# US 10,478,899 B2 · Method of making a transparent conductive composite material

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- Number: US 10,478,899 B2
- Document ID: US10478899B2
- Status: Granted
- Kind: B2
- Application number: 15/596,636
- Filed: 2017-05-16
- Published: 2017-08-31
- Granted: 2019-11-19
- Earliest claimed: 2014-06-11
- Assignees: National Tsing Hua University
- Applicants: National Tsing Hua University
- Inventors: Nyan-Hwa Tai; Yi-Ting Lai
- Web page: https://patentgrep.com/patent/US10478899B2

## CPC

- B22F 1/16: Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10)
- B22F 1/0547: {Nanofibres or nanotubes}
- B22F 9/24: starting from liquid metal compounds, e.g. solutions
- B82Y 40/00: Manufacture or treatment of nanostructures
- C01B 32/182: Graphene
- C01B 32/194: After-treatment
- H01B 1/02: mainly consisting of metals or alloys
- H01B 1/04: mainly consisting of carbon-silicon compounds, carbon or silicon
- H01B 1/08: oxides
- H10D 62/882: {Graphene}
- B22F 2009/245: {Reduction reaction in an Ionic Liquid [IL]}
- B22F 2301/255: Silver or gold
- B22F 2302/40: Carbon, graphite
- B22F 2304/05: Submicron size particles
- B22F 2998/10: Processes characterised by the sequence of their steps
- Y10T 428/249921: Web or sheet containing structurally defined element or component
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- 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})
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method of making a transparent conductive material includes: preparing a reactive solution that contains a solvent, a metal salt which is dissolved in the solvent, and a powder of graphene oxide which is dispersed in the solvent; and simultaneously reducing metal ions of the metal salt and the graphene oxide in the reactive solution to form a plurality of core-shell nanowires, each of which includes a core of a metal reduced from the metal ions, and a shell of graphene surrounding the core.

## Claims

### Claim 1

A method of making a transparent conductive material, comprising steps of:
a) preparing a precursor solution that contains a metal salt, a templating reagent, a buffer agent, and a first solvent which also serves as a reducing agent;
b) preparing a graphene oxide solution by dispersing a graphene oxide in a second solvent which is miscible with the first solvent; and
c) slowly adding the graphene oxide solution to the precursor solution at an elevated temperature of no smaller than 150° C. and less than 290° C. so as to permit growth of graphene on metal nanowire seeds which are formed as a result of a reduction of the metal salt to thereby obtain a network structure which includes a plurality of core-shell nanowires interconnected to each other and a plurality of nanowebs of graphene extending from the core-shell nanowires.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first solvent is a polyhydroxy alcohol.

### Claim 3 (depends on 2)

The method of claim 2, wherein the polyhydroxy alcohol is selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, glycerin, and combinations thereof.

### Claim 4 (depends on 1)

The method of claim 1, wherein the metal salt is selected from the group consisting of silver nitrate, silver perchlorate, and silver fluoride.

### Claim 5 (depends on 1)

The method of claim 1, wherein the templating reagent is selected from the group consisting of polyvinylpyrrolidone, polyvinyl alcohol, poly(dimethylsiloxane), poly(oxyethylene), and combinations thereof.

### Claim 6 (depends on 1)

The method of claim 1, wherein the buffer agent is selected from the group consisting of a metal halide, a metal sulfide, and a metal nitrate.

### Claim 7 (depends on 6)

The method of claim 6, wherein the metal halide is silver bromide or silver chloride.

### Claim 8 (depends on 1)

The method of claim 1, further comprising, prior to step c), a step of heating the precursor solution up to the elevated temperature to initiate the reduction of a portion of the metal salt to form the metal nanowire seeds.

### Claim 9 (depends on 1)

The method of claim 1, wherein the second solvent is selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, glycerin, and combinations thereof.