III-V Multijunction and Concentrator Photovoltaics ... · III-V Mul(jun(on & Concentrator...
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III-V Mul(jun(on & Concentrator Photovoltaics Research at NREL John Geisz SUN UP webinar October 18, 2016
Transcript of III-V Multijunction and Concentrator Photovoltaics ... · III-V Mul(jun(on & Concentrator...
III-VMul(jun(on&ConcentratorPhotovoltaicsResearchatNRELJohnGeisz
SUNUPwebinarOctober18,2016
III-V multijunctions used in high value applications
Space: Large, flat panels - High efficiency at 1-sun AM0 - Light weight is critical - High radiation resistance - Cost not so important
Terrestrial: Small cells, high concentration - High efficiency under concentration - Low system cost - Balance of system (optics, tracking…) - Sensitivity to spectral changes
Efficiencyiscri?cal!
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• Mul?junc?ons–reducethermaliza?onlosses• Concentra?on–efficiencyandeconomics• Radia?veefficiency–materialscienceandop?cs• III-Valloys–highqualityandversa?le
ProvenStrategiesforHighEfficiencySolarCells
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MetalorganicVaporPhaseEpitaxy(MOVPE)
EasytogrowcomplexstructureswithmanyalloysusingelementsinGroupIIIandVcolumns
Usedinsolarcells,lasers,LEDs,transistors,powerelectronics
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III-Vmaterialsystem
• Highlycrystalline
• LaXce-matchedalloys
• Directbandgaps
• Widerangeofbandgaps
• N-typeandP-typedoping
• Confinementlayers
• Stable
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Mul?junc?onsolarcells
70
60
50
40ef
ficie
ncy
(%)
87654321number of junctions
ideal multijunctioncell efficiency
Mul(junc(onstrategy:• Absorbabroadpor?onofthespectrum• Usemul?plejunc?onswithdifferentbandgapstominimizethermaliza?on
1stjunc?on
2ndjunc?on
3rdjunc?on
4thjunc?on
0.5 Eg1 Eg2 Eg3 Eg4 4Photon Energy (eV)
Eg4 Eg3 Eg2 Eg1
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HistoryofSolarCellEfficiency
Mul?junc?onconcentratorsarehighestands?llclimbing!
NRELmul?junc?onteamleadingefficiencygainsthroughresearch
4JIMM
Invented3JIMM
InventedGaInP/GaAsTandem Invented3J
dilutenitridebutrealizedbySolarJunc?on’sMBE
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InvertedMetamorphicMul?junc?on(IMM)SolarCell• Near-op?mumbandgapscanbeachievedbychangingthe
laXceconstant• Invertedgrowthhasmanyadvantages• Worldrecord40.8%with3JIMM(nowinproduc?on)• Demonstrated45.6%with4JIMM• Targetof50%with5Jor6JIMMinnearfuture
GaInAs 1.0 eV
GaInP 1.8 eV
GaAs 1.4 eV
Transparent GaInP buffer
GaInAs 0.7 eV
Transparent GaInP buffer
GaAs substrate Growth
direc?on
LaXceconstant
TJ
TJ
TJ
Mismatch1.9%
3.8%
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Understandingroleofop?csinsolarcells
-Somephotonsescapeoutthefront-Somephotonsarere-absorbedinthebulk-Mostphotonsdirecteddownwardtowardthesubstratearelost
(Enhanced)photonrecycling:Photonsdirecteddownwardarereflectedbackintothecell,enhancingthephotonrecyclingINCREASESVOLTAGE
Luminescentcouplinginamul?junc?on:Photonsdirecteddownwardcanbecoupledtoalowerbandgapjunc?onINCREASESCURRENTbandgapjunc?on
(e+ h! ⇄ ℎ!)!
