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Title: Multiple exciton generation for photoelectrochemical hydrogen evolution reactions with quantum yields exceeding 100%

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 2S 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. Finally, our results demonstrate a new direction in exploring high-efficiency approaches to solar fuels.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ; ORCiD logo [4] ;  [4]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States); New Jersey Institute of Technology, Newark, NJ (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States); Colorado School of Mines, Golden, CO (United States)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States); San Diego State Univ., San Diego, CA (United States)
  4. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  5. National Renewable Energy Lab. (NREL), Golden, CO (United States); Univ. of Colorado, Boulder, CO (United States)
Publication Date:
Report Number(s):
NREL/JA-5900-66234
Journal ID: ISSN 2058-7546
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Nature Energy
Additional Journal Information:
Journal Volume: 2; Journal Issue: 5; Journal ID: ISSN 2058-7546
Publisher:
Nature Publishing Group
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; solar fuels; multiple exciton generation; quantum dots; QD; solar energy conversion; hydrogen energy; photocatalysis; photochemistry
OSTI Identifier:
1351583