Multiple Exciton Generation for Photoelectrochemical Hydrogen Evolution Reactions with Quantum Yields Exceeding 100%

Matthew Beard, Ryan Crisp, John Turner, Gregory Pach, Yong Yan, Boris Chernomordik, Ashley Marshall, Jing Gu

Research output: Contribution to journalArticlepeer-review

168 Scopus Citations

Abstract

Multiple exciton generation (MEG) in quantum dots (QDs) has the potential to greatly increase the power conversion efficiency in solar cells and in solar-fuel production. During the MEG process, two electron-hole pairs (excitons) are created from the absorption of one high-energy photon, bypassing hot-carrier cooling via phonon emission. Here we demonstrate that extra carriers produced via MEG can be used to drive a chemical reaction with quantum efficiency above 100%. We developed a lead sulfide (PbS) QD photoelectrochemical cell that is able to drive hydrogen evolution from aqueous Na 2 S solution with a peak external quantum efficiency exceeding 100%. QD photoelectrodes that were measured all demonstrated MEG when the incident photon energy was larger than 2.7 times the bandgap energy. Our results demonstrate a new direction in exploring high-efficiency approaches to solar fuels.

Original languageAmerican English
Article numberArticle No. 17052
Number of pages7
JournalNature Energy
Volume2
Issue number5
DOIs
StatePublished - 27 Mar 2017

Bibliographical note

Publisher Copyright:
© 2017 Macmillan Publishers Limited, part of Springer Nature.

NREL Publication Number

  • NREL/JA-5900-66234

Keywords

  • multiple exciton generation
  • QD
  • quantum dots
  • solar energy conversion
  • solar fuels
  • solar-photochemistry

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