Ultrafast response of semiconductor nanocrystals to high-photon energy absorption: Multiexcitons from a single photon

Richard D Schaller, Milan Sykora, Jeffrey M. Pietryga, Victor I Klimov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have observed that absorption of a single photon by a semiconductor nanocrystal can produce multiple excitons with up to 100% efficiency depending upon the energy of the photon [Phys. Rev. Lett. 2004, 92, 186601]. Generation of multiexcitons from a single photon, which has been confirmed by several other research groups since our initial demonstration, also begins to occur once the process is energetically possible. This is in contrast to bulk materials, which undergo this process with low efficiency and only for significantly higher photon energies relative to the semiconductor band gap. We monitor multiexciton generation as a function of absorbed photon energy and observe that multiexcitons are produced on an ultrafast timescale following the photon absorption event. This effect is particularly attractive as a means of increasing solar cell power conversion efficiency via an increase in photocurrent for photon absorption at the blue end of the solar spectrum and has been cited as a possible operation mechanism for low-cost, high-efficiency Generation III solar cells.

Original languageEnglish
Title of host publicationACS National Meeting Book of Abstracts
Publication statusPublished - 2008
Event235th National Meeting of the American Chemical Society, ACS 2008 - New Orleans, LA, United States
Duration: Apr 6 2008Apr 10 2008

Other

Other235th National Meeting of the American Chemical Society, ACS 2008
CountryUnited States
CityNew Orleans, LA
Period4/6/084/10/08

Fingerprint

Energy absorption
Nanocrystals
Photons
Semiconductor materials
Solar cells
Photocurrents
Excitons
Conversion efficiency
Energy gap
Demonstrations
Costs

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

Cite this

Ultrafast response of semiconductor nanocrystals to high-photon energy absorption : Multiexcitons from a single photon. / Schaller, Richard D; Sykora, Milan; Pietryga, Jeffrey M.; Klimov, Victor I.

ACS National Meeting Book of Abstracts. 2008.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Schaller, RD, Sykora, M, Pietryga, JM & Klimov, VI 2008, Ultrafast response of semiconductor nanocrystals to high-photon energy absorption: Multiexcitons from a single photon. in ACS National Meeting Book of Abstracts. 235th National Meeting of the American Chemical Society, ACS 2008, New Orleans, LA, United States, 4/6/08.
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