OPV Stability Characterization OPV Stability, Characterization & Standardization at Plextronics

Darin Laird Darin Laird Director of Technology

Power & Circuitry Teams

July 15, 2008

Agenda

• Plextronics Company Overview• Plextronics Company Overview• OPV efficiency and lifetime vs. LCOE• Current State-of-the-art for OPV LifetimeCurrent State of the art for OPV Lifetime• Plextronics OPV Stability Investigations• Causes of Failure and Analysis• Standardization of OPV stability measurement • Conclusion

Organic PV Value Proposition

WeightCost• < 0.5 micron total active layers • Potential for plastic substrates

• <$50/m2 achievable• Clear pathway to

< $0.50/W Real Market

Form Factor Options• Semi-transparent• Color tunable

LifetimeOpportunities Exist

at Achievable

P f

• Rapid progress underway• Potential to equal inorganic?

Environmental

Color tunable• Formable or flexible

Efficiency

Performanceq g

• Low energy manufacturing process• All-organic active layers

• Clear pathway to 10% single junction and 15% tandem

• Performs under low light / low angle conditionsangle conditions

Current Development Focus

Broad Market Opportunities for OPV

Smart

Microdevices Consumer Products On-Grid PowerSmart Packaging Wireless Sensors

Source: Aveso Displays Source: IMEC

Active Clothing

Battery Charging

Off-Grid Power OPV Potential• Operates well under various

lighting sources• Low dependence on angle of

incidenceTransportationRural Power • Flexible/conformable form factor

• Long-term attractive LCOE

Plextronics Company Snapshot

Plextronics Key Facts: Plexcore® OCO i C d ti I k f

LIGHT.

Founded in 2002

Headquartered in Pittsburgh, PA

53 Employees including 20 PhD’s

Organic Conductive Ink for Printed Displays & Lighting

53 Employees, including 20 PhD s

$41 Million in Equity InvestmentsPlexcore® PVOrganic Conductive Ink

POWER.

Investors: Organic Conductive Ink System for Printed Solar Power

Plexcore® OSOrganic Semiconductor

CIRCUITRY.

for Printed Circuitry

Plextronics Delivers Enabling Technology

Device design and process technology

Device fabrication

Material synthesis and ink formulation

Device analysisand feedback

Organic Photovoltaics

Photoactive Layer Requirements:

Efficient Light Harvesting

Organic Photovoltaic Cell Architecture

High External Quantum Efficiency

Excellent Film Formation

Hole Transport Layer Requirements:

Tunable Properties

Eff ti Pl i tiEffective Planarization

Chemical & Thermal Stability

Organic Photovoltaics is enabled by a systematic approach to:

Molecular design

Organic Materials+

Solution Printing Ink formulationDevice design

g=

Low Cost Solar Power

Plexcore® PV Systems Demonstrate Broad Range of Voc

Pl V Eff

Range of Voc

Plexcore® PV 1000

Plexcore® PV 1000 = P3HT + PCBMP3HT = Plexcore® OS2100

PlexcoreSystem

Voc (V)

Eff(%)

PV 1000 0.60 3.70

2

4

cm2 )

Typical Fill Factor

6

-4

-2

Den

sity

(mA/

c

-10

-8

-6

Cur

rent

D

0.0 0.2 0.4 0.6 0.8 1.0-12

Voltage (V)

* AM1.5G @ 100 mW/cm2; NREL Certified KG-5 Filtered Si reference; Spectral mismatch applied (M ~ 0.98 – 1.02)

Plexcore® PV Systems Demonstrate Broad Range of Voc

Pl V Eff

Range of Voc

Plexcore® PV 1000A B C

Plexcore® PV 1000 = P3HT + PCBMP3HT = Plexcore® OS2100

PlexcoreSystem

Voc (V)

Eff(%)

PV 1000 0.60 3.7

A 0 65 4 10

2

4

cm2 )

