Prof. Dr. Esko I. Kauppinen

NanoMaterials Group (NMG)

Department of Applied Physics

Helsinki University of Technology

(TKK)

Espoo, Finland

FINNISH-JAPANESE WORKSHOP on FUNCTONAL MATERIALS

Säätytalo 26.5.2009, Helsinki, Finland

Carbon NanoBuds (CNB) – Synthesis,

Structure and Thin Film Device

Applications

NanoMaterials

(NanoMat)

GroupDepartment of Applied Physics

and Center for New Materials

Helsinki University of Technology (TKK)

1). Synthesis of carbon nanotubes and nanobuds

2). Synthesis of multicomponent nano- and microparticles for drug

and gene delivery

3). Structural characterization of nanotubes and nanoparticles by

electron microscopy

4). Generation of novel 2-D and 3-d nanotube, nanobud and

polymer/protein structures for transparent electronics and

energy applications

5). MD and DFT

Nanobud

Carbon nanotube http://www.fyslab.hut.fi/nanomat

NanoMaterials Group, Helsinki University of Technology

Dept. of Applied Physics & Center for New Materials

http://www.fyslab.hut.fi/nanomat/

Acknowledgement for Funding

* Academy of Finland

* EU FP6 & FP7

* TEKES FinNano Program

Dr. Albert G. Nasibulin Dr. Hua Jiang Dr. Janne Raula

Dr. David P. Brown

CEO, Canatu Oy

Mrs. Jing Tian

Ms. Marina Zavodchikova

TKK 100th Anniv. Fund

Also: Antti Kaskela, Toma Susi

NEDO

• Personnel

– 1 prof. and 5 post-docs

– 10 graduate and 7 undergraduate students

• Doctoral level expertise

– Carbon nanotubes, nanobuds, metal oxide nanowires

(Albert G. Nasibulin - phys.chem)

– Drug, polymer, peptide and protein chemistry, nanoparticle synthesis and CNT & CNB surface functionalisation (Janne Raula – polymer mat.)

– Transmission electron microscopy of nanomaterials (Hua Jiang - physics)

– Electrochemistry with carbon nanomaterials – FC&SC (Virginia Ruiz – phys. chem)

– Molecular dynamics and DFT (Markus Kaukonen - physics)

• External Funding

– More than 1 000 k€/year

– EU: BNC Tubes – Strep 2007-2010 3 500 k€; NanoTox – SSA

– Academy of Finland (e.g. NanoDuraMEA), TEKES, companies

– CNB-E 2008-2012 MIDE/TKK 100 Years Anniversary Research Program

Acknowledgements for Collaboration –Prof. Yutka Phno, Nagoya U.

Prof. Florian Banhart, U. Strasbourg

Brad Aitchison, Jussi Sarkkinen, Canatu Oy

Dr. Peter V. Pikhitsa and Prof. Mansoo Choi

National CRI Center for Nano Particle Control, Institute of Advanced

Machinery and Design, Seoul National University, Korea

Dr. Abdou Hassanien and Dr. Günther Lientschnig

AIST, Tsukuba, Japan

Dr. Giulio Lolli and Prof. Daniel E. Resasco

Chemical Biological and Materials Engineering, University of Oklahoma,

USA

Dr. Arkady V. Krasheninnikov and Prof. Risto Nieminen

Laboratory of Physics, Helsinki University of Technology, Finland

Prof. David Tománek

Physics and Astronomy Department, Michigan State University, USA

Known forms of Carbon NanomaterialsCarbon Nanotube (SWCNT):

Roll of carbon sheet one atomic layer thick

= Graphene NanoRibbons (GNR)

1 000 000 times thinner than paper

(10,10) armchair tube

METALLIC

(10,5) helical (chiral) tube

SEMICONDUCTING

Rolling in different directions makes different kinds of tubes

By Prof. Shigeo Maruyama, Tokyo Universssity, Japan

CNTN -Materials for Flexible Electronics

Mo

bility

Year

CNTN FET

According to Prof. G. Gruner, UCLA,USA

Properties of Carbon Nanotubes

• Better conductor than copper

• Better transistor material than silicon

• Conduct heat twice as efficiently as diamond

• Field emit 500 times as efficiently as molybdenum

• Thermally stable up to 1500 oC while polymers degrade below 150 oC

• Half as dense as aluminum

• 25 times stronger than steel

• Very inert and difficult to integrate into composite materials and to incorporate into electronics manufacturing

Three allotropic modifications of carbon: diamond, graphite,

and fullerene structures (fullerenes and CNTs).

??

PEAPOD

Graphene

CNB- Carbon NanoBudTM

New Carbon NanoMaterial

NanobudTM combines Carbon Nanotubes and Fullerenes in

Single Structure with Covalent Bonding

Nasibulin & Kauppinen et al. Nature Nanotechnology, 2(3) 156 March 2007

Content of the Talk

• CNB’s (Carbon NanoBuds = C60+SWCNT) –floating CVD synthesis, structure and properties

• Novel Dry Thin Film Device Manufacturing Method

• Field Electron Emission of CNB vs SWCNT films

• Transparent flexible electrode and TFT

• Preliminary results on nanocarbon PEMFC applications

Mechanism of

CNB Formation

from CO with Fe

Cluster Catalyst

CO

CO

. .

.

.

. .

. .

.

. CO

. CO

CO

Particle saturation by C- REACTIONS: 2CO=C+CO2 AND H2+CO=C+H2O- C RELEASE ON SURFACE- C DISSOLUTION

CO.

. CO

Formation of graphene layer- HEXAGON AND PENTAGON FORMATION

CO.

CNT nucleation- HEPTAGON FORMATION

Steady-state growth of CNT- C INCORPORATION INTO GRAPHENE LAYER - REACTIONS OF CARBON RELEASE AND ETCHING:

FE particle formation - VAPOUR NUCLEATION - CONDENSATION- CLUSTER COAGULATION

H2/N2

. . . .

. . . .

. . . .

. . .

. . . .

. . .

. . . .

. . . . . . . . . . .

Fe(g)

H2

End of CNT growth - CARBON DISPROPRTIONATION IS PROHIBITED (t > 900 °C)

HE

AT

ING

ZO

NE

TE

MP

ER

AT

UR

E

HIG

H

ZO

NE

CO.

CO.

CO.

400 °C

900 °C

CO2 reaction with amorphous carbon:

C+CO2 = 2CO

CO. CO.

CO2

C

- REACTIONS ON REACTOR WALLS: 2CO=C+CO2 H2+CO=C+H2O

- CO2 AND H2O

RELEASE

.

.

CO2

H2O

. . 2CO<=>C+CO2 AND H2+CO<=>C+H2O

.

. H2

H2

.

. H2

H2H2

H2O

CO2

Bundling α NCNT2 α NCat

2

COCO2H O2

H O2

CO

CO

HWG method Ferrocene-based method

Synthesis of NanoBuds (CNB) –

add CO2 or H2O

Lab scale (7) and pilot scale (1) reactors for CNT&CNB

synthesis and in-situ thin film-based device manufacturing

Flow reactors (3) for nanoparticle synthesis

Lab scale reactors Pilot scale reactor

CNB formation mechanisms –

Fullerenes nucleate from the graphene at

the cluster surface

Fullerens attached to graphene at Fe cluster surface

TEM of CNB

Fe Catalyst via PVD

Carbon from ethanol

10 nm10 nm

10 nm10 nm

Conclusion: nothing happened with fullerenes, they were

not dissolved – stronger than Van der Waals bonding

TEM observation of the sample after washing in toluene and decaline

10 nm10 nm 5 nm5 nm

toluene decaline

Controll of Fullerene density on

CNB’s via H2O

10 nm10 nm 10 nm10 nm 10 nm10 nm 10 nm10 nm

10 nm10 nm 10 nm10 nm 10 nm10 nm 10 nm10 nm

increase H2O concentration

increase H2O concentration

50

40

30

20

10

0

200 400 600 800 1000 1200

particles

CNTs and fullerenesposi

tion in

react

or, c

m

Temperature, °C

CO

CO

10

0 c

m3 /

min

30

0 c

m3 /

min

water coolingcirculation

ferrocenecartridge

dilutor N2 12 L/min

Filter

water

FT-IR/ ESP

CO

2 o

r N

2

0 -

20

cm

3/m

in

10 nm10 nm

0.2 µm0.2 µm

0.2 µm0.2 µm

A.G.Nasibulin & E.I.Kauppinen et al, Chem.Phys.Lett, 446(2007), 109-114.

885 ºC

945 ºC

2 nm

Synthesis of Carbon NanoBuds

NanoBudsTM on FEI Titan TEM at 80kV with image Cs-corrector - Movie

Image :B.Freitag FEI; samples : Prof. Kauppinen Helsinki, Finnland

Individual

Fullerene

Cluster

of

Fullerenes

Fullerenes

are NOT

removed

by electron

beam

Number size distribution of

NanoBudTM fullerenes measured from

HR-TEM images

0.00

0.05

0.10

0.15

0.20

0.25

0.300.

410.

430.

450.

470.

500.

520.

550.

580.

600.

630.

670.

700.

730.

770.

810.

850.

890.

930.

981.

03

0.390.410.430.450.470.500.520.550.580.600.630.670.700.730.770.810.850.890.930.98Diameter of fullerenes (nm)

Fre

qu

en

cy

C60

C42

C20

C34

C86

Comparison of ultraviolet-visible absorption

spectra of CNB’s, C70 and C60 standards

200 300 400 500 6000.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

700 800 900 1000 1100

in hexane: in toluene:

C60

C60

C70

C70

FFCNTs FFCNTs

Absorb

ance (

au)

Wavelength (nm)

SWCNT absortion bands:Fullerene absortion bands:

Raman spectra of NanoBuds carried out by using red (633 nm), green (514 nm), and

blue (488 nm) lasers.

200 400 600 800 1000 1200 1400 1600 1800

0.0

5.0x103

1.0x104

1.5x104

2.0x104

Inte

nsity (

au

)

Raman shift (cm-1)

Bonding scenarios of fullerenes on

nanotubes based on DFT calculations

Calculations By Arkady

Krasheninnikov, TKK

Nasibulin & Kauppinen et al. Nature Nanotechnology, 2(3) 156 March 2007

LT UHV STM:

Chemisorbed

Fullerene on

Nanotube

Lattice

Peaks in the LDOS

are due to nanobuds,

cannot be assigned to

physisorbed

fullerenesNanometer Range

Controll for DOS !

Ambient STM

Calculations by Arkady

Krasheninnikov, TKK

Experiment

This suggests that

chemically attached

fullerene via 2+2

cycloaddition is

energetically favorable

.

. CNT

Aerosol

Synthesis

Process

Control of Material Direct Manufacture

Deposition

Process

Dry, direct deposition method for Integrated Component Manufacturing

Products

Traditional CNT film processes are complex

Increases cost and may deteriorate performance

Dirty raw bundled CNTs as powder

Collect CNT

powder

“Clean” bundled damaged CNTs in liquid

Acid purify &

sonicateProduce CNT

powder

Dirty raw bundled CNTs aerosol or on substrate

Surfactant coated unbundled damaged CNTs in liquid

Surfactant treat &

centrifuge

“Clean” unbundled functionalized damaged

CNTs on substrate

Chemically purify,

functionalize & dry

Surfactant coated unbundled damaged CNTs

on substrate

Filter, spray or

spin coat and dry

Experimental

set up:

Ferrocene Reactor

CO

CO

100 c

m3 /

min

300 c

m3 /

min

furn

ace

ESP

water coolingcirculation

ferrocenecartridge

dilutor N2 12 L/min

Filter

FT-IR

Moisala, Nasibulin, Brown, Jiang, Khriachtchev,

Kauppinen, (2006) Chem. Eng. Sci. 61, 4393.

Ferrocene: Fe(C5H5)2

Catalyst precursor:

CO + CO = C(s) + CO2

Fe

Carbon source:

6243585

1005002930

Large ReactorSmall Reactor

Flow rate 0.3 liters/min

Reactor Tube Diameter Inner 2.5 cm

Lentgh 50 cmFlow rate 10-100 x Small Reactor

SEM images demonstrating

CNT film densification by ethanol(b)

as deposited CNT film after treatment with ethanol

Nasibulin, Ollikainen, Kauppinen et al. Chem. Engin. J. (2008) 136, 409.

Cold field emission properties of as-deposited CNB

films on Au substrate: comparison with SWCNTs

0.0 0.5 1.0 1.5 2.0 2.50

100

200

300

400

500

600

700

0.0 0.5 1.0 1.5 2.0 2.50

1

2

3

4

SWNTs

NanoBuds (H2O: 65 ppm)

NanoBuds (H2O: 100 ppm)

NanoBuds (H2O: 150 ppm)

C

urr

en

t d

en

sity (

A/c

m2)

Field strength (V/ m)

ACCVD; Tanamura et al., APL (2006)-

SWCNT grown on glass

- Large reactor

Large reactor tubes - HRTEM at 385C

Maria A1 Ethanol treatment heating 485C

Large reactor tubes - HRTEM at 485C

Large reactor tubes - HRTEM at 485C

Dry deposition of CNT networks for TF-FETs

Te

flo

n

Me

tal

Schematic of an ESP

substrate

size is up

to 12х12mm

substrate

holder

12х12mm

Meta

l

T.J. Krinke et al., Aerosol Science 33, 2002

Condensation particle counter (CPC)

CNT networks with various densities

0 1 2 3 4 5

0

2

4

6

8

10

12

0 1 2 3 4 50

2

4

6

8

10

12

0 1 2 3 4 50

2

4

6

8

10

12

Estim

ate

d a

ve

rag

e d

en

sity [C

NT

bu

nd

les/u

m2]

Deposition time [min]

SiO2

SiO2

Cr

SiO2

ρcalc.~12 CNT bundles/µm2

ρcalc.~5 CNT bundles/µm2 ρcalc.~2,5 CNT bundles/µm2 ρcalc.~1 CNT bundles/µm2

CrSiO2

ρcalc.~8 CNT bundles/µm2

SiO2Cr

AZ

.calc

t C Q

S

ρ-estimated average density (CNTs/µm2);

t-time of collection; C-particle concentration

by CPC (CNTs/cm3); Q- particle flow (cm3/min);

S-substrate area (µm2).

SWCNTN FETs on Si and Kapton substrates –

on/off`= 105, mobility = 5 cm2/(V*s) on Si (L=W=50 µm)

on/off`= 105, mobility = 1cm2/(V*s) on polymer (L=150 µm, W=200 µm)

THANKS TO YOU FOR YOUR

ATTENTION !