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Long-range order enabled stability in quantum dot light-emitting diodes

Abstract:
Light-emitting diodes (LEDs) based on perovskite quantum dots (QDs) have produced external quantum efficiencies (EQEs) of more than 25% with narrowband emission1,2, but these LEDs have limited operating lifetimes. We posit that poor long-range ordering in perovskite QD films—variations in dot size, surface ligand density and dot-to-dot stacking—inhibits carrier injection, resulting in inferior operating stability because of the large bias required to produce emission in these LEDs. Here we report a chemical treatment to improve the long-range order of perovskite QD films: the diffraction intensity from the repeating QD units increases three-fold compared with that of controls. We achieve this using a synergistic dual-ligand approach: an iodide-rich agent (aniline hydroiodide) for anion exchange and a chemically reactive agent (bromotrimethylsilane) that produces a strong acid that in situ dissolves smaller QDs to regulate size and more effectively removes less conductive ligands to enable compact, uniform and defect-free films. These films exhibit high conductivity (4 × 10−4 S m−1), which is 2.5-fold higher than that of the control, and represents the highest conductivity recorded so far among perovskite QDs. The high conductivity ensures efficient charge transportation, enabling red perovskite QD-LEDs that generate a luminance of 1,000 cd m−2 at a record-low voltage of 2.8 V. The EQE at this luminance is more than 20%. Furthermore, the stability of the operating device is 100 times better than previous red perovskite LEDs at EQEs of more than 20%.
Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1038/s41586-024-07363-7

Authors


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Role:
Author
ORCID:
0000-0002-8970-6856
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Role:
Author
ORCID:
0000-0001-8137-9152
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Institution:
University of Oxford
Division:
MPLS
Department:
Physics
Sub department:
Condensed Matter Physics
Role:
Author
ORCID:
0000-0001-9638-3453
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Role:
Author
ORCID:
0000-0001-5920-4022


Publisher:
Springer Nature
Journal:
Nature More from this journal
Volume:
629
Issue:
8012
Pages:
586-591
Place of publication:
England
Publication date:
2024-05-08
Acceptance date:
2024-03-27
DOI:
EISSN:
1476-4687
ISSN:
0028-0836
Pmid:
38720080


Language:
English
Pubs id:
1995419
Local pid:
pubs:1995419
Deposit date:
2024-05-22

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