The electron transport behavior across the interface plays an important role in determining the performance of op- toelectronic devices based on heterojunctions. Here through growing CdS thin film on silicon nanoporou...The electron transport behavior across the interface plays an important role in determining the performance of op- toelectronic devices based on heterojunctions. Here through growing CdS thin film on silicon nanoporous pillar array, an untraditional, nonplanar, and multi-interface CdS/Si nanoheterojunction is prepared. The current density versus voltage curve is measured and an obvious rectification effect is observed. Based on the fitting results and model analyses on the forward and reverse conduction characteristics, the electron transport mechanism under low forward bias, high forward bias, and reverse bias are attributed to the Ohmic regime, space-charge-limited current regime, and modified Poole-Frenkel regime respectively. The forward and reverse electrical behaviors are found to be highly related to the distribution of inter- facial trap states and the existence of localized electric field respectively. These results might be helpful for optimizing the preparing procedures to realize high-performance silicon-based CdS optoelectronic devices.展开更多
Electromagnetic wave(EMW)-absorbing materials have considerable capacity in the military field and the prevention of EMW radiation from harming human health.However,obtaining lightweight,high-performance,and broadband...Electromagnetic wave(EMW)-absorbing materials have considerable capacity in the military field and the prevention of EMW radiation from harming human health.However,obtaining lightweight,high-performance,and broadband EMW-absorbing material remains an overwhelming challenge.Creating dielectric/magnetic composites with customized structures is a strategy with great promise for the development of high-performance EMW-absorbing materials.Using layered double hydroxides as the precursors of bimetallic alloys and combining them with porous biomass-derived carbon materials is a potential way for constructing multi-interface heterostructures as efficient EMW-absorbing materials because they have synergistic losses,low costs,abundant resources,and light weights.Here,FeNi alloy nanosheet array/Lycopodium spore-derived carbon(FeNi/LSC)was prepared through a simple hydrothermal and carbonization method.FeNi/LSC presents ideal EMW-absorbing performance by benefiting from the FeNi alloy nanosheet array,sponge-like structure,capability for impedance matching,and improved dielectric/magnetic losses.As expected,FeNi/LSC exhibited the minimum reflection loss of-58.3 dB at 1.5 mm with 20wt%filler content and a widely effective absorption bandwidth of 4.92 GHz.FeNi/LSC composites with effective EMW-absorbing performance provide new insights into the customization of biomass-derived composites as high-performance and lightweight broadband EMW-absorbing materials.展开更多
Integrating the power grid technology with renewable power generation technologies, Demand Response (DR) programs enabled by the Advanced Metering Infrastructure (AMI) were introduced into the power grid in the intere...Integrating the power grid technology with renewable power generation technologies, Demand Response (DR) programs enabled by the Advanced Metering Infrastructure (AMI) were introduced into the power grid in the interest of both utilities and residents. They help to achieve load balance and increase the grid reliability by encouraging residents to reduce their power usage during peak load periods in return for incentives. To automate this process, appliances, in-house sensors, and the AMI controller need to be networked together. In this paper, we compare mainstream network technologies applicable to home appliance control and propose a solution combining Power Line Communication (PLC) with wireless communication in smart homes for the purpose of energy saving. We extended NS-2, a popular network simulator, to model such combined network scenarios. Using a number of different routing strategies, we then model and evaluate the network performance of DR programs in smart homes in such a combined network.展开更多
Supported noble metal catalysts have the promising application in volatile organic compounds(VOCs)catalytic combustion but suffer from the deactivation due to noble metal sintering at high temperatures.Herein,we repor...Supported noble metal catalysts have the promising application in volatile organic compounds(VOCs)catalytic combustion but suffer from the deactivation due to noble metal sintering at high temperatures.Herein,we report the construction of shellsandwiched MnO_(2)-Ag-CeO_(2)hollow spheres with remarkable sintering resistance and high activity in toluene combustion.Ag clusters were sandwiched between outer MnO_(2)and inner CeO_(2)shell to enlarge and stabilize metal–support active interface.The unique hollow structure could alter the electronic states of catalysts sites and increase the adsorbed site of reactant molecules.Meanwhile,Mn–Ag–Ce multi-interfaces in MnO_(2)-Ag-CeO_(2)could facilitate the sustainable activation and the stable release of oxygen species via a tandem transfer.The oxygen species at Ag–Mn interface perimeter were instantly replenished by Ag–Ce interface to accelerate a deep oxidation of intermediates,guaranteeing the opening of benzene ring to generate maleic anhydride.This investigation provides a promising method for constructing efficient and sintering-resistant cluster catalysts for VOCs oxidation.展开更多
