Copper nanowires （Cu NWs） have attracted increasing attention as building blocks for electronics due to their outstanding electrical properties and low cost. However, organic residues and oxide layers ubiquitously e...Copper nanowires （Cu NWs） have attracted increasing attention as building blocks for electronics due to their outstanding electrical properties and low cost. However, organic residues and oxide layers ubiquitously existing on the surface of Cu NWs impede good inter-wire contact. Commonly used methods such as thermal annealing and acid treatment often lead to nanowire damage. Herein, hydrogen plasma treatment at room temperature has been demonstrated to be effective for simultaneous surface cleaning and selective welding of Cu NWs at junctions. Transparent electrodes with excellent optical-electrical performance （19 ff）-sq-1 @ 90% T） and enhanced stability have been fabricated and integrated into organic solar cells. Besides, Cu NW conductors with superior stretchability and cycling stability under stretching speeds of up to 400 mm-min-＇ can also be produced by the nanowelding process, and the feasibility of their application in stretchable LED circuits has been demonstrated.展开更多
A procedure for joining polyol-synthesized silver nanowires in air using current-induced Joule heat welding is reported. Using a common probe station and photolithographically patterned gold electrodes, the welding pr...A procedure for joining polyol-synthesized silver nanowires in air using current-induced Joule heat welding is reported. Using a common probe station and photolithographically patterned gold electrodes, the welding process is completed using a common semiconductor analyzer. A unique two-step procedure eliminates the dielectric barrier at the point of contact without damaging the nanowires away from the junction. This procedure is designed for metal–metal contacts where a strong dielectric intermediate layer might exist, which can occur with metals prone to oxidation or corrosion in air, or as a result of the electrode deposition process. Ohmic connections are also established in cases where there is an initial gap between two nanowires.展开更多
A random two-dimensional large scale nano-network of silver nanowires （Ag-NWs） is fabricated by MeV hydrogen （H＋） ion beam irradiation. Ag-NWs are irradiated under H＋ ion beam at different ion fluences at room t...A random two-dimensional large scale nano-network of silver nanowires （Ag-NWs） is fabricated by MeV hydrogen （H＋） ion beam irradiation. Ag-NWs are irradiated under H＋ ion beam at different ion fluences at room temperature. The Ag-NW network is fabricated by H＋ ion beam-induced welding of Ag-NWs at intersecting positions. H＋ ion beam induced welding is confirmed by transmission electron microscopy （TEM） and scanning electron microscopy （SEM）. Moreover, the structure of Ag NWs remains stable under H＋ ion beam, and networks are optically transparent. Morphology also remains stable under H＋ ion beam irradiation. No slicings or cuttings of Ag-NWs are observed under MeV H＋ ion beam irradiation. The results exhibit that the formation of Ag-NW network proceeds through three steps： ion beam induced thermal spikes lead to the local heating of Ag-NWs, the formation of simple junctions on small scale, and the formation of a large scale network. This observation is useful for using Ag-NWs based devices in upper space where protons are abandoned in an energy range from MeV to GeV. This high-quality Ag-NW network can also be used as a transparent electrode for optoelectronics devices.展开更多
Three-dimensional(3D)nanoporous gold(NPG)shows promising applications in various fields.However,its most common fabrication strategy(i.e.,dealloying)faces the problems of high energy consumption,resource waste,the use...Three-dimensional(3D)nanoporous gold(NPG)shows promising applications in various fields.However,its most common fabrication strategy(i.e.,dealloying)faces the problems of high energy consumption,resource waste,the use of corrosive solvent,and residue of the sacrificial component.Here,we report a general bottom-up nanowelding strategy to fabricate high-purity NPG from Au nanoparticles(NPs),accomplished via interfacial self-assembly of the Au NPs into monolayer Au NP film,its subsequent layer-by-layer transfer onto a solid substrate,and direct current(DC)nanowelding.We show that the DC nanowelding process can gradually