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Solid State Lighting: A Bright Opportunity for Nanotechnology to Impact Energy EfficiencyPaul E. BurrowsPacific Northwest National LaboratoryRichland, WA 99352
National Science FoundationJoint U.S. Korea NanoForum April 26th 2007
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Items for DiscussionSolid state lighting as a high payoff research area in energy efficiencyThe Department of Energys Basic Research Needs Report in Solid State LightingThe role of nanoscience in optimizing next generation solid state lighting
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Artificial lighting was among the first inventions of mankindThe FirstInventionWARMTHCOOKINGLIGHT
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Each subsequent improvement in lighting led to major lifestyle improvementsand improvements in the energy efficiency of the light
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Lighting consumes 22% of the electricity generated in the U.S.A.Thats 8% of the total energy consumptionCosts $50 billion per yearReleases 150 million tons of CO2 into the atmosphere each yearMuch of it is 19th century technology with poor efficiencyWhy does lighting impactenergy conservation?
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We should be able to do betterEfficiencies of energy technologies in buildings:Heating:70 - 80%Elect. motors:85 - 95%Fluorescent:20%Incandescent:5%Lighting is a highly attractive target for reducing energy consumption!
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33%DOE Natl Labs33%Universities20% Federal 14% Industry & others Total 79 participantsBasic Research Needs for Solid State LightingMay 22-24, 2006Science Panel Chairs:LED: Jerry Simmons (SNL)Bob Davis (Carnegie Mellon U)OLED: Franky So (U of Florida)George Malliaras (Cornell)Cross-Cutting: Jim Misewich (BNL)Arto Nurmikko (Brown U) Darryl Smith (LANL) Workshop Chairs: Julia Phillips (Sandia National Labs) Paul Burrows (Pacific Northwest National Lab)Charge: identify transformational scienceOutput: www.sc.doe.gov/bes/reports/list.html
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All Attendees
d Panel 1HiroshiAmanoMeijo [email protected](81) 52-832-1151, X-5064CYa
d Panel 1AndreasHangleiterTechnical University [email protected] 391 8501CYa
d Panel 3PeterLittlewoodUniversity of [email protected] (3)32987CYa
ee BESChristieAshtonBESchristie.ashton@science.doe.gov301-903-0511CNf
em BESKristinBennettBESCNf
g Invited Guest [email protected]
d Panel [email protected]
ea BESPatriciaDehmerBESpatricia.dehmer@science.doe.gov301-903-3081CNf
ec BESTimFitzsimmonsBESTim.Fitzsimmons@science.doe.gov301-903-9830CNf
d Panel [email protected]
en BESHelenKerchBESf
d Panel 2JianminShiArmy Research [email protected]
d Panel 2 WriterMaryGalvinAir [email protected]
c Plenary SpeakerGeorgeCrafordLumiLedsgeorge.craford@lumileds.com408-435-6561CYi
g Invited Guest EEREDougFreitagDow [email protected]
d Panel [email protected]
g Invited Guest NASNataliaMelcerNational Academy of SciencesINi
g Invited Guest [email protected]
g Invited Guest EEREFredWelshRadcliffe [email protected]
g Invited Guest [email protected]
d Panel 2 WriterJosephShinarAmes [email protected]
f Lab [email protected]
ab Workshop [email protected]
f Lab [email protected]
d Panel 1 [email protected]
d Panel 2 [email protected]
f Lab [email protected]
el BESDanielFriedmanBESdaniel.friedman@science.doe.gov301-903-1048CNl
f Lab [email protected]
d Panel [email protected]
f Lab ObserverKai-MingHoAmes [email protected]
d Panel [email protected]
f Lab [email protected]
f Lab [email protected]
b Panel Chair [email protected]
g Invited Guest [email protected]
aa Workshop [email protected]
f Lab [email protected]
d Panel [email protected]
f Lab [email protected]
b Panel Chair [email protected]
d Panel 1JaspritSinghUniversity of [email protected]
b Panel Chair [email protected]
d Panel 1 [email protected]
d Panel 3PeidongYangUC [email protected]
d Panel 3MarcAchermannU Mass [email protected]
d Panel 3VladimirAgranovichUniversity of [email protected]
d Panel 2PaulBarbaraUT [email protected]
d Panel [email protected]
d Panel 1 WriterTonyCheethamUC Santa [email protected] 8767CYu
d Panel [email protected]
b Panel Chair 1BobDavisCarnegie Mellon [email protected]
d Panel 2SteveForrestUniversity of [email protected]
c Plenary SpeakerAlanHeegerUC Santa [email protected]
d Panel [email protected]
d Panel [email protected]
b Panel Chair 2GeorgeMalliarasCornell [email protected]
f Lab [email protected]
d Panel 1DavidNortonUniversity of [email protected]
d Panel 3LukasNovotnyUniversity of [email protected]
b Panel Chair 3ArtoNurmikkoBrown [email protected]
c Plenary [email protected]
b Panel Chair 2FrankySoUniversity of [email protected]
d Panel 2 [email protected]
d Panel 1JimSpeckUC Santa [email protected]
d Panel 2ChingTangUniversity of [email protected]
d Panel 2MarkThompsonUniversity of Southern [email protected]
d Panel 2ValyVardenyUniversity of [email protected]
d Panel 1 [email protected]
c Plenary [email protected]
d Panel 3RashidZiaBrown [email protected]
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LED Science
OLED Science
Workshop Output12 Priority Research Directions (PRDs), each specific to an individual panel2 Grand Challenges (GCs) which overarch all panelswww.sc.doe.gov/bes/reports/list.htmlCross-cutting Science
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Today, light-emitting solid state materials are discovered rather than designed.
