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 to band 50 photons edges 25 Usable electric power 0 0 1 2 3 Bandgap (eV)

Limitations Single bang gap energy C V “ Excess energy ”

Limitations Single bang gap energy 1-Sun irradiance

Limitations Single bang gap energy 1-Sun irradiance One e-h pair per photon

Limitations Single bang gap energy 1-Sun irradiance One e-h pair per photon No use of photon with E<E gap

Limitations Single bang gap energy 1-Sun irradiance C One e-h pair per photon V No use of photon with E<E gap Single population of e and h

Limitations Opportunities Single bang gap energy 1-Sun irradiance One e-h pair per photon No use of photon with E<E gap Single population of e and h

Multijunction C C V “ Excess “ Excess V energy ” energy ”

Limitations Opportunities Multijunction Single bang gap energy Concentrator Solar Cells 1-Sun irradiance One e-h pair per photon No use of photon with E<E gap Single population of e and h

Limitations Opportunities Multijunction Single bang gap energy Concentrator Solar Cells 1-Sun irradiance Down Conversion One e-h pair per photon Multiple Exciton Generation No use of photon with E<E gap Single population of e and h

Limitations Opportunities Multijunction Single bang gap energy Concentrator Solar Cells 1-Sun irradiance Down Conversion One e-h pair per photon Multiple Exciton Generation Up Conversion No use of photon with E<E gap Single population of e and h

Limitations Opportunities Multijunction Single bang gap energy Concentrator Solar Cells 1-Sun irradiance Down Conversion One e-h pair per photon Multiple Exciton Generation Up Conversion No use of photon with E<E gap Intermediate Band Solar Cells Single population of e and h Hot Carrier Solar Cells

Opportunity: down conversion e - e - e - c c versus v v h + h + h +

Opportunity: Multiple Exciton Generation E photon >2E gap e - heat e - e - e - e - C C C versus V V V h + h + h + h +

Quantum Dots CB 1P e CB 1S e E g 1S h VB 1P h VB 6 nm 2 nm

Down conversion: based on QDs Process: Si NC Si NC 1 CB CB 2 2 3 VB VB 1 3 3 3

Down conversion: based on QDs Process: Si NC Si NC 1 CB CB 2 2 VB VB 1

Down Conversion in QDs structures Jursberg et al, Appl. Phys. Lett. 233116 (2008)

Multiple Exciton Generation in QDs structures Semonin et al., Science 334, 1530 (2011).

Opportunity: up conversion e - c c versus v v h +

Opportunity: intermediate band solar cell Conduction band e - v h + Valence band

Opportunity: intermediate band solar cell Conduction band e - e - e - Intermediate band v v h + h + h + Valence band

Opportunity: Intermediate band solar cells Band-edge Built-in field metallic engineering Conduction Band E fn 1 3 Intermediate Band E fi 2 E fp Valence Band

Opportunity: Intermediate band solar cells qV + p n IB-material

Hot Carrier Solar Cell E BG hot electron and hole Energy distributions

Hot Carrier Solar Cell qV > qE gap qV E BG hot electron and hole Energy distributions

Hot Carrier Solar Cell Selective energy contacts E BG electron hot electron and hole contact Energy distributions

Hot Carrier Solar Cell Selective energy contacts E BG hole contact electron hot electron and hole contact Energy distributions

Hot Carrier Solar Cell qV > qE gap Selective energy contacts qV E BG hole contact electron hot electron and hole contact Energy distributions

` (Source: NASA)

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