As the main distribution place of deep-level defects and the entrance of water, the interface is critical to determining both the power conversion efficiency(PCE) and the stability of perovskite solar cells(PSCs). Sui...As the main distribution place of deep-level defects and the entrance of water, the interface is critical to determining both the power conversion efficiency(PCE) and the stability of perovskite solar cells(PSCs). Suitable interface design can dramatically passivate interface defects and optimize energy level alignment for suppressing the nonradiative recombination and effectively extracting the photogenerated carriers towards higher PCE. Meanwhile, a proper interface design can also block the interface diffusion of ions for high operational stability. Therefore, interface modification is of great significance to make the PSCs more efficient and stable. Upon optimized material choices, the three-dimensional halide perovskite graded junction layer, low-dimensional halide perovskite interface layer and organic salt passivation layer have been constructed on perovskite films for superior PSCs, yet a systematic review of them is missing. Thus, a guide and summary of recent advances in modulating the perovskite films interface is necessary for the further development of more efficient interface modification.展开更多
To realize the continuous production of hydrogen energy,the efficient photocatalysts are required in the heterogeneous reaction for water splitting.Herein,we reported a surface modulation strategy,via doping oxygen at...To realize the continuous production of hydrogen energy,the efficient photocatalysts are required in the heterogeneous reaction for water splitting.Herein,we reported a surface modulation strategy,via doping oxygen atoms to tune the surface state of ZnIn_(2)S_(4)nanosheets with cocatalyst MoS_(2)modification,to enhance water adsorption and surface catalytic reaction for boosting the photocatalytic activity.Consequently,MoS_(2)/O-ZnIn_(2)S_(4)photocatalysts showed a remarkably superior photocatalytic H_(2)production performance of 4.002 mmol g^(-1)h^(-1)and an apparent quantum yield(AQY)of~2.53%,5.4 folds higher than ZnIn_(2)S_(4).Using operando infrared spectroscopy and DFT calculation,we revealed the dynamic structural evolution,as well as the active sites for water adsorption and the catalytic reaction at the MoS_(2)/O ZnIn_(2)S_(4)interface.This work reveals the effect of surface modulation on the photocatalytic activity for MoS_(2)/O-ZnIn_(2)S_(4)and offers a feasible method to devise excellent nanomaterial photocatalysts for H_(2)production.展开更多
We predict ultrafast modulation of the pure molten metal surface stress fields under the irradiation of the single femtosecond laser pulse through the two-temperature model molecular-dynamics simulations. High-resolut...We predict ultrafast modulation of the pure molten metal surface stress fields under the irradiation of the single femtosecond laser pulse through the two-temperature model molecular-dynamics simulations. High-resolution and precision calculations are used to resolve the ultrafast laser-induced anisotropic relaxations of the pressure components on the time-scale comparable to the intrinsic liquid density relaxation time. The magnitudes of the dynamic surface tensions are found being modulated sharply within picoseconds after the irradiation, due to the development of the nanometer scale non-hydrostatic regime behind the exterior atomic layer of the liquid surfaces.The reported novel regulation mechanism of the liquid surface stress field and the dynamic surface tension hints at levitating the manipulation of liquid surfaces, such as ultrafast steering the surface directional transport and patterning.展开更多
ZrCo alloy holds great promise for hydrogen isotope storage,yet its susceptibility to poisoning by impurity gases,especially CO,poses a challenge.This susceptibility arises due to the electron acceptor nature of the s...ZrCo alloy holds great promise for hydrogen isotope storage,yet its susceptibility to poisoning by impurity gases,especially CO,poses a challenge.This susceptibility arises due to the electron acceptor nature of the surface Co element and the formation of the d-πfeedback bond,thereby impeding the surface hydrogen dissociation.Accordingly,we propose a novel local activity modulation strategy,where substituent elements are sacrificed to protect the active Co sites for hydrogen dissociation.Considering CO absorption capacity,solid solubility,and hydrogen affinity,we selected V,Cr,and Mn as microalloying elements and successfully prepared the single-phase ZrCo_(0.97)(VCrMn)_(0.03)alloy.Compared to pristine ZrCo,ZrCo_(0.97)(VCrMn)_(0.03)demonstrates significantly enhanced poisoning resistance.Notably,the hydrogenation kinetics of ZrCo_(0.97)(VCrMn)_(0.03)is 2.4 times higher than that of ZrCo in 4 bar H_(2)+5000 ppm CO.Interestingly,the controllable in situ formation of the Co_(2)C phase shell structure during cycling further safeguards the surface reactivity of ZrCo_(0.97)(VCrMn)_(0.03).Consequently,its capacity retention ratio after 25 cycles has been improved to 74.5%from 55.3%of the ZrCo alloy.These findings suggest that micro-alloying engineering could be a promising strategy for surface activity modulation to enhance the anti-poisoning properties of hydrogen storage materials.展开更多
