Pristine and functionalized graphene materials

Patent metadata

Field	Value
Publication number	US-9991391-B2
Application number	US-50875409-A
Country	US
Kind code	B2
Filing date	Jul 24, 2009
Priority date	Jul 25, 2008
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

Disclosed are dispersed graphene sheets, ribbons, graphene molecules and the like which are pristine in the plane, i.e., free of significant defects and chemical modifications such as oxidation. The materials could be functionalized at the edges. These materials are dispersed in solutions rather than in aggregated or insoluble forms as their parent starting materials. Also disclosed is a method comprising the steps of intercalating an insoluble graphitic material. The method may comprise exfoliating graphite and re-intercalating the resultant material with an acid composition, such as oleum, and a strong organic base such as tetrabutylammonium hydroxide in a solvent solution to form a homogenous suspension, which is then agitated to form dispersed graphene materials. The materials may be solubilized with a hydrophilic polymer and can be further manipulated by transfer into different solvents, formation of films, application to optical and electronic devices, and other applications. The materials are solubilized by functional groups mostly at the edges.

First claim

What is claimed is:

1. A method of making a graphene material in the form of a plurality of sheets dispersed in solution, which sheets are a single atom thick and which sheets further contain functional groups, said method comprising the steps of:
(a) providing as a starting material a graphitic material in aggregated or insoluble form;
(b) intercalating the graphitic material from step (a) with an acid;
(c) forming a suspension of intercalated graphitic material from step (b) in a liquid medium;
(d) agitating the suspension from step (c) to form dispersed sheets of graphene material reacted with the acid to form said functional groups at edges of said dispersed sheets but not on internal aromatic rings; and
(e) recovering said graphene material as separate sheets from a solution formed in step (d), wherein said material is stable in the solution.

2. The method of claim 1 further comprising the step of exfoliating the graphitic material to form exfoliated graphite.

3. The method of claim 1 further comprising the step of exfoliating the graphitic material, said graphitic material being in the form of expandable graphite.

4. The method of claim 1 wherein said intercalating step further comprises the step of intercalating the graphitic material which has been intercalated with acid further by contacting the material with an organic base.

5. The method of claim 1 wherein the graphene material is one of dispersed sheets, ribbons or polyphenylene molecules.

6. The method of claim 1 wherein said reacting with acid to form functional groups forms functional groups selected from the group consisting of oxide, epoxide, carboxyl and hydroxyl.

7. A method of making a graphene material in the form of a plurality of sheets, ribbons or large graphene molecules dispersed in solution, which graphene material is a single atom thick, comprising the steps of:
(a) providing as a starting material graphite flakes;
(b) exfoliating the graphite flakes of step (a) to form exfoliated graphite;
(c) intercalating the exfoliated graphite from step (b) with an acid and an organic base, forming a suspension in a liquid medium with or without the organic base;
(d) agitating the suspension of step (c) to form dispersed sheets, ribbons or large graphene molecules, which are stable in solution; and
(e) recovering from the suspension of step (d), respectively, individual graphene sheets, graphene ribbons or large graphene molecules a single atom thick from the solution.

8. The method of claim 7 wherein recovering is one of a graphene sheet, a graphene nanoribbon, a polyacene molecule, and a polyphenylene molecule.

9. The method of claim 7 wherein the intercalating acid comprises oleum.

10. The method of claim 7 wherein the organic base comprises TBA.

11. The method of claim 7 wherein the agitation comprises sonication.

12. The method of claim 7 further comprising a step of reducing recovered sheets to obtain nearly pristine graphene material.

13. The method of claim 12 further comprising the step of attaching the recovered sheet to an electrical device.

14. The method of claim 7 further comprising the step of placing the recovered sheet in an organic solvent and contacting it with an aqueous phase to prepare an LB film.

15. The method of claim 14 further comprising the step of attaching a recovered sheet as recited in step (d) to a transparent substrate.

16. The method of claim 15 wherein the recovered sheet is attached to a hydrophilic polymer.

17. The method of claim 15 wherein the hydrophilic polymer is PEG.

18. The method of claim 17 wherein the PEG is linked to the recovered sheet by a lipid.

Assignees

• Dai Hongjie
• Li Xiaolin
• Sun Xiaoming
• Univ Leland Stanford Junior

Inventors

• Dai Hongjie
• Li Xiaolin
• Sun Xiaoming

Classifications

• C01B2204/02

  Single layer graphene · CPC title

• C01B32/19

  by exfoliation · CPC title

• C01B2204/04

  Specific amount of layers or specific thickness · CPC title

• H01L29/1606

  Electricity · mapped topic

• Y10T428/30

  Self-sustaining carbon mass or layer with impregnant or other layer · CPC title