Claims
- 1. A method for making an asymmetric composite particle, comprising:
a) asymmetrically confining a substrate particle so as to define a first surface portion and a second surface portion; b) selectively layering a primary metallic material over one of the first surface portion and the second surface portion so as to form a partial metal shell comprising the primary metallic material.
- 2. The method according to claim 1 wherein step (a) comprises reversibly attaching the substrate particle to a support.
- 3. The method according to claim 2 wherein the substrate particle is attached such that the first surface portion contacts the support and the second surface portion is fully exposed.
- 4. The method according to claim 2 where step (a) comprises electrophoretically attaching the substrate particle to the support.
- 5. The method according to claim 4 wherein the support comprises a base and a metallizing coating.
- 6. The method according to claim 5 wherein the metallizing coating comprises titanium dioxide.
- 7. The method according to claim 5 wherein the base comprises glass.
- 8. The method according to claim 5 wherein the base comprises plastic.
- 9. The method according to claim 3 wherein step (a) comprises evaporatively depositing the substrate particle on the support.
- 10. The method according to claim 3 wherein step (a) comprises gravitationally attaching the substrate particle to the support.
- 11. The method according to claim 3 wherein step (a) comprises centrifugally attaching the substrate particle to the support.
- 12. The method according to claim 3 wherein step (a) comprises electrostatically attaching the substrate particle to the support.
- 13. The method according to claim 1 wherein step (b) comprises attaching a plurality of colloids comprising a precursor metallic material to one of the first surface portion and the second surface portion.
- 14. The method according to claim 13 wherein the precursor metallic material and the primary metallic material are chemically identical.
- 15. The method according to claim 13 wherein the precursor metallic material and the primary metallic material are chemically distinct.
- 16. The method according to claim 13 wherein step (b) comprises reducing the primary metallic material onto the colloids.
- 17. The method according to claim 1 wherein step (b) comprises reducing the primary metallic material directly onto one of the first surface portion and the second surface portion.
- 18. The method according to claim 1 wherein the primary metallic material is selected from the group consisting of elemental metals, alloys, and synthetic metals.
- 19. The method according to claim 18 wherein the primary metallic material is selected from the group consisting of gold, silver, platinum, palladium, iron, nickel, and copper.
- 20. The method according to claim 1 further comprising:
c) chemically modifying the substrate particle so as to form an activated portion.
- 21. The method according to claim 20 wherein the activated portion comprises the whole surface of the substrate particle and where step (c) precedes step (a).
- 22. The method according to claim 20 wherein the activated portion comprises one of the first surface portion and the second surface portion and step (c) follows step (a) and precedes step (b).
- 23. The method according to claim 20 wherein step (c) comprises binding a plurality of activating agents to one of the first surface portion and the second surface portion.
- 24. The method according to claim 23 wherein step (c) further comprises binding a plurality of passivating agents to the other of the first surface portion and the second surface portion.
- 25. The method according to claim 23 wherein each activating agent comprises a functionalizing metal atom selected from the group consisting of tin and titanium.
- 26. The method according to claim 23 wherein each activating agent comprises a functionalizing nonmetallic compound selected from the group consisting of CdSe and CdS.
- 27. The method according to claim 23 wherein the substrate particle comprises silica and each activating agent comprises an aminoalkysilanetriol.
- 28. The method according to claim 27 wherein step (c) further comprises binding a plurality of passivating agents to the other of the first surface portion and the second surface portion.
- 29. The method according to claim 28 wherein substrate particle comprises silica and each passivating agent comprises an alkylsilanetriol.
- 30. The method according to claim 28 wherein the substrate particle comprises silica and each passivating agent comprises a trialkylsilanol.
- 31. The method according to claim 1 wherein the substrate particle comprises a substrate material selected from the group consisting of silicon dioxide, titanium dioxide, polymethyl methacrylate, polystyrene, gold sulfide, cadmium selenium, cadmium sulfide, gallium arsenide, and dendrimers.
- 32. A method for making an asymmetric composite particle, comprising:
a) electrophoretically attaching a core particle to a metallized support such that the core particle has an exposed portion and a remaining portion; b) selectively attaching a plurality of activating agents to either the exposed portion or the remaining portion; c) depositing a plurality of metal colloids onto the activating agents; and d) reducing additional metal onto the metal colloids so as to form a partial metal shell.
- 33. The method according to claim 32 wherein step (b) comprises:
b1) attaching a plurality of activating agents to the exposed portion.
- 34. The method according to claim 32 wherein step (b) comprises:
b1) attaching a plurality of passivating agents to the exposed portion of the particle; b2) detaching the particle from the metallized support; and b3) attaching a plurality of activating agents to the remaining portion of the particle.
- 35. A method for making a nonuniform composite particle, comprising:
a) immobilizing a substrate particle against a surface defining a contact region and a corresponding exposed region; b) chemically modifying the exposed region; and c) selectively forming a partial metal layer over either the contact region or the exposed region as determined by the nature of the modification in step (b).
- 36. The method according to claim 35 wherein step (b) comprises activating the exposed region for receipt of the metal.
- 37. The method according to claim 35 wherein step (b) comprises passivating the exposed region and step (c) further comprises activating the contact region for receipt of the metal.
- 38. An asymmetric composite particle comprising:
a substrate particle; and a partial metal shell layered on said substrate particle within a solid angle less that 360°.
- 39. The composite particle according to claim 38 wherein said solid angle is at least 180°.
- 40. The composite particle according to claim 38 wherein said solid angle is less than 180°.
- 41. The composite particle according to claim 38 wherein the particle has a plasmon resonance associated with said metallic shell.
- 42. The composite particle according to claim 38 wherein the particle is magnetic.
- 43. The composite particle according to claim 38 wherein said particle is made by a method comprising:
a) asymmetrically confining said substrate particle so as to define a first surface portion and a second surface portion; b) selectively layering a primary metallic material over one of the first surface portion and the second surface portion so as to form said partial metal shell.
- 44. The composite particle according to claim 43 wherein said composite particle comprises a nanocup.
- 45. The composite particle according to claim 43 wherein said composite particle comprises a nanocap.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application Serial No. 60/245,532, filed Nov. 3, 2000, entitled “Growth Technique for Partial Gold Nanoshells”, hereby incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Funding from the Office of Naval Research Grant Number R12670 supported this work.
Provisional Applications (1)
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Number |
Date |
Country |
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60245532 |
Nov 2000 |
US |