1. No category

Future of Paper as Substrate for
Printed Electronics and Sensors
Martti Toivakka
Laboratory of Paper Coating and Converting
Center for Functional Materials
Åbo Akademi University
Fulton Innovation
Martti Toivakka/ ISAB 2012
Paper Electronics =
Printed Electronics on Paper
Martti Toivakka/ ISAB 2012
Market Prediction for Printed Electronics
•IDTechEx, April 19, 2012:
› “…printed electronics is expected to reach $45 billion in
2022…” (2011 market size = $2.2 Billion)
•electronics.ca, April 11, 2012:
› “Global Market for Printed
Electronics to Reach $12.6
Billion in 2016”
•NanoMarkets report, 2010:
› Thin film/printable batteries
market to reach $5.6 Billion
by 2015
IDTechEx, 2007
› Printed sensors generate $5.4 billion in revenues by 2016
Martti Toivakka/ ISAB 2012
Market Prediction for Printed Electronics
…but recently also:
Martti Toivakka/ ISAB 2012
Printing Electronics on Paper
•Paper & printing not developed for electronics
Recyclable paper for printed electronics:
•Optical
vs. electrical
print coatings
Mineral
pigment
and latex barrier
Calendered to RMS roughness: <100 nm
[Org. Electron. 10 (2009) 1020]
Martti Toivakka/ ISAB 2012
Printability of Functional Inks on Paper
•Printability determined by compatibility of ink – printing
method – substrate
•Inks (solution processable functional materials):
› Conductive particulate inks, e.g. nanoparticle/micron-size silver, carbon,
gold, copper…
› Conductive polymer inks, e.g. PEDOT:PSS, PANI…
› Semiconducting inks, e.g. P3HT, PQT…
› Insulators, e.g. PVP, PMMA…
•Printing / coating method:
› Inkjet, flexography, rotogravure, screen printing…
› Reverse gravure, spray, slot, curtain…
•Substrate:
Paper or board, i.e. natural fiber-based substrate
Martti Toivakka/ ISAB 2012
Making Paper Compatible with Printed
Electronics
•We need to measure and control surface properties of the
substrate: roughness, (surface) porosity, wettability, chemical
activity/inertness, barrier properties, mechanical properties,
dimensional stability, humidity
•Surface treatment methods to improve printability:
•Existing:
– surface sizing
– pigment coating
– dispersion coating
– extrusion coating
– corona treatment
•Novel methods:
– plasma activation/coating
– nanoparticle deposition
– sol-gel coating
– atomic layer deposition
– chemical vapor deposition
Martti Toivakka/ ISAB 2012
The Ink Behavior on a Substrate is Controlled
by (in Addition to Ink and Printer properties):
•Barrier properties (permeability)
•Surface roughness
Surface Rougness, RMS [nm]
300
Cut-off Length
100 µm
250
50 µm
25 µm
200
12.5 µm
150
100
50
0
0.5 g/m2
1 g/m2
3 g/m2
5 g/m2
Coat Weight Top Layer
•Surface energy
•(Surface) porosity
and pore volume
Martti Toivakka/ ISAB 2012
Example Substrate Concept
For Paper Electronics
Topcoating (Kaolin) 0.5 - 5 µm
Barrier layer (Latex) 1 - 25 µm
Smoothing layer (Kaolin)
Precoating (GCC)
Basepaper
Bollström, R., A. Määttänen, D. Tobjörk, P. Ihalainen, N. Kaihovirta, R. Österbacka, J. Peltonen, and M. Toivakka. "A multilayer
coated fiber-based substrate suitable for printed functionality." Organic Electronics 10, no. 5 (2009): 1020–1023.
Martti Toivakka/ ISAB 2012
Multilayer Coated Paper with
Varying Topcoat Thickness
K05
K1
K3
K5
Topcoat:
Topcoat:
Topcoat:
Topcoat:
Kaolin + 4 SB latex
Kaolin + 4 SB latex
Kaolin + 4 SB latex
Kaolin + 4 SB latex
0.5
g/m2
1.0
g/m2
3.0
g/m2
5.0 g/m2
Martti Toivakka/ ISAB 2012
Measurement of Surface Porosity
- Print Penetration Test
Low Surface Porosity
High Surface Porosity
Martti Toivakka/ ISAB 2012
Print Penetration Test
15
Higher Surface Pore Volume
Stain Length [cm]
14
13
12
11
10
0.5 g/m2
1 g/m2
3 g/m2
5 g/m2
Coat Weight Top Layer
Martti Toivakka/ ISAB 2012
Surface Pore Volume by Hg-porosimetry
Surface Pore Volume [pl/cm2]
140000
120000
100000
80000
60000
40000
20000
0
0.5 g/m2
1 g/m2
3 g/m2
5 g/m2
Coat Weight Top Layer
Porosity x [Coat Weight]
Martti Toivakka/ ISAB 2012
Print Penetration vs. Hg-porosimetry
Surface Pore Volume [pl/cm2]
140000
120000
100000
80000
60000
R² = 0.9733
40000
20000
0
11
12
13
14
Stain Length [cm]
Martti Toivakka/ ISAB 2012
600
30
500
25
400
20
300
15
200
10
100
5
0
0
0.5 g/m2
1 g/m2
3 g/m2
5 g/m2
Resistivity [Ω/sq]
Line width [µm]
Flexography & Silver Ink
Coat Weight Top Layer
•Increasing surface smoothness
•Increasing apparent surface energy
•Increasing surface pore volume
Martti Toivakka/ ISAB 2012
Surface Porosity Minimizes
Characteristic “Squeeze” in Flexography
Low surface porosity
High surface porosity
Martti Toivakka/ ISAB 2012
Flexography & Carbon Ink
200
Line width [µm]
480
150
460
440
100
420
50
400
380
0.5 g/m2
1 g/m2
3 g/m2
5 g/m2
Resistivity [Ω/sq]
500
0
Coat Weight Top Layer
•Increasing surface smoothness
•Increasing apparent surface energy
•Increasing surface pore volume
Martti Toivakka/ ISAB 2012
Inkjet – Nanoparticle Silver Ink
90
93.6
80
Drop spacing = 20 µm
Drop volume = 10 pl
> 10 MΩ/sq
150
89 Ω/sq
88.4
89.5
90
80.7
70
60
50
120
60
1.3 Ω/sq
0.5 g/m2
1 g/m2
3 g/m2
5 g/m2
30
Resistivity [Ω/sq]
Line width [µm]
100
> 10 MΩ/sq
0
Coat Weight Top Layer
•Increasing surface smoothness?
•Increasing apparent surface energy
•Increasing surface pore volume
Inkjet Printed PH3T in DCB
Resistivity [GΩ/sq]
120
Martti Toivakka/ ISAB 2012
Doped in air
100
2 printed layers
80
60
1 printed layer
40
20
0
0.5 g/m2
1 g/m2
3 g/m2
5 g/m2
Coat Weight Top Layer
•Increasing surface smoothness
•Increasing apparent surface energy
•Increasing surface pore volume
Martti Toivakka/ ISAB 2012
Surface Pore Volume vs. Semiconductor
Performance
4.0
Total printed volume 800 nl/cm²
at 0.25% à
3.0
TΩ/sq
P3HT volume on paper = 2 nl/cm²
R² = 0.9348
3.5
2.5
2.0
1.5
1.0
0.5
0.0
0
20
40
60
80
100
Pore volume [nl/cm²]
à A thinner and less porous topcoat preferable
R. Bollström, D. Tobjörk, P. Dolietis, P. Salminen, J. Preston, R. Österbacka and M. Toivakka, Printability of functional inks on multilayer
curtain coated paper, Chemical Engineering and Processing (Submitted)
Martti Toivakka/ ISAB 2012
Influence of Surface Pore Volume on
Printability of Functional Inks
•Printability of particulate inks improves on porous
surfaces (if particles > pore size):
› Less squeeze in flexography
› Less spreading in inkjet
› Coffee stain effect minimized
•Printability of dissolved functional inks improves on
low porosity surfaces:
› Functionality is reduced due to penetration into
the porous surface
Compromise or new concepts
(use other parameters)
Martti Toivakka/ ISAB 2012
Roll-to-roll Production – FunPrinter
à Roger Bollström: High volume printing of devices and sensors on paper
Martti Toivakka/ ISAB 2012
Barr et al., Direct Monolithic Integration of Organic Photovoltaic Circuits on Unmodified Paper,
Adv.
Mat. 2011
Martti
Toivakka/
ISAB 2012
Future of Paper Electronics
•Paper as substrate for printed electronics is
“different” from plastics – in “good” and “bad”
•FunMat has demonstrated printed transistors
and other devices on paper
•Main challenges are non-existence of suitable
hybrid printers, niche market position and
market ”resistance”
•First products will be simple
sensors for biological,
biomedical and chemical
applications
Martti Toivakka/ ISAB 2012
Recent Publications
• Bollström, R., M. Tuominen, A. Määttänen, J. Peltonen, and M. Toivakka. "Top layer coatability on barrier coatings."
Progress in Organic Coatings 73, no. 1 (2012): 26–32.
• Bollström, R., J. J. Saarinen, J. Räty, and M. Toivakka. "Measuring solvent barrier properties of paper." Measurement
Science and Technology 23 (2012): 015601.
• Tobjörk, D., H. Aarnio, P. Pulkkinen, R. Bollström, A. Määttänen, P. Ihalainen, T. Mäkelä, J. Peltonen, M. Toivakka, H.
Tenhu et al. "IR-sintering of ink-jet printed metal-nanoparticles on paper." Thin Solid Films 520, no. 7 (2012): 2949–
2955.
• Ihalainen, P., A. Määttänen, U. Mattinen, M. Stepien, R. Bollström, M. Toivakka, J. Bobacka, and J. Peltonen.
"Electrodeposition of PEDOT-Cl film on a fully printed Ag/polyaniline electrode." Thin Solid Films 519 (2011): 2172–
2175.
• Saarinen, J. J., P. Ihalainen, A. Määttänen, R. Bollström, and J. Peltonen. "Printed sensor and electric field assisted
wetting on a natural fibre based substrate." Nordic Pulp and Paper Research Journal 26, no. 1 (2011).
• Määttänen, A., D. Fors, S. Wang, D. Valtakari, P. Ihalainen, and J. Peltonen. "Paper-based planar reaction arrays for
printed diagnostics." Sensors and Actuators B: Chemical 160, no. 1 (2011): 1404–1412.
• Määttänen, A., P. Ihalainen, R. Bollström, M. Toivakka, and J. Peltonen. "Wetting and print quality study of an inkjetprinted poly(3-hexylthiophene) on pigment coated papers." Colloids and Surfaces A: Physicochemical and Engineering
Aspects 367, no. 1-3 (2010): 76–84.
• Määttänen, A., P. Ihalainen, R. Bollström, S. Wang, M. Toivakka, and J. Peltonen. "Enhanced Surface Wetting of Pigment
Coated Paper by UVC Irradiation." Industrial & Engineering Chemistry Research 49, no. 22 (2010): 11351–11356.
• Pykönen, M., K. Johansson, R. Bollström, P. Fardim, and M. Toivakka. "Influence of Surface Chemical Composition on
UV-Varnish Absorption into Permeable Pigment-Coated Paper." Industrial & Engineering Chemistry Research 49, no. 5
(2010): 2169–2175.
• Bollström, R., A. Määttänen, D. Tobjörk, P. Ihalainen, N. Kaihovirta, R. Österbacka, J. Peltonen, and M. Toivakka. "A
multilayer coated fiber-based substrate suitable for printed functionality." Organic Electronics 10, no. 5 (2009): 1020–
1023.
http://www.funmat.fi/
Martti Toivakka/ ISAB 2012