Although VB-Group transition metal disulfides(TMDs)VS_(2)nanomaterials with specific electronic properties and multiphase microstructures have shown fascinating potential in the field of electro-magnetic wave(EMW)abso...Although VB-Group transition metal disulfides(TMDs)VS_(2)nanomaterials with specific electronic properties and multiphase microstructures have shown fascinating potential in the field of electro-magnetic wave(EMW)absorption,the efficient utilization of VS_(2)is limited by the technical bottleneck of its narrow effective absorption bandwidth(EAB)which is attributed to environmental instability and a deficient electromagnetic(EM)loss mechanism.In order to fully exploit the maximal utilization values of VS_(2)nanomaterials for EMW absorption through mitigating the chemical instability and optimizing the EM parameters,biomass-based glucose derived carbon(GDC)like sugar-coating has been decorated on the surface of stacked VS_(2)nanosheets via a facile hydrothermal method,followed by high-temperature carbonization.As a result,the modulation of doping amount of glucose injection solution(Glucose)could effectively manipulate the encapsulation degree of GDC coating on VS_(2)nanosheets,further imple-menting the EM response mechanisms of the VS_(2)/GDC hybrids(coupling effect of conductive loss,interfacial polarization,relaxation,dipole polarization,defect engineering and multiple reflections and absorptions)through regulating the conductivity and constructing multi-interface heterostructures,as reflected by the enhanced EMW absorption performance to a great extent.The minimum reflection loss(Rmin)of VS_(2)/GDC hybrids could reach52.8 dB with a thickness of 2.7 mm at 12.2 GHz.Surprisingly,compared with pristine VS_(2),the EAB of the VS_(2)/GDC hybrids increased from 2.0 to 5.7 GHz,while their environmental stability was effectively enhanced by virtue of GDC doping.Obviously,this work provides a promising candidate to realize frequency band tunability of EMW absorbers with exceptional perfor-mance and environmental stability.展开更多
Recently,transition metal dichalcogenides(TMDCs)nanoscrolls have exhibited unique electronic and optical properties due to their spiral tubular structures,which are formed by rolling up monolayer TMDCs nanosheets.Insp...Recently,transition metal dichalcogenides(TMDCs)nanoscrolls have exhibited unique electronic and optical properties due to their spiral tubular structures,which are formed by rolling up monolayer TMDCs nanosheets.Inspired by the excellent physical and chemical properties of TMDCs van der Waals heterostructures(vdWHs),it is highly desirable to scroll TMDCs vdWHs for potential optoelectronic applications.In this work,WS2/MoS2 vdWHs nanoscrolls were massively prepared by dropping aqueous alkaline droplet on chemical vapor deposition(CVD)-grown bilayer WS2/MoS2 vdWHs,which were formed by growing monolayer WS2 islands on top of monolayer MoS2 nanosheets simultaneously.The optical microscopy(OM),atomic force microscopy(AFM),ultralow frequency(ULF)Raman spectroscopy and transmission electron microscopy(TEM)were utilized to characterize the WS2/MoS2 vdWHs nanoscrolls.As-obtained WS2/MoS2 vdWHs nanoscrolls exhibited new ULF breathing mode as well as shear mode peaks due to the strong interlayer interaction.Notably,the photosensitivities of WS2/MoS2 vdWHs nanoscrolls-based devices were about ten times higher than those of WS2/MoS2 vdWHs-based devices under blue,green and red lasers,respectively,which could be attributed to the ultrafast charge transfer at alternative WS2/MoS2 and MoS2/WS2 multi-interfaces in scrolled structure.Our work suggested that TMDCs vdWHs scrolls could be promising candidates for optoelectronic applications.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61176044 and 11074224)the Science and Technology Project for Innovative Scientist of Henan Province,China(Grant No.1142002510017)the Science and Technology Project on Key Problems of Henan Province,China(Grant No.082101510007)
文摘The electron transport behavior across the interface plays an important role in determining the performance of op- toelectronic devices based on heterojunctions. Here through growing CdS thin film on silicon nanoporous pillar array, an untraditional, nonplanar, and multi-interface CdS/Si nanoheterojunction is prepared. The current density versus voltage curve is measured and an obvious rectification effect is observed. Based on the fitting results and model analyses on the forward and reverse conduction characteristics, the electron transport mechanism under low forward bias, high forward bias, and reverse bias are attributed to the Ohmic regime, space-charge-limited current regime, and modified Poole-Frenkel regime respectively. The forward and reverse electrical behaviors are found to be highly related to the distribution of inter- facial trap states and the existence of localized electric field respectively. These results might be helpful for optimizing the preparing procedures to realize high-performance silicon-based CdS optoelectronic devices.
