Accelerating FRET between Near-Infrared Emitting Quantum Dots Using a Molecular J-Aggregate as an Exciton Bridge

Chen Wang, Emily A Weiss

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Fast energy transfer (EnT) among quantum dots (QDs) with near-infrared (NIR) emission is essential for fully exploiting their light harvesting and photon downconversion (multiexciton generation) abilities. This paper demonstrates a relayed EnT mechanism that accelerates the migration of NIR excitons between PbS QDs by a factor of 20 from that of one-step EnT through a polyelectrolyte and even a factor of ∼2 from that of one-step EnT between QDs in direct contact, by employing a J-aggregate (J-agg) of a cyanine dye as an exciton bridge. The donor QDs, acceptor QDs, and J-agg are electrostatically assembled into a sandwich structure with layer-by-layer deposition. Estimates of EnT rate and yield from transient and steady-state absorption and photoluminescence spectroscopies show that the rate-limiting step in the relay is EnT from the donor QD to the J-agg, while EnT from the J-agg to the acceptor QD occurs in <10 ps. A comparison of this system to the analogous solution-phase system suggests that the overall donor-to-acceptor EnT yield in the relay (18%) can be improved by depositing the J-agg with more intermolecular order. This work demonstrates the viability of relayed EnT through a molecular bridge as a strategy for accelerating long-distance exciton migration in assemblies of QDs, in particular in the near-infrared.

Original languageEnglish
Pages (from-to)5666-5671
Number of pages6
JournalNano Letters
Volume17
Issue number9
DOIs
Publication statusPublished - Sep 13 2017

Fingerprint

Excitons
Energy transfer
Semiconductor quantum dots
energy transfer
quantum dots
excitons
Infrared radiation
relay
LDS 751
Photoluminescence spectroscopy
Sandwich structures
sandwich structures
Polyelectrolytes
Absorption spectroscopy
viability
assemblies
absorption spectroscopy
Coloring Agents
Photons
Dyes

Keywords

  • cyanine dye
  • FRET
  • J-aggregate
  • layer-by-layer
  • near-infrared
  • PbS quantum dots

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Accelerating FRET between Near-Infrared Emitting Quantum Dots Using a Molecular J-Aggregate as an Exciton Bridge. / Wang, Chen; Weiss, Emily A.

In: Nano Letters, Vol. 17, No. 9, 13.09.2017, p. 5666-5671.

Research output: Contribution to journalArticle

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