Continued progress in the electronics industry depends on downsizing, to a few micrometers, the wire bonds required for wiring integrated chips into circuit boards. We developed an electrodeposition method that exploits the thermodynamic stability of a microscale or nanoscale liquid meniscus to "write" pure copper and platinum three-dimensional structures of designed shapes and sizes in an ambient air environment. We demonstrated an automated wire-bonding process that enabled wire diameters of less than 1 micrometer and bond sizes of less than 3 micrometers, with a breakdown current density of more than 10(11) amperes per square meter for the wire bonds. The technology was used to fabricate high-density and high-quality interconnects, as well as complex three-dimensional microscale and even nanoscale metallic structures.
Differing
from graphene, the activated groups on the surface of
layered two-dimensional titanium carbide (MXene) materials bestow
superiority to self-assemble some novel MXene derivatives with intriguing
chemical/physical properties. Here we first report a series of new
MXene-Ag composites by directly mixing AgNO3 and alkalization-intercalated
MXene (alk-MXene, Ti3C2(OH/ONa)2)
solution containing polyvinylpyrrolidone (PVP) at room temperature,
in which an analogous urchin-shaped MXene-Ag0.9Ti0.1 bimetallic nanowire composite exhibits unexpected electrocatalytic
activity for the oxygen reduction reaction. The addition of PVP solution
induces the formation of 5-fold nanotwin Ag seeds, which then grow
into Ag/Ti (Ag0.9Ti0.1) bimetallic nanowires.
The unique bimetallic nanowires favor a four-electron transfer process,
and exhibit high current density and good stability by offering numerous
oxygen adsorption sites and shortening the diffusion path of adsorbed
oxygen. The results represent a new step for the electrocatalytic
applications of MXene materials, and also motivate enthusiasm in the
quest for new MXene derivations.
Direct tensile mechanical loading of an individual single-crystal BaTiO(3) nanowire was realized to reveal the direct piezoelectric effect in the nanowire. Periodic voltage generation from the nanowire was produced by a periodically varying tensile mechanical strain applied with a precision mechanical testing stage. The measured voltage generation from the nanowire was found to be directly proportional to the applied strain rate and was successfully modeled through the consideration of an equivalent circuit for a piezoelectric nanowire under low-frequency operation. The study, besides demonstrating a controlled experimental method for the study of direct piezoelectric effect in nanostructures, implies also the use of such perovskite piezoelectric nanowires for efficient energy-harvesting applications.
In this study, the hydrogel materials of reduced graphene oxide (RGO)/chitosan/silver nanoparticle composites were designed and prepared via a self-assembly process and simultaneous reduction of chitosan molecules with GO. These as-prepared hydrogels were characterized by different techniques. The morphology of the internal network structure of the nanocomposite hydrogels was investigated. The catalytic capacity results demonstrate that the prepared GO-based composite hydrogels can efficiently remove two tested dye molecules from wastewater in good accordance with the pseudo-second-order model. The dye photocatalytic capacity of the obtained hydrogels is mainly attributed to the silver nanoparticle on RGO sheets, whereas the chitosan molecule was incorporated to facilitate the gelation process of the GO sheets. Interestingly, the as-prepared catalytic composite material serves as a good photocatalyst for two presently used dyes even for dye mixtures, suggesting the potentially real applications of the GO composite materials for wastewater treatment as well as the removal of harmful dyes.
We report the fabrication and characterization of individual nanotube-based, long and straight needle nanoprobes for electrochemistry and the study of their applicability and behavior in microenvironments. The needle nanoprobe, with a nanoscale ring-shaped Au electrode at the tip of the needle serving as the active electrode, was characterized by electrochemical current measurement and cyclic voltammetry and analyzed with electrochemical models. Such a needle nanoprobe, in combination with another metal-coated nanowire as a reference electrode, was further used, for the first time, for local electrochemical sensing inside microdroplets having volumes down to a few picoliters. We explain the acquired voltammetric behaviors of redox-active molecules in confined microscale environments and reveal a unique electrochemical mechanism which allows the regeneration of the redox-active molecules and the establishment of a stable reference potential in the microenvironments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.