SINGLE WALL CARBON NANOTUBES FOR PRINTED ELECTRONICS … · 01-03-2012  · SINGLE WALL CARBON NANOTUBES FOR PRINTED ELECTRONICS . CONTENTS • What are Carbon Nanotubes? • Properties

Philip Wallis, SouthWest NanoTechnologies

SINGLE WALL CARBON NANOTUBES FOR

PRINTED ELECTRONICS

CONTENTS

• What are Carbon Nanotubes?

• Properties of Carbon Nanotubes

• Advantages of Printed Electronics

• Overcoming Barriers to Adoption

• Current Status for TCF and TFTs

MAJOR CATEGORIES OF CARBON NANOTUBES

Multiwall Carbon nanotubes

5 < d < 200 nm

Additives for plastics and resins.

Single Wall Carbon Nanotubes

d ~ 1 nm

Thin Films for Electronics

SWCNT CHIRALITY AND DIAMETER

Armchair

n = m Metallic

Zig-Zag

Chiral

Distance from origin is

proportional to nanotube

diameter

Zig-Zag; (n,0) ; chiral angle = 0

7,4

7,2

9,0

9,1

8,3

8,0

8,2

8,1

7,3

7,1

6,3

6,0

6,2

6,1

5,3

5,0

5,2

5,1

4,3

4,0

4,2

4,1

6,4

3,0

3,2

3,1

5,4

7,0

2,1

2,0 1,0

4,4

3,3

5,5

2,2

1,1

6,5

6,6

(6,6) = 0.81 nm

7,5 (7,5) = 0.82 nm

8,4 (8,4) = 0.83 nm

9,3 (9,3) = 0.85 nm

9,2 (9,2) = 0.79 nm

10,1 (10,1) = 0.82 nm

10,0 (10,0) = 0.78 nm

SWCNT DENSITY OF STATES

Metallic tubes have non-zero electron density at the Fermi level.

Semiconducting tubes have zero density and exhibit a band gap.

Gap energies

E11

E22

OPTICAL ABSORBANCE SPECTRA

400 600 800 1000 1200 1400

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

S11

(6,5)

(6,5)

No

rma

lize

d A

bso

rba

nce

(7

80

nm

)

Wavelength (nm)

(8,7)

(8,6)

(7,6)

(8,7)

(8,6)(7,6)

Optical Absorbance Spectrum for SWeNT® SG65 and SG76

M11

S22

WHY CARBON NANOTUBES

• “Discovered” by IIjima in 1991 >20 Years Ago

• 50X Stronger than Steel

• More Conductive than Copper

• ½ Density of Al

• Metallic or Semiconducting

• Optically Transparent

POTENTIAL APPLICATIONS

High Performance Computing

Carbon Electronics

Lighting Displays Touch TFTs Sensors Solar

9 3/1/2012

Additive Process

(Printing)

Expose

Develop

Etch / strip

• Less steps

• Less waste

• Lower cost

• Short cycle time

Subtractive Process

(Photolithography)

WHY PRINT ELECTRONICS?

Expose

Develop

Etch/Strip

Deposit Film

Apply Resist Print

OVERCOMING THE BARRIERS TO ADOPTION

• Quality and Consistency

• Availability

• Cost

• Purity

• Other Carbon Forms

• Residual catalyst

• Chiral Mixture

• Handling

• Processing / Printing

2001

Founded Dr. Resasco

MANUFACTURING PLATFORM

Large Scale Production

2008

Norman, OK

Apps Dev Ctr

Canton, MA

2009

TSCA Listing

OVERCOMING THE BARRIERS TO ADOPTION

• Quality and Consistency

• Availability

• Cost

• Purity

• Other Carbon Forms

• Residual catalyst

• Chiral Mixture

• Handling

• Processing / Printing

TECHNOLOGY PLATFORM - CoMoCAT

• CO disproportionation ( 2 CO → C + CO2 )

• Supported transition metal catalysts

• Moderate pressures = 1 – 10 atm

Zone 3

Zone 2

Zone 1

Zone 4

Flo

w

P

• Fluidized bed for uniformity

690

695

700

705

710

715

720

10:48 10:55 11:02 11:09 11:16 11:24 11:31 11:38 11:45 11:52

Tem

per

atu

re (

C)

Time

Tuned Furnace Internal Temperatures

14" Above D. Plate

10" Above D. Plate

6" Above D. Plate

2" Above D. Plate

Set Point

Carbon Monoxide On

Thermocouples Within Fluidized Catalyst Bed

Thermocouples Above Fluidized Catalyst Bed

• Moderate temperatures (700 – 900°C) with precise

control (±1° C)

