The Clear Solution®

Application of Zirconia Nanocomposites for High Refractive Index Light Extraction

Dr. Sang-Hun Choi

22 Sep. 2017

Agenda

2

I. Company overview

II. Current OLED lighting technology with HRI

III. Future OLED display technology with HRI

IV.Conclusion

Pixelligent Highlights

• The PixClear® Product and Manufacturing Platforms are Disrupting the mature chemical composite industry

• Highest Index, Most Transparent & Solution Processable Materials

• Markets Served: Display, Solid State Lighting, and Optical Components

• Fully Scaled Manufacturing, The PixClearProcess™

• Over $45M Invested in Product Platform

• Global Customer Base with Market Leaders

3

Technology Leader in High Refractive Index Materials

4

Left: 50wt% ZrO2 Nanocrystals | Right: Pure Solvent

• ZrO2 Nanocrystal Dispersions

• Best Dispersions Available

– 5~10nm Spheres

– Fully Uniform

– High Loadings (>80wt%)

– 95% Transmittance

– High RI >1.8

– Broad Compatibility

• Highly Scaled Process with 40 – 50 MT capacity

• Strong IP Position 46+ issued and pending patents

Characteristics of Pixelligent HRI Enabled Material

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

Ra = 0.472 nmRMS = 0.597 nmRz = 9.25 nm

5 x 5 um scan area

PixClear® Enables High RI, High Transmittance, and Smoother Surface

400 500 600 700

1.56

1.60

1.64

1.68

1.72

1.76

1.80

1.84

1.88

Ref

ract

ive

Inde

x

Wavelength (nm)

90 wt%

80 wt%

50 wt%

Pure Polymer

Pixelligent ZrO2 Nanocrystal Dispersion Properties

6

• Monodisperse with 99.99% of particle diameter < 30nm

• Viscosity remains low over 50-80wt% loading range prior to solvent removal and curing

• Tunable refractive index and formulation options derived from suite of capping agents

• Long shelf life = 6+ Months

7

Select Customers & Partners

8

OLED Lighting Challenges

Higher Efficiency Technology and Soluble Processing with the Right Economics is required.

(Source: Solid-State Lighting R&D Plan by Department of Energy (June, 2016) DOE/EE-1418)

OLED Lighting Panel Target Performance in 2020

Lifetime (L70) > 50,000 hrs

LuminousEfficiency

> 125 lm/W

Cost $50/klm

9

OLED Light Extraction Problem

• Total Internal Reflection traps most of the light in the device

• Different light extraction schemes vary in how and where light is redirected

• SPM and substrate mode can be reduced by corrugation and surface control, respectively

• Waveguide mode (ITO/substrate interface) is where light should be redirected for maximum benefit

(5~35%) (20~50%)

(20~30%)

10

Transparent Anode (n=1.8)

OLED

Glass (n=1.5)

High Index nano composite smoothing Layer (n = 1.75 – 1.85)

Pixelligent Approach for OLED Lighting

Pixelligent IEL with High RI layer shows 100% Higher Light Extraction Efficiency

PixClear® IEL(Internal Extraction Layer)

0 deg 28.1 48.3 1.7X

Integrate 32.3 46.2 1.4X

0 deg 56.5 2.0X 57.3 2.0X

Integrate 67.9 2.1X 61.9 1.9X

Control (No IEL)

With Pixelligent IEL

No EEL EEL

(Source from OLEDWorks)

2.0X

2.4X

2.0X

2.2X

1.1X

(n = 2.0 – 2.2)

Polymer

ZrO2 Nanocrystals

• Distributed Scattering Layer with PixClear® High Refractive Index Layer• More efficient than condensed scattering layer• More functional material and simple manufacturing process

11

Pixelligent Approach for OLED Lighting

Transparent Anode (n=1.8)

OLED

Glass (n=1.5)

High Index Smoothing Layer n = 1.75 – 1.85High Index Layer n = 1.75 – 1.85

Transparent Anode (n=1.8)

OLED

Glass (n=1.5)

HRI Smoothing Layer(ZrO2 nanocomposite)

Scattering HRI Extraction Layer(ZrO2 nanocomposite + scatterer)

• Nanocomposite plus scatterer- Tunable viscosity, Uniform thickness, Uniform scatterer loading,

Low defect rate, UV Curable, Low surface roughness,by Slot-die, Spin or Inkjet coating

(n = 2.0 – 2.2)(n = 2.0 – 2.2)

Functional Polymer

ZrO2 Nanocrystals

12

Summary of High RI ZrO2 Enabled Smoothing Layer

Performance Criteria Performance Targets Pixelligent IEL

Optical Properties

Refractive Index > 1.75 – 1.85@ 550 nm

% Transmittance > 90% in visible region

Physical Properties

Smoothing Surface Planarize scattering structures on substrate <1 nm Ra

Compatible with CurrentManufacturing Processes

Spin coating, slot die coating, screen printing, vacuum coating process, etc.

