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Abstract Lead sulfide (PbS) quantum dots (QDs) hold great promise for solar energy conversion, yet their efficiency is compromised by a substantial Stokes shift that adversely affects their performance in photonic devices. Here, PbS QDs are integrated within single plasmonic nanocavities, significantly mitigating Stokes shifts through Purcell enhancement of their band edge emission. This approach entails bottom‐up assembly of QDs into nanoparticle‐on‐mirror structures, leading to direct emission from band‐edge excitons with radiative lifetimes suppressed below 1 ns, a drastic decrease from the 1600 ns observed in unmodified QDs. This manipulation of the Stokes shift is attributed to the increased photonic density of states within the nanocavity, which accelerates the radiative decay process and modifies exciton relaxation pathways. These results underscore the critical role of plasmonic nanocavities in modifying QD emission characteristics, offering opportunities for enhancing QD‐based device performance across a spectrum of photonic applications.
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General strategy for tuning the Stokes shifts of near infrared cyanine dyes
We report a significant Stokes shift enhancement in near-infrared fluorescing cyanines as a result of C4′-substitution with cyclic or acyclic amines. Based on a combined experimental and density functional study, a simple strategy for optimizing the Stokes shift is proposed. By tuning the relative energies of cyanine-like and bis-dipolar conformers, differing in the rotational angle of the amine substituent, it is possible to develop molecules that undergo conformational change upon excitation, resulting in a predictable Stokes shift.
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- PAR ID:
- 10296631
- Date Published:
- Journal Name:
- Journal of Materials Chemistry C
- Volume:
- 8
- Issue:
- 47
- ISSN:
- 2050-7526
- Page Range / eLocation ID:
- 16769 to 16773
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d0tc03615c
