Systems and methods for fabrication of nanostructures

Abstract

Systems and methods for fabricating nanostructures using other nanostructures as templates. A method includes mixing a dispersion and a reagent solution. The dispersion includes nanostructures such as nanowires including a first element such as copper. The reagent solution includes a second element such as silver. The second element at least partially replaces the first element in the nanostructures. The nanostructures are optionally washed, filtered, and / or deoxidized.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 665,796, filed Jun. 28, 2012, entitled “Systems and Methods for Fabrication of Nanostructures,” the entirety of which is hereby incorporated herein by reference. U.S. patent application Ser. No. 13 / 360,999, filed Jan. 30, 2012, published as U.S. Pub. No. 2012 / 0217453, entitled “Metallic Nanofiber Ink, Substantially Transparent Conductor, and Fabrication Method,” (the '999 application) is hereby incorporated by reference in its entirety.BACKGROUND[0002]1. Field[0003]The present application relates to fabrication of nanostructures such as silver nanowires.[0004]2. Description of the Related Art[0005]Materials reduced to the nanoscale exhibit different physical and chemical properties compared to those on macroscale. The different properties are due in part to the increase in surface area to volume ratio, which alter mechanical, electrical, optical, and catalytic prop...

AI Technical Summary

Benefits of technology

The patent text describes a system and method for making silver nanowires (AgNW) using copper nanowires (CuNW) as templates. The advantage of using CuNW templates is that it allows for the fabrication of longer AgNW, which have higher conductivity and better light transmittance. The longer AgNW also have lower resistivity, which is important for applications like solar panels and touch screens. The use of metal nanowires like copper or silver can provide the benefits of indium tin oxide (ITO) without the drawbacks of cost and limited applications. Additionally, AgNW have higher resistance to corrosion and can be used in applications where they may be exposed to oxidizing environments. Overall, the use of metal nanowires like copper or silver can reduce costs and expand the use of conductive materials in various applications.

Problems solved by technology

While ITO has a high light transmittance and electrical conductivity (e.g., depending on thickness, composition, etc., 90% over the visible spectrum between 400 nm and 700 nm and resistivity of 120 Ω / sq), ITO is brittle, slow and difficult to deposit, expensive, and its deposition entails handling of toxic precursor materials.

Copper (Cu) nanowires (CuNW) are commercially available, but their electrical conductivity (Cu resistivity ρ=1.7×10−6 Ωcm, or 9.25×103 Ωm in a 2.0 vol % CuNW / low density polyethylene (LDPE)) and light transmittance (65% at a resistance of 15 Ω / sq) properties in dispersions, meshes, inks, and / or films are not as good as for silver (Ag) nanowires (AgNW) (Ag resistivity ρ=1.6×10−6 Ωcm, or less than 6.88×102 Ωm in a 2.0 vol % AgNW / LDPE, and 85% at a resistance of 15 Ω / sq, respectively).

While AgNW are also commercially available, and have a higher conductivity and light transmittance in films, fabrication methods for AgNW are inefficient and expensive.

In fabrication steps or applications with exposure to a corroding environment, CuNW can oxidize quickly and conductivity degrades.

For example, printed electronics using electrically conductive fillers in polymer composites or active inks used in magazines, consumer packaging, and clothing designs are often exposed to oxidizing environments.

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