Typical Fill Factor

A 0.65 4.1

B 0.71 3.6

C 0.80 5.06

-4

-2

Den

sity

(mA/

c

> 0.65

PV 2000 0.85 5.4

-10

-8

-6

Cur

rent

D

Plexcore® PV 2000

0.0 0.2 0.4 0.6 0.8 1.0-12

Voltage (V)

40% I t i Effi i th h M t i l D i

* AM1.5G @ 100 mW/cm2; NREL Certified KG-5 Filtered Si reference; Spectral mismatch applied (M ~ 0.98 – 1.02)

> 40% Improvement in Efficiency through Material Design

Plexcore® PV Systems Demonstrate Broad Range of Voc

Pl V Eff

Range of Voc

Plexcore® PV 1000A B C D E

Plexcore® PV 1000 = P3HT + PCBMP3HT = Plexcore® OS2100

PlexcoreSystem

Voc (V)

Eff(%)

PV 1000 0.60 3.7

A 0 65 4 10

2

4

cm2 )

Typical Fill Factor

A 0.65 4.1

B 0.71 3.6

C 0.80 5.06

-4

-2

Den

sity

(mA/

c

> 0.65

PV 2000 0.85 5.4

D 0.92 1.6

E 1.00 2.6-10

-8

-6

Cur

rent

D

Plexcore® PV 2000~ 0.40

0.0 0.2 0.4 0.6 0.8 1.0-12

Voltage (V)

40% I t i Effi i th h M t i l D i

* AM1.5G @ 100 mW/cm2; NREL Certified KG-5 Filtered Si reference; Spectral mismatch applied (M ~ 0.98 – 1.02)

> 40% Improvement in Efficiency through Material Design

Plexcore® PV 2000 Based on Technology with NREL-Certified World-Class Performance

Si l J ti OPV C ll Single Junction OPV Cell NREL Certified at 5.4%

Published in Published in Solar Cell Efficiency Tables(Version 31)Prog. Photovolt: Res. Appl. 2008; 16:61–67g pp ;

Representative Module Efficiency ResultsNREL Certified Module – 2.3% Active Area Efficiency

Plexcore ® PV 1000 Active Layer

• Plextronics 152mm x 152mm Module• Total Certified at 1.1%• Active Area coverage = 46%• Active Area efficiency = 2.3%• Largest OPV Module Certified at NREL

Agenda

• Plextronics Company Overview• Plextronics Company Overview• OPV efficiency and lifetime vs. LCOE• Current State-of-the-art for OPV LifetimeCu e t State o t e a t o O et e• Plextronics OPV Stability Investigations• Causes of Failure and Analysis• Standardization of OPV stability measurement• Conclusion

OPV Efficiency Status: Lab-Cells

Tandem Cell Potential

~ Single Cell Lab Potential

Source L.L. Kazmerski, NREL

Agenda

• Plextronics Company Overview• Plextronics Company Overview• OPV efficiency and lifetime vs. LCOE• Current State-of-the-art for OPV LifetimeCu e t State o t e a t o O et e• Plextronics OPV Stability Investigations• General Modes of OPV failure• Standardization of OPV stability measurement• Conclusion

OPV Stability: What factors are important?

Cell Architecture,Cell Architecture,Composition, and

Packaging

Test Method and Analysis

Exposure to Specific Conditions

Key Factors to Consider:Charge carrier

Density (buildup)

Cell/Module Packaging Electrodes Hole/Electron-

transport layerPhotoactive

layer

Pretreatment Light IntensityPretreatment (light soak, heat, etc.)