Defects at the surface and grain boundaries of the perovskite films are extremely detrimental to both the efficiency and stability of perovskite solar cells(PSCs).Herein,a simple and stable quaternary ammonium halide,...Defects at the surface and grain boundaries of the perovskite films are extremely detrimental to both the efficiency and stability of perovskite solar cells(PSCs).Herein,a simple and stable quaternary ammonium halide,named chlormequat chloride(i.e.,chlorinated choline chloride,CCC),is introduced to regulate the upper surface chemical environment of perovskite films.The anion(Cl^(-))and cation[ClCH_(2)CH_(2)N(CH_(3))_(3)]+in CCC could effectively self-search and passivate positively and negatively charged ionic defects in per ovskites,respectively,which contributes to inhibited nonradiative recombination and reduced energy los in PSCs.As a result,the champion power conversion efficiency(PCE)of PSCs can be significantly enhanced from 22.82%to 24.07%.Moreover,the unencapsulated device with CCC modification retains 92.0%of it original PCE even subject to thermal aging at 85℃ for 2496 h.This work provides guidance for the ratio nal design of functional molecules as defect passivators in PSCs,which is beneficial for the improvement in both device performance and stability.展开更多
CeO2 film plays an essential role in nucleation and growth of YBa2 Cu3 O（7-x）（YBCO） films. In this work,the dependence of superconducting properties of YBCO on CeO2 films with different thicknesses was investigate...CeO2 film plays an essential role in nucleation and growth of YBa2 Cu3 O（7-x）（YBCO） films. In this work,the dependence of superconducting properties of YBCO on CeO2 films with different thicknesses was investigated,in order to achieve fabrication of high-performance YBCO coated conductors in industrial scale. The crystalline structure and morphology of CeO2 films with thickness ranging from 21 to 563 nm were systematically characterized by means of X-ray diffraction（XRD）, atomic force microscope（AFM） and reflection high-energy electron diffraction（RHEED）. Additional focus was addressed on evolution of the surface quality of CeO2 films with thickness increasing. The results show that at the optimal thickness of 221 nm, CeO2 film exhibits sharp in-plane and out-of-plane texture with full width of half maximum（FWHM） values of 5.9° and 1.8°, respectively, and smooth surface with a mean root-mean-square（RMS） roughness value as low as 0.6 nm. Combing RHEED and transmission electron microscope（TEM） cross-sectional analysis, it is found that nucleation and growth of CeO2 films at early stage remain in island growth mode with rougher surface,while further increasing the thickness beyond the optimal thickness leads to weak surface quality, consequently resulting in degradation of superconductor layers deposited subsequently. Eventually, a critical current density（Jc） as high as 4.6×10-6 A·cm-（-2）（77 K, self-field） is achieved on a YBCO film on a thickness-modulated CeO2/MgO/Y2 O3/Al2 O3/C276 architecture, demonstrating the advantages of CeO2 films as buffer layer in high-throughput manufacture of coated conductors.展开更多
Water electrolysis has been regarded as a promising technology to produce clean hydrogen fuel with high purity. However, large-scale water electrolysis has been greatly hindered due to the lack of non-noble metal cata...Water electrolysis has been regarded as a promising technology to produce clean hydrogen fuel with high purity. However, large-scale water electrolysis has been greatly hindered due to the lack of non-noble metal catalysts with high catalytic performance. Benefitting from unique hollow structures with large surface area and adjustable chemical compositions, hollow design plays an important role in improving the electrocatalytic performance for hydrogen evolution reaction(HER). Herein, we report an effective multi-step strategy to prepare hierarchical Co-decorated Mo_(2)C hollow spheres(CMCHSs) as electrocatalyst for HER. To be specific, the preparation process involves a metal-chelated polymerization and a subsequent surface modulation process. Owing to the unique hollow structure and incorporation of Co species,the as-prepared CMCHSs demonstrate largely enhanced HER performance with a low overpotential of 139 mV at the current density of 10 m A·cm^(-2) and good cycling durability in acid. The present research work highlights a new feasible strategy for the design of HER electrocatalyst via hollow designs and surface engineering.展开更多
