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

[0008]Systems and methods disclosed herein can fabricate AgNW using CuNW as templates. One advantage of certain embodiments disclosed herein is that using CuNW as templates can aid in the fabrication of relatively long AgNW as compared to previous AgNW fabrication methods. For example, AgNW are generally less than about 10 μm long, and are typically about 4 microns (μm) to about 5 μm long. By contrast, CuNW may be much longer, and use of long CuNW as a template for AgNW can form long AgNW, for example having a length greater than about 10 μm, between about 70 μm and about 150 μm, and other lengths. Longer AgNW can allow for higher conductivity (lower resistivity) due to more cross points in the percolative network. This higher conductivity may be achieved while having less mass per square area, which can result in better light transmittance. In CuNW and AgNW films, inks, and other applications, conductivity and transmittance have an inverse relationship—conductivity decreases as transmittance increases. Certain fabrication processes disclosed herein can advantageously control the size of the AgNW by using CuNW as templates, reducing Ag waste, and thereby reducing costs. The reduced costs can allow for use of AgNW in a wide variety of applications such as, for example, solar panels, touch screens, and displays. Replacing ITO with metal nanowires can provide many of th

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 (A

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