Dye-Sensitized Multiple Exciton Generation in Lead Sulfide Quantum Dots

Zhiyuan Huang, Matthew Beard

Research output: Contribution to journalArticlepeer-review

8 Scopus Citations

Abstract

Multiple exciton generation (MEG), the generation of multiple excitons from the absorption of a single high-energy photon, is a strategy to go beyond the limiting efficiencies that define current-day solar cells by harvesting some of the thermalization energy losses that occur when photons with an energy greater than the semiconductor bandgap are absorbed. In this work, we show that organic dyes can sensitize MEG in semiconductor quantum dots (QDs). In particular, we found that surface-anchored pyrene ligands enhanced the photon-to-charge carrier quantum yield of PbS QDs from 113 ± 3% to 183 ± 7% when the photon energy was 3.9 times the band gap. A wavelength dependence study shows that the enhancement is positively correlated with the pyrene absorptivity. Transient absorption and steady-state photoluminescence measurements suggest that the MEG sensitization is based on an initial fast electron transfer from the pyrene ligands to the PbS QDs producing hot-electrons in the QDs that subsequently undergo MEG. This work demonstrates that hybrid and synergistic organic/inorganic interactions can be a successful strategy to enhance MEG.

Original languageAmerican English
Pages (from-to)15855-15861
Number of pages7
JournalJournal of the American Chemical Society
Volume144
Issue number34
DOIs
StatePublished - 31 Aug 2022

Bibliographical note

Publisher Copyright:
© 2022 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-83320

Keywords

  • hybrid organic/inorganic systems
  • multiple exciton generation
  • nanostructures
  • PbS QDs
  • solar-photochemistry

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