Patterning of a composition comprising silver nanowires

Patent metadata

Field	Value
Publication number	US-10073549-B2
Application number	US-201414905160-A
Country	US
Kind code	B2
Filing date	Jul 18, 2014
Priority date	Jul 22, 2013
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

The present invention relates to the production of a layer structure, comprising the following process steps:
i) coating a substrate with a composition at least comprising silver nanowires and a solvent; ii) at least partial removal of the solvent, thereby obtaining a substrate that is coated with an electrically conductive layer, the electrically conductive layer at least comprising the silver nanowires; iii) bringing into contact selected areas of the electrically conductive layer with an etching composition, thereby reducing the conductivity of the electrically conductive layer in these selected areas, wherein the etching composition comprises an organic compound capable of releasing chlorine, bromine or iodine, a compound containing hypochloride, a compound containing hypo-bromide or a mixture of at least two of these compounds.

The invention also relates to a layer structure obtainable by this method, a layer structure, the use of a layer structure, an electronic component and the use of an organic compound.

First claim

The invention claimed is:

1. A method for producing a layer structure, comprising the process steps:
i) coating a substrate with a composition comprising silver nanowires, a sulfonated polymer, a conductive polymer and a solvent,

wherein the conductive polymer is a polythiophene;
ii) partially removing the solvent, thereby obtaining a substrate that is coated with an electrically conductive layer, the electrically conductive layer comprising the silver nanowires, the sulfonated polymer and the conductive polymer; and
iii) bringing into contact selected areas of the electrically conductive layer with an etching composition, thereby reducing the conductivity of the electrically conductive layer in these selected areas, wherein the etching composition comprises an organic compound capable of releasing chlorine, bromine or iodine, a compound containing hypochloride, a compound containing hypobromide or a mixture of at least two of these compounds;

wherein the surface resistance of the selected areas that have been brought into contact with the etching composition in step iii) is at least 10 times greater than the surface resistance of the layer provided in process step ii); and
wherein the color difference (ΔE) between the selected areas that have been brought into contact with the etching composition in step iii) and the electrically conductive layer provided in step ii) is at most 4.5.

2. The method according to claim 1 , wherein the silver nanowires in the composition used in process step i) have a length of from 1 μm to 200 μm, a diameter of from 20 nm to 1,300 nm and an aspect ratio (length/diameter) of at least 5.

3. The method according to claim 1 , wherein the silver nanowires in the composition used in process step i) are obtained by a process comprising the process steps:
a) providing a reaction mixture comprising
a polyol,
an organic chemical which is adsorbed on to a silver surface,
a chemical which forms a halide and/or one which forms a pseudohalide, wherein the chemical which forms a halide is a salt of one of the halides Cl − , Br − and/or I − and wherein the chemical which forms a pseudohalide is a salt of one of the pseudohalides SCN − , CN − , OCN − and/or CNO − ,
a chemical which forms a redox pair, chosen from the group consisting of bromine, iodine, vanadium and mixtures thereof, and
a silver salt, and

b) heating the reaction mixture to a temperature of at least 100° C.

4. The method according to claim 1 , wherein the sulfonated polymer in the composition used in process step i) is polystyrene sulfonic acid (PSS).

5. The method according to claim 1 , wherein the conductive polymer is present in the form of a complex formed from the polythiophene and the sulfonated polymer.

6. The method according to claim 5 , wherein the conductive polymer is poly(3,4-ethylenedioxythiophene) (PEDOT) and is present in the form of a PEDOT/PSS-complex.

7. The method according to claim 1 , wherein the organic compound capable of releasing chlorine, bromine or iodine comprises at least one structural element (II)

wherein
Hal is a halogen selected from the group consisting of chlorine, bromine and iodine,
Y is selected from N, S and P, and
X 1 and X 2 can be the same or different and each denote respectively a halogen, a carbon atom or a sulphur atom, and wherein one or more further atoms can optionally be bonded to X 1 and X 2 .

8. The method according to claim 7 , wherein the organic compound capable of releasing chlorine or bromine comprises at least two structural elements (II) in which Hal denotes a chlorine atom or a bromine atom and Y denotes nitrogen, wherein the at least two structural elements (II) can optionally be different from one another.

9. The method according to claim 8 , wherein the organic compound capable of releasing chlorine or bromine comprises the structural element (III)

in which a chlorine atom or a bromine atom is bonded to at least two of the nitrogen atoms.

10. The method according to claim 9 , wherein the organic compound capable of releasing chlorine or bromine is sodium dichloroisocyanurate, sodium dibromoisocyanurate, tribromoisocyanuric acid or trichloroisocyanuric acid.

11. The method according to claim 1 , wherein the etching composition used in process step iii) comprises the organic compound capable of releasing chlorine, bromine or iodine, the compound containing hypochloride, the compound containing hypobromide or the mixture of at least two of these compounds in a concentration in a range from 0.01 to 50 wt.-%, relative to the total weight of the etching composition.

12. The method according to claim 1 , wherein the bringing into contact of the electrically conductive layer with the etching composition is performed by dipping the electrically conductive layer into the etching composition or by printing the electrically conductive layer with the etching composition.

13. The method according to claim 1 , wherein the method comprises as a further process step:
iv) washing the electrically conductive layer brought into contact with the etching composition.

14. The method of claim 1 , wherein step iii) is performed without affecting the optical appearance of the selected areas.

15. The method of claim 1 , wherein the surface resistance of the selected areas that have been brought into contact with the etching composition in step iii) is at least 100 times greater than the surface resistance of the layer provided in process step ii).

16. The method of claim 1 , wherein the surface resistance of the selected areas that have been brought into contact with the etching composition in step iii) is at least 1,000 times greater than the surface resistance of the layer provided in process step ii).

17. The method of claim 1 , wherein the surface resistance of the selected areas that have been brought into contact with the etching composition in step iii) is at least 10,000 times greater than the surface resistance of the layer provided in process step ii).

18. The method of claim 1 , wherein the surface resistance of the selected areas that have been brought into contact with the etching composition in step iii) is at least 100,000 times greater than the surface resistance of the layer provided in process step ii).

19. The method of claim 1 , wherein the color difference (ΔE) between the selected areas that have been brought into contact with the etching composition in step iii) and the electrically conductive layer provided in step ii) is at most 3.0.

20. The method of claim 1 , wherein the color difference (ΔE) between the selected areas that have been brought into contact with the etching composition in step iii) and the electrically conductive layer provided in step ii) is at most 1.5.

Assignees

• Heraeus Deutschland Gmbh & Co Kg

Inventors

• Lovenich Wilfried
• Sauer Rüdiger
• Guntermann Udo

Classifications

• B22F1/0547

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• G06F3/041 Primary

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• H05K3/067

  Etchants · CPC title

• H05K2201/026

  Nanotubes or nanowires · CPC title