Thermal Stability

150 C – 250 C 30 min Maintain High R.I. and High % T

Chemical Properties

Compatible with polymers Maintain uniform, transparent planarizing coatings

Compatible with scatters Maintain uniform, transparent planarizing coatings

Compatible with chemical processingStable to ITO patterning processes, acids, bases, solvents, etc.

13

Agenda

I. Company overview

II. Current OLED lighting technology with HRI

III. Future OLED display technology with HRI

IV.Conclusion

• Pixelligent Display Applications: OLED Displays, QD Displays, Reflective Displays

• PixClear® nanocomposites:

– Have Demonstrated 100%+ improvement in Light Extraction

– Can be applied using Inkjet, Slot Die, and Lithography processes

– Can be applied to rigid or flexible substrates

– Have Highest Index, Lowest Haze, and 95%+ Transmittance

• Broad Relationships with Leading Consumer Electronics, Device, and Advanced Materials Companies

14

Leveraging PixClear® for OLED Display Applications

15

Process Changes Occurring in OLED Display

Forecast for OLED display- The market for plastic and flexible AMOLED

panels will reach $18bn by 2020- This corresponds to 42% of total OLED display

revenues in 2020

Vacuum Soluble

Substrate Glass Soluble PI

OLED Small, Evaporation Polymer, Inkjet etc.

Encapsulation Inorganic, getterPolymer hybrid,

Inkjet etc.

Polarizer - Coated process

Process changes (Vacuum Soluble process)

16

Source: http://www.rtings.com/tv/learn/led-oled-power-consumption-and-electricity-cost, LED(S8000) vs OLED (C7), Android Forums at AndroidCentral.com

OLED vs. LCD

OLED displays exhibit excellent picture quality but have sub-par power consumption

OLED LCD

Black level (CR) Winner Loser

Viewing angle Winner Loser

Uniformity Winner Loser

Brightness Loser Winner

Energy consumption Loser Winner

TV

Mobile

OLED

• LCD panel: Blu/Pol/TFT/LC/CF/Pol• OLED panel: OLED/TFT/CF/C.Pol

OLED/Metal/Encap/C.Pol

17

Source: Solid-State Lighting R&D Plan by Department of Energy (June, 2016) DOE/EE-1418

• Electrical & spectral Efficiency

- Almost developed

• Internal Quantum Efficiency

- TADF, Phosphorescence for blue

• Extraction Efficiency- Defined by Optical Material &

Structure Design

Improved Light Extraction Significantly Increases

Display Efficiency

Electrical Efficiency

Internal Quantum Efficiency (IQE)

Extraction Efficiency

Spectral Efficiency

OVERALL PANEL Efficiency

80%

65%

35%

91%

4%

25%

35%

9%

18% 35%

OLED Panel Loss channels and Efficiencies

Potential ImprovementLight Extraction Technology is Important to achieve High Panel Efficiency

(The goal corresponds to an LER (Luminous Efficacy of Radiation) of 360 lm/W and a panel efficacy of 190 lm/W.)

18

Capping layer approach with soluble HRI layer

Top emission with capping layer

Source: The Optical Outcoupling of Organic Light Emitting Diodes (Duncan Hill, Fraunhofer 2008) & Jpn. J. Appl. Phys. 55, 112102(2016)

NPB(n=1.75)/ CaF2(Scattering layer)

1: WG+SPP@Bottom side of cathode2: WG+SPP@Top side of cathode

WO/ CP

W/ CP

• EQE was shown to increased by using capping layer

• Waveguide mode shifted out of metal cathode

• NPB is for index matching and buffer layer

• Damage-free deposition is required for capping layer

19

Thin Metal CathodeOLED

Substrate

High Index Layer(w/scatters)

Reflective electrode

HRI layer allow for more escape paths and an increased escape cone.

