Silver nanoparticles, method for producing silver nanoparticles, and silver nanoparticle ink
A method for producing silver nanoparticles according to the present invention includes the steps of: mixing an amine mixture and a silver compound to yield a complex compound; and heating and decomposing the complex compound to form silver nanoparticles. The amine mixture contains: a primary amine (A) having 8 or more carbon atoms and a melting point of 20° C. or lower; a diamine (B) having a primary amino group, a tertiary amino group, 4 or more carbon atoms, and a melting point of 20° C. or lower; and a cis-unsaturated primary amine (C) having 12 or more carbon atoms and a melting point of 30° C. or lower.
1. A silver nanoparticle ink comprising:
an organic solvent having a boiling point of 150° C. or higher; and
silver nanoparticles dispersed in the organic solvent, the silver nanoparticles being covered with amines, wherein
the silver nanoparticles covered with amines comprise:
protective molecules comprising a primary amine (A) having 8 or more carbon atoms and a melting point of 20° C. or lower, a diamine (B) having a primary amino group, a tertiary amino group, 4 or more carbon atoms, and a melting point of 20° C. or lower, and a cis-unsaturated primary amine (C) having 12 or more carbon atoms and a melting point of 30° C. or lower; and
silver nanoparticles each covered with the protective molecules, and
the organic solvent is a mixed solvent comprising an alcohol having a boiling point of 150° C. or higher and a nonpolar solvent having a boiling point of 150° C. or higher.
2. The silver nanoparticle ink according to claim 1 , wherein the alcohol is a linear primary alcohol having 6 or more carbon atoms and a melting point of 20° C. or lower.
3. The silver nanoparticle ink according to claim 1 , wherein both the alcohol and the nonpolar solvent have a dielectric constant of 15 or less.
4. The silver nanoparticle ink according to claim 1 , wherein the nonpolar solvent is an organic solvent having a surface free energy of 20 mN/m to 50 mN/m.
5. The silver nanoparticle ink according to claim 1 , wherein the nonpolar solvent contains at least one selected from the group consisting of 1,4-diisopropylbenzene, tetralin, decahydronaphthalene, and 1-methylnaphthalene.
6. An electrode, formed using the silver nanoparticle ink according to claim 1 .
7. A thin-film transistor, formed using the silver nanoparticle ink according to claim 1 .
8. The silver nanoparticle ink according to claim 1 , wherein the primary amine (A) is a linear primary amine in which the number of carbon atoms is 8 to 10.
9. The silver nanoparticle ink according to claim 1 , wherein the primary amine (A) comprises at least one selected from the group consisting of octylamine, nonylamine, 1-aminodecane, 2-ethylhexylamine, 3-(2-ethylhexyloxy)propylamine, 3-decyloxypropylamine, and 3-lauryloxypropylamine.
10. The silver nanoparticle ink according to claim 1 , wherein the number of carbon atoms in the diamine (B) is 4 to 12.
11. The silver nanoparticle ink according to claim 1 , wherein the diamine (B) comprises at least one selected from the group consisting of N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-propanediamine, 3-(dibutylamino)propylamine, 2-diisopropylaminoethylamine, and dimethylaminoethoxypropylamine.
12. The silver nanoparticle ink according to claim 1 , wherein the cis-unsaturated primary amine (C) comprises at least one selected from the group consisting of oleylamine, cis-9-hexadecenylamine, and cis-9-tetradecenylamine.
13. The silver nanoparticle ink according to claim 1 , wherein the protective molecules further comprise a fatty acid.
14. The silver nanoparticle ink according to claim 1 , wherein the protective molecules further comprise a thiol.
15. A method for producing silver nanoparticle ink, comprising the steps of:
mixing an amine mixture and a silver compound to yield a complex compound, the amine mixture containing a primary amine (A) having 8 or more carbon atoms and a melting point of 20° C. or lower, a diamine (B) having a primary amino group, a tertiary amino group, 4 or more carbon atoms, and a melting point of 20° C. or lower, and a cis-unsaturated primary amine (C) having 12 or more carbon atoms and a melting point of 30° C. or lower;
heating and decomposing the complex compound to form silver nanoparticles; and
dispersing the silver nanoparticles in an organic solvent having a boiling point of 150° C. or higher,
wherein the organic solvent is a mixed solvent containing an alcohol having a boiling point of 150° C. or higher and a nonpolar solvent having a boiling point of 150° C. or higher.
16. The method for producing silver nanoparticle ink according to claim 15 , wherein
the primary amine (A) is a linear primary amine in which the number of carbon atoms is 8 to 10, and
the number of carbon atoms in the diamine (B) is 4 to 12.
17. The method for producing silver nanoparticle ink according to claim 15 , wherein the amine mixture further contains a fatty acid.
18. The method for producing silver nanoparticle ink according to claim 15 , wherein the amine mixture further contains a thiol.