Air-stable conductive ink

Patent metadata

Field	Value
Publication number	US-2022010160-A1
Application number	US-202117305583-A
Country	US
Kind code	A1
Filing date	Jul 9, 2021
Priority date	Jul 10, 2020
Publication date	Jan 13, 2022
Grant date	—

Abstract

A low temperature sinterable copper nanoparticle or nanowire, comprising gold, zinc, nickel, tin, or aluminum as an alloying metal, and a capping agent. The nanoparticles or nanowires may be deposited on porous or fibrous substrates, the capping agent desorbed, and sintered at low temperature to form conductive traces or sensing elements. The nanoparticles or nanowires may be deposited by aerosol jet, inkjet or dispenser printers, for example.

First claim

1 . A method of forming a conductive coating on a porous substrate, comprising:
printing nanowires decorated with nanoparticles comprising an alloy of 1% copper, capped with a capping agent, by a reaction solution aging and annealing procedure on the porous substrate; and allowing the decorated nanowires to sinter at a temperature below 150° C., to form the conductive coating.

2 . The method according to claim 1 , wherein the nanoparticles have a diameter between 2 to 20 nm, and comprise at least 50% copper and at least 1% gold, nickel, aluminum, zinc, or tin.

3 . The method according to claim 1 , wherein said printing comprises:
digitally defining a deposition pattern on the porous substrate; electronically selectively forming regions of the decorated nanowires on the porous substrate corresponding to the defined deposition pattern by printing; and desorbing the capping agent from the nanoparticles or nanowires.

4 . The method according to claim 1 , wherein the nanoparticles comprise copper-gold alloy nanoparticles comprising at least 50% copper, having a bimodal distribution of diameter having a first peak between 1-2 nanometers and a second peak between 5-10 nanometers.

5 . The method according to claim 1 , wherein the decorated nanowires are allowed to sinter at a temperature below 100° C.

6 . The method according to claim 1 , wherein the porous substrate a cellulosic paper.

7 . The method according to claim 1 , wherein conductive coating has a conductivity which reversibly varies by at least 2% in dependence on an external condition.

8 . The method according to claim 1 , wherein the decorated nanowires sinter by surface-mediated Ostwald ripening.

9 . A sinterable composition adapted to form a conductive layer of sintered overlapping nanowires at a sintering temperature below 150° C., the sinterable composition comprising:
a plurality of nanowires;
nanoparticles decorating the plurality of nanowires, comprising an alloy of at least 1% copper and at least 1% of gold, zinc, nickel, aluminum, or tin, having a diameter between 2 to 20 nm, the nanoparticles being capped with a capping agent; and
a buffer solution in which the decorated nanowires are suspended and free to move.

10 . The sinterable composition according to claim 9 , wherein the nanowires comprise at least 50% copper.

11 . The sinterable composition according to claim 10 , wherein the nanowires comprise between 1-10% Ni.

12 . The sinterable composition according to claim 10 , wherein the nanoparticles comprise a copper-gold alloy.

13 . The sinterable composition according to claim 9 , wherein the nanoparticle decoration of the nanowires is dendritic.

14 . The sinterable composition according to claim 9 , wherein the capping agent comprises at least one of an amine, a thiolate and an acrylate.

15 . A conductive coating, comprising:
nanowires in an overlapping array; a sintered coating bridging the overlapping array of nanowires, the sintered coating comprising at least 1% metallic copper and 1% of metallic gold, zinc, nickel, aluminum, or tin, forming a conductive path between overlapping nanowires; and a residual capping agent, wherein the capping agent is adapted to:
maintain the nanowires decorated with nanoparticles comprising the at least 1% metallic copper and 1% of metallic gold, zinc, nickel, aluminum, or tin in a freely suspended state in a buffer before deposition on a substrate, and
permit sintering of the nanoparticles at a temperature of less than 150° C. after deposition on the substrate and formation of the overlapping array of nanoparticles.

16 . The conductive coating composition according to claim 15 , wherein the sintered coating results from surface-mediated Ostwald ripening.

17 . The conductive coating composition according to claim 15 , wherein:
the nanowires comprise at least 50% copper and have a diameter between 2 to 20 nm; and the sintered coating comprises at least 50% copper.

18 . The conductive coating composition according to claim 15 , wherein the conductive coating has a conductivity which reversibly varies by at least 2% in dependence on an external condition.

19 . The conductive coating composition according to claim 15 , wherein the residual capping agent comprises at least one of an amine, a thiolate and an acrylate.

20 . The conductive coating composition according to claim 15 , wherein the nanowires comprise at least one of copper and a copper-nickel alloy, and the nanoparticles comprise a copper-gold alloy.

21 . The conductive coating composition according to claim 15 , wherein the overlapping array is configured to form a conductive path on a fibrous substrate, wherein a resistance of the conductive path is reversibly responsive to at least one of a chemical and a mechanical condition.

Assignees

• Univ New York State Res Found

Inventors

• Zhong Chuan-Jian
• Yan Shan
• Shan Shiyao
• He Ning
• Kang Ning
• Luo Jin

Classifications

• C22C9/00

  Alloys based on copper · CPC title

• B41M5/0023

  Digital printing methods characterised by the inks used (inks per se C09D11/00) · CPC title

• D21H19/02

  Metal coatings (D21H19/66 takes precedence) · CPC title

• C09D11/037

  characterised by the pigment · CPC title

• C09D11/322

  Pigment inks · CPC title