Method for Optical Visualization of Graphene Domains

Hee Tae Jung

Patent

Atlas literature

Patent

US 8,610,884

Method for Optical Visualization of Graphene Domains

Hee Tae Jung

Drawings

Patent drawings and their descriptions. Click a drawing to enlarge it.

FIG. 1

FIG. 1, graphene 10 to be measured is transferred onto a substrate 5 to form a graphene layer, and a layer of liquid crystals 15 is formed on the formed layer …

FIG. 2

FIG. 2b) may also be used which comprises injecting a liquid crystal into the fabricated sandwich cell by the capillary phenomenon between the graphene layer …

FIG. 3

FIG. 3 shows a 200x magniﬁcation OM image (a), a 10,000x magniﬁcation SEM image (b) and a Raman spectrum graph for a graphene transferred onto an SiO₂/Si …

FIG. 4

FIG. 4, (a): an image of a liquid crystal layer formed on graphene; (a'): an image of graphene having no liquid crystal layer formed thereon; (b) and (c): …

FIG. 5

FIG. 5 shows polarizing microscope images of graphene domains observed using liquid crystal materials of ZOC-5162XX- 2 (a), ZOC-5162XX-5 (b) and C H-100 (c).

FIG. 6

FIG. 6 shows polarizing microscope images of liquid crystal layers formed on a graphene layer using a drop-coating method (a), a drop-coating/nitrogen gas …

FIG. 7

FIG. 7 is a polarizing microscope image of a liquid crystal layer formed on a graphene layer using a method of injecting a liquid crystal into a sandwich cell …

FIG. 8

FIG. 8 shows polarizing microscope images of graphene domains observed using a glass substrate (a) and a PET substrate (b). <Description of reference numerals …

Claims

Claims define the patent's legal scope. Independent claims stand alone; dependent claims (nested) narrow them. Click a claim to expand its dependents.

1 independent · 9 dependent

1
Independentgrapheneliquid crystal
A method for optical visualization of graphene domains, the method comprising the steps of: (a) forming a graphene layer on a substrate to be measured; (b) forming a liquid crystal layer on the formed graphene layer; and (c) measuring the optical properties of the formed liquid crystal layer, thereby visualizing the domains and domain boundaries of the graphene.
1. 2
  Dependent← claim 1substrate
  The method of claim 1, wherein the substrate is selected from the group consisting of glass, polymer, semiconductor, and combination of thereof.
2. 3
  Dependent← claim 1nematic liquid crystal
  The method of claim 1, wherein the liquid crystal of the liquid crystal layer is a nematic liquid crystal.
3. 5
  Dependent← claim 1graphene
  The method of claim 1, wherein the step (a) further comprise heat-treating the layer of the graphene to be 22 measured to remove impurities after forming the layer of the graphene to be measured on the substrate.
4. 7
  Dependent← claim 1liquid crystal
  The method of claim 1, the thickness of the liquid crystal layer in the step (b) is in the range of 300 nm to 100 IM.
5. 8
  Dependent← claim 1liquid crystal
  The method of claim 1, wherein the optical properties of the liquid crystal layer in the step (c) is measured using polarized light.
6. 9
  Dependent← claim 1liquid crystal
  The method of claim 1, the method of forming selected from the group consisting of a drop-coating temperature vapor deposition method, a method a doctor blade method, a paint brushing method, method.
7. 10
  Dependent← claim 1grapheneliquid crystal
  The method of claim 1, the liquid crystal layer liquid crystal molecules on a surface of grephene. the layer of the liquid crystals in the step (b) is method, a spin-coating method, a low-of injecting a liquid crystal into a sandwich cell, a spray-coating method and a dip coating in the step (b) is formed epitaxially rearranging

Worked examples

Embodiments described in the patent, grouped by the materials and process steps they use.

Example 1-1

example section example

5 materials2 process steps

Graphene synthesized by CVD on copper foil following the Li et al. method. Copper foil heated to 1000°C under H₂ (10 sccm, 90 mtorr), annealed 2 hours, then CH₄ (30 sccm) and H₂ (10 sccm) passed for 30 min. Rapid cooling to room temperature. PMMA spin-coated as support layer, copper foil removed with FeCl₃ etchant, graphene/PMMA film transferred to glass or SiO₂/Si substrate, PMMA removed with acetone, graphene heat-treated at 400°C for 30 min.

Example 1-2

example section example

2 materials1 process step

4-pentyl-4'-cyanobiphenyl (5CB) spin-coated on graphene from Example 1-1. Also, 5CB injected between graphene and cover substrate via capillary phenomenon. Liquid crystal layer thicknesses of 2 µm, 5 µm, and 10 µm formed.

Example 1-3

example section example

2 materials

Optical properties of 5 µm-thick 5CB layer spin-coated on graphene on SiO₂/Si substrate evaluated using polarizing microscope (LV 100-POL, Nikon) with hot stage. Graphene domain shapes and boundaries visualized; domains >200 µm distinguished. Mosaic-like structures with different colors and birefringence observed upon rotation.

Test Example 1

example section example

4 materials1 process step

Various commercially available liquid crystals (ZOC-5162XX-2, ZOC-5162XX-5, CH-100) spin-coated to 5 µm thickness on graphene layer. Optical properties measured with polarizing microscope equipped with hot stage. Graphene domains visually observable with all tested liquid crystals.

Test Example 2

example section example

2 materials1 process step

Various liquid crystal layer formation methods tested: drop-coating, drop-coating with N₂ blowing, injection into sandwich cell (gaps of 2 µm, 5 µm, 10 µm), and spin-coating at 2000 rpm or 3000 rpm. Graphene domains and boundaries observed in all cases.

Materials

Materials described outside the worked examples.

liquid crystal

Visualization Layer

substrate

Substrate

Characterization

Measurements and analyses referenced in the patent, with their drawing references.

thickness

Thickness

FIG. 2b) may also be used which comprises injecting a liquid crystal into the fabricated sandwich cell by the capillary phenomenon between the graphene layer …

Figure references

FIG. 2

graphene

Reported properties

Performance values and ranges asserted in the specification or claims.

Property	Value	Material
Duration	1–60 minute	—

Why these are connected

Related documents with shared materials, methods, properties, or citations.

Method for Optical Visualization of Graphene Domains | Matter42 Literature