Method for synthesizing non-spherical nanostructures
The disclosure provides methods of synthesizing non-spherical nanostructures. One embodiment has steps of providing a solution of nanoparticles (NPs) wherein each of the NPs comprises a non-spherical NP that includes gold and a surfactant coating covering the non-spherical NP; mixing the NPs and a pH modifier solution making a pH-modified solution of NPs having a pH within a predefined pH range; and adding a silica precursor solution to the solution of nanoparticles at a constant rate for at least one (1) minute to provide a homogeneous silica solution of NPs. Another embodiment has steps of providing a solution of NPs wherein each of the NPs comprises a non-spherical NP that includes gold and a surfactant coating covering the non-spherical NP; and adding a silica precursor solution to the solution of nanoparticles at a constant rate for at least one (1) minute to provide a homogeneous silica solution of NPs.
1. A method for synthesizing non-spherical nanostructures comprising:
providing nanoparticles (NPs) wherein each of the NPs comprises a non-spherical NP that includes gold and a surfactant coating covering the non-spherical NP;
mixing the NPs and a pH modifier solution to provide a pH-modified solution of NPs having a pH within a predefined pH range; and
adding a silica precursor solution to the pH-modified solution of NPs at a constant rate for at least one (1) minute to provide a homogeneous silica solution of NPs.
2. The method for synthesizing non-spherical nanostructures of claim 1 wherein adding the silica precursor solution to the pH-modified solution of NPs is conducted at a constant rate for at least two (2) minutes to provide a homogeneous silica solution of NPs.
3. The method for synthesizing non-spherical nanostructures of claim 1 wherein adding the silica precursor solution to the pH-modified solution of NPs is conducted at a constant rate for at least three (3) minutes to provide a homogeneous silica solution of NPs.
4. The method for synthesizing non-spherical nanostructures of claim 1 wherein adding the silica precursor solution to the pH-modified solution of NPs is conducted at a constant rate for at least four (4) minutes to provide a homogeneous silica solution of NPs.
5. The method for synthesizing non-spherical nanostructures of claim 1 wherein adding the silica precursor solution to the pH-modified solution of NPs is conducted at a constant rate for at least five (5) minutes to provide a homogeneous silica solution of NPs.
6. The method for synthesizing non-spherical nanostructures of claim 1 further comprising depositing a silica overcoat onto the surfactant coating of each of the NPs by maintaining the homogeneous silica solution of NPs at a temperature that is between 25° C. and 40° C. for a predetermined reaction time to provide silica-coated NPs.
7. The method for synthesizing non-spherical nanostructures of claim 6 further including adding a deposition stop solution to the homogeneous silica solution of NPs to terminate deposition of silica on the silica-coated NPs before the predetermined reaction time is reached to provide silica-coated NPs having a silica coating thickness that is less than 10 nanometers (nm) thick.
8. The method for synthesizing non-spherical nanostructures of claim 6 further including adding an iron oxide particulate coating onto the silica-coated NPs.
9. The method for synthesizing non-spherical nanostructures of claim 8 wherein adding the iron oxide particulate coating does not add a linker to bind the iron particulate coating to the silica-coated NPs.
10. The method for synthesizing non-spherical nanostructures of claim 1 wherein the NPs are gold nanorods.
11. The method for synthesizing non-spherical nanostructures of claim 1 wherein the NPs are made of gold alloy having a percentage of gold composition that is at least 40 atomic %.
12. The method for synthesizing non-spherical nanostructures of claim 1 wherein the surfactant coating is cetyltrimethylammonium bromide (CTAB).
13. The method for synthesizing non-spherical nanostructures of claim 1 wherein the pH modifier solution is a base solution of sodium hydroxide (NaOH).
14. The method for synthesizing non-spherical nanostructures of claim 13 wherein the predefined pH range is from about 10 to 12.
15. The method for synthesizing non-spherical nanostructures of claim 1 wherein the silica precursor solution is tetraethoxysilane (TEOS).
16. The method for synthesizing non-spherical nanostructures of claim 6 wherein the predetermined reaction time is between 1 hour and 30 hours.
