Method for forming nano-scale metal particles

• US 20090090214A1
• Filed: 10/03/2008
• Published: 04/09/2009
• Est. Priority Date: 10/04/2007
• Status: Abandoned Application

• Current Assignee: Chung-Yuan Christian University
• Original Assignee: Chung-Yuan Christian University
• Inventors: Cheng, Chun-Lin
• Application Number:
  US12/244,849
• Publication Number:
  US 20090090214A1
• Time in Patent Office: Days
• US Class Current: 75/370
• CPC Class Codes: B22F 1/052 characterised by a mixture of particles of different sizes or by the particle size distribution
• CPC Class Codes: B22F 9/24 starting from liquid metal compounds, e.g. solutions

Abstract

A method for forming nano-scale metal particles by a novel reducing agent is described. The method can be carried out at room temperature and under an atmospheric environment by relatively simple processes to prepare nano-scale metal particles with a diameter less than 20 nm. This method comprises the following steps. At first, a first blending process is performed to blend a metal salt and a first solvent together to form a first solution. Then, a second blending process is performed to blend a reducing agent and a second solvent together to form a second solution. The reducing agent comprises one compound selected from the group consisting of the following or combination thereof: boron-containing hydride and boron-containing hydrocarbon. Following that, a third blending process is performed to blend the first solution and the second solution together to form a third solution. Finally, the reducing agent is used to reduce the metal salt in the third solution to form the nano-scale metal particles. In addition, if a dispersing agent is added after the nano-scale metal particles are formed, the nano-scale metal particles can have a particle diameter less than 10 nm.

Claims

1. A method for forming nano-scale metal particles, comprising:

performing a first blending process to blend a metal salt and a first solvent together to form a first solution;

performing a second blending process to blend a reducing agent and a second solvent together to form a second solution wherein said reducing agent comprises one compound selected from the group consisting of the following or combination thereof;

boron-containing hydride and boron-containing hydrocarbon;

performing a third blending process to blend said first solution and said second solution together to form a third solution; and

using said reducing agent to reduce said metal salt in said third solution to form said nano-scale metal particles.

2. The method according to claim 1, wherein the temperature in said first, second, and third blending processes is less than or equal to 40°

C.

3. The method according to claim 1, wherein in said first solution the molar concentration of said metal salt is less than or equal to 10⁻

4M.

4. The method according to claim 1, wherein in said second solution the molar concentration of said reducing agent is less than or equal to 10⁻

4M.

5. The method according to claim 1, wherein said reducing agent is tetraethylammonium borohydride.

6. The method according to claim 1, wherein said metal salt has a general formula:

MX where M is selected from the group consisting of the following;

tin, copper, silver, and gold; and

X is selected from the group consisting of the following;

halogen, sulfate ion, phosphate ion, sulfonate ion, nitrate ion, and carboxylate ion.

7. The method according to claim 1, wherein said first solvent and said second solvent are independently selected from the group consisting of the following or combination thereof:

water, alcohol, and a polar solvent.

8. The method according to claim 7, wherein said nano-scale metal particles are dispersed in solution by a dispersing agent after formed where said dispersing agent is selected from the group consisting of the following:

water, alcohol, n-hexane, toluene, and tetrahydrofuran.

9. The method according to claim 7, wherein the molar ratio of said reducing agent to said metal salt is between 60 and 300.

10. The method according to claim 7, wherein the particle diameter of said formed nano-scale metal particles is 5˜

70 nm.

11. The method according to claim 1, wherein said first solvent and said second solvent are independently selected from the group consisting of the following or combination thereof:

N,N-dimethyl-acetamide (DMAC), dimethyl-sulfoxide (DMSO), and 1-methyl-2-pyrrolidinone (NMP).

12. The method according to claim 11, wherein the molar ratio of said reducing agent to said metal salt is between 5 and 25.

13. The method according to claim 11, wherein the particle diameter of said formed nano-scale metal particles is 15˜

60 nm.

