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

Document Type

Article

Publication Date

3-27-2017

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.

Identifier

85019063675 (Scopus)

Publication Title

Nature Energy

External Full Text Location

https://doi.org/10.1038/nenergy.2017.52

e-ISSN

20587546

Issue

5

Volume

2

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