Highly Efficient Organic Devices

Size: px

Start display at page:

Download "Highly Efficient Organic Devices"

Marcus Waters
6 years ago
Views:

1 Highly Efficient Organic Devices Karl Leo Institut für Angewandte Photophysik, TU Dresden, Dresden, Germany and Fraunhofer-IPMS, Dresden

2 Motivation Sony 2010

3 Organic Semiconductors Large area & flexible substrates possible Large variety of materials Low cost Organic materials Organic light emitting diodes Photovoltaic cells Transistors and memory

4 Progression of Organic Products 3rd wave: Solar cells 4th wave: Organic electronics 2nd wave: OLED lighting 1st wave: OLED Displays Time

5 Organic Light Emitting Diode (OLED) OLEDs: Basic Principles Hair: 18m A V Cathode Emitter Layer Transparent Anode Glass Substrate 3cm Organics 300m Glass Light Emission Organic material needed: 0.5g/m 2

6 The pin-oled structure p i n Electron Blocker Cathode Anode p-htl Emitter Hole Blocker n-etl Device operates in flat-band condition Carriers are injected through thin space-charge layers

7 P-doped ZnPc: Conductivity vs. Doping Concentration e - Conductivity [S/cm] 10-2 ZnPc series 1 ZnPc series T= 30 C linear dependence Molar Doping Ratio F 4 -TCNQ : ZnPc Nominally undoped ZnPc: S/cm Doping increases conductivity by orders of magnitude M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett. 73, 3202 (1998); K. Walzer, B. Maennig, M. Pfeiffer, K. Leo, Chem. Rev. 107, 1233 (2007)

8 The most simple device: pn homo junction 40 nm 30 nm 15 nm Al n-znpc i-znpc p-znpc ITO Current Density ( A/cm 2 ) 1x10-1 1x10-2 1x10-3 1x10-4 1x10-5 1x10-6 1x10-7 1x10-8 Al ITO ZnPc - homo ( d i = 30 nm ) n - ZnPc i - ZnPc p - ZnPc 24.0 C -1.8 C C C C C 1x Voltage ( V ) ZnPc: K. Harada et al., Phys. Rev. Lett. 94, (2005); Pentacene: K. Harada et al., Phys. Rev. B 77, (2008)

9 Investigation of a complete pin-oled by UPS S. Olthof et al., Phys. Rev. B 79, (2009)

10 The all-organic device: Red pin OLED at 2.4V Best devices: 1.89V thermodynamic limit + 20%

11 Spin Statistics: Phosphorescent Emitters are needed (Thompson & Forrest) hole electron exciton + Triplet Ir(ppy) Triplet Triplet Singlet N Ir Phosphorescent Emitter: Ir(ppy) 3 3 e-h-recombination: 75% triplet- and 25% singlet-excitons Phosphorescent emitters: triplets are used as well due to spin-orbit coupling by heavy metals (Ir, Pt, Cu ) 100% internal quantum efficiency reached

12 Determination of the External Quantum Efficiency Calculations by Mauro Furno Experiment: bottom-emitting OLED Comparison yields radiative efficiency: 90% for both red and green Ir emitters M. Furno et al., unpublished

13 OLED display market forecasts and the reality..

14 Some OLED Products on the Market Passive Matrix Active Matrix Phone SNMD RGB PM Samsung phone Nokia phone Car Audio Pioneer Car Audio TDK 2009 market: Approx. 700 M$ 100% small molecule OLED 98% Asian Manufacturers LG OLED TV

OLED-ON-CMOS: KEY FEATURES highly-efficient OLED light source in/on CMOS extremely thin (~100nm) arbitrary shapes all colors monochrome, white, NIR excellent

acqusition, processing, control,... sensor co-integration CMOS-compatible sensors (embedded photodetectors, temperature, magnetic (Hall) M(O)EMS,.