Steineretal.,APL100,251106(2012)
Steineretal.,JAP113,123109(2013)
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Mul?junc?ons-Complexoptoelectroniccircuit
Tunnel
Photocurrent
LED
Reverse
Shunt
SeriesResistance
Breakdown
DiodeTunnel
Photocurrent
LED
Reverse
Shunt
Breakdown
DiodeTunnel
Photocurrent
LED
Reverse
Shunt
Breakdown
Diode
Photocurrent
LED
Reverse
Shunt
Breakdown
J1em J2
emJ3em J4
emJ1ext
J23LC
J3ext J4
ext
J12LC
J2ext
J34LC
Geiszetal.,“Generalizedoptoelectronicmodelofseries-connectedmul?junc?onsolarcells”,IEEEJPV,5,1827(2015)
Advancedcharacteriza?onandunderstandingforimproveddesign
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Highperformancedevicesthroughmaterialsciencesolu?ons
• Solarcellsthatglow• HighqualitylayerswithdifferentcrystallaXce
Franceetal.,MRSBulle?n,41,202(2016)
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• Reduc?onofdisloca?onsinmetamorphicalloys• Effectsofalloyordering• TransparencyoflayersusingBurstein-Mossshin• Reduc?onofnon-radia?verecombina?on• Metastablealloycombina?ons
Materialsciencechallenges
(1.4 eV)
LM#line#
InGaP&&(1.88eV)&
1.69 eV Ga0.68In0.32As0.34P0.66
1.66 eV Ga0.73In0.27As0.43P0.57
1.61 eV Ga0.78In0.22As0.54P0.46
1.79 eV Ga0.60In0.40As0.17P0.83
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• Funding:DOEEERESETOSunLamp• Goal:5J–6Jinvertedmetamorphicsolarcellsforhighconcentra?on
Mul?junc?onsolarcellsfor50%efficiency
GaxIn1-xP CGB
1.4eV GaAs
1.05eV Ga.21In.79As.44P.56
2.1 eV Al.18Ga.34In.48P
1.7eV Al.23Ga.77As
reflective metal contact
front metal grid
c) 5J IMM w/ one CGB
TJ
TJ
TJ
TJ
b) 5J IMM w/ two CGB
a) 4J IMM w/ two CGB
reflective metal contact reflective metal contact
0.73eV In.53Ga.47As
GaxIn1-xP CGB
GaxIn1-xP CGBGaxIn1-xP CGB
GaxIn1-xP CGB
1.4eV GaAs1.4eV GaAs
1.7eV Al.23Ga.77As
2.1 eV Al.18Ga.34In.48P
1.8eV Ga.5In.5P
TJ
TJ
TJ
TJ
TJ
TJ
TJ
front metal grid
front metal grid
1.0eV In.3Ga.7As
0.73eV In.53Ga.47As0.73eV In.53Ga.47As
1.0eV In.3Ga.7As
GaxIn1-xP CGB
1.4eV GaAs
1.05eV Ga.21In.79As.44P.56
2.1 eV Al.18Ga.34In.48P
1.7eV Ga.65In.35As.27P.73
0.73eV Ga.47In.53As
reflective metal contact
front metal grid
TJ
TJ
TJ
TJ
1.2eV Ga.1In.9As.21P.79
TJ
d) 6J IMM"w/ one CGB"
Presentstatus Targetdesignsfor50%efficiency45.7%now
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• Funding:ARPA-EFOCUS• Collaborators:Yale,NREL,SolAero• Goal:Hightemperaturetandemsforsolar-thermalhybridcogenera?on
HighTemperatureSolarCellsforHybridEnergy
1.0
0.8
0.6
0.4
0.2
0.0
Curr
ent
(A)
3.02.52.01.51.00.50.0
Voltage (V)
25°C100°C200°C300°C400°C
100
90
80
70
60
50
40
30
20
10
0
IQE
(%)
750700650600550500450400350
Wavelength (nm)
25°C 400°C
MO098
HigherRTEgforop?malhightemperatureEg
2Jsolarcellopera?ngat400°Cand1000X
Perletal,IEEEJPV,6,1345(2016)
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• Funding:ARPA-EMOSAIC• Collaborators:Caltech,UIUC,LBNL,NREL• Goal:Tracker-free,low-profileconcentratorusinghighradia?veefficiencyquantumdotsinpolymerwaveguidecoupledtoGaInPmicrocellsandSicells
LuminescentSolarConcentrators
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• MOVPEcrystalgrowth• III-Vsemiconductormaterialscience• Mul?junc?onsolarcelldesign• ConcentratorandSpaceapplica?ons• Op?calmodeling• Deviceprocessing• Physicsofoptoelectronicdevices
Opportuni?esforresearch
Contributetoadvancingthestate-of-the-artinmul?junc?onsolarcellefficiencies!
