Methods of controlling nanostructure formations and shapes
A method of forming monodispersed metal nanowires comprising: forming a reaction mixture including a metal salt, a capping agent and an ionic additive in a reducing solvent; and reducing the metal salt to the monodispersed metal nanostructures.
1. A method of forming monodispersed metal nanostructures comprising:
forming a reaction mixture comprising a metal salt, a capping agent and a chloride additive in a reducing solvent; and
reducing the metal salt to the monodispersed metal nanostructures, wherein the monodispersed metal nanostructures comprise at least 85% by weight of metal nanowires.
2. The method of claim 1 , wherein a molar ratio of the chloride additive and the metal salt is between about 0.005 and about 0.01.
3. The method of claim 1 , wherein a solubility of the metal salt in the reducing solvent is at least 0.001 g/ml.
4. The method of claim 1 , wherein the metal salt is silver nitrate, silver acetate, silver perchlorate, gold perchlorate, palladium chloride, or platinum chloride.
5. The method of claim 1 , wherein a concentration of the metal salt in the reaction mixture is of about 0.01M to 0.2M.
6. The method of claim 1 , wherein the capping agent is poly(vinyl pyrrolidone), polyacrylamide, polyacrylic or a copolymer thereof.
7. The method of claim 1 , wherein a concentration of the capping agent in the reaction mixture is of about 0.01M to 0.2M.
8. The method of claim 1 , wherein the chloride ionic additive is represented by a formula of NR 4 + Cl − , wherein each R is the same or different and independently an alkyl, alkenyl, alkynyl, aryl, or aralkyl.
9. The method of claim 8 , wherein the capping agent is compatible with quaternary ammonium ions (NR 4 + ) in the formula of NR 4 + Cl − .
10. The method of claim 8 , wherein the chloride additive is quaternary ammonium chloride, and a concentration of the quaternary ammonium chloride in the reaction mixture is less than 0.1 M.
11. The method of claim 1 , wherein the reducing solvent comprises at least two hydroxyl groups.
12. The method of claim 1 , wherein the reducing solvent is ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerin, glycerol, or glucose.
13. The method of claim 1 , wherein the reaction mixture is formed at a first temperature of about 20° C. to about 40° C.
14. The method of claim 13 , wherein the reducing is carried out at a second temperature of about 50° C. to about 170° C.
15. The method of claim 1 , wherein the reducing is carried out at a second temperature of about 50° C. to about 170° C.
16. The method of claim 1 , wherein the metal nanowires have aspect ratios of greater than 100.
17. The method of claim 1 , wherein the monodispersed metal nanostructures comprise at least 90% by weight of the metal nanowires.
18. The method of claim 1 , wherein the metal salt is silver nitrate, and the metal nanowires are silver nanowires.
19. The method of claim 1 , further comprising:
reducing the metal salt to seeds comprising a lateral surface and a cross section surface; and
passivating the lateral surface by the capping agent, and performing a one-dimensional growth of the seeds on the cross section surface to form the metal nanowires.
20. The method of claim 1 , wherein the reducing solvent is a polar solvent in which the metal salt, the chloride additive and the capping agent are soluble, and is a reducing agent to reduce the metal salt.