Aqueous Ni-Zn microbatteries are safe,reliable and inexpensive but notoriously suffer from inadequate energy and power densities.Herein,we present a novel mechanism of superoxide-activated Ni substrate that realizes t...Aqueous Ni-Zn microbatteries are safe,reliable and inexpensive but notoriously suffer from inadequate energy and power densities.Herein,we present a novel mechanism of superoxide-activated Ni substrate that realizes the redox reaction featuring three-electron transfers(Ni↔Ni3+).The superoxide activates the direct redox reaction between Ni substrate and KNiO_(2)by lowering the reaction Gibbs free energy,supported by in-situ Raman and density functional theory simulations.The prepared chronopotentiostatic superoxidation-activated Ni(CPS-Ni)electrodes exhibit an ultrahigh capacity of 3.21 mAh cm^(-2)at the current density of 5 mA cm^(-2),nearly 8 times that of traditional one-electron processes electrodes.Even under the ultrahigh 200 mA cm^(-2)current density,the CPS-Ni electrodes show 86.4%capacity retention with a Columbic efficiency of 99.2%after 10,000 cycles.The CPS-Ni||Zn microbattery achieves an exceptional energy density of 6.88 mWh cm^(-2)and power density of 339.56 mW cm^(-2).Device demonstration shows that the power source can continuously operate for more than 7 days in powering the sensing and computation intensive practical application of photoplethysmographic waveform monitoring.This work paves the way to the development of multi-electron transfer mechanisms for advanced aqueous Ni-Zn batteries with high capacity and long lifetime.展开更多
The avalanche multiplication principle of electron multiplication CCD (EMCCD) was discussed on the basis of single type of carrier, and the multiplication model was built by using a classic piecewise ionization rate m...The avalanche multiplication principle of electron multiplication CCD (EMCCD) was discussed on the basis of single type of carrier, and the multiplication model was built by using a classic piecewise ionization rate model and avalanche multiplication integral formula. Wolff's ionization rate model was selected according to the structure and the multiplication gate amplitude of the actual devices. Compared the theoretical result with the multiplication curve of the actual device, it was found that only enough fringing field strength and multiplication area length could lead to adequate signal charge multiplication. The relationship between the multiplication gate amplitude and the total gain of the cascaded boosting EMCCD can be conveniently determined by using this model.展开更多
Organic materials with redox-active centers are regarded as promising candidates for rechargeable batteries in recent years for their light weight, low cost, environmental friendliness and structural diversity [1–4]....Organic materials with redox-active centers are regarded as promising candidates for rechargeable batteries in recent years for their light weight, low cost, environmental friendliness and structural diversity [1–4]. Organic materials, such as conducting polymers (polyacetylene, polypyrrole, polyaniline, etc.)[5], conjugated carbonyl compounds (quinone compounds, imides, etc.)[6–9] and nitroxide radical (N-O.)[10,11] compounds have been attempted as cathode materials in lithium-ion batteries (LIBs).展开更多
We present the experimental results of nitrogen-vacancy （NV） electron spin decoherence, which are linked to the coexistence of electron spin bath of nitrogen impurity （PI center） and 13C nuclear spin bath. In prev...We present the experimental results of nitrogen-vacancy （NV） electron spin decoherence, which are linked to the coexistence of electron spin bath of nitrogen impurity （PI center） and 13C nuclear spin bath. In previous works, only one dominant decoherence source is studied： P1 electron spin bath for type-Ⅰb diamond; or 13C nuclear spin bath for type-Ⅱa diamond. In general, the thermal fluctuation from both spin baths can be eliminated by the Hahn echo sequence, resulting in a long coherence time （T2 ） of about 400#8. However, in a high-purity type-Ⅱa diamond where 1℃ nuclear spin bath is the dominant decoherence source, dramatic decreases of NV electron spin T2 time caused by P1 electron spin bath are observed under certain magnetic field. We further apply the engineered Hahn echo sequence to confirm the decoherenee mechanism of multiple spin baths and quantitatively estimate the contribution of P1 electron spin bath. Our results are helpful to understand the NV decoherence mechanisms, which will benefit quantum computing and quantum metrology.展开更多