• Diameter Control and Distribution

• Tube Length

• Bundle Size

• Purity

• Temperature

• Pressure

• Catalyst Composition

• Gas composition

CUSTOMIZATION OF SWCNT

Variables Effects

400 600 800 1000 1200

0.5

1.0

1.5

2.0

2.5

3.0

A

bsorb

ance (

norm

aliz

edat

780 n

m)

Wavelength (nm)

T1

T2

T3

T4

Effect of Temperature

EFFECT OF TEMPERATURE

QUALITY MEASUREMENTS

OPTICAL ABSORBANCE SPECTRA

400 600 800 1000 1200 1400

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

(6,5)

(6,5)

No

rma

lize

d A

bso

rba

nce

(7

80

nm

)

Wavelength (nm)

(8,7)

(8,6)

(7,6)

(8,7)

(8,6)(7,6)

Optical Absorbance Spectrum for SWeNT® SG65 and SG76

M11

S22

QUALITY MEASUREMENTS

17

6,5

0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.50.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

Diameter Distribution from Fluorescence Analysis

Re

lative

ab

un

da

nce

Nanotube diameter (nm)

100 200 300 400 500 600 700 800

0

1

2

3

4

5

6

100 200 300 400 500 600 700 800

0.0

0.5

1.0

1.5

2.0

Weig

ht

Temp

Derivative

Temp

TGA for SG76

OVERCOMING THE BARRIERS TO ADOPTION

• Quality and Consistency

• Availability

• Cost

• Purity

• Other Carbon Forms

• Residual catalyst

• Chiral Mixture

• Handling

• Processing / Printing

0.1 1 10 100 1000

0.1

1

10

100

VC100 Screen Ink

VC200 Gravure Ink

Vis

co

sity (

Pa

.s)

Shear Rate (s-1)

Viscosity vs. Shear for V-Series Conductive Inks

Courtesy Dr. Erika Rebrosova, Western Michigan University

Recovery to 80% of original

viscosity ~7 seconds after

reduction of shear rate

0 100 200 300 400 500

0

2

4

6

8

10

12

Shear Rate returns to 2 s-1

Vis

co

sity (

Pa

.s)

Time (sec)

Viscosity Recovery after Shear is Removed for VC100

Shear Rate Increased from 2 s-1

to 1,000 s-1

0

200

400

600

800

1000

Sh

ea

r R

ate

(s

-1)

RHEOLOGY OF V-SERIES SCREEN AND GRAVURE INKS

CNT Ink

* Patents pending

20

V2V™ INK TECHNOLOGY*

No residual surfactants

or processing aids!

CNTs can be printed using Standard

Industrial Printing Equipment

SWCNT TAILORED FOR APPLICATIONS

Semiconducting Enriched for TFTs

84 86 88 90 92 94 96 98 100

SG65 Production

R & D Enhanced SG65

New R & D Material

Synthesis Goal

90

95

97

99

Metallic Enriched for TCF Electrodes etc.

0 20 40 60 80

SG76

R & D Material

Synthesis Goal

33

45

67

METALLIC ENRICHED FOR TCF

10

100

1000

10000

75 80 85 90 95 100

Su

rfac

e R

esis

tan

ce (

/)

Transmittance at 550 nm (%)

SWeNT SG76

R & D Champion 4/14/11

R & D Champion with TopCoat

269 ohm/sq @

89.7% VLT

Chasm Film Ref # 128301 Our Champion Sample

(April 2011)

CNT TFTs ref. Zhou et al, Nano Lett. 9, 4285 (2009)

Red = Metallic CNT

Gray = SC CNT

FLEXIBLE, HIGH PERFORMANCE CARBON

NANOTUBE INTEGRATED CIRCUITS

CNT TFTs can have 100X higher Mobility than a-Si and Organic semiconductors!

Ref. Sun, D.M. et. al. Nature Nanotechnology Letts 6, 156–161 (2011).

Raw material Max

ON/OFF

Max Mobility

cm2/V.s

Channel L

µm

Channel W

µm

Goal >106 > 10 cm2/V/s

20 – 40 µm

40 – 80 µm

Current

Commercial

SWCNT

105 > 10 cm2/V/s 35 50 - 150

SEMICONDUCTING ENRICHED SWCNT INKS FOR

PRINTING THIN FILM TRANSISTORS

S D CNT film

G

SiO2

Low R Si

Cross-Sectional View of BSI Test TFT

THANK YOU

QUESTIONS?