evolve the layered Au NP film into NPG at low temperatures within 10 s,while not damaging their spherical structure.This is because during the nanowelding,electrons are preferred to be localized at the high-resistance NP/NP junctions,whose electrostatic repulsion in turn strengthens their surface atom diffusion to initiate a mild solid-state diffusion nanowelding.Furthermore,when using differently sized Au NPs as the starting building blocks,this strategy allows readily tuning the thickness,ligament size,and pore size,thereby offering great flexibility to create functional porous nanomaterials,e.g.,electrocatalyst for methanol electrooxidation.Surely,low-temperature nanowelding can play a role for the production of diverse nanoporous materials from other NPs beyond Au NPs.展开更多
The accomplishment of nanowelding typically requires the input of high energy,possibly causing appreciable damages to the brittle nanomaterial.Herein,we report an external field(EF,i.e.,light,direct current(DC),and al...The accomplishment of nanowelding typically requires the input of high energy,possibly causing appreciable damages to the brittle nanomaterial.Herein,we report an external field(EF,i.e.,light,direct current(DC),and alternating current(AC))-strengthened Ostwald nanowelding(ONW)strategy to enable low-temperature nanowelding of Au nanoparticles(NPs)with nanoscale spacing in solution and propose an electron localization mechanism to understand it.We reveal that the EF-derived local electrons not only greatly strengthen the dissolution of surface atoms and the reduction of Au3+ions dissolved,but also confine(together with ordered water molecules)the transport of Au^(3+)ions within the nanogap.Consequently,the electrochemical Ostwald ripening(OR)process of the Au NPs is actively strengthened,which,along with the local electron-strengthened surface atom diffusion(as a result of the strong electrostatic repulsion created),enables feasible ONW for solution processing of interdigital electrodes(IDEs)from Au NPs and high-performance transparent conductor(TC)from Ag nanowires(NWs).Our low-temperature nanowelding strategy offers an efficient interconnection technique for the processing of functional nanodevices from individual nanomaterials.展开更多
基金This work was financially supported by the National Basic Research Program of China （No. 2012CB932303）, the National Natural Science Foundation of China （No. 61301036）, Shanghai Municipal Natural Science Foundation （No. 13ZR1463600）, and the Innovation Project of Shanghai Institute of Ceramics.
文摘Copper nanowires （Cu NWs） have attracted increasing attention as building blocks for electronics due to their outstanding electrical properties and low cost. However, organic residues and oxide layers ubiquitously existing on the surface of Cu NWs impede good inter-wire contact. Commonly used methods such as thermal annealing and acid treatment often lead to nanowire damage. Herein, hydrogen plasma treatment at room temperature has been demonstrated to be effective for simultaneous surface cleaning and selective welding of Cu NWs at junctions. Transparent electrodes with excellent optical-electrical performance （19 ff）-sq-1 @ 90% T） and enhanced stability have been fabricated and integrated into organic solar cells. Besides, Cu NW conductors with superior stretchability and cycling stability under stretching speeds of up to 400 mm-min-＇ can also be produced by the nanowelding process, and the feasibility of their application in stretchable LED circuits has been demonstrated.
基金partially supported by the strategic research funds from the Natural Sciences and Engineering Research Council of Canada (NSERC)
文摘A procedure for joining polyol-synthesized silver nanowires in air using current-induced Joule heat welding is reported. Using a common probe station and photolithographically patterned gold electrodes, the welding process is completed using a common semiconductor analyzer. A unique two-step procedure eliminates the dielectric barrier at the point of contact without damaging the nanowires away from the junction. This procedure is designed for metal–metal contacts where a strong dielectric intermediate layer might exist, which can occur with metals prone to oxidation or corrosion in air, or as a result of the electrode deposition process. Ohmic connections are also established in cases where there is an initial gap between two nanowires.
