R2R coating system for printed organic solar cell DK Choi SAM SPEL (Sungan Printed Electronics Lab.)

Outline Introduction SAM Printed Electronics Laboratory (SPEL) Tests and Results Summary

SUNG AN MACHINERY CO. LTD.

- Location : Mado Industrial Complex - Location : Mado Industrial Complex (50km away from Seoul) (50km away from Seoul) - Plant : Land: 20,000m 2 ( Building : 12,000m 2 ) - Plant : Land: 20,000m 2 ( Building : 12,000m 2 )

SAM’S Products and Services: SAM’S Products and Services: Converting machinery: Converting machinery: - Printing Press: Gravure Press - Printing Press: Gravure Press In-line Flexo Press In-line Flexo Press - Extrusion Coating & Laminating - Extrusion Coating & Laminating - Solution Coating & Laminating - Solution Coating & Laminating Converting process & solution support Converting process & solution support - Controls & Drives Integration - Controls & Drives Integration - Process Optimization & Training - Process Optimization & Training

Production Capacity :30 lines / year :30 lines / year No. of Employees :130 Persons :130 Persons

SAM North America LLC (U.S.A) SAM North America LLC (U.S.A) SAM SUNGAN PAGENDARM GmbH SAM SUNGAN PAGENDARM GmbH N.C.T (New Control Technology) N.C.T (New Control Technology)

PRINTED ELECTRONICS LABORATORY

SAM Printed Electronics Laboratory – SPEL Capabilities Slot Die (sheet/roll) Gravure Offset gravure Rotary screen printer Substrate Organic Material Inorganic Material Application OPV – Organic Layer OLED Lighting – Organic Layer OPV/OLED – Electrode Lithium Polymer Battery Barrier layer coating EMI mesh OPV – mesh type electrode TFT - insulator RFID Metal grid for flexible solar cell H.C. PET H.C. PET/ITO Metal Foil H.C. PET PET Metal Foil HTL Active Layer Plextronics Silver ZnO TiO2 ANP Silver

SPEL - Test system for electronic ink coating Material & device structure research (OPV, OLED lighting, ink type solar cell) Research system (flexible solar cell module research, Flexible OLED lighting, and others) 1.Coating method : slot die 2.Substrate : glass/plastic sheet film 3.Chucking method : vacuum check(option) 4.Required ink volume : > 20ml 5.Coating speed : 0.01 ~ 0.5 mpm(meter/min) 6.PC base system control 1.Coating method : slot die 2.Substrate : plastic/metal foil 3.Required ink volume : > 50ml 4.Coating speed : 0.1 ~ 2 mpm(meter/min) 5.Drying temp : <200 ℃ 6.Tension control range : 1 ~ 10 kgf 7.Inspection system : line scan camera 8.PC base system control After matching ink & coating condition Apply process condition to roll system

SPEL - Test system for optical & metal ink process coating Metal oxide ink coating system 1.Coating method : slot die 2.Substrate : polymer film, metal foil(roll) 3.Coating speed : max 70mpm 4.Dry temp : under 150 ℃ 5.Include ATM plasma treatment 6.Tension control range : 1~10Kgf 7.PC base control system Metal paste printing system 1.Coating method : gravure/gravure offset 2.Substrate : polymer film 3.Coating speed : max 100mpm 4.Registration resolution : < 50 ㎛ (typical), depends on ink and web material 5.Dry temp : under 150 ℃ 6.Tension control range : 1~10Kgf 7.PC base control system

Tests and results

Pretreatment (ATM Plasma) ATM Plasma can modify the surface energy of web without web surface mechanical damage. The cleaning process is by only chemically reaction, so in case of using ITO coated PET, the ITO surface energy is controllable without changing ITO surface roughness. Process gas : Air(N2+O2) Power source : RF Plasma Cooling method : air cooling Web material : ITO coated PET Coating ink : PEDOT:PSS Web path ATM Plasma Unit Pretreated Zone Un-pretreated Zone We can enhance the wettability of ink to substrate by modification of solvent surface tension or web surface energy Befor e 88° Afte r 34° By ATM plasma treatment Befor e 30° By solvent surface tension control After 9° By ATM plasma treatment