17. The method for synthesizing non-spherical nanostructures of claim 16 wherein the predetermined reaction time is between 19 hours and 21 hours.
18. The method for synthesizing non-spherical nanostructures of claim 6 wherein the homogeneous silica solution of NPs is contained without agitation for the predetermined reaction time after adding the silica precursor solution to the pH-modified solution of NPs.
19. The method for synthesizing non-spherical nanostructures of claim 6 wherein a shell thickness of a SiO 2 shell encapsulating individual ones of the silica-coated NPs is between 2 nm and 30 nm.
20. The method for synthesizing non-spherical nanostructures of claim 6 yielding at least 190 milligrams of silica-coated NPs per a process batch of the homogeneous silica solution of NPs.
21. The method for synthesizing non-spherical nanostructures of claim 6 wherein at least 50% of the silica-coated NPs are dumbbell-shaped such that bulbous opposing ends are connected by a waist, which has a waist diameter that is less than an average of maximum diameters of the bulbous opposing ends.
22. The method for synthesizing non-spherical nanostructures of claim 1 comprising:
depositing a silica overcoat onto the surfactant coating of each of the NPs by maintaining the homogeneous silica solution of NPs at a temperature that is between 25° C. and 40° C. for a predetermined reaction time to provide silica-coated NPs;
mixing a deposition stop solution and the homogeneous silica solution of NPs to terminate deposition of silica on the silica-coated NPs; and
adding an iron oxide particulate coating onto the silica-coated NPs.
23. The method for synthesizing non-spherical nanostructures of claim 22 wherein a shell thickness of a SiO 2 shell encapsulating individual ones of the silica-coated NPs is less than 10 nm thick.
24. The method for synthesizing non-spherical nanostructures of claim 22 wherein adding the iron oxide particulate coating does not add a linker to bind the iron oxide particulate coating to the silica-coated NPs.
25. The method for synthesizing non-spherical nanostructures of claim 22 wherein the NPs are gold nanorods.
26. A method for synthesizing non-spherical nanostructures comprising:
providing a solution of nanoparticles (NPs) wherein each of the NPs comprises a non-spherical NP that includes gold and a surfactant coating covering the non-spherical NP; and
adding a silica precursor solution to the solution of NPs at a constant rate for at least one (1) minute to provide a homogeneous silica solution of NPs.
27. The method for synthesizing non-spherical nanostructures of claim 26 wherein adding the silica precursor solution to the solution of NPs is conducted at a constant rate for at least two (2) minutes to provide a homogeneous silica solution of NPs.
28. The method for synthesizing non-spherical nanostructures of claim 26 wherein adding the silica precursor solution to the solution of NPs is conducted at a constant rate for at least three (3) minutes to provide a homogeneous silica solution of NPs.
29. The method for synthesizing non-spherical nanostructures of claim 26 wherein adding the silica precursor solution to the solution of NPs is conducted at a constant rate for at least four (4) minutes to provide a homogeneous silica solution of NPs.
30. The method for synthesizing non-spherical nanostructures of claim 26 wherein adding the silica precursor solution to the solution of NPs is conducted at a constant rate for at least five (5) minutes to provide a homogeneous silica solution of NPs.
31. The method for synthesizing non-spherical nanostructures of claim 26 further including depositing a silica overcoat onto the surfactant coating of each of the NPs by maintaining the homogeneous silica solution of NPs at a temperature that is between 25° C. and 40° C. for a predetermined reaction time to provide silica-coated NPs.
32. The method for synthesizing non-spherical nanostructures of claim 31 further including adding a deposition stop solution to the homogeneous silica solution of NPs to terminate deposition of silica on the silica-coated NPs before the predetermined reaction time is reached to provide silica-coated NPs having a silica coating thickness that is less than 10 nm thick.
33. The method for synthesizing non-spherical nanostructures of claim 31 further including adding an iron oxide particulate coating onto the silica-coated NPs.
34. The method for synthesizing non-spherical nanostructures of claim 33 wherein adding the iron oxide particulate coating does not add a linker to bind the iron oxide particulate coating to the silica-coated NPs.
35. The method for synthesizing non-spherical nanostructures of claim 26 wherein the non-spherical NP is a gold nanorod.