science and Technology Program(2022YFSY0040)。
