Methods for controlling metal nanostructures morphology
View Patent ↗Described herein are methods of controlling metal nanowire morphologies by adjusting the reaction conditions of a polyol synthesis. In particular, by purging the reaction with an inert gas, batch-to-batch consistency can be achieved.
1. A method of preparing metal nanowires comprising:
(a) providing a first reaction mixture by combining a polyol solvent, a capping reagent, and an ionic additive in a reaction vessel;
(b) purging the first reaction mixture with an inert gas for a purging time;
(c) after (b), providing a second reaction mixture by combining the first reaction mixture with a metal salt; and
(d) providing a plurality of metal nanostructures by reducing the metal salt, wherein the plurality of metal nanostructures comprise metal nanowires at a first yield.
2. The method of claim 1 , further comprising heating the first reaction mixture to a reaction temperature prior to (b).
3. The method of claim 1 wherein purging the first reaction mixture includes purging the reaction vessel and forming a blanket of inert gas above a top surface of the first reaction mixture.
4. The method of claim 1 wherein purging the first reaction mixture includes sparging the first reaction mixture.
5. The method of claim 1 wherein providing the plurality of metal nanostructures includes reducing the metal salt while purging the second reaction mixture.
6. The method of claim 1 wherein the polyol solvent is ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, or glycerol.
7. The method of claim 6 wherein the capping reagent is poly(vinylpyrrolidone).
8. The method of claim 7 wherein the ionic additive provides a chloride ion.
9. The method of claim 8 wherein the ionic additive is a tetraalkylammonium chloride.
10. The method of claim 6 wherein the metal salt is a silver salt and the metal nanowires are silver nanowires.
11. The method of claim 1 wherein the plurality of metal nanostructures includes at least 80% of metal nanowires.
12. The method of claim 1 further comprising adjusting the purging time to provide different morphologies of the metal nanostructures.
13. The method of claim 1 further comprising adjusting the purging time to provide a different yield of the metal nanowires.