Multiple Exciton Generation in PbSe Quantum Dots and Quantum Dot Solar Cells: Abstract No. ENFL-1

Research output: Contribution to conferencePaper


Multiple exciton generation in quantum dots (QDs) has been intensively studied as a way to enhance solar energy conversion by channeling the excess photon energy (energy greater than the bandgap) to produce multiple electron-hole pairs. Among other useful properties, quantum confinement can both increase Coulomb interactions that drive the MEG process and decrease the electron-phonon couplingthat cools hot-excitons in bulk semiconductors. We have demonstrated that MEG in PbSe QDs is about two times as efficient at producing multiple electron-hole pairs than bulk PbSe. I will discuss our recent results investigating MEG in PbSe, PbS and PbSxSe1-x, which exhibits an interesting size-dependence of the MEG efficiency. Thin films of electronically coupled PbSe QDs have shown promise insimple photon-to-electron conversion architectures with power conversion efficiencies above 5%. We recently reported an enhancement in the photocurrent resulting from MEG in PbSe QD-based solar cells. We find that the external quantum efficiency (spectrally resolved ratio of collected charge carriers to incident photons) peaked at 114% in the best devices measured, with an internal quantumefficiency of 130%. These results demonstrate that MEG charge carriers can be collected in suitably designed QD solar cells. We compare our results to transient absorption measurements and find reasonable agreement.
Original languageAmerican English
StatePublished - 2012
EventAmerican Chemical Society. 244th ACS National Meeting - Philadelphia, Pennsylvania
Duration: 19 Aug 201223 Aug 2012


ConferenceAmerican Chemical Society. 244th ACS National Meeting
CityPhiladelphia, Pennsylvania

NREL Publication Number

  • NREL/CP-5900-56365


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