Efficiency of Solar Cells
Outline
Intrinsic Semiconductors
Extrinsic Semiconductors: p-type
p-n Junctions
Photogeneration of Charge Carriers
Charge Carrier Separation
Efficiency of Solar Cells
Ultimate Efficiency Derivation: Assumptions
Parameters and Definitions
Ultimate Efficiency Derivation
Ultimate Efficiency Derivation
More Realistic Situation:Detailed Balance Principle
Alternative Explanation…
Inclusion of Recombination Losses
Inclusion of Impedance Matching Factor
Exceeding the Shockley-Queisser Limit: Multi-Junction Solar Cells
Exceeding the Shockley-Queisser Limit: Concentration of Sunlight
Exceeding the Shockley-Queisser Limit: Multiple Exciton Generation (MEG)
Conclusion
References
References (Images)

Exceeding the Shockley-Queisser Limit: Multiple Exciton Generation (MEG)

Nanocrystal-based solar cell efficiency can be theoretically improved by the generation of multiple electron-hole pairs from the absorption of one photon.
MEG been demonstrated in nanocrystals (quantum dots) such as PbS, PbSe, PbTe, CdS, CdSe, and InAs, as well as in single-walled carbon nanotubes.
The origin of MEG is complicated and still under debate, but one explanation is that light excites a high energy exciton which then decays irreversibly into a quasi-continuum of states available at that energy.