基金financial support from the National Natural Science Foundation of China(Nos.21776026,22075034,and 22178037)the Liaoning Revitalization Talents Program,China(Nos.XLYC1902037 and XLYC2002114)the Natural Science Foundation of Liaoning Province of China(No.2021-MS-303)。
文摘Electromagnetic wave(EMW)-absorbing materials have considerable capacity in the military field and the prevention of EMW radiation from harming human health.However,obtaining lightweight,high-performance,and broadband EMW-absorbing material remains an overwhelming challenge.Creating dielectric/magnetic composites with customized structures is a strategy with great promise for the development of high-performance EMW-absorbing materials.Using layered double hydroxides as the precursors of bimetallic alloys and combining them with porous biomass-derived carbon materials is a potential way for constructing multi-interface heterostructures as efficient EMW-absorbing materials because they have synergistic losses,low costs,abundant resources,and light weights.Here,FeNi alloy nanosheet array/Lycopodium spore-derived carbon(FeNi/LSC)was prepared through a simple hydrothermal and carbonization method.FeNi/LSC presents ideal EMW-absorbing performance by benefiting from the FeNi alloy nanosheet array,sponge-like structure,capability for impedance matching,and improved dielectric/magnetic losses.As expected,FeNi/LSC exhibited the minimum reflection loss of-58.3 dB at 1.5 mm with 20wt%filler content and a widely effective absorption bandwidth of 4.92 GHz.FeNi/LSC composites with effective EMW-absorbing performance provide new insights into the customization of biomass-derived composites as high-performance and lightweight broadband EMW-absorbing materials.
文摘Integrating the power grid technology with renewable power generation technologies, Demand Response (DR) programs enabled by the Advanced Metering Infrastructure (AMI) were introduced into the power grid in the interest of both utilities and residents. They help to achieve load balance and increase the grid reliability by encouraging residents to reduce their power usage during peak load periods in return for incentives. To automate this process, appliances, in-house sensors, and the AMI controller need to be networked together. In this paper, we compare mainstream network technologies applicable to home appliance control and propose a solution combining Power Line Communication (PLC) with wireless communication in smart homes for the purpose of energy saving. We extended NS-2, a popular network simulator, to model such combined network scenarios. Using a number of different routing strategies, we then model and evaluate the network performance of DR programs in smart homes in such a combined network.
基金the National Natural Science Foundation of China(Nos.22076192,22006032,21777166,42175133,and 21806169)Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXXM-202011)the National Key Research and Development Program of China(No.2016YFC0202202)。
文摘Supported noble metal catalysts have the promising application in volatile organic compounds(VOCs)catalytic combustion but suffer from the deactivation due to noble metal sintering at high temperatures.Herein,we report the construction of shellsandwiched MnO_(2)-Ag-CeO_(2)hollow spheres with remarkable sintering resistance and high activity in toluene combustion.Ag clusters were sandwiched between outer MnO_(2)and inner CeO_(2)shell to enlarge and stabilize metal–support active interface.The unique hollow structure could alter the electronic states of catalysts sites and increase the adsorbed site of reactant molecules.Meanwhile,Mn–Ag–Ce multi-interfaces in MnO_(2)-Ag-CeO_(2)could facilitate the sustainable activation and the stable release of oxygen species via a tandem transfer.The oxygen species at Ag–Mn interface perimeter were instantly replenished by Ag–Ce interface to accelerate a deep oxidation of intermediates,guaranteeing the opening of benzene ring to generate maleic anhydride.This investigation provides a promising method for constructing efficient and sintering-resistant cluster catalysts for VOCs oxidation.