15 OLED-ON-CMOS: KEY FEATURES highly-efficient OLED light source in/on CMOS extremely thin (~100nm) arbitrary shapes all colors monochrome, white, NIR excellent efficiencies (low-voltage, low-power) good/improving lifetime (several 10kh) self-emissive fast response time (MHz) electronics feature integration driving, acqusition, processing, control,... sensor co-integration CMOS-compatible sensors (embedded photodetectors, temperature, magnetic (Hall) M(O)EMS,... _ transparent conductor organic layers metal cathode substrate top-emitting Light emission + intransparent substrate (Silicon CMOS wafer) CMOS cross-section with OLED on top Fraunhofer IPMS

16 OLED on CMOS Orange top emitting PIN-OLED on CMOS OLED Cam test chip (0.35µm CMOS) Active matrix OLED- Microdisplay Photodiode camera matrix Fraunhofer IPMS

PROCESS FLOW FOR MICRODISPLAY MANUFACTURING IPMS-CMOS or external CMOS foundry CMOS-surface modification (optional) pin-oled deposition thin film

17 PROCESS FLOW FOR MICRODISPLAY MANUFACTURING IPMS-CMOS or external CMOS foundry CMOS-surface modification (optional) pin-oled deposition thin film encapsulation & colour filter deposition dicing & assembly The whole process chain is available at COMEDD to prepare OLED microdisplays. Fraunhofer IPMS

VGA OLED MICRODISPLAY colour VGA (640x480) OLED microdisplay for HMD and microprojection 24 bit parallel video interface color options monochrome (8 bit)

18µm CMOS foundry process core supply 1.8V digital 1.8V I/O interfaces negative OLED cathode voltage (max. -5.5V) active area 7.68x5.

18 VGA OLED MICRODISPLAY colour VGA (640x480) OLED microdisplay for HMD and microprojection 24 bit parallel video interface color options monochrome (8 bit) full colour (24 bit) digital pixel cell luminance control by pulse width (PWM) color, contrast and gamma correction control via I²C 0.18µm CMOS foundry process core supply 1.8V digital 1.8V I/O interfaces negative OLED cathode voltage (max. -5.5V) active area 7.68x5.76mm² (chip size 12x11mm²) High brightness up to 10,000 nits for monochrome green (micro-projection) 1,000 nits for RGB colour (HMD) I²C interface (configuration) 50/60Hz frame rate 5.8mm 7.7mm Fraunhofer IPMS

19 OLED lighting demonstrators

20 OLED lighting market forecast

21 White OLED: The different approaches OLED Converter Blue OLED + Fluorescence Conversion Stacked RGB OLEDs Single OLED with RGB emitter layers

22 All-phosphorescent white OLED S. Reineke et al., Nature 459, 234 (2009) Novel emitter layer design High-index substrate and higher-order electron transport layer

23 Emitter layer design Blue emitter is nearly resonant with host: low voltage Transfer to red and green controlled by undoped interlayer Low exciton density prevents triplet-triplet annihilation S. Reineke et al., Nature 459, 234 (2009)

24 IV-Curves and Spectra Very low voltages: - 1,000Cd/m about 3V - 10,000Cd/m about 4V Spectra warm white, but too yellowish (deeper blue needed) S. Reineke et al., Nature 459, 234 (2009)

25 High-Index Substrate High-Index substrate (n=1.78): no index step to organics/ito However, more light gets trapped in the substrate Can be harvested with half sphere or patterned surface S. Reineke et al., Nature 459, 234 (2009)

26 Efficacies LI: low-index glass HI1: ETL is first order (40nm) HI2/3: ETL is second order (205/210nm) With pattern: Cd/m 5.000Cd/m 2 With half sphere: Cd/m 2 S. Reineke et al., Nature 459, 234 (2009)

27 Improvement in Outcoupling

28 LED performance vs time 180 green OLED K. Leo/IAPP AlInGaP Red/Yellow TU Dresden/Novaled pin technology Efficacy (Lumen/Watt) PLED InGaN green OLED white Konica/Minolta Fluorescent Tube La Tungsten Bulb Year

