# US 2019/0378633 A1 · Thin and uniform silver nanowires, method of synthesis and transparent conductive films formed from the nanowires

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- Number: US 2019/0378633 A1
- Document ID: US20190378633A1
- Status: Published application
- Kind: A1
- Application number: 16/549,204
- Filed: 2019-08-23
- Published: 2019-12-12
- Earliest claimed: 2017-12-06
- Assignees: C3Nano Inc.
- Applicants: C3Nano Inc.
- Inventors: Yongxing Hu; Ying-Syi Li; Xiqiang Yang; Jing Shun Ang; Ajay Virkar
- Web page: https://patentgrep.com/patent/US20190378633A1

## CPC

- H01B 1/02: mainly consisting of metals or alloys
- H01B 1/22: the conductive material comprising metals or alloys
- H01B 5/00: Non-insulated conductors or conductive bodies characterised by their form
- H01B 13/0006: {for reducing the size of conductors or cables}
- H01B 13/0016: {for heat treatment}
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 35/00: Methods or apparatus for measurement or analysis of nanostructures
- B82Y 40/00: Manufacture or treatment of nanostructures
- H05K 2201/026: Nanotubes or nanowires
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

Highly uniform and thin silver nanowires are described having average diameters below 20 nm and a small standard deviation of the diameters. The silver nanowires have a high aspect ratio. The silver nanowires can be characterized by a small number of nanowires having a diameter greater than 18 nm as well as with a blue shifted narrow absorption spectrum in a dilute solution. Methods are described to allow for the synthesis of the narrow uniform silver nanowires. Transparent conductive films formed from the thin, uniform silver nanowires can have very low levels of haze and low values of ΔL*, the diffusive luminosity, such that the transparent conductive films can provide little alteration of the appearance of a black background.

## Claims

### Claim 1

A transparent electrically conductive structure comprising:
a transparent substrate and a first sparse metal conductive layer over a first surface of the transparent substrate,
wherein the transparent electrically conductive structure has a sheet resistance of no more than about 100 ohms/sq, a total transmittance of visible light of at least about 90% and a haze of no more than about 0.60%, and
wherein the value of ΔL* obtained in a diffuse reflection configuration on a substrate with a black surface is no more than a value of 2.0, ΔL*=L* of the electrically conductive structure minus L* of the structure without the sparse metal conductive layer.

### Claim 2 (depends on 1)

The transparent electrically conductive structure of claim 1 wherein the first sparse metal conductive layer comprises a polysaccharide.

### Claim 3 (depends on 1)

The transparent electrically conductive structure of claim 1 wherein the first sparse metal conductive layer comprises a fused metal conductive network.

### Claim 4 (depends on 1)

The transparent electrically conductive structure of claim 1 further comprising a polymer overcoat on the first sparse metal conductive layer.

### Claim 5 (depends on 4)

The transparent electrically conductive structure of claim 4 wherein the transparent electrically conductive structure has a sheet resistance of no more than about 75 ohms/sq, a total transmittance of visible light of at least about 91% and a haze of no more than about 0.35%.

### Claim 6 (depends on 5)

The transparent electrically conductive structure of claim 5 having a haze of no more than 0.40% and a ΔL* associated with the first sparse metal conductive layer and the polymer overcoat of no more than 1.5.

### Claim 7 (depends on 5)

The transparent electrically conductive structure of claim 5 wherein the polymer overcoat comprises an acrylate polymer.

### Claim 8 (depends on 1)

The transparent electrically conductive structure of claim 1 wherein the transparent electrically conductive structure has a sheet resistance of no more than about 75 ohms/sq, a total transmittance of visible light of at least about 91% and a haze of no more than about 0.40%.

### Claim 9 (depends on 1)

The transparent electrically conductive structure of claim 1 further comprising:
a second sparse metal conductive layer over a second surface of the substrate opposite the first surface,
wherein the second surface of the transparent electrically conductive structure has a sheet resistance of no more than about 100 ohms/sq.

### Claim 10 (depends on 9)

The transparent electrically conductive structure of claim 9 wherein each surface of the transparent electrically conductive structure has a sheet resistance from about 60 to about 90 ohms/sq.

### Claim 11 (depends on 9)

The transparent electrically conductive structure of claim 9 wherein each surface of the transparent electrically conductive structure has a sheet resistance from about 40 to about 60 ohms/sq.

### Claim 12 (depends on 3)

The transparent electrically conductive structure of claim 3 wherein the fused metal nanostructured network comprises nanowire segments having an average diameter of no more than about 20 nm and a standard deviation of the diameter of no more than about 2.5 nm.

### Claim 13 (depends on 12)

The transparent electrically conductive structure of claim 12 wherein the nanowire segments have an average diameter of no more than about 18 nm.

### Claim 14 (depends on 12)

The transparent electrically conductive structure of claim 12 wherein the nanowire segments have an average diameter of no more than about 16 nm.

### Claim 15 (depends on 12)

The transparent electrically conductive structure of claim 12 wherein the nanowire segments have a standard deviation of the diameter of no more than about 2.25 nm.

### Claim 16 (depends on 12)

The transparent electrically conductive structure of claim 12 wherein the nanowire segments have a standard deviation of the diameter of no more than about 2.0 nm.

### Claim 17 (depends on 12)

The transparent electrically conductive structure of claim 12 wherein no more than 25% of the nanowire segments have a diameter greater than 18 nm.

### Claim 18 (depends on 12)

The transparent electrically conductive structure of claim 12 wherein no more than about 10% of the nanowire segments have a diameter greater than 18 nm.

### Claim 19 (depends on 12)

The transparent electrically conductive structure of claim 12 wherein the nanowire segments have a noble metal coating.