基金supported by the National Natural Science Foundation of China(52102368,52072192,51977009)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905).
文摘Although VB-Group transition metal disulfides(TMDs)VS_(2)nanomaterials with specific electronic properties and multiphase microstructures have shown fascinating potential in the field of electro-magnetic wave(EMW)absorption,the efficient utilization of VS_(2)is limited by the technical bottleneck of its narrow effective absorption bandwidth(EAB)which is attributed to environmental instability and a deficient electromagnetic(EM)loss mechanism.In order to fully exploit the maximal utilization values of VS_(2)nanomaterials for EMW absorption through mitigating the chemical instability and optimizing the EM parameters,biomass-based glucose derived carbon(GDC)like sugar-coating has been decorated on the surface of stacked VS_(2)nanosheets via a facile hydrothermal method,followed by high-temperature carbonization.As a result,the modulation of doping amount of glucose injection solution(Glucose)could effectively manipulate the encapsulation degree of GDC coating on VS_(2)nanosheets,further imple-menting the EM response mechanisms of the VS_(2)/GDC hybrids(coupling effect of conductive loss,interfacial polarization,relaxation,dipole polarization,defect engineering and multiple reflections and absorptions)through regulating the conductivity and constructing multi-interface heterostructures,as reflected by the enhanced EMW absorption performance to a great extent.The minimum reflection loss(Rmin)of VS_(2)/GDC hybrids could reach52.8 dB with a thickness of 2.7 mm at 12.2 GHz.Surprisingly,compared with pristine VS_(2),the EAB of the VS_(2)/GDC hybrids increased from 2.0 to 5.7 GHz,while their environmental stability was effectively enhanced by virtue of GDC doping.Obviously,this work provides a promising candidate to realize frequency band tunability of EMW absorbers with exceptional perfor-mance and environmental stability.
基金This work was supported by the National Key Research and Development Program of China(No.2017YFB1002900)the National Natural Science Foundation of China(Nos.21571101,51322202,51832001)+1 种基金the Natural Science Foundation of Jiangsu Province in China(No.BK20161543)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.15KJB430016).
文摘Recently,transition metal dichalcogenides(TMDCs)nanoscrolls have exhibited unique electronic and optical properties due to their spiral tubular structures,which are formed by rolling up monolayer TMDCs nanosheets.Inspired by the excellent physical and chemical properties of TMDCs van der Waals heterostructures(vdWHs),it is highly desirable to scroll TMDCs vdWHs for potential optoelectronic applications.In this work,WS2/MoS2 vdWHs nanoscrolls were massively prepared by dropping aqueous alkaline droplet on chemical vapor deposition(CVD)-grown bilayer WS2/MoS2 vdWHs,which were formed by growing monolayer WS2 islands on top of monolayer MoS2 nanosheets simultaneously.The optical microscopy(OM),atomic force microscopy(AFM),ultralow frequency(ULF)Raman spectroscopy and transmission electron microscopy(TEM)were utilized to characterize the WS2/MoS2 vdWHs nanoscrolls.As-obtained WS2/MoS2 vdWHs nanoscrolls exhibited new ULF breathing mode as well as shear mode peaks due to the strong interlayer interaction.Notably,the photosensitivities of WS2/MoS2 vdWHs nanoscrolls-based devices were about ten times higher than those of WS2/MoS2 vdWHs-based devices under blue,green and red lasers,respectively,which could be attributed to the ultrafast charge transfer at alternative WS2/MoS2 and MoS2/WS2 multi-interfaces in scrolled structure.Our work suggested that TMDCs vdWHs scrolls could be promising candidates for optoelectronic applications.