29 LARGE SIZE OLED LIGHTING PANEL Module size: 330 x 330 mm² Active lighting area: 5 x 174 cm² = 870 cm² (= 80 % of module size) Project OLED100.eu Made in COMEDD Gen2- line Fraunhofer IPMS

30 OLED AT LIGHT & BUILDING TRADE FAIR, FRANKFURT APRIL 2010 LEDON OLED Lighting with IPMS and OSRAM Ingo Maurer with Novaled Fraunhofer IPMS

31 Photovoltaics just taking off PV power generation market will grow by another factor of 1000!

32 Organic Solar Cells where is the Market? Window of opportunity in power market: OPV What is needed: 8-10% in module = 13-15% in lab Lifetime at least 10 years

33 European Roadmap for Organic PV From: EC strategic research agenda for Organic and Large-Area Electronics

34 Classes of Organic PV Dye-sensitized solar cell Polymer/small-molecule heterojunction Hybrid organicinorganic

35 Exciton separation at a heterojunction anode (e.g. ITO) cathode (e.g. Al) anode cathode donor acceptor C. W. Tang, Appl. Phys. Lett. 48, 183 (1986) M. Hiramoto et al., Appl. Phys. Lett. 58, 1062 (1991) J. J. Hall et al., Nature 376, 498 (1995) G. Yu et al. Science 270, 1789 (1995)

36 New low gap thiophene oligomers DCV1T University of Ulm Department Organic Chemistry II DCV3T E.Brier, E. Reinold, P. Kilickiran, P. Bäuerle DCV4T DCV5T DCV6T DCV7T

37 Comparison DCV5T vs. ZnPc: Double Voltage current density (ma/cm 2 ) ZnPc / C mw/cm 2 white light U oc = 0.49 V j sc = 10.1 ma/cm² FF = 55 % = 2.3 % voltage (V) ADA-BCO 2 / C mw/cm 2 white light U oc = 0.98 V j sc = ma/cm² FF = 48.5 % = 4.26 % = 3,4% DCV5T ZnPc C60 C 60 Best thiophene cells: 5%@1cm 2

38 p-i-n Tandem Solar Cells Single Al Bphen n-c60 C60 (40) DCV6T-E (6) p-npb ITO-Substrat Current Density / ma/cm² Single DCV6T-E:C Voltage / V Single: V oc =0.93V, 7.0mA/cm²(104mW/cm²), FF=49.5%, =~2.2% David Wynands et al.

39 p-i-n Tandem Solar Cells Single Al Bphen n-c60 C60 (40) DCV6T-E (6) p-npb ITO-Substrat Tandem Al Bphen C60 (25) DCV6T-E (6) p-npb n-c60 C60 (15) DCV6T-E (6) p-npb ITO-Substrat Current Density / ma/cm² Single DCV6T-E:C60 Tandem DCV6T-E:C Voltage / V Single: Tandem: V oc =0.93V, 7.0mA/cm²(104mW/cm²), FF=49.5%, h=~2.2% V oc =1.89V, 4.5mA/cm²(105mW/cm²), FF=59.8%, h=~3.4% with both heterojunctions in the first optical maximum David Wynands et al.

40 p-i-n Tandem Solar Cells (with Heliatek) I SC =6.78 ma/cm 2 Cooperation Heliatek/IAPP (+ BASF material) V OC =1.67V FF=67.7% ISE measurement: 7.7% (world record for area > 1cm 2 ) Power (mw) Area: 1.1cm 2

Lifetime of small-molecule high-efficiency cells stressed at: 50 C, 1.5 suns (halogen light) Lifetimes >20 years achieved on glass Time / h 0 2257 V oc / V 1.55 1.