Initial Efficiency

Light Source and Spectrum

Light Intensity (# Suns) and

variationTemperature

Cycling of Load Flexure/% Relative Humidity

y gTemp, Light,

%RH (weather conditions)

Loadconditions during test

Test method and parameters

Flexure/physical stressing

DOE OPV Roadmap: Guiding Technology Development1Guiding Technology Development

• Internal NREL target• Translates to T80 in > 4,000 h

• OPV lifetime target• Translates to T80 in > 10,000 h, ,

• Standardization of OPV lifetime testing is neededStandardization of OPV lifetime testing is needed• Difficult to correlate stability data between different labs• Plextronics is actively exploring various testing methods

NREL/Pl t i d l i t t th d d l

1 Ginley, David National Solar Technology Roadmap: Organic PV, Management Report NREL/MP-520-41738, 2007

• NREL/Plextronics developing test methods and analyses

OPV Lifetime Working Definition

Typical Fade Patterns of OPV Cells with Definable Phases

Catastrophic Failure

cien

cy

η0 η0S

T80S 1. Initial Efficiency (η0)2. Burn-In

Decay Phases

1.0

1

2

34

5

wer

or E

ffi 3. Initial Stabilized Efficiency (η0S)

4. Linear Decay Region5. Catastrophic Failure6 C ll Lif ti t T80S

0.86

Burn-In Time

Pow 6. Cell Lifetime to T80S

Working Definition of OPV Lifetime: The amount of time that an OPV cellWorking Definition of OPV Lifetime: The amount of time that an OPV cell, sub-module, or module diminishes to 80% (T80) of its initial ‘stabilized’ power output (or power conversion efficiency), normalized by illumination intensity (lamp variations, spectral mismatch), under ~1 Sun simulated by a Xenon arc lamp with (or converted to) 50% duty cycle.

Extrinsic Degradation: Protection from Water and OxygenProtection from Water and Oxygen

Glove Box RT85C dark 85C Light

PEDOT/P3HT:PCBM Films on GlassStorage-- Globe Box/RT

PEDOT/P3HT:PCBM Films on GlassStorage-- 85C/Dark

t=0 hrst 15 h 1 0

PEDOT/P3HT:PCBM Films on GlassStorage-- 85C/LIGHT

t=0 hrst=15 hrs

PEDOT/P3HT:PCBM on glass

0.4

0.6

0.8

1.0

Abs

g t=0 hrs t=15 hrs t=24 hrs t=36 hrs t=48 hrs

0.4

0.6

0.8

1.0

Abs

t=15 hrs t=24 hrs t=36 hrs t=48 hrs

0.4

0.6

0.8

1.0

Abs

t 15 hrs t=24 hrs t=36 hrs t=48 hrs

~100 hrs~100 hrs

~100 hrs

Oxidation of Polymer

300 400 500 600 700 800

0.0

0.2

Wavelength300 400 500 600 700 800

0.0

0.2

Wavelength300 400 500 600 700 800

0.0

0.2

wavelength

Results in Bleaching of Backbone Chromophore

Seal Failure & Water

Exposure

Intrinsic Degradation: Prevent/Mitigate Inherent System InstabilitiesPrevent/Mitigate Inherent System Instabilities

• Perfect Seal?Degradation Not Completely Suppressed

• Plextronics Analog: Vacuum Flange• Intrinsic Degradation Study Vehicle

I ti ti i P

M. Jørgensen, et al., Sol. Energy Mater. Sol. Cells (2008), doi:10.1016/j.solmat.2008.01.005

• Degradation Not Completely Suppressed • Investigations in Progress

Agenda

• Plextronics Company Overview• Plextronics Company Overview• OPV efficiency and lifetime vs. LCOE• Current State-of-the-art for OPV LifetimeCu e t State o t e a t o O et e• Plextronics OPV Stability Investigations• Causes of Failure and Analysis• Standardization of OPV stability measurement• Conclusion

Plextronics OPV Test Capabilities• Fully equipped with software and hardware capabilities for high through-put

device testing.• Thin film analysis with Large Area Microscopy, Elipsometry, AFM,UV-Vis,

