processing of conductive polymers & nanocomposites · • our publications on the inkjet...

Processing of conductive polymers & nanocomposites and fabrication of devices with

conductive, transparent, optoelectronic, energy harvesting, energy storage and

electromechanical functionalities

Dr Tina Lekakou

Department of Mechanical Engineering Sciences University of Surrey, Guildford, Surrey, UK

email: [email protected]

Researchers , Co-investigators and Collaborators [2007-2015]

Dr Beatrice Lindsey Mr Guillaume Rebord Dr Peter Wilson Dr Omar Moudam Mr Tom Andrews Dr Foivos Markoulidis Professor John Watts Professor Graham Reed

QinetiQ Smart Network BAE Systems GKN Transparency Systems ARJOWIGGINS Teknoflex Ltd Bayer Technology Services Xennia Technology Ltd.

Inkjet printing of PEDOT:PSS: Inkjet printing system, process modelling & optimisation

[P.Wilson, C.Lekakou, J.F.Watts, ASME J Micron-Nano-Manufacturing, 2(1), 2014]

Snapshots at 500 ms after the ink exits the nozzle for the 30V single waveform

Spin coating and inkjet printing of PEDOT:PSS – Material developments

[P.Wilson, C.Lekakou, J.F.Watts, Organic Electronics, 13(3), 2011, 409–418]

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

0 1 2 3 4 5

Sh

ee

t Re

sis

tan

ce W

/□

DMSO %wt

InkJet (0%wt Surfynol)

InkJet (1%wt Surfynol)

Spin Coated (0%wt Surfynol)

Spin Coated (1%wt Surfynol)

7

1% DMSO Spin coated

5% DMSO

Inkjet printed

Spin coating and inkjet printing of PEDOT:PSS: in-plane conductivity

• As DMSO is increased, the charge transport model evolves from Mott 3d-VRH to

pseudo 1d-VRH. • The hopping length is

reduced by 70% for DMSO from 0% to 3%, and thereafter increased adding DMSO to 5%.

This contrasts with a steady increase of the hopping length for similar spin coated films.

[P.Wilson, C.Lekakou, J.F.Watts, Organic Electronics, 14(12), 2013, 3277-3285]

Spin coating and inkjet printing of PEDOT:PSS: transverse conductivity

• 1D-VRH transverse charge transport for inkjet printed PEDOT:PSS compared to the nn-H model for spin coated films.

• These findings justify measurements of the transverse conductivity of inkjet printed PEDOT:PSS films in this study being 600 times higher than that of spin coated films.

Conduction γ T0 [K] σ0 [S cm-1] σrt [S cm-1] In-Plane

0.25 516793 0.1 0.014 Transverse

0.5 1039 0.11 0.018

Inkjet printed PEDOT:PSS films (0% DMSO)

0.001

0.01

0.27 0.28 0.29 0.3 0.31 0.32

In-p

lan

e c

on

du

cti

vit

y (

S/c

m)

T (K) -0.25

(a) In-plane conductivity

0.001

0.01

0.1

0.05 0.06 0.07 0.08 0.09 0.1

Tra

nsvers

e c

on

du

cti

vit

y (

S/c

m)

T (K) -0.5

(b) Transverse conductivity

[P.Wilson, C.Lekakou, J.F.Watts, Organic Electronics, 15(9), 2014, 2043-2051]

T

TVRHM

00 exp

d

1

1

Spin coated and inkjet printed PV cells

[Prepatterned ITO glass from Ossila]

Spin coated and inkjet printed PV cells

Spin coated – 3 cells in parallel Inkjet printed– 3 cells in parallel

Decreasing RSH and increasing Rs decreased the fill factor (FF) & PMAX

Ideal PV: Rs=0 (slope at Voc), Rsh=∞ (slope at Isc)

Fabrication of MWCNT coatings- Mixing effects on the dispersion of MWCNTs

0.01% CNTs; sonication;

magnetic stirring

0.1% CNTs; sonication;

medium shear mechanical

stirring

1% CNTs; sonication;

high shear mechanical stirring

25,000 rpm

Fabrication of MWCNT coatings- Effect of solvents and polymer wrapping

1.00E-11

1.00E-10

1.00E-09

1.00E-08

1.00E-07

CNT-re

PU-M

etha

nol

acid-C

NT-r

ePU-m

etha

nol

CNT-re

PU-T

HF

acid-C

NT-r

ePU-T

HF

acid-C

NT-r

ePU-N

MP

acid-C

NT-r

ePU-D

MF

acid-C

NT-r

ePU-N

VP

PVP

-CNT-r

ePU-M

etha

nol

Sulfo

nate

PVP

-CNT-r

ePU-M

etha

nol

Co

nd

ucti

vit

y (

S/c

m)

0.05%CNT

0.1%CNT

DMSO low temperature resistance (2 layers)

-5000

0

5000

10000

15000

20000

25000

30000

35000

40000

-20000 0 20000 40000 60000 80000 100000 120000 140000

Z'

Z"

Ink jet printed (two passes) of 0.14% MWNT suspension in DMSO on Melinex substrate.

99% light transmittance

Electrospinning of MWNT-PVA

76% Light transmittance Conductivity = 300x higher in

fibre orientation

Manufacturing of MWCNT –Epoxy nanocomposites

[O.Moudam, T.Andrews, C.Lekakou, J.F.Warrs, G.Reed, Journal of Nanomaterials, 2013]

Manufacturing of MWCNT –Epoxy nanocomposite actuators

MWCNT-Epon nanocomposite actuator of 50x25x0.150 mm in 2M NaCI solution. Actuation by applying 4 V dc:

A = 0min. B = 1min. C = 2min. D = 3 min. E = 3 min 15 sec. F = 3 min 22 sec.

MWCNT –Polyurethane nanocomposites

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

1.00E+08

1.00E+09

1.00E+10

1.00E+11

0 2 4 6 8

CNTs (%)

Bu

lk r

es

isti

vit

y

(oh

m c

m)

1.00E-11

1.00E-10

1.00E-09

1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

Bu

lk c

on

du

cti

vit

y

(S/c

m)

r (ohm cm)

s (S/cm)

MWCNT nanocomposites with in situ reacted PU matrix

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0 2 4 6 8

CNTs (%)

Bu

lk r

es

isti

vit

y

(oh

m c

m)

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

Bu

lk c

on

du

cti

vit

y

(S/c

m)

r (ohm cm)

s (S/cm)

MWCNT nanocomposites with thermoplastic PU matrix

[G.Rebord, N.Hunsrisuk, B.Lindsay, C.Lekakou, J.F.Warrs, G.Reed, ESTC 2008]

MWCNT –Polyurethane nanocomposites

MWCNT nanocomposites with in situ reacted PU matrix

MWCNT nanocomposites with thermoplastic PU matrix

0.00E+00

2.00E+01

4.00E+01

6.00E+01

8.00E+01

1.00E+02

0 2 4 6 8

CNTs (%)

Re

lati

ve

pe

rmit

tiv

ity

0

20000

40000

60000

80000

100000

0 2 4 6 8

CNTs (%)

Rela

tive p

erm

itti

vit

y


MWCNT –Polyurethane nanocomposite actuator


Electric Field: E = V/H

Actuating stress:

T = e r eo E2

MWCNT –Polyurethane nanocomposite actuator


7% MWNT –PU nanocomposite of 19 x15x1.8 mm exhibited a maximum deflection of 0.03 mm under 10 V.

MWCNT –Polyurethane nanocomposite actuator: FEA simulations


•Bending of a cantilever plate of 1.65x1.65x0.050 mm and a Young’s modulus of 4 MPa.

•For a maximum deflection of 0.2 mm, suitable for optical applications in electronic displays, the

following actuating voltage DV is required, depending on the relative permittivity, er of the

nanocomposite material:

er = 2000, DV = 1.2 V

er = 5000 (as in 1% CNTs in PU), DV = 0.75 V

er = 79000 (as in 7% CNTs in PU), DV = 0.2 V

MWCNT –based Supercapacitors

Separator: GF/F glass microfibre filter Electrolyte: PEO-LiClO4-EC-THF organic gel. Cell of 1 cm2. Electrode mass of 0.2 mg for each electrode

CV at 0.2 V/s Charge-discharge test at 20 micro-A

[O.Moudam, F.Markoulidis, T.Andrews, C.Lekakou, J.F.Warrs, G.Reed, Journal of Nanotechnology, 2011]

Transversely oriented MWCNTs by electrophoresis

MWCNTs drop-casted

[F.Markoulidis, C.Lei, C.Lekakou, Applied Physics A,]

MWCNTs electrophoretically deposited on Al foil

Transversely oriented MWCNTs by electrophoresis

[F.Markoulidis, C.Lei, C.Lekakou, Applied Physics A, 111, 2013, 227-236]

MWCNTs electrophoretically deposited on ITO-coated PET

MWCNTs electrophoretically deposited on PET

Transversely oriented MWCNT-based supercapacitors

[F.Markoulidis, C.Lei, C.Lekakou, Applied Physics A, 111, 2013, 227-236]

Separator: Lens tissue Electrolyte: 1 M TEABF4 in PC

Impact and Future developments

• Follow on research on High Energy density/High Power density Supercapacitors funded by (i) EPSRC/MOD and (ii) EC: FP7 project AUTOSUPERCAP

• Findings on electrically conductive MWCNT nanocomposites widely

disseminated within UK > related developments by BAE Systems and Thomas Swan

• We have a current research proposal on specific application of

actuating MWCNT and graphene nanocomposites

• Our publications on the inkjet printing of PEDOT:PSS have been well cited worldwide. We would be most interested in collaborating in further research projects with other academic and industrial partners in this area and also in the area of printing PV cells or other devices (e.g. printing of batteries, supercapacitors, etc).

Acknowledgements

a BIG THANK YOU to

IeMRC

for the research funding we received and the Dissemination and Liaison activities organised by the IeMRC

processing of conductive polymers & nanocomposites · • our publications on the inkjet...

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