14. A method for forming tin-containing nano-scale metal particles, comprising:

performing a blending process to blend a tin salt, a reducing agent, and a solvent together to form a mixture solution wherein said mixture solution selectively comprises other metal salts and said reducing agent comprises one compound selected from the group consisting of the following or combination thereof;

boron-containing hydride and boron-containing hydrocarbon; and

using said reducing agent to reduce said metal salt in said mixture solution to form said tin-containing nano-scale metal particles.

15. The method according to claim 14, wherein the temperature in said blending processes is less than or equal to 40°

C.

16. The method according to claim 14, wherein said blending process is performed under an atmospheric environment.

17. The method according to claim 14, wherein said reducing agent is tetraethylammonium borohydride.

18. The method according to claim 14, wherein said solvent is selected from the group consisting of the following or combination thereof:

water, alcohol, a polar solvent.

19. The method according to claim 14, wherein said tin salt has a general formula:

SnX where and X is selected from the group consisting of the following;

halogen, sulfate ion, phosphate ion, sulfonate ion, nitrate ion, and carboxylate ion.

20. The method according to claim 14, wherein said other metal salt is selected from the group consisting of the following or combination thereof:

silver salt, copper salt, and gold salt.

21. The method according to claim 14, wherein said nano-scale metal particles are dispersed in solution by a dispersing agent after formed where said dispersing agent is selected from the group consisting of the following:

water, alcohol, n-hexane, toluene, and tetrahydrofuran.

22. The method according to claim 14, wherein the molar ratio of said reducing agent to all of said metal salts is between 60 and 300.

23. The method according to claim 14, wherein the particle diameter of said formed tin-containing nano-scale metal particles is 5˜

70 nm.

34. The method according to claim 14, wherein the particle diameter of said formed copper nano-scale metal particles is 15˜

60 nm.

24. A method for forming copper nano-scale metal particles, comprising:

performing a first blending process to blend a copper salt and a first solvent together to form a first solution;

performing a second blending process to blend a reducing agent and a second solvent together to form a second solution wherein said reducing agent comprises one compound selected from the group consisting of the following or combination thereof;

boron-containing hydride and boron-containing hydrocarbon and said second solvent is selected from the group consisting of the following;

N,N-dimethyl-acetamide (DMAC), dimethyl-sulfoxide (DMSO), and 1-methyl-2-pyrrolidinone (NMP);

performing a third blending process to blend said first solution and said second solution together to form a third solution and using said reducing agent to reduce said copper salt in said third solution to form dispersed copper nano-scale metal particles.

25. The method according to claim 24, wherein the temperature of said first, second, and third blending processes is less than or equal to 40°

C.

26. The method according to claim 24, wherein said first, and second, and third blending processes are performed under a nitrogen environment.

27. The method according to claim 24, wherein in said first solution the molar concentration of said metal salt is less than or equal to 10⁻

4M.

28. The method according to claim 24, wherein in said second solution the molar concentration of said reducing agent is less than or equal to 10⁻

4M.

29. The method according to claim 24, wherein said reducing agent is tetraethylammonium borohydride.

30. The method according to claim 24, wherein said first solvent is independently selected from the group consisting of the following or combination thereof:

N,N-dimethyl-acetamide (DMAC), dimethyl-sulfoxide (DMSO), and 1-methyl-2-pyrrolidinone (NMP).

31. The method according to claim 24, wherein said first solvent is N,N-dimethyl-acetamide (DMAC) and said second solvent is dimethyl-sulfoxide (DMSO).

32. The method according to claim 24, wherein said copper salt has a general formula:

CuX where and X is selected from the group consisting of the following;

halogen, sulfate ion, phosphate ion, sulfonate ion, nitrate ion, and carboxylate ion.

33. The method according to claim 24, wherein the molar ratio of said reducing agent to said copper-containing metal salts is between 5 and 25.