Coating unit design (Slot Die) Purpose of slot die coating at PE industry Compatible to low viscosity E-ink Compatible to low contents ink Nano-thickness control Polymer ink test data Typical polymer ink : PEDOT:PSS Web material : PET Pretreatment method : ATM Plasma Metal oxide ink test data Typical metal ink : ZnO Web material : PET Pretreatment method : ATM plasma Thickness check point 200mm Thickness (nm) thickness SEM The film roughness is normally under 10nm The film by slot die coating is under 5nm Checked by AFM(Atomic Force Microscope) Cross coating direction profile (nm) G sideCenterM side Thickness profile by cross sectional SEM RMS roughness [nm] Surface resistance [Ω/ □ ] Light transmittancy [%] Surface roughness by AFM Surface resistance by eddy current Transmittance by UV-visible spectrum Cross sectional SEM AFM image

P3HT:PCBM OPV Active Ink Test Coating Method : Slot die Substrate : ITO Coated PET Coating Speed : 3mpm HTL/Active Layer/Al

PEDOT:PSS Hole Transport Ink Test Coating Method : Slot die Pretreatment : ATM Plasma Substrate : ITO Coated PET Coating Speed : 3 mpm Thickness Control Range : 60nm ~ 1,000nm Thickness (nm)RMS roughness 123Avg.[nm] 측정위치

P3HT:PCBM (Coating Thickness vs. Coating gap & Flow rate) Before thermal treatment After thermal treatment Optical property is changed

ZnO Slot GapCoating GapFlow RateCoating SpeedViscosityDrying Temp.Solid Contents [um] [ml/min][m/min][cps] [℃][℃] [wt%] Cross coating direction profile (nm) G sideCenterM side RMS roughness [nm] Surface resistance [Ω/ □ ] Light transmittancy [%] Cross sectional SEM data Surface roughness by AFM

Silver Silver Ink Test Coating Method : Slot die Substrate : ITO Coated PET Coating Speed : 3mpm

SiO2 slurry / gol Optical property (Transparency) PET < PET/SiO2 sol < PET/SiO2 slurry RoughnessRMS(nm)Rpv(nm)Ra(nm) #1(5um x 5um) #1(2um x 2um) #2(5um x 5um) #2(2um x 2um) #3(5um x 5um) #3(2um x 2um) Roughness (by AFM) PET/SiO2 slurry > PET > PET/SiO2 sol

Registration at roll system(CD control) Registration error source analysis (in case of CD control) # 1 Drying & Transfer # 2 Error of CD ± a Error of CD ± c Error of CD ± b Control factor -. EPC -. Idle roll setup Error of CD = ±(a+b+c) Control factor : -. Printing roll -. Nip roll Control factor : -. Printing roll -. Nip roll 30 ㎛ 200 ㎛ 30 ㎛ >260 ㎛ Without EPC control Without CD control 1# printing position error 2# printing position error 1# printing position error after 2# printing roll printing position error between 1# and 2# mark With EPC control CD control CD position error relative to position mark #1 : <30 ㎛

Registration at roll system(MD control) Registration error by (in case of MD control) Web’s elongation rate change Web velocity change Mark detection camera Change the coating roll speed to match the mark The control signal is also combined with the main roll system signal Main roll system signal is controlled by tension & web speed control logic hardware configuration & photo. of mark detection Print#1 Register Green line : tension of print#1 Red line : tension of print#2 Registration erorr is controlled under ±30 ㎛

Summary Development work has been carried out with the support of Korean government grants and local electronics suppliers Substrates have been pre-treated with atmospheric plasma to control wettability and coating surface characteristic Polymer inks were applied at a nominal coating thickness of 350 nm with a surface roughness of 5 nm

Summary Metal inks were applied by slot die method at a nominal 70 nm thickness with a surface roughness of 16 nm and transparency of nearly 90% and surface resistance of 392 ohms/square Key to commercial application is enhanced registration control which has been refined to less than ±30 µm

Summary On going work will focus on developing commercial capabilities and continuously improved process control in registration and coating consistency Future work will include – Fine patterned coatings (e.g. TFT) – Hybrid coating system (sequential application of different coating methods) Applied work with development partners

Thank You For additional information or to discuss development applications at SPEL – DK Choi – AW Christie