41 Lifetime of small-molecule high-efficiency cells stressed at: 50 C, 1.5 suns (halogen light) Lifetimes >20 years achieved on glass Time / h V oc / V J sc / ma/cm² FF / % Transition from glassto-glass to thin-film encapsulation difficult UV protection needed Data courtesy Gregor Schwartz Heliatek

5 mm Pretreatment by ion beam and heating Coating Stations: up to 9 novel linear evaporators for organic materials in total (5

42 ROLL-TO-ROLL COATER FOR FLEXIBLE SUBSTRATES Batch type Roll-to-Roll Coater Substrate material: metal strip or polymer web width 300 mm, thickness mm Pretreatment by ion beam and heating Coating Stations: up to 9 novel linear evaporators for organic materials in total (5 double, 4 single) 2 evaporators for metals 1 DC/RF magnetron OLED-specific substrate handling strip guidance w/o front side roller contact un/rewinding with plastic liner transfer of coated substrate under inert atmosphere Fraunhofer IPMS

43 ROLL-TO-ROLL PILOT EQUIPMENT: FIRST RESULTS Fabrication of first basic OLED-stacks in R2flex 300 in September 2009 OLED with doped layer since April 2010 OLEDs produced in roll-to-roll coater 634 Fraunhofer IPMS

44 Organic Electronics Saxony: Value Chain industry Industry materials modeling organic technology Tools Products R&D R&D Currently about 850 coworkers!

45 Novaled AG Founded in 2001, operative 2003, 80 coworkers World leader in OLED efficiency and stability New topics: Organic Electronics VC Financing, 3 rounds 30M

46 Heliatek GmbH Founded in 2006 Production of Small-Molecule Organic Solar Cells 2investment rounds: BASF, Bosch, RWE, VC 1cm 2 efficiency reached (with TU Dresden)

47 Plastic Logic QUE e-reader Founded at U Cambridge Manufacturing plant in Dresden QUE e-reader released (and withdrawn) in 2010 Source: gizmodo

48 Conclusions Organic semiconductors: a material to make superb devices White OLED beat incandescent bulb and fluorescent tube Organic Solar Cells: Promising progress, but much improvement needed Organic Electronics: A solution looking for a problem

49 Acknowledgment S. Reineke, R. Schüppel, F. Lindner, X. Zhou, J. Huang, A. Werner, S. Hofmann, K. Schulze, C. Uhrich, R. Lessmann, T. Müller, J. Meiss, S. Scholz, K. Harada, M. Furno, C. Sachse, L. Müller-Meskamp, M.K. Riede, B. Lüssem, R. Gresser, N. Seidler, D. Wynands, M. Hummert, T. Fritz (IAPP) J. Amelung, K. Fehse C. May, M. Eritt, C. Kirchhof, M. Schreil, M. Toerker, Y. Tomita, M. Hoffmann, U. Todt (FhG-IPMS) J. Blochwitz-Nimoth, J. Birnstock, T. Canzler, S. Murano, M. Vehse, M. Burghard, M. Hofmann, Q. Huang, G. He, G. Sorin (Novaled) M. Pfeiffer, B. Männig, G. Schwartz, K. Walzer (Heliatek) D. Gronarz (OES) E. Brier, E. Reinold, P. Bäuerle (Ulm) D. Alloway, P.A. Lee, N. Armstrong (Tucson) U. Zokhavets, H. Hoppe, G. Gobsch (Ilmenau) K. Schmidt-Zojer (Graz), J.-L. Bredas (Atlanta) N. Karl (Stuttgart) A. Hinsch, A. Gombert (ISE) D. Wöhrle (Bremen), J. Salbeck (Kassel), H. Hartmann (Merseburg/Dresden) C.J. Bloom, M. K. Elliott (CSU) W. Lövenich, A. Elschner (HCStarck) P. Erk (BASF) and others from OPEG BMBF, SMWA, SMWK, DFG, EC, FCI, NEDO

PROCESS TECHNOLOGIES FOR ADVANCED ORGANIC ELECTRONIC DEVICES: MICRODISPLAYS, LIGHTING AND SOLAR CELLS

PROCESS TECHNOLOGIES FOR ADVANCED ORGANIC ELECTRONIC DEVICES: MICRODISPLAYS, LIGHTING AND SOLAR CELLS Dr. Christian May Fraunhofer IPMS - Center for Organic Materials and Electronic Devices Dresden COMEDD