EQE Photo CELIV

EQE measurement set upLarge area and small area solar simulators

EQE, Photo-CELIV

Large area High intensity Xe exposure

Large area 6 X 6 inch module

Photo-CELIV

Blue M temp/humidity chamber

Xe-Lamp Testing ApparatusImproved Solar Spectrum Matching

0.5

0.6Lamp spectrums

Metal Halide AM1.5G Xe High intensity Xe

Large area High intensity Xe exposure

Improved Solar Spectrum Matching

0.2

0.3

0.4

Arb

Uni

ts

300 400 500 600 700 800

0.0

0.1

Wavelength (nm)

MPP Testing at 1 Sung ( )

32-Channel OPV Test Array for MPP Monitoring

ModulesLab cells

Champion Module Stability ResultsModule 3070 – 1 48% Initial Efficiency

Monitoring of Xe-Lamp Variation1 0

3070 100% Duty Cycle

Module 3070 – 1.48% Initial Efficiency

0.6

0.8

1.0Si Photodiode

uA) 0.6

0.8

1.0

on N

B

• > 2000h PredictedNormalize

0.0

0.2

0.4

Initial Brightness (0.0766 uA)

NB

(u

Si-photodiode

0 200 400 600 800 10000.0

0.2

0.4

NP

o

• ~ 9.8%/1000h decay rate• On track with > 1080 h on test

0 100 200 300 400 5000.0

0.8

1.0Module under 100% Duty Cycle

ower

)

0 200 400 600 800 1000Life Time (hours)

0 00

0.05 Module 3070

cm2 ) Fresh

Aged

After 550h Light Soaking

0.2

0.4

0.6

Initial Power (115mW)NP

(on

Initi

al P

o

Raw Data0 15

-0.10

-0.05

0.00nt

Den

sity

(mA/

c

153 mW

0 100 200 300 400 5000.0

Initial Power (115mW)N

Life Time (hrs) 0 5 10 15 20 25 30-0.20

-0.15

Cur

ren

Voltage (V)

158 mW

Rooftop Lifetime TestingWestern PennsylvaniaWestern Pennsylvania

Open Circuit Testing

Lab Cell Data

Large Area OPV ModuleC d ti D t il

Test Components Conditions

Condensation Detail

Light Source Outdoor Western PA

Duty Cycle Variable (<50%)

Temp range Variable

Humidity range Variable

• Remote MPP Continuous Rooftop Testing

NEW

Cycling pattern None

Data Collection Intermittent • Weather monitoring and data collection

OPV Lifetime Testing StrategyGoal: Establish Indoor to Outdoor Correlation

Indoor 2008Establish Core Testing Conditions;Elucidate Degradation Pathways/Accel Factors

2010

Goal: Establish Indoor to Outdoor Correlation

Improvements in Correlation/Round Robins

Elucidate Degradation Pathways/Accel. Factors2015 Goals (?):• 13+ yr Lifetimes• Clear Specifications

Outdoor

Statistical Data Sets; Multiple Representative Global Locations

Clear Specifications

Key Activities for Outdoor Testing • Output Power tracking/weatherproof

stations• Different global locations

-- Eastern USA, Plextronics, PA-- Southern USA, Q-Lab, FL-- Western USA, NREL, CO-- Europe, Germany

Plextronics Remote OPV Weatherproof Test Rig

Agenda

• Plextronics Company Overview• Plextronics Company Overview• OPV efficiency and lifetime vs. LCOE• Current State-of-the-art for OPV LifetimeCu e t State o t e a t o O et e• Plextronics OPV Stability Investigations• Causes of Failure and Analysis• Standardization of OPV stability measurement• Conclusion

General Causes of OPV FailureMany Not Universally Well Founded

Extrinsic:

Many Not Universally Well Founded

Extrinsic:• Ingress of Water and Oxygen• Mechanical and heat stress

Intrinsic:• Delamination of organic layers

Anaerobic/Aerobic photochemistry• Anaerobic/Aerobic photochemistry• Migration of mobile species

