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Arno Smets
`
(Source: NASA)
Third Generation PV and Other Ways to Utilize Solar Energy Third - - PowerPoint PPT Presentation
Third Generation PV and Other Ways to Utilize Solar Energy Third - - PowerPoint PPT Presentation
Third Generation PV and Other Ways to Utilize Solar Energy Third Generation PV Technologies Week 6.1 Arno Smets ` (Source: NASA) Shockley-Queisser limit 100 Other losses Percentage of incident 75 Relaxation light energy Below-bandgap
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75 50 25
Bandgap (eV)
Shockley-Queisser limit
Percentage of incident light energy
1 3 2 100
Usable electric power Below-bandgap photons Relaxation to band edges Other losses
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Limitations
Single bang gap energy “Excess energy” V C
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Limitations
Single bang gap energy 1-Sun irradiance
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Limitations
Single bang gap energy 1-Sun irradiance One e-h pair per photon
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Limitations
Single bang gap energy 1-Sun irradiance One e-h pair per photon No use of photon with E<Egap
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Limitations
Single bang gap energy 1-Sun irradiance One e-h pair per photon No use of photon with E<Egap Single population of e and h V C
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Limitations Opportunities
Single bang gap energy 1-Sun irradiance One e-h pair per photon No use of photon with E<Egap Single population of e and h
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Multijunction
“Excess energy” V C “Excess energy” V C
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Limitations Opportunities
Single bang gap energy 1-Sun irradiance One e-h pair per photon No use of photon with E<Egap Single population of e and h Multijunction Concentrator Solar Cells
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Limitations Opportunities
Single bang gap energy 1-Sun irradiance One e-h pair per photon No use of photon with E<Egap Single population of e and h Multijunction Concentrator Solar Cells Down Conversion Multiple Exciton Generation
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Limitations Opportunities
Single bang gap energy 1-Sun irradiance One e-h pair per photon No use of photon with E<Egap Single population of e and h Multijunction Concentrator Solar Cells Down Conversion Multiple Exciton Generation Up Conversion
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Limitations Opportunities
Single bang gap energy 1-Sun irradiance One e-h pair per photon No use of photon with E<Egap Single population of e and h Multijunction Concentrator Solar Cells Down Conversion Multiple Exciton Generation Intermediate Band Solar Cells Hot Carrier Solar Cells Up Conversion
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Opportunity: down conversion
versus
c v e- h+ e- h+ c v e- h+
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Opportunity: Multiple Exciton Generation
e- h+ e-
heat
C V
e- h+ e- h+
Ephoton>2Egap
h+ e-
C V C V versus
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Quantum Dots
CB VB
1Pe 1Se 1Sh 1Ph
Eg CB VB 2 nm 6 nm
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Down conversion: based on QDs
CB 1 3 3 2 Si NC Si NC CB VB VB
3 3 2 1
Process:
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Down conversion: based on QDs
CB 1 2 Si NC Si NC CB VB VB
2 1
Process:
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Down Conversion in QDs structures
Jursberg et al, Appl. Phys. Lett. 233116 (2008)
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Multiple Exciton Generation in QDs structures
Semonin et al., Science 334, 1530 (2011).
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Opportunity: up conversion
versus
c v e- h+ c v
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Opportunity: intermediate band solar cell
Conduction band v e- h+ Valence band
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Opportunity: intermediate band solar cell
Conduction band v e- h+ Valence band v e- h+ e- h+ Intermediate band
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Opportunity: Intermediate band solar cells
metallic Built-in field Band-edge engineering
Conduction Band Intermediate Band Valence Band
1 3 2 Efn Efi Efp
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Opportunity: Intermediate band solar cells
qV
IB-material
n p +
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Hot Carrier Solar Cell
EBG
hot electron and hole Energy distributions
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Hot Carrier Solar Cell
EBG
hot electron and hole Energy distributions
qV qV > qEgap
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Hot Carrier Solar Cell
EBG
electron contact hot electron and hole Energy distributions Selective energy contacts
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Hot Carrier Solar Cell
EBG
electron contact hot electron and hole Energy distributions hole contact Selective energy contacts
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Hot Carrier Solar Cell
EBG
electron contact hot electron and hole Energy distributions hole contact Selective energy contacts
qV qV > qEgap
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`
(Source: NASA)
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