Efficient and selective regeneration of enzymatically active 1,4-NADH from NAD^(+)is pivotal for accelerating photoenzymatic CO_(2)conversion.However,constructing photocatalysts that sustain continuous electron flow a...Efficient and selective regeneration of enzymatically active 1,4-NADH from NAD^(+)is pivotal for accelerating photoenzymatic CO_(2)conversion.However,constructing photocatalysts that sustain continuous electron flow and provide sufficient hydride supply remains a major challenge.Herein,we report a rhodium-coordinated three-dimensional conjugated polymer(3D-Bpy-Rh)photocatalyst featuring multiple electron channels,designed through dimensionality engineering and incorporation of hydride-forming active centers.Such a 3D structure promotes rapid charge separation and multidimensional electron migration,while facilitating trapped-electron release to Rh centers for accelerated electron transfer.As a result,3D-Bpy-Rh achieves a visible-light driven NADH regeneration efficiency of 90.8%with 99.2%selectivity toward 1,4-NADH,surpassing state-of-the-art photocatalysts.Furthermore,the mechanism between the electron reduction capability of the photocatalyst and the selective formation of 1,4-NADH was elucidated,combining transient absorption spectroscopy analysis and DFT calculations.When integrated into photoenzymatic systems,this photocatalyst enhances CO_(2)conversion,boosting methanol and ethanol yields by 5.2-and 2.0-fold,respectively.These results highlighted the potential of dimensionality-engineered photocatalysts for selective 1,4-NADH regeneration and efficient photoenzymatic fuel synthesis.展开更多
Nanoscale lithographic technologies have been intensively studied for the development of the next generation of semiconductor manufacturing practices.While mask-less/direct-write electron beam(EB)lithography methods s...Nanoscale lithographic technologies have been intensively studied for the development of the next generation of semiconductor manufacturing practices.While mask-less/direct-write electron beam(EB)lithography methods serve as a candidate for the upcoming 10-nm node approaches and beyond,it remains difficult to achieve an appropriate level of throughput.Several innovative features of the multiple EB system that involve the use of a thermionic source have been proposed.However,a blanking array mechanism is required for the individual control of multiple beamlets whereby each beamlet is deflected onto a blanking object or passed through an array.This paper reviews the recent developments of our application studies on the development of a high-speed massively parallel electron beam direct write(MPEBDW)lithography.The emitter array used in our study includes nanocrystalline-Si(nc-Si)ballistic electron emitters.Electrons are drifted via multiple tunnelling cascade transport and are emitted as hot electrons.The transport mechanism allows one to quickly turn electron beamlets on or off.The emitter array is a micro-electro-mechanical system(MEMS)that is hetero-integrated with a separately fabricated active-matrix-driving complementary metal-oxide semiconductor(CMOS)large-scale integration(LSI)system that controls each emitter individually.The basic function of the LSI was confirmed to receive external writing bitmap data and generate driving signals for turning beamlets on or off.Each emitted beamlet(10×10μm^(2))is converged to 10×10 nm^(2) on a target via the reduction electron optic system under development.This paper presents an overview of the system and characteristic evaluations of the nc-Si emitter array.We examine beamlets and their electron emission characteristics via a 1:1 exposure test.展开更多
The slow oxygen-reduction reaction(ORR)kinetics is due to the high reaction barrier during the multiple electron transfer process,therefore,finding efficient catalysts to reduce the reaction barrier is of great signif...The slow oxygen-reduction reaction(ORR)kinetics is due to the high reaction barrier during the multiple electron transfer process,therefore,finding efficient catalysts to reduce the reaction barrier is of great significance.Currently,the most efficient ORR electrocatalysts are based on platinum-based materials,but their commercial application is limited by their high cost and low stability.To solve this problem,in this paper,a honeycomb carbon substrate with a porous structure and large specific surface area was formed by etching SiO_(2) templates,and subsequently,an SnSb-NC catalyst was prepared by anchoring Sn and Sb onto the honeycomb carbon substrate.In alkaline media,SnSb-NC has outstanding ORR activity with a greater half-wave potential(E_(1/2))of 0.87 V than Pt/C(0.83 V)and excellent electrochemical stability.The excellent ORR electrocatalyst performance may be attributed to the porous honeycomb structure with a high specific surface area(1717.4 m^(2) g^(−1)),which facilitates mass/electron transfer and exposure of more active sites,as well as the synergistic effect generated by the atomically dispersed Sn and Sb metal sites in the honeycomb carbon substrate.On this basis,the assembled Zn–air battery has a great power density(195.8 mW cm^(−2)),while the battery can run stably for more than 1100 hours,and is more stable than most of the Zn–air batteries reported so far.展开更多