基金supported by the National Research Foundation of South Africa(NRF),the French Centre National pour la Recherche Scientifique,iThemba-LABS,the UNESCO-UNISA Africa Chair in Nanosciences & Nanotechnology,the Third World Academy of Science(TWAS),Organization of Women in Science for the Developing World(OWSDW),the Abdus Salam ICTP via the Nanosciences African Network(NANOAFNET),and the Higher Education Commission(HEC)of Pakistan
文摘A random two-dimensional large scale nano-network of silver nanowires （Ag-NWs） is fabricated by MeV hydrogen （H＋） ion beam irradiation. Ag-NWs are irradiated under H＋ ion beam at different ion fluences at room temperature. The Ag-NW network is fabricated by H＋ ion beam-induced welding of Ag-NWs at intersecting positions. H＋ ion beam induced welding is confirmed by transmission electron microscopy （TEM） and scanning electron microscopy （SEM）. Moreover, the structure of Ag NWs remains stable under H＋ ion beam, and networks are optically transparent. Morphology also remains stable under H＋ ion beam irradiation. No slicings or cuttings of Ag-NWs are observed under MeV H＋ ion beam irradiation. The results exhibit that the formation of Ag-NW network proceeds through three steps： ion beam induced thermal spikes lead to the local heating of Ag-NWs, the formation of simple junctions on small scale, and the formation of a large scale network. This observation is useful for using Ag-NWs based devices in upper space where protons are abandoned in an energy range from MeV to GeV. This high-quality Ag-NW network can also be used as a transparent electrode for optoelectronics devices.
基金Supported by Innovation Program of Shanghai Municipal Education Commission(12ZZ163)Key Project of Chinese Ministry of Education(212056)+2 种基金Shanghai Outstanding Subject Leader Project(14XD1424300)Scientific Innovation Act Key Basic Research Foundation of Shanghai Science and Technology Committee(11JC1404700)National Maritime Bureau Renewable Energy Specific Project(SHME2013JS01)
基金supported by the National Natural Science Foundation of China (21872047 and 21673070)Hunan Key Laboratory of Two-Dimensional Materials (2018TP1010)。
文摘Three-dimensional(3D)nanoporous gold(NPG)shows promising applications in various fields.However,its most common fabrication strategy(i.e.,dealloying)faces the problems of high energy consumption,resource waste,the use of corrosive solvent,and residue of the sacrificial component.Here,we report a general bottom-up nanowelding strategy to fabricate high-purity NPG from Au nanoparticles(NPs),accomplished via interfacial self-assembly of the Au NPs into monolayer Au NP film,its subsequent layer-by-layer transfer onto a solid substrate,and direct current(DC)nanowelding.We show that the DC nanowelding process can gradually evolve the layered Au NP film into NPG at low temperatures within 10 s,while not damaging their spherical structure.This is because during the nanowelding,electrons are preferred to be localized at the high-resistance NP/NP junctions,whose electrostatic repulsion in turn strengthens their surface atom diffusion to initiate a mild solid-state diffusion nanowelding.Furthermore,when using differently sized Au NPs as the starting building blocks,this strategy allows readily tuning the thickness,ligament size,and pore size,thereby offering great flexibility to create functional porous nanomaterials,e.g.,electrocatalyst for methanol electrooxidation.Surely,low-temperature nanowelding can play a role for the production of diverse nanoporous materials from other NPs beyond Au NPs.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21872047,21673070,and 91750205)lHunan Key Laboratory of Two-Dimensional Materials(No.2018TP1010).
文摘The accomplishment of nanowelding typically requires the input of high energy,possibly causing appreciable damages to the brittle nanomaterial.Herein,we report an external field(EF,i.e.,light,direct current(DC),and alternating current(AC))-strengthened Ostwald nanowelding(ONW)strategy to enable low-temperature nanowelding of Au nanoparticles(NPs)with nanoscale spacing in solution and propose an electron localization mechanism to understand it.We reveal that the EF-derived local electrons not only greatly strengthen the dissolution of surface atoms and the reduction of Au3+ions dissolved,but also confine(together with ordered water molecules)the transport of Au^(3+)ions within the nanogap.Consequently,the electrochemical Ostwald ripening(OR)process of the Au NPs is actively strengthened,which,along with the local electron-strengthened surface atom diffusion(as a result of the strong electrostatic repulsion created),enables feasible ONW for solution processing of interdigital electrodes(IDEs)from Au NPs and high-performance transparent conductor(TC)from Ag nanowires(NWs).Our low-temperature nanowelding strategy offers an efficient interconnection technique for the processing of functional nanodevices from individual nanomaterials.
基金National High-Tech R&D Program of China(2011AA050504)Shanghai Natural Science Foundation(13ZR1456600)Shanghai Science and Technology Grant(12NM0503800)