Coupling efficiency between the localized surface plasmons(LSPs) of metal nanoparticles(NPs) and incident light dominates the sensitivities of plasmon-based sensing spectroscopies and imaging techniques, e.g., surface...Coupling efficiency between the localized surface plasmons(LSPs) of metal nanoparticles(NPs) and incident light dominates the sensitivities of plasmon-based sensing spectroscopies and imaging techniques, e.g., surfaceenhanced Raman scattering(SERS) spectroscopy. Many endogenous features of metal NPs(e.g., size, shape,aggregation form, etc.) that have strong impacts on their LSPs have been discussed in detail in previous studies.Here, the polarization-tuned electromagnetic(EM) field that facilitates the LSP coupling is fully discussed.Numerical analyses on waveguide-based evanescent fields(WEFs) coupled with the LSPs of dispersed silver nanospheres and silver nano-hemispheres are presented and the applicability of the WEF-LSPs to plasmon-enhanced spectroscopy is discussed. Compared with LSPs under direct light excitation that only provide 3–4 times enhancement of the incidence field, the WEF-LSPs can amplify the electric field intensity about 30–90 times(equaling the enhancement factor of 10~6–10~8 in SERS intensity), which is comparable to the EM amplification of the SERS"hot spot" effect. Importantly, the strongest region of EM enhancement around silver nanospheres can be modulated from the gap region to the side surface simply by switching the incident polarization from TM to TE, which widely extends its sensing applications in surface analysis of monolayer of molecule and macromolecule detections. This technique provides us a unique way to achieve remarkable signal gains in many plasmon-enhanced spectroscopic systems in which LSPs are involved.展开更多
Boron nitride nanotubes(BNNTs)show exceptional physical properties including high mechanical strength and thermal conductivity;however,their applications have been restricted due to limited dispersibility in processin...Boron nitride nanotubes(BNNTs)show exceptional physical properties including high mechanical strength and thermal conductivity;however,their applications have been restricted due to limited dispersibility in processing solvents.Here,a novel BNNT dispersion method with exceptional dispersibility in a wide range of solvents has been demonstrated by surtace polarity modulation through short-molecule pyridine attachment.Nitrogen atoms in pyridine are selectively bonded to electron-deficient boron atoms of the BNNT surface through Lewis acid-base reaction,which changes the surface polarity of BNNTs from neutral to negative.Re-dispersing pyridine-attached BNNTs(Py-BNNTs)create a thick and stable electronic double layer(EDL),resulting in uniform dispersion of BNNTs in solvents with an exceptional solubility parameter range of 18.5-48 MPa^1/2.The uniform dispersion of BNNTs is maintained even after the mixing with diverse polymers.Finally,composites incorporating uniformly-distributed BNNTs have been realized,and extraordinary property enhancements have been observed.The thermal conductivity of 20 wt.%Py-BNNT/epoxy composite has been significantly improved by 69.6%and the tensile strength of 2 wt.%Py-BNNT/PVA has been dramatically improved by 75.3%.Our work demonstrates a simple and facile route to dispersing BNNTs in diverse solvents,consequently leading to selective utlization of BNNT dispersed solvents in various application fields.展开更多
Employing a simple and efficient method of electro-chemical anodization, ZnO nanowire films are fabricated on Zn foil, and an ultraviolet （UV） sensor prototype is formed for investigating the electronic transport th...Employing a simple and efficient method of electro-chemical anodization, ZnO nanowire films are fabricated on Zn foil, and an ultraviolet （UV） sensor prototype is formed for investigating the electronic transport through back-to-back double junctions. The UV （365 nm） responses of surface-contacted ZnO film are provided by I-V measurement, along with the current evolution process by on/off of UV illumination. In this paper, the back-to-back metal-seconductor-metal （M-S-M） model is used to explain the electronic transport of a ZnO nanowire film based structure. A thermionic-field electron emission mechanism is employed to fit and explain the as-observed UV sensitive electronic transport properties of ZnO film with surface-modulation by oxygen and water molecular coverage.展开更多
