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Strongly Confined CsPbBr3 Quantum Dots as Quantum Emitters and Building Blocks for Rhombic Superlattices.

Published version
Peer-reviewed

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Authors

Bodnarchuk, Maryna I  ORCID logo  https://orcid.org/0000-0001-6597-3266
Bertolotti, Federica  ORCID logo  https://orcid.org/0000-0002-6001-9040
Cherniukh, Ihor 

Abstract

The success of the colloidal semiconductor quantum dots (QDs) field is rooted in the precise synthetic control of QD size, shape, and composition, enabