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“Flexible and Printed Electronics for

Sensors, Displays and Photovoltaics”

Jurgen Daniel, T. Ng, A.C. Arias, L. Lavery,

S. Garner, R. Lujan, W. Wong, R. Street, B. Russo, B. Krusor

(daniel@parc.com)

Palo Alto Research CenterPalo Alto, California

International Workshop on Flexible and Printed Electronics (IWFPE 10), Sept8-10, 2010, Muju Resort, Korea

DARPA

about PARC (www.parc.com)

Research with client companies

Government contracts

Partnerships with new ventures

(startup @PARC)

New business creation

Licensing and

technology transfer

Research as a business:

• formerly Xerox PARC

• Incorporated in 2002

• ~170 researchers

Palo Alto Research Center

Computer Sciences

Intelligent Systems

Hardware and Systems

Electronic Materials & Devices

4 Labs:

• MEMS, Optoelectronics, Printing concepts/Systems, PiezoMaterials, Biomedical Systems, Clean Technology, ...

Large area + Printed Electronics

Nokia concepts

The Vision of Flexible/Printed Electronics

Antenna Design conceptElectronic Patch Network (DK)

Displays, sensors, RFID, batteries, solar cells, lighting, …

Freshness sensor

(RF, H2S gas)

ITRI/ UCSB

Flexio : Yanko design

e-Drum

PARC Competences in Flexible Electronics Low-T a-Si and poly-Si, GIZO, nanowires

Organic electronics

Printed Electronics

Materials and substrate evaluation

Device physics and design

Device, array and systems prototyping

Circuit design and prototyping

Charge transport

Display system

X-ray imaging system

Printing system Printed pixel circuit Thin-film transistor

A portfolio of technologies

Flexible displays for electronic paper applications

6” digital lithography a-Si:H array

bistable image after ~1 month

8” low-T a-Si:H photolithography array

Display medium: E-ink electrophoretic imaging film

“for electronic paper applications”

Flexible Electrophoretic Displays (with low-T a-Si:H)

340 m pixels (74ppi)

• on/off ratio: ~107

• ~0.9 cm2/Vs

TFT: T < ~170 degC

(Inkjet based digital lithography)

W.S. Wong, et al., “Digital lithography for large-area electronics on flexible substrates”, J. Non-Crystalline Solids 352 (2006) 1981

W.S. Wong, et al., “Digital lithographic processing for large-area electronics”, J. of the SID, 15/7 (2007) 463

J. Daniel, et al., “Jet-printed Active-Matrix Backplanes and Electrophoretic Displays”, JJAP, Vol.46, 3B (2007) 1363-1369

Flexible Displays with Printed Backplane

50x50 pixels(~2 inch diag.)

37ppi

PEN substrate

PVP gate dielectric

Printed Ag

PQT semiconductor680 m pixels; PQT-12 jet-printed

Semiconductor

Display medium: E-ink electrophoretic imaging film

„active-Matrix pixel circuits for electrophoretic media‟

All-additive solution processA.C. Arias, et al., J. of the SID, 15/7 (2007) 485

J. Daniel, et al., SID 09, 44.3, 660

J. Daniel, et al., Proc. NIP25 and Digital Fabrication 2009, 599

movie

Printed TFT Backplane : layers

50x50 pixel arrayGate layer

Data layer

Pixel design

Printed pixels (PQT TFT)

Larger feature sizes -> good, e.g. for poster size displays

50x50 pixels37ppi

680 m pixels

PQT-12 jet-printed OSC

Jet-printed nano-silver

192 m

Printed Display Challenges Resolution and speed are important considerations

Consider printed displays for poster-type or small disposable displays

Data line

(4.5 micron)

Pixel pad

Photolithography Jet-printing

37 ppi

74 ppi

(~50 micron)

Commercial backplane

Multi-Layer pixel design requires via interconnect formation

200 m pixels should be possible without

further reducing a 50 m line width

Multi-layer Pixel Design

side view

top view

Display Resolution: Multi-Layer Pixels

„Printed Metal Mask‟ (PMM) Via Process

“Process uses same printer for

mask deposition as for

metal conductors”

Via processes are required also for many other electronic circuits

photopolymer

GND

20.619.3

12.414.2

8.3 8.7

7.2

Process:

- Deposit photopolymer

- Print silver mask -UV expose

- Remove unexposed polymer

- Print top-layer with silver

Via chain

Circuits with Printed Metal Mask Via ProcessShift-register and Pixel circuit

1G-2D pixel circuitDynamic shift-register

Complex circuits can be patterned using silver jet-printing only

Pixel TFT:

- PBTTT

(spin-coated)

PBTTT

-also well formation to confine OSC

PARC Printed Blast SensorTape

Pressure, acoustic, acceleration, light sensor integration

Readout electronics and memory (data storage for 7 days)

Printing/lamination processes for low cost (target ~<$1)

Peak-detect and 5ms recording of events

challenges

“to record blast events

that can cause

Traumatic Brain Injury (TBI)”

• pressure wave

• sound

• acceleration

• (light)

• (temperature)

explosion

source: MicroVision

disposable blast dosimeter tape

DARPA Sensor Tape Program

Approved for Public Release, Distribution Unlimited

Sensor tape development faces many new challenges

www.brainline.org

Existing Football Helmet Sensor

Lower cost solutions are desirable

The HITS helmet (for Head Impact Telemetry System)

monitors the precise location and severity of impacts.

Acceleration sensing:

-uses 6 accelerometers

Stick-on Sensor Tape Examples

Paksense: Temp data logger

Parlex: Oximetry sensor patch

Huggies: UV sensor patch

Axcess: Asset & patient tag

IMEC(NL): Flexible ECG patch

Electronic PatchNetwork (DK)

Ocean Optics:Oxygen sensor patch

NASA: sensor medical patch

Flexible, disposable sensors

“Printing” may include many Processes

Inkjet, gravure, offset, flexo, (rotary) screen, …

Microcontact, Nanoimprinting

(Laser) transfer printing (of high performance circuits)

Dip-pen nanolithography

Hot embossing

Vapor-phase printing

Laser processing (cutting sintering, patterning)

Stamping/die cutting

Slot-, dip-, spray-coating

Etching, R2R photolithography (!)

Lamination, …

The consumer does not care if and how a product is ‟printed‟

Requirements are more demanding !

Sensor Tape in Comparison to EP Displays

Low-voltage operation (low power)

CMOS (p- and n-type TFTs)

Higher speed

Continuous operation (some circuits)

Readout Precision

…

(Electrophoretic)

sensors

clock circuit

amplifiers

memory

thin-film battery

printed

+ conventional external

readout electronics

Sensor tape

Sensors

Light sensor

•100-400klux

•„all-printed‟

Accelerometer Pressure / Sound

- mechanical sensors based on

piezoelectric polymer (PVDF):• low power

• low drift

• compatible with R2R process

Sensor fabrication compatible with R2R fabrication

• 0-1000g (+/-10%)• 5-100psi (+/- 10%)

• 100-180dB (+/-10%)

Light Sensor All –inkjet printed

In comparison: PCBM (EQE>50%)

had stability issues when processed in air

All-printed light sensor with photo response up to 400,000 lux

air-stable blend

Leah, Lavery, submitted to ‘Organic Electronics’

Piezoelectric sensing is well suited for blast events

Mechanical Sensor Options

• Substrate flexure

• Stress

• Low power consumption

• Fabrication process (printing/ R2R)

Considerations:

methods Properties/issues

Capacitive drift issues, readout relative complex

Piezoresistive drift, high power consumption

optical complex; high power consumption

Magnetic high power consumption; complex

Piezoelectric low power; good for transients

Compatible with solution/web

processing

: stress

t: thickness

g: piezo-coefficient

Piezoelectric sensing

Sensor Components Piezoelectric sensing (laminated PVDF foil or PVDF-TrFE solution)

punched

polycarbonate

rigid

substrate

Flexible PCB sensor

foil

sensor with charge

amplifier

printed silver electrodes on

PVDF/steel foil

Components of sensors with conventional electronic amplifier readout

pressure

acceleration

Approved for Public Release, Distribution Unlimited

Similar processes for pressure, acoustic and acceleration sensors

Measurement Setup – example: pressure

PARC blast tube (for faster pulses)

To simulate blast event and to enable repetitive measurements

Pressure Pulse Generator

Enfieldvalve

PARC sensor

Endevco reference sensor

Pressure

chamber

~ 4 psi blast

Commercial sensor

PARC sensor

P

sensor

Pressure / Acoustic Sensors

~ 4 psi blast

Commercial sensor

PARC sensor

PARC sensor

commercial sensor

• 10 pressure sensors: 5-100psi

• 10 acoustic sensors: 100-175dB

sound

pressure

Piezoelectric polymers by lamination or solution process

Piezoelectric sensing (PVDF / PVDF-TrFE)

Sensor Calibration and Verification

@ 500Hzacoustic

pressure~1% error

Light sensorAccelerometer

Pressure Sound

Sensors were within +/-10% allowed error

Verification was performed with DARPA observer present

Sensor Endurance Test

PARC Sensor

Endevco

Pressure sensor withstands multiple pressure pulses

The Electronic Components

Ring oscillator Shift Register

-120

-80

-40

0

-60 -30 0 30 60

gate voltage [V]

so

urc

e-d

rain

cu

rre

nt

[nA

]

Vsd= -10 V

(a)

0

25

50

0 -20 -40 -60

switching voltage [V]

dif

fere

nce

in

cu

rre

nt

at

Vg=

0V

[n

A]

(b)-120

-80

-40

0

-60 -30 0 30 60

gate voltage [V]

so

urc

e-d

rain

cu

rre

nt

[nA

]

Vsd= -10 V

(a)-120

-80

-40

0

-60 -30 0 30 60

gate voltage [V]

so

urc

e-d

rain

cu

rre

nt

[nA

]

-120

-80

-40

0

-60 -30 0 30 60

gate voltage [V]

so

urc

e-d

rain

cu

rre

nt

[nA

]

Vsd= -10 V

(a)

0

25

50

0 -20 -40 -60

switching voltage [V]

dif

fere

nce

in

cu

rre

nt

at

Vg=

0V

[n

A]

(b)

0

25

50

0 -20 -40 -60

switching voltage [V]

dif

fere

nce

in

cu

rre

nt

at

Vg=

0V

[n

A]

(b)

Memory

Inverter

T. Ng, APL 94 (2009) 233307

- Complementary Electronics

- Ferroelectric (PVDF) memory

- Peak detect circuit for speed

CMOS electronics for low power and better performance

Low Voltage TFTs ALD dielectric (100nm HfO2 on printed Ag gate electrode)

Ci~ 60-65 nF/cm2

Low voltage TFTs are required for low power and battery operation

2V

10V

3V

10V

N-type P-type PBTTT

collaboration:

(additional thin

low-k polymer on HfO)

• printed Ag source/darin

Printed Complimentary Inverters

DC characteristics AC characteristics

Inkjet-printed complementary inverter

• Gain of -4 at supply voltage of 20V

• printed TFTs show p type mobility ~0.1cm2/Vs,

n type ~0.05cm2/Vs

Inverters as building block for logic and amplifier circuits

T. Ng, APL 94 (2009) 233307

Pressure Sensor with Printed Inverter

Endevco

Inverter as high-impedance sensor-signal input

Confirmed inverter operation

printed inverter

pressure sensor

Printed Uni-polar inverter coupled to

PVDF-TrFE pressure sensor

J. Daniel, et al. (to be published in Proc. IEEE Sensors 2010)

Stick-on Sensor Tape Concepts

Approved for Public Release, Distribution Unlimited

Printing enables large-area multifunctional sensors with redundancy

Printing enables multifunctional designs with redundancy

- conformal

- large area

- with redundancy

Sensor designs:

Large-area flexible Photosensors

p-i-n aSi

Array sensitivity limit on flexible substrates:

• organic blend = 30 pW/cm2

• amorphous silicon = 1.2 pW/cm2

T.N. Ng, et al : Appl. Phys. Lett. 92(2008) 213303; Appl. Phys. Lett. 91(2007) 063505

organic heterojunction blend (MEHPPV: PCBM 1:3)

p-i-n amorphous silicon

Starlight ~50 lx ~7 pW/cm2

Clear night sky ~1 mlx ~150 pW/cm2

Flexible photosensors processed at low temperature (<160 degC)

Flexible PV Concept by Mosaic TilingConcept:

• use high efficiency conventional cells

• flexible or textile substrates

• combine with other electronic tiles

mixing of tiles

Novel tiling concept enables multi-axis flexibility

contacting concept

SunPower cell

Summary

PARC has a portfolio of technologies and services for flexible and printed electronics

PARC is evaluating materials and developing processes for printed electronics

Inkjet-printing is particularly advantageous in prototyping phase and for applications where non-contact printing is desirable

Flexible and printed sensor technology will enable novel applications

Acknowledgment

PARC: S. Sambandan, C. Paulson, S.E. Ready

DARPA (contr. # W81XWH-08-C-0065)

Cambridge Nano Tech Inc. : Jill Becker, Ritwik

Bhatia, Ganesh Sundaram

Naval Medical Center San Diego: Ron Jackson,

Jianzhong Liu, John Coleman

Polyera

Xerox Research Center of Canada

Measurement Specialties (MSI): Mitch Thomson

DuPont Teijin

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