Low surface photogenerated charge concentration is a critical limitation hindering conventional graphitic carbon nitride(CN)from efficiently reducing CO_(2)to high-value products.In this work,a pollution-free oxygen o...Low surface photogenerated charge concentration is a critical limitation hindering conventional graphitic carbon nitride(CN)from efficiently reducing CO_(2)to high-value products.In this work,a pollution-free oxygen oxidation strategy was devised to enhance the surface charge enrichment sites of CN.This approach led to the successful fabrication of a tubular CN photocatalyst functionalized with oxygen-containing groups(C-O-C and C-OH),named O-TCN.The introduction of oxygen functional groups not only effectively widen the light absorption range and narrowed the bandgap but also optimized the surface electronic structure,realizing substantial photogenerated charge accumulation on the O-TCN surface.Photocatalytic performance evaluations revealed that O-TCN achieved exceptional catalytic activity and selectivity in CO_(2)reduction,stably converting CO_(2)to CO.The average CO yield of O-TCN reaches 49.8μmol g^(-1)h^(-1),representing enhancements of 5.5-fold and 7.7-fold compared to TCN and the classical bulk CN,respectively.This work highlights the potential of surface oxygen functionalization as a powerful strategy to boost the photocatalytic activity of CN-based materials,offering new insights for advancing sustainable energy conversion technologies.展开更多
The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the ap...The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the application of PSCs.Here,we develop a strategy for molecular modulation of a perovskite surface using thiol copper(Ⅱ)porphyrin(CuP)to post-treat the perovskite film.展开更多
基金supported by the National Key Research and Development Program of China (Grant Nos. 2019YFA0707003 and 2019YFE0114100)the National Natural Science Foundation of China (Grant No. 51872007)Beijing Municipal Natural Science Foundation, China (Grant No. 7202094)。
文摘As the main distribution place of deep-level defects and the entrance of water, the interface is critical to determining both the power conversion efficiency(PCE) and the stability of perovskite solar cells(PSCs). Suitable interface design can dramatically passivate interface defects and optimize energy level alignment for suppressing the nonradiative recombination and effectively extracting the photogenerated carriers towards higher PCE. Meanwhile, a proper interface design can also block the interface diffusion of ions for high operational stability. Therefore, interface modification is of great significance to make the PSCs more efficient and stable. Upon optimized material choices, the three-dimensional halide perovskite graded junction layer, low-dimensional halide perovskite interface layer and organic salt passivation layer have been constructed on perovskite films for superior PSCs, yet a systematic review of them is missing. Thus, a guide and summary of recent advances in modulating the perovskite films interface is necessary for the further development of more efficient interface modification.
基金supported by the National Natural Science Foundation of China(22005164)the Natural Science Foundation of Shandong Province(BS2015CL002)the Basic Research Project of Qingdao Source Innovation Program Fund(17-1-1-82-jch)。
文摘To realize the continuous production of hydrogen energy,the efficient photocatalysts are required in the heterogeneous reaction for water splitting.Herein,we reported a surface modulation strategy,via doping oxygen atoms to tune the surface state of ZnIn_(2)S_(4)nanosheets with cocatalyst MoS_(2)modification,to enhance water adsorption and surface catalytic reaction for boosting the photocatalytic activity.Consequently,MoS_(2)/O-ZnIn_(2)S_(4)photocatalysts showed a remarkably superior photocatalytic H_(2)production performance of 4.002 mmol g^(-1)h^(-1)and an apparent quantum yield(AQY)of~2.53%,5.4 folds higher than ZnIn_(2)S_(4).Using operando infrared spectroscopy and DFT calculation,we revealed the dynamic structural evolution,as well as the active sites for water adsorption and the catalytic reaction at the MoS_(2)/O ZnIn_(2)S_(4)interface.This work reveals the effect of surface modulation on the photocatalytic activity for MoS_(2)/O-ZnIn_(2)S_(4)and offers a feasible method to devise excellent nanomaterial photocatalysts for H_(2)production.
