Metallic nanoparticle dispersion
A metallic nanoparticle dispersion includes metallic nanoparticles, a liquid carrier, and a dispersion-stabilizing compound according to Formulae I, II, III or IV, wherein Q represents the necessary atoms to form a substituted or unsubstituted a five or six membered heteroaromatic ring; M is selected from the group consisting of a proton, a monovalent cationic group and an acyl group; R1 and R2 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thioether, an ether, an ester, an amide, an amine, a halogen, a ketone and an aldehyde, R1 and R2 may represent the necessary atoms to form a five to seven membered ring; R3 to R5 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thiol, a thioether, a sulfone, a sulfoxide, an ether, an ester, an amide, an amine, a halogen, a ketone, an aldehyde, a nitrile and a nitro group; and R4 and R5 may represent the necessary atoms to form a five to seven membered ring.
1. A metallic nanoparticle dispersion comprising:
metallic nanoparticles;
a liquid carrier; and
a non-polymeric dispersion-stabilizing compound according to Formula I, II, III, or IV:
Q represents atoms necessary to form a substituted or unsubstituted five or six membered heteroaromatic ring;
M is selected from the group consisting of a proton, a monovalent cationic group, and an acyl group;
R1 and R2 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thioether, an ether, an ester, an amide, an amine, a halogen, a ketone, and an aldehyde;
R1 and R2 may represent necessary atoms to form a five to seven membered ring;
R3 to R5 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thiol, a thioether, a sulfone, a sulfoxide, an ether, an ester, an amide, an amine, a halogen, a ketone, an aldehyde, a nitrile, and a nitro group; and
R4 and R5 may represent necessary atoms to form a five to seven membered ring.
2. The metallic nanoparticle dispersion according to claim 1 , wherein the non-polymeric dispersion-stabilizing compound is Formula I and Q represents atoms necessary to form a five membered heteroaromatic ring.
3. The metallic nanoparticle dispersion according to claim 2 , wherein the five membered heteroaromatic ring is selected from the group consisting of an imidazole, a benzimidazole, a thiazole, a benzothiazole, an oxazole, a benzoxazole, a 1,2,3-triazole, a 1,2,4-triazole, an oxadiazole, a thiadiazole, and a tetrazole.
4. The metallic nanoparticle dispersion according to claim 1 , wherein the non-polymeric dispersion-stabilizing compound is selected from the group consisting of N,N-dibutyl-(2,5-dihydro-5-thioxo-1H-tetrazol-1-yl-acetamide, 5-heptyl-2-mercapto-1,3,4-oxadiazole, 1-phenyl-5-mercaptotetrazol, 5-methyl-1,2,4-triazolo-(1,5-a) primidine-7-ol, and S[5-[(ethoxy-carbonyl)amino]-1,3,4-thiadiazol-2-yl] O-ethyl thiocarbonate.
5. The metallic nanoparticle dispersion according to claim 1 , wherein an amount of the non-polymeric dispersion-stabilizing compound expressed as wt % relative to a total weight of silver in the metallic nanoparticle dispersion is between 0.005 and 10.0.
6. The metallic nanoparticle dispersion according to claim 1 , wherein the liquid carrier is a high boiling solvent.
7. The metallic nanoparticle dispersion according to claim 6 , wherein the high boiling solvent is selected from the group consisting of 2-fenoxy ethanol, 4-methyl-1,3-dioxolan-2-one, n-butanol, 1,2 propanediol, 4-hydroxy-4-methyl pentan-2-one, pentan-3-one, 2-butoxy-ethanol, 1-methoxy-2-propanol, and mixtures thereof.
8. The metallic nanoparticle dispersion according to claim 1 , wherein a viscosity of the metallic nanoparticle dispersion is between 2 and 100 mPa·s at 25° C. at a shear rate of 90 s −1 .
9. The metallic nanoparticle dispersion according to claim 1 , wherein the metallic nanoparticle dispersion is a conductive inkjet ink or a conductive flexographic ink.
10. A method for preparing metallic nanoparticles comprising:
dispersing metallic or metallic precursor particles in a dispersion medium including a solvent according to Formula V:
wherein Ra and Rb represent an optionally substituted alkyl group, and Ra and Rb may form a ring;
washing the metallic or metallic precursor particles with a washing liquid including water to substantially remove the solvent according to Formula V;
evaporating the metallic or metallic precursor particles to substantially remove the water thereby producing the metallic nanoparticle dispersion according to claim 1 ;
wherein
the step of evaporating is carried out in the presence of a high boiling solvent and a non-polymeric dispersion-stabilizing compound according to Formula I, II, III, or IV:
wherein
Q represents atoms necessary to form a substituted or unsubstituted five or six membered heteroaromatic ring;
M is selected from the group consisting of a proton, a monovalent cationic group, and an acyl group;
R1 and R2 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thioether, an ether, an ester, an amide, an amine, a halogen, a ketone, and an aldehyde;
R1 and R2 may represent necessary atoms to form a five to seven membered ring;
R3 to R5 are independently selected from the group consisting of a hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl or heteroaryl group, a hydroxyl group, a thiol, a thioether, a sulfone, a sulfoxide, an ether, an ester, an amide, an amine, a halogen, a ketone, an aldehyde, a nitrile, and a nitro group; and
R4 and R5 may represent necessary atoms to form a five to seven membered ring.
11. The method according to claim 10 , wherein the dispersion medium includes a solvent selected from 2-pyrrolidone, 4-hydroxy-2-pyrrolidone, 6-valerolactam, or ε-caprolactam.
12. The method according to claim 10 , wherein the high boiling solvent is selected from the group consisting of 2-fenoxy ethanol, 4-methyl-1,3-dioxolan-2-one, n-butanol, 1,2 propanediol, 4-hydroxy-4-methyl pentan-2-one, pentan-3-one, 2-butoxyethanol, 1-methoxy-2-propanol, and mixtures thereof.
13. The method according to claim 10 , wherein the step of dispersing includes an in-situ reduction while mixing a metal precursor selected from a metal oxide, a metal hydroxide, a metal salt, or a combination thereof with a reductant.
14. The method according to claim 13 , wherein the step of dispersing includes an in-situ reduction of silver oxide with a reductant.
15. A method of preparing a metallic layer or pattern comprising:
applying a metallic nanoparticle dispersion as defined in claim 1 on a substrate; and
sintering the metallic nanoparticle dispersion applied on the substrate.