Applications of Graphitic Carbon Materials

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Frontier NanoCarbon Research groupResearch Center for Applied Sciences, Academia Sinica

Dr. Lain-Jong Li (Lance Li)Associate Research Fellow Research Center for Applied ScienceAcademia Sinica, Taiwan

Single-Walled Carbon Nanotubes for Macroelectronics

Solution processable

Printable

( Adv. Mater. 2010)(Chem. Comm. 2009)

1. Transistors based on carbon nanotube networks

2. Carbon Nanotube Networks as DNA sensors 1. Devices are fabricated by microelectronic fabrication.2. DNA addition directly affects the transfer characteristics3. Detection limit: ~ 10 nM DNA

-10 -5 0 5 100

Vg (V)

bare device immobilization hybridization intercalation

(a)Bare

Immobilized

Hybridized

Intercalated

Appl. Phys. Lett. 89, 232104 (2006)

Changing the contact metals

2.1 Study of Sensing Mechanism

Covering the contacts

SWNT channels slightly response to DNA moleculesBut electrode-SWNT Contacts seem to play more important

( J. Am. Chem. Soc. 129, 14427, 2007)

More charges can be introduced to the DNA with reporter DNA

2.2 Introducing more charges

The DNA detection limit is dramatically improved from 1 nM to 100 fM

by using reporter DNA-AuNP conjugates

( Adv. Mater. 20, 2389, 2008)

Sensitivity enhancement

Graphene-related

1. Large Size Graphene Oxides

Chem. of Mater. 21, 5674 (2009)

Ultra-large single layer graphene oxides

( up to mm size)( absorption ~ 2%)

* 1st stage: I(D) increases with richness of 6-fold aromatic rings

* 2nd stage: I(D) is inversely proportional to the graphene domain size (T-K relations)

2. Graphene Oxide Reduction by Alcohol

* Graphene domain size is dominating conduction properties

(submitted)

Graphene Oxide Reduction by Alcohol

Substrate: Ni foil, 30 μm in thickness

Step 1: H2

Step 2: H2

Step 3: CH4/H2 Step 4: Ar

900 ºC

RT1 2 3 4

Pressure: 0.1~1 Torr and 750 Torr on Cu and Ni substrates respectively.

30 min 30 min 10~20 min

3. CVD Graphene

FLGCu foil

Rub one side FLG by sandpaper

FLGCu foil

Immerse FLG/Cu foil in ~ 1.5 wt% FeCl3 solution

FeCl3 solution

Wait for several hours

Dilute FeCl3 solution and transfer to new substrate, such as PET, SiO2

Heat at 80 0C for 5-10 minutes

FLGNew Substrate

New Substr

ateFLG

Transfer to the desired substrates

4.1 Doping of Graphene from Substrates

Charge exchange may occur between graphene and SiO2

Effective doping in graphenemonolayer

Doping of Monolayered graphene dependson the surface potential of SiO2 substrates

Phys. Rev. B 79, 115402 (2009)

4.2 Doping of Graphene by Aromatic Molecular Adsorption

Small 5, 1422 (2009)

4.3 Stable Doping of CVD Graphene by AuCl3

Work Function is Tunable

Work function

Work function is tunable

ACS Nano (2010 in press)

Tetrasodium 1,3,6,8-pyrenetetrasulfonic acid (TPA)

Strong electron-withdrawing groups attached to pyrene

5. Aromatic molecules on Graphene

a full geometry optimization is performed including the optimization of the lattice constants using the DMol3 package (with all electrons considered) and the GGA (PBE) and DNP basis sets. Once the optimized structure is obtained, the force constants are calculated directly by altering atomic positions in both pristine and decorated graphene. ( ~4% different from those in pristine graphene)

*Various aromatic molecules result in different energies of G-band splitting.

Phys. Rev. Lett. 102, 135501 (2009)

Phonon Symmetry Breaking- DFT calculation

1. Gap Opening: Stripping ? AB-stacked bilayer graphene ? How to grow bilayer graphene with desired stacking

2. Effect of defects on transport?

3. Effect of graphene edge (or edge defect)?

Ongoing study

Applications of Graphitic Carbon Materials

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