• Indium and electrode materialsHTL d AL t i l• HTL and AL materials

• High energy excited state chemistry at interfacesCh i d it /SCLC

M. Jørgensen, et al., Sol. Energy Mater. Sol. Cells (2008), doi:10.1016/j.solmat.2008.01.005

• Charge carrier density/SCLC

Krebs, et al. Propose Methods for OPV Stability InvestigationStability Investigation

M. Jørgensen, et al., Sol. Energy Mater. Sol. Cells (2008), doi:10.1016/j.solmat.2008.01.005

Photocurrent Mapping Employed to Evaluate Encapsulation and Degradation Modesp g

• 50 micron laser spot size, 12 micron step size, ~80,000 data pointsp

• Major degradation originates at edge of encapsulation

• “Dark” spots possibly due toDark spots possibly due to cathode pinholes

• No photocurrent outside device areadevice area

0 09 cm2 Lab Cell0.09 cm2 Lab-Cell

An Example Timeline for OLED Lifetime Improvements with Red Singlet Devices

Red PHOLED device-1,000,000 hrs at 500 nits and RT; from Novaled

Red DCJTB By optimizing host (mixed-host of Rubrene/Alq) achieved Lifetimes of 1200 hrs at

Red DCJTB singlet devices-Lifetimes of 5000 hrs at 400 nits nits and RT; from Novaled

APL, 89, 2006,061111

1100 nits and 70oC ; from Kodak

JSID, 12, 2004, 323

and RT; from Kodak

JSID, 12, 2004, 323

1987 1997 2001 2003 2006 2007

Red DCJTB singletRed DCJTB by

TPAC/Alq3 devices –Lifetime of 100 hours at

Red DCJTB singlet devices- 760 hrs at 430 nits and 70oC ; from Kodak

optimizing mixed host and ETL achieved lifetimes of ~100,000 hrs at 1300 nits and

50 nits and RT; Kodak

APL, 51, 913

Red RD3 by optimizing host (mixed-host of Rubrene/Alq) achieved Lifetimes of 8600 hrs at 686 nits and 70oC ; from Kodak

hrs at 1300 nits and RTRed RD3 by optimizing host, ETL, HIL yields devices with >65 000

JSID, 12, 2004, 323

686 nits and 70oC ; from Kodak

SID 2008, P-169

devices with >65,000 hrs at 1000 nits, RT and 10.8 cd/A

Agenda

• Plextronics Company Overview• Plextronics Company Overview• OPV efficiency and lifetime vs. LCOE• Current State-of-the-art for OPV LifetimeCu e t State o t e a t o O et e• Plextronics OPV Stability Investigations• Causes of Failure and Analysis• Standardization of OPV stability measurement• Conclusion

OPV Device Lifetime StrategyCan we adopt methods like IEC 61646?Can we adopt methods like IEC 61646?

• IEC 61646 reference

• Employ cycling based on, but p y y gnot restricted to, IEC standard?

• Amend and suggest changes in the protocolthe protocol

• Cooperate on test method development

Ulti t th d f h i TBD• Ultimate method of choice TBD

Agenda

• Plextronics Company Overview• Plextronics Company Overview• OPV efficiency and lifetime vs. LCOE• Current State-of-the-art for OPV LifetimeCu e t State o t e a t o O et e• Plextronics OPV Stability Investigations• General Modes of OPV failure• Standardization of OPV stability measurement• Conclusion

Conclusions

• ‘Initial’ standardization work has begun

• Estimations of OPV stability range from short-lived toEstimations of OPV stability range from short lived to longer, commercially relevant timescales

• What is needed?

– Identify key degradation mechanisms

– Standard testing methods for OPV community

Statistical database for meaningful reliability– Statistical database for meaningful reliability estimates

– Legitimacy of lifetime reports

• Much like area criteria for ‘class records’ for OPV efficiency (ie, 1.0 cm2 or larger)

?• 500 h minimum?

• Ultimately1000 h with temp/humidity

Darin Laird, Director of [email protected]

www.plextronics.com