基金the National Key R&D Program of China (Grant No. 2019YFA0705000)the National Natural Science Foundation of China (Grant Nos. 11874147, 11933005, and 12134001)+3 种基金the Science and Technology Commission of Shanghai Municipality (Grant No. 21DZ1101500)the Shanghai Municipal Science and Technology Major Project (Grant No. 2019SHZDZX01)the Natural Science Foundation of Chongqing, China (Grant No. cstc2021jcyj-msxm X1144)the State Key Laboratory of Solidification Processing in NWPU (Grant No. SKLSP202105)。
文摘We predict ultrafast modulation of the pure molten metal surface stress fields under the irradiation of the single femtosecond laser pulse through the two-temperature model molecular-dynamics simulations. High-resolution and precision calculations are used to resolve the ultrafast laser-induced anisotropic relaxations of the pressure components on the time-scale comparable to the intrinsic liquid density relaxation time. The magnitudes of the dynamic surface tensions are found being modulated sharply within picoseconds after the irradiation, due to the development of the nanometer scale non-hydrostatic regime behind the exterior atomic layer of the liquid surfaces.The reported novel regulation mechanism of the liquid surface stress field and the dynamic surface tension hints at levitating the manipulation of liquid surfaces, such as ultrafast steering the surface directional transport and patterning.
基金financially supported by the National Key Research and Development Program of China(2022YFE03170002)the National Natural Science Foundation of China(52071286,U203020852171223)。
文摘ZrCo alloy holds great promise for hydrogen isotope storage,yet its susceptibility to poisoning by impurity gases,especially CO,poses a challenge.This susceptibility arises due to the electron acceptor nature of the surface Co element and the formation of the d-πfeedback bond,thereby impeding the surface hydrogen dissociation.Accordingly,we propose a novel local activity modulation strategy,where substituent elements are sacrificed to protect the active Co sites for hydrogen dissociation.Considering CO absorption capacity,solid solubility,and hydrogen affinity,we selected V,Cr,and Mn as microalloying elements and successfully prepared the single-phase ZrCo_(0.97)(VCrMn)_(0.03)alloy.Compared to pristine ZrCo,ZrCo_(0.97)(VCrMn)_(0.03)demonstrates significantly enhanced poisoning resistance.Notably,the hydrogenation kinetics of ZrCo_(0.97)(VCrMn)_(0.03)is 2.4 times higher than that of ZrCo in 4 bar H_(2)+5000 ppm CO.Interestingly,the controllable in situ formation of the Co_(2)C phase shell structure during cycling further safeguards the surface reactivity of ZrCo_(0.97)(VCrMn)_(0.03).Consequently,its capacity retention ratio after 25 cycles has been improved to 74.5%from 55.3%of the ZrCo alloy.These findings suggest that micro-alloying engineering could be a promising strategy for surface activity modulation to enhance the anti-poisoning properties of hydrogen storage materials.
基金supported by the National Natural Science Foundation of China(No.21773218)and Huacai Solar Co.,Ltd.。
文摘Defects at the surface and grain boundaries of the perovskite films are extremely detrimental to both the efficiency and stability of perovskite solar cells(PSCs).Herein,a simple and stable quaternary ammonium halide,named chlormequat chloride(i.e.,chlorinated choline chloride,CCC),is introduced to regulate the upper surface chemical environment of perovskite films.The anion(Cl^(-))and cation[ClCH_(2)CH_(2)N(CH_(3))_(3)]+in CCC could effectively self-search and passivate positively and negatively charged ionic defects in per ovskites,respectively,which contributes to inhibited nonradiative recombination and reduced energy los in PSCs.As a result,the champion power conversion efficiency(PCE)of PSCs can be significantly enhanced from 22.82%to 24.07%.Moreover,the unencapsulated device with CCC modification retains 92.0%of it original PCE even subject to thermal aging at 85℃ for 2496 h.This work provides guidance for the ratio nal design of functional molecules as defect passivators in PSCs,which is beneficial for the improvement in both device performance and stability.