The CHALLENGE:Can we design optimized device components that assemble into a high efficiency charge-to-light conversion system?GRAND CHALLENGE 1: Rational design of solid-state lighting structures
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GRAND CHALLENGE 2: Control of radiative and nonradiative processes in light-emitting materialsLight-emitting efficiency is determined by competition between radiative and non-radiative processes. The CHALLENGE:Can we understand and control the physics of photon generation and emission?
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Colored LEDs: Red, Yellow - AlInGaPBlue, Green InGaNWhite LEDs: Red + Green + Blue, or Blue + phosphorInorganic solid state lightingComposition and nanostructure determine color- With applied voltage positive and negative charge carriers recombine- Energy may be released as light or heat- Theoretically they can be 100% efficient with unlimited life! (compared to incandescent which is 5% efficient, 2000 hour life) - Commercial LEDs can be expected to reach 50% efficiency and possibly more Semiconductor BandgapDetermines ColorNegatively charged carriers+_Postively charged carriersBuckingham Palace, London, England Lit by Lumileds LEDsCourtesy George Craford, Philips Lumileds
BlueGreenRedMolecular Light Emitting Materials:Molecular Structure Determines ColorFluorescent Phosphorescent Weakly interacting molecules mean the photophysics of a film is controlled by the molecular structure of the fundamental building block
Research-Scale Organic LightbulbsGeneral Electric: 2 ft OLED panelNote the lack of a luminaire,- these are large area, low intensity emitters)Universal Display Corporation
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Efficiency performance of OLEDShowa Denko K.K.:single layer phosphorescent polymer OLEDs external quantum efficiency of 17% (green) and 16% (blue) with durability of 350,000 hours at 100 cd/m2. They will build a trial volume-production line by the middle of this year.Novaled claims "groundbreaking" results with its p-i-n OLED technology.. White top emission devices achieved a lifetime of 18,000 hours at 3 V and 1,000 cd/m2. Green top-emission OLEDs achieve 1,000 cd/m2 at 2.5 V and 95 cd/A (about 110 lm/W) These green devices are based on Ir(ppy)3.Universal Display Corporation achieved 30 lm/W at 1000 cd/m2 (warm white).Osram: 25 lm/W white polymer devicesKonica Minolta 60 lm/W, details unclear
UDCNovaledKonica-MinoltaOsram
The problem of efficient white electrophosphorescencephosphorescencePHOSPHORESCENTDOPANTSGroundstateTripletExcitonsCHARGE TRANSPORTINGHOST MOLECULESExciton levels must be even higher than blueENERGYT1 > 2.9 eVS1What is this molecule?
The problem of efficient white electrophosphorescencephosphorescencePHOSPHORESCENTDOPANTGroundstateTripletExcitonsCHARGE TRANSPORTINGMOLECULESExciton levels must be even higher than blueENERGYT1S1
3.04 eV3.08 eV3.12 eVAromatic and Heteroaromatic Chromophores with Interesting Triplet Exciton EnergiesAll too volatile and do not form stable films!TOOLOWCan we use these as building blocks?
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Phosphine Oxide (PO) CompoundsLinda Sapochak, Paul Burrows, Asanga Padmaperuma and Paul VecchiHigh triplet energy small molecule fragmentPhosphine oxide point of saturation to isolate photophysics on bridgeOuter groups enhance thermal properties++inductive effect of P=O renders aryl groups electron deficient
Phosphorescence of phosphine oxides compared to brominated bridges(77K in DCM)PO1
LiF/AlITO ~4.7eV5.3 eV3.6 eV?? ! eV?? ! eVPO1Ultraviolet Emission from PO1 OLEDsITOPO1NPDLiF/AlITOAlq3PO1LiF/AlNPD emissionNo light338 nm
DeviceGeometryPO1 thickness ()OperatingVoltage (V)at 13 mA/cm2ExternalQE (%)CuPc/PO12703.10.0084304.30.0325405.30.0448107.60.016
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SummaryNew lighting technology is low-hanging fruit in the drive for energy efficiency Increase efficiency by 10XExtrapolations of current technologies will not meet this goal Old technologies; fundamental limitsSolid-state lighting can transform the way we light the worldSuccess requires:Fundamental understanding to optimize current SSL approachesDiscovery research to reveal the basis for breakthrough efficienciesSSL research will also drive discoveries in photon-matter interactions, new materials/structures, and new tools/methodswww.sc.doe.gov/bes/reports/list.html
If you look at how lighting fits in our energy consumption patterns, its obvious that it plays a very role. In general, electricity is responsible for about 1/3 of all energy consumption. About 20% of all electricity consumption is due to lighting, or general illumination. That rough percentage is true for both the U.S., and for the world, and without SSL it is not expected to change significantly in the future.Picture of EdisonDevice components to be optimized = charge transport, light emission, optical coupling etc.Left: high precision scanning probe near-field enhancement experiment. A tip with a nanoscale metal coupler (or antenna) enhances the electric field to modulate the optical properties of a molecule. Right: experimental plot showing the nanoscale sensitivity of the fluorescence on distance between the emitter and the antenna.