基金supported by InnoHK Project at Hong Kong Centre for Cerebro-cardiovascular Health Engineering (COCHE)City University of Hong Kong (7006108)。
文摘Aqueous Ni-Zn microbatteries are safe,reliable and inexpensive but notoriously suffer from inadequate energy and power densities.Herein,we present a novel mechanism of superoxide-activated Ni substrate that realizes the redox reaction featuring three-electron transfers(Ni↔Ni3+).The superoxide activates the direct redox reaction between Ni substrate and KNiO_(2)by lowering the reaction Gibbs free energy,supported by in-situ Raman and density functional theory simulations.The prepared chronopotentiostatic superoxidation-activated Ni(CPS-Ni)electrodes exhibit an ultrahigh capacity of 3.21 mAh cm^(-2)at the current density of 5 mA cm^(-2),nearly 8 times that of traditional one-electron processes electrodes.Even under the ultrahigh 200 mA cm^(-2)current density,the CPS-Ni electrodes show 86.4%capacity retention with a Columbic efficiency of 99.2%after 10,000 cycles.The CPS-Ni||Zn microbattery achieves an exceptional energy density of 6.88 mWh cm^(-2)and power density of 339.56 mW cm^(-2).Device demonstration shows that the power source can continuously operate for more than 7 days in powering the sensing and computation intensive practical application of photoplethysmographic waveform monitoring.This work paves the way to the development of multi-electron transfer mechanisms for advanced aqueous Ni-Zn batteries with high capacity and long lifetime.
文摘The avalanche multiplication principle of electron multiplication CCD (EMCCD) was discussed on the basis of single type of carrier, and the multiplication model was built by using a classic piecewise ionization rate model and avalanche multiplication integral formula. Wolff's ionization rate model was selected according to the structure and the multiplication gate amplitude of the actual devices. Compared the theoretical result with the multiplication curve of the actual device, it was found that only enough fringing field strength and multiplication area length could lead to adequate signal charge multiplication. The relationship between the multiplication gate amplitude and the total gain of the cascaded boosting EMCCD can be conveniently determined by using this model.
基金financially supported by the National Key R&D Program of China(2017YFA0206700)the National Natural Science Foundation of China(grant No.21822506&51671107)+1 种基金the 111 project of B12015the Natural Science Foundation of Tianjin(grant No.19JCJQJC62400)。
文摘Organic materials with redox-active centers are regarded as promising candidates for rechargeable batteries in recent years for their light weight, low cost, environmental friendliness and structural diversity [1–4]. Organic materials, such as conducting polymers (polyacetylene, polypyrrole, polyaniline, etc.)[5], conjugated carbonyl compounds (quinone compounds, imides, etc.)[6–9] and nitroxide radical (N-O.)[10,11] compounds have been attempted as cathode materials in lithium-ion batteries (LIBs).
基金Supported by the National Basic Research Program of China under Grant Nos 2014CB921402 and 2015CB921103the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB07010300the National Natural Science Foundation of China under Grant No 11574386
文摘We present the experimental results of nitrogen-vacancy （NV） electron spin decoherence, which are linked to the coexistence of electron spin bath of nitrogen impurity （PI center） and 13C nuclear spin bath. In previous works, only one dominant decoherence source is studied： P1 electron spin bath for type-Ⅰb diamond; or 13C nuclear spin bath for type-Ⅱa diamond. In general, the thermal fluctuation from both spin baths can be eliminated by the Hahn echo sequence, resulting in a long coherence time （T2 ） of about 400#8. However, in a high-purity type-Ⅱa diamond where 1℃ nuclear spin bath is the dominant decoherence source, dramatic decreases of NV electron spin T2 time caused by P1 electron spin bath are observed under certain magnetic field. We further apply the engineered Hahn echo sequence to confirm the decoherenee mechanism of multiple spin baths and quantitatively estimate the contribution of P1 electron spin bath. Our results are helpful to understand the NV decoherence mechanisms, which will benefit quantum computing and quantum metrology.
基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDC0120103)Guangdong Basic and Applied Basic Research Foundation(2023B151520034)CAS Project for Young Scientists in Basic Research(YSBR-072)。
文摘Efficient and selective regeneration of enzymatically active 1,4-NADH from NAD^(+)is pivotal for accelerating photoenzymatic CO_(2)conversion.However,constructing photocatalysts that sustain continuous electron flow and provide sufficient hydride supply remains a major challenge.Herein,we report a rhodium-coordinated three-dimensional conjugated polymer(3D-Bpy-Rh)photocatalyst featuring multiple electron channels,designed through dimensionality engineering and incorporation of hydride-forming active centers.Such a 3D structure promotes rapid charge separation and multidimensional electron migration,while facilitating trapped-electron release to Rh centers for accelerated electron transfer.As a result,3D-Bpy-Rh achieves a visible-light driven NADH regeneration efficiency of 90.8%with 99.2%selectivity toward 1,4-NADH,surpassing state-of-the-art photocatalysts.Furthermore,the mechanism between the electron reduction capability of the photocatalyst and the selective formation of 1,4-NADH was elucidated,combining transient absorption spectroscopy analysis and DFT calculations.When integrated into photoenzymatic systems,this photocatalyst enhances CO_(2)conversion,boosting methanol and ethanol yields by 5.2-and 2.0-fold,respectively.These results highlighted the potential of dimensionality-engineered photocatalysts for selective 1,4-NADH regeneration and efficient photoenzymatic fuel synthesis.
文摘Nanoscale lithographic technologies have been intensively studied for the development of the next generation of semiconductor manufacturing practices.While mask-less/direct-write electron beam(EB)lithography methods serve as a candidate for the upcoming 10-nm node approaches and beyond,it remains difficult to achieve an appropriate level of throughput.Several innovative features of the multiple EB system that involve the use of a thermionic source have been proposed.However,a blanking array mechanism is required for the individual control of multiple beamlets whereby each beamlet is deflected onto a blanking object or passed through an array.This paper reviews the recent developments of our application studies on the development of a high-speed massively parallel electron beam direct write(MPEBDW)lithography.The emitter array used in our study includes nanocrystalline-Si(nc-Si)ballistic electron emitters.Electrons are drifted via multiple tunnelling cascade transport and are emitted as hot electrons.The transport mechanism allows one to quickly turn electron beamlets on or off.The emitter array is a micro-electro-mechanical system(MEMS)that is hetero-integrated with a separately fabricated active-matrix-driving complementary metal-oxide semiconductor(CMOS)large-scale integration(LSI)system that controls each emitter individually.The basic function of the LSI was confirmed to receive external writing bitmap data and generate driving signals for turning beamlets on or off.Each emitted beamlet(10×10μm^(2))is converged to 10×10 nm^(2) on a target via the reduction electron optic system under development.This paper presents an overview of the system and characteristic evaluations of the nc-Si emitter array.We examine beamlets and their electron emission characteristics via a 1:1 exposure test.
基金financial support from the National Natural Science Foundation of China(no.22173072,21973074,and 22273073)Innovation Capability Support Program of Shaanxi Province(no.2022TD-32)Joint Fund Project-Enterprise-Shaanxi Coal Joint Fund Project(2021JLM-38)is acknowledged.
文摘The slow oxygen-reduction reaction(ORR)kinetics is due to the high reaction barrier during the multiple electron transfer process,therefore,finding efficient catalysts to reduce the reaction barrier is of great significance.Currently,the most efficient ORR electrocatalysts are based on platinum-based materials,but their commercial application is limited by their high cost and low stability.To solve this problem,in this paper,a honeycomb carbon substrate with a porous structure and large specific surface area was formed by etching SiO_(2) templates,and subsequently,an SnSb-NC catalyst was prepared by anchoring Sn and Sb onto the honeycomb carbon substrate.In alkaline media,SnSb-NC has outstanding ORR activity with a greater half-wave potential(E_(1/2))of 0.87 V than Pt/C(0.83 V)and excellent electrochemical stability.The excellent ORR electrocatalyst performance may be attributed to the porous honeycomb structure with a high specific surface area(1717.4 m^(2) g^(−1)),which facilitates mass/electron transfer and exposure of more active sites,as well as the synergistic effect generated by the atomically dispersed Sn and Sb metal sites in the honeycomb carbon substrate.On this basis,the assembled Zn–air battery has a great power density(195.8 mW cm^(−2)),while the battery can run stably for more than 1100 hours,and is more stable than most of the Zn–air batteries reported so far.