基金financially supported by the International Thermonuclear Experimental Reactor (ITER) Project from Ministry of Science and Technology of China (No.2011GB113004)the National High Technology Research and Development Program of China(No.2014AA032402)+1 种基金the Shanghai Commission of Science and Technology (Nos.11DZ1100402 and 13DZ0500100)the Natural Science Foundation of China(Nos.11204174 and 51372150)
文摘CeO2 film plays an essential role in nucleation and growth of YBa2 Cu3 O（7-x）（YBCO） films. In this work,the dependence of superconducting properties of YBCO on CeO2 films with different thicknesses was investigated,in order to achieve fabrication of high-performance YBCO coated conductors in industrial scale. The crystalline structure and morphology of CeO2 films with thickness ranging from 21 to 563 nm were systematically characterized by means of X-ray diffraction（XRD）, atomic force microscope（AFM） and reflection high-energy electron diffraction（RHEED）. Additional focus was addressed on evolution of the surface quality of CeO2 films with thickness increasing. The results show that at the optimal thickness of 221 nm, CeO2 film exhibits sharp in-plane and out-of-plane texture with full width of half maximum（FWHM） values of 5.9° and 1.8°, respectively, and smooth surface with a mean root-mean-square（RMS） roughness value as low as 0.6 nm. Combing RHEED and transmission electron microscope（TEM） cross-sectional analysis, it is found that nucleation and growth of CeO2 films at early stage remain in island growth mode with rougher surface,while further increasing the thickness beyond the optimal thickness leads to weak surface quality, consequently resulting in degradation of superconductor layers deposited subsequently. Eventually, a critical current density（Jc） as high as 4.6×10-6 A·cm-（-2）（77 K, self-field） is achieved on a YBCO film on a thickness-modulated CeO2/MgO/Y2 O3/Al2 O3/C276 architecture, demonstrating the advantages of CeO2 films as buffer layer in high-throughput manufacture of coated conductors.
基金financially supported by the National Natural Science Foundation of China (No.51902016)the Fundamental Research Funds for the Central Universities (Nos.buctrc201829 and buctrc201904)the "Double-First Class" Construction Projects (No.XK1804-02)。
文摘Water electrolysis has been regarded as a promising technology to produce clean hydrogen fuel with high purity. However, large-scale water electrolysis has been greatly hindered due to the lack of non-noble metal catalysts with high catalytic performance. Benefitting from unique hollow structures with large surface area and adjustable chemical compositions, hollow design plays an important role in improving the electrocatalytic performance for hydrogen evolution reaction(HER). Herein, we report an effective multi-step strategy to prepare hierarchical Co-decorated Mo_(2)C hollow spheres(CMCHSs) as electrocatalyst for HER. To be specific, the preparation process involves a metal-chelated polymerization and a subsequent surface modulation process. Owing to the unique hollow structure and incorporation of Co species,the as-prepared CMCHSs demonstrate largely enhanced HER performance with a low overpotential of 139 mV at the current density of 10 m A·cm^(-2) and good cycling durability in acid. The present research work highlights a new feasible strategy for the design of HER electrocatalyst via hollow designs and surface engineering.
基金National Natural Science Foundation of China(NSFC)(21373096,21573087,21573092,91441105)National Instrumentation Program(NIP)of the Ministry of Science and Technology of the People’s Republic of China(MOST)(2011YQ03012408)Science and Technology Development Program Funded Projects of Jilin Province
文摘Coupling efficiency between the localized surface plasmons(LSPs) of metal nanoparticles(NPs) and incident light dominates the sensitivities of plasmon-based sensing spectroscopies and imaging techniques, e.g., surfaceenhanced Raman scattering(SERS) spectroscopy. Many endogenous features of metal NPs(e.g., size, shape,aggregation form, etc.) that have strong impacts on their LSPs have been discussed in detail in previous studies.Here, the polarization-tuned electromagnetic(EM) field that facilitates the LSP coupling is fully discussed.Numerical analyses on waveguide-based evanescent fields(WEFs) coupled with the LSPs of dispersed silver nanospheres and silver nano-hemispheres are presented and the applicability of the WEF-LSPs to plasmon-enhanced spectroscopy is discussed. Compared with LSPs under direct light excitation that only provide 3–4 times enhancement of the incidence field, the WEF-LSPs can amplify the electric field intensity about 30–90 times(equaling the enhancement factor of 10~6–10~8 in SERS intensity), which is comparable to the EM amplification of the SERS"hot spot" effect. Importantly, the strongest region of EM enhancement around silver nanospheres can be modulated from the gap region to the side surface simply by switching the incident polarization from TM to TE, which widely extends its sensing applications in surface analysis of monolayer of molecule and macromolecule detections. This technique provides us a unique way to achieve remarkable signal gains in many plasmon-enhanced spectroscopic systems in which LSPs are involved.
基金This study was supported financially by the Fundamental Research Program(PNK6050 and PNK6550)of the Korea Institute of Materials Science(KIMS).
文摘Boron nitride nanotubes(BNNTs)show exceptional physical properties including high mechanical strength and thermal conductivity;however,their applications have been restricted due to limited dispersibility in processing solvents.Here,a novel BNNT dispersion method with exceptional dispersibility in a wide range of solvents has been demonstrated by surtace polarity modulation through short-molecule pyridine attachment.Nitrogen atoms in pyridine are selectively bonded to electron-deficient boron atoms of the BNNT surface through Lewis acid-base reaction,which changes the surface polarity of BNNTs from neutral to negative.Re-dispersing pyridine-attached BNNTs(Py-BNNTs)create a thick and stable electronic double layer(EDL),resulting in uniform dispersion of BNNTs in solvents with an exceptional solubility parameter range of 18.5-48 MPa^1/2.The uniform dispersion of BNNTs is maintained even after the mixing with diverse polymers.Finally,composites incorporating uniformly-distributed BNNTs have been realized,and extraordinary property enhancements have been observed.The thermal conductivity of 20 wt.%Py-BNNT/epoxy composite has been significantly improved by 69.6%and the tensile strength of 2 wt.%Py-BNNT/PVA has been dramatically improved by 75.3%.Our work demonstrates a simple and facile route to dispersing BNNTs in diverse solvents,consequently leading to selective utlization of BNNT dispersed solvents in various application fields.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11274082 and 51172194)the Excellent Young Scientist Research Award Fund of Shandong Province,China(Grant No.BS2011CL002)
文摘Employing a simple and efficient method of electro-chemical anodization, ZnO nanowire films are fabricated on Zn foil, and an ultraviolet （UV） sensor prototype is formed for investigating the electronic transport through back-to-back double junctions. The UV （365 nm） responses of surface-contacted ZnO film are provided by I-V measurement, along with the current evolution process by on/off of UV illumination. In this paper, the back-to-back metal-seconductor-metal （M-S-M） model is used to explain the electronic transport of a ZnO nanowire film based structure. A thermionic-field electron emission mechanism is employed to fit and explain the as-observed UV sensitive electronic transport properties of ZnO film with surface-modulation by oxygen and water molecular coverage.
基金supported by the National Natural Science Foundation of China(21901154)the Shanghai Pujiang Program(21PJD022)+1 种基金the Hunan Provincial Natural Science Foundation(2023JJ60522)supported by the Shanghai Technical Service Center of Science and Engineering Computing,Shanghai University。
文摘Low surface photogenerated charge concentration is a critical limitation hindering conventional graphitic carbon nitride(CN)from efficiently reducing CO_(2)to high-value products.In this work,a pollution-free oxygen oxidation strategy was devised to enhance the surface charge enrichment sites of CN.This approach led to the successful fabrication of a tubular CN photocatalyst functionalized with oxygen-containing groups(C-O-C and C-OH),named O-TCN.The introduction of oxygen functional groups not only effectively widen the light absorption range and narrowed the bandgap but also optimized the surface electronic structure,realizing substantial photogenerated charge accumulation on the O-TCN surface.Photocatalytic performance evaluations revealed that O-TCN achieved exceptional catalytic activity and selectivity in CO_(2)reduction,stably converting CO_(2)to CO.The average CO yield of O-TCN reaches 49.8μmol g^(-1)h^(-1),representing enhancements of 5.5-fold and 7.7-fold compared to TCN and the classical bulk CN,respectively.This work highlights the potential of surface oxygen functionalization as a powerful strategy to boost the photocatalytic activity of CN-based materials,offering new insights for advancing sustainable energy conversion technologies.
基金National Natural Science Foundation of China(no.21801104)and Fundamental Research Funds for the Central Universities(no.lzujbky-2019-sp01).Y.-Y.W.acknowledges funding support from the U.S.Department of Energy(award no.DEFG02-07ER46427).The authors sincerely thank the theoretical calculation support of Prof.Penji Yan from Hexi University of China.
文摘The formation of undersaturated lead or iodide ions and I_(2) on the perovskite surface can decrease the performance and stability of perovskite solar cells(PSCs).Additionally,the leakage of noxious lead limits the application of PSCs.Here,we develop a strategy for molecular modulation of a perovskite surface using thiol copper(Ⅱ)porphyrin(CuP)to post-treat the perovskite film.