Capping layer approach with soluble HRI layer

Color Filter

Top emission with soluble HRI layer

• Capping layer with HRI is best wayto increase efficiency in top emission

• Damage-free Solution process- Simple process: Scatterers in solution- No buffer layer

• Before or after encapsulation, soluble HRI layer can be applied to device

• No picture quality issue with design structure (Color filter)

20

Literature Review of Out-Coupling Strategies

Structure Efficiency enhancement

Micro lens array (on back side of the sub.)Opt. Exp. (2011)

100% (in EQE)

Micro lens array (on top of TOLEDs)Small (2012)

120% (in EQE)

Silica sphere (on back side of the sub.)Photon. Rev (2016)

60% (in cd/A)

Periodic gratings inside deviceAdv. Funct. Mater. (2012)

70% (in cd/A)

2-D photonic crystalsJ. Appl. Phys. (2004)

52% (in cd/A)

Random patterns inside deviceNature Photon. (2010)

120% (in cd/A)

Micro cones array (T) + Micro lens array (B) Adv. Mater. (2013)

160% (in EQE)

Bucking + Hemispherical on back sideAdv. Funct. Mater. (2014)

150% (in EQE)

Source:

Micro Lens Array (MLA) shows highest extraction efficiency vs other methods- But, scale and process should be optimized.

Micro cones array (T) + Micro lens array (B) Adv. Mater. 25, 3571–3577 (2013)

Current issues for display with MLA

21

• Optical Crosstalk- Reflection angle with material- Mixed color crosstalk

• Picture Quality- Haze & ghost image- Color shift with lens shape

Efficiency improvement and image quality of organic light-emitting display by attaching cylindrical microlens arrays(Jiun-Haw Lee et al., Optics Express, Jan 2009)

t=5um

MLA is best candidate to increase EQE. However the challenges include:

Microlenses approach for OLED Display Light Extraction

22

• Drawbacks of microlenses such as crosstalk or back-scattering can be addressed though optimized lens design and colored lens structures (Lens per pixel) - Distance “t”- Black matrix- Color coated HRI lens (or HRI lens on CF)

• Refractive index modulation and HRI gives greater design freedom through higher focusing power and increased light extraction- Capping layer- Encapsulation

• Scalability and simple fabrication of lenses can be achieved through solution processable HRI material

Concept with soluble HRI material

HRI color coated lens(or color filter)

t

HRI Extraction layer(or in encapsulation)

OLED Display Simulation Using High RI Lenses

23

• Greater luminance at all viewing angles

• Reduced color shift from 0 - 60 degrees

• Based on optical modeling 50% - 300%

more light output

0.00

200.00

400.00

600.00

800.00

1000.00

1200.00

1400.00

0 10 20 30 40 50 60

Lum

inan

ce (

Cd

/m^2

)

Angle (deg)

3X Luminance Improvement

Control

21

Source : Data from joint development with DuPont

3X

HRI Lens

Enh

ance

men

t

Distance (μm)US Patent 2016/0380238 A1

~

24

Creating Lens Structures with HRI Material

Uniform Lenses Created with Pixelligent HRI Formulation by Inkjet Printing

Side Profile: = 45Side Profile: = 54

(On soda lime glass)Side Profile: = 9.4Side Profile: = 26.0

25

PixClear® Nanocomposite Flexible Applications

Conclusion

26

• The ability to create High Refractive Index structures that extract light and preserve image quality is key to improve efficiency in OLED devices.

• These extraction structures are best made with solution process-able HRI nanocomposite materials include flexible applications.

• Using PixClear® HRI enabled structures has the potential to boost light efficiency anywhere from 50% to 300%, dramatically improving overall OLED device efficiencies!

27

• DOE SBIR Phase I and Phase II Award #DE-SC0011295

• DOE SSL Award #DE-EE0006673

• FROST & SULLIVAN Manufacturing Award

Acknowledgements

28

For more technical details, please read our white paper:http://www.pixelligent.com/resources/

Thank you

Shree Deshpande (VP Business Development): sdeshpande@pixelligent.comDr. Matthew Healy (VP Product Management): mhealy@pixelligent.com

Dr. Sang-Hun Choi (Senior Scientist): schoi@pixelligent.com