High Refractive Index Materials in Lighting Applications · 2019. 1. 29. · Transparent. Not...
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The Clear Solution® High Refractive Index Materials in Lighting Applications 2019 SSL R&D Workshop Dr. Selina Monickam January 29, 2019
Transcript of High Refractive Index Materials in Lighting Applications · 2019. 1. 29. · Transparent. Not...
The Clear Solution®
High Refractive Index Materials in Lighting Applications
2019 SSL R&D Workshop
Dr. Selina MonickamJanuary 29, 2019
Outline
• Company Overview• High Refractive Index (HRI) Material• Application of HRI Materials in OLED Lighting• OLED Device Results• Conclusion• Acknowledgements
22019 SSL R&D Workshop
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Company Overview
Locations
Disruptive Technology
Customers & Partners
• Baltimore, MD - HQ• Taipei, Taiwan - Sales
• Technology leader in Next Generation High-RI Nanocomposites
Key Markets Served
• OLED Display, HD Display, OLED Lighting, LED Lighting
Manufacturing • 5 MT Pilot Baltimore, MD• 40 MT Full-scale, PA, 4Q18
Distributors • Korea, Japan, Taiwan
• 50+ Leading Device, Advanced Materials, & Consumer Electronics Companies
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High Refractive Index Material (PixClear®)
Capped Nanocrystals
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ZrO2 NanocrystalsUniform 5~10 nm spheresHigh RITransparentNot photoactiveBandgap ~5.8 eV
Nanocrystals in polymer matrixDisperse in monomer/oligomers with and without solventHigh transparency (>80%)Low viscosity
NanocompositesMolded into HRI structures such as thin films, lenses…Solution processableCompatible with many different deposition methods
High Refractive Index Nanocomposite
5
0102030405060708090
100
0 10 20 30 40 50 60 70 80 90 100
%Tr
ansm
issi
on
NC wt% Loading
%T_650nm %T_350nm
5 x 5 um scan area
High RI, High Transmittance, and Smooth Surface
400 500 600 700
1.56
1.60
1.64
1.68
1.72
1.76
1.80
1.84
1.88
Refra
ctive
Index
Wavelength (nm)
90 wt% 80 wt% 50 wt% Pure Polymer
Ra = 0.529 nmRMS = 0.665 nmRz = 6.455 nm
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Pixelligent’s HRI Material in OLED Lighting:- for Internal Light Extraction (ILE) Layer
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• High Refractive Index - reduces index mis-match between the ITO and the substrate
• Low surface roughness ꟷ smoothing layer for scatterers or textured surfacedꟷ Binder for suspending scatterer particles
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Developed 2 HRI Formulations
HRI Material for Light Extraction
High Refractive Index Formulation
High Refractive Index Scatterer Formulation
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Light Extraction Structures
Transparent Anode (n=1.8)OLED
Glass/Barrier Film Layer (n=1.5)
High Index Smoothing Layer n = 1.75 – 1.85
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Transparent Anode (n=1.8)OLED
Glass/Barrier Film Layer (n=1.5)
High Index Layer n = 1.75 – 1.85
Transparent Anode (n=1.8)
Glass/Barrier Film Layer (n=1.5)
1-D Gradient Index Layer Structured Gradient Index LayerTransparent Anode (n=1.8)
Glass/Barrier Film Layer (n=1.5)
Generation 1 Generation 2
Generation 3 Generation 4OLEDOLED
3-D Gradient Index Layer
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OLED Lighting Device with HRI ILE
(Source: OLEDWorks)
As high as 2.8X Improvement in Light Extraction in Device with Pixelligent ZrO2ILE compared to controls
Formulation coated on glass
Extraction efficiency
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OLED Lighting Device with PixClear HRI ILE
HRI integrated devices Uniform extraction efficiency and efficacy Can achieve ~90 lm/W at 3000 cd/m2
Extraction efficiency and Efficacy as a function of Luminance
2019 SSL R&D Workshop(Source: OLEDWorks)
0 2000 4000 6000 80000
20
40
60
80
100
Effic
acy
(lm/W
)
Luminance (cd/m2)
ILE ILE w/EEL
control
control w/EEL
0 2000 4000 6000 80000
20
40
60
80
100
120
EQE
(%)
Luminance (cd/m2)
ILE w/EEL ILE
control w/EEL
control
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HRI integrated devices Uniform extraction efficiency over angles Much reduced angular color variation (<0.001) Much lower voltage at high brightness >50,000 hours lifetime based on accelerated tests
0 20 40 60 800
20
40
60
80
100
EQ
E (%
)
Angles (deg)
control w/EEL
control
ILE
ILE w/EEL
OLED Lighting Device with HRI ILE
-80 -60 -40 -20 0 20 40 60 800.00
0.01
0.02
0.03
0.04
duv'
Angle (deg)
ILE ILE w/EEL
control w/EEL
control
2019 SSL R&D Workshop(Source: OLEDWorks)
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HRI integrated devices Minimal to no change in efficacy after device is bend once around
50 mm radius
0 2000 4000 60000
20
40
60
80
100
Effic
acy
(lm/W
)
Luminance (cd/m2)
control - before bendcontrol - after bend
ILE - before bendILE - after bend
HRI ILE in flexible OLED Lighting Device
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Formulation coated on polyimide substrate
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Properties that can improve device efficiency Scatterer concentration Scatterer size Binder RI
Optimization of ILE Properties
40
60
80
100
120
EQE
(%)
Haze or scatterer loading (%)
Control with no EEL
Control with EEL
IEL with EEL
IEL with no EEL
Low High 1.3x% x% x% 1.1x% 1.4x%
40
60
80
100
120
Relative haze (%) of HRI-ILE
Higher RI Medium RI Lower RI
EQE (%)
efficacy (lm/W)
x% x% 1.1x% 1.3x% 1.2x% 50
60
70
80
90
100
110
Relative haze (%) of the HRI-ILE
medium larger small + large
EQE (%)
Efficacy (lm/W)
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Shown FeasibilityWorking OLED
devicesHigh extraction
efficiency (~50%)High lumens (~90
lm/W)Uniform efficiency
over all anglesBetter angular color
uniformity FlexibilityPassed preliminary
reliability test
Next Steps and Challenges Prove ILE integrated OLEDs
on larger panels Processibility Compatibility with other
layers Uniform ILE surface and
low surface roughness Low Moisture permeability
Room for more improvements Optimum scatterer size Optimum binder RI Optimum scatterer RI
Commercialize
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Conclusion
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• High Refractive Index is needed to improve light extraction efficiency
• PixClear High Refractive Index structures can improve efficiency in OLED lighting devices achieving as high as 90 lm/W efficacy
• The formulation is solution processable and can be used for both rigid as well as flexible substrates
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• DOE SBIR Phase I, Phase II and phase IIB
Award #DE-SC0011295
• DOE SSL Award #DE-EE0006673
• DOE SBIR Phase I Award #DE-SC0017038,
DE-SC0018604
• OLEDWorks LLC
• FROST & SULLIVAN Manufacturing Award
Acknowledgements
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For more technical details, read our white paper:http://www.pixelligent.com/resources/
Thank you
Dr. Selina Monickam (Product Development Manager) [email protected]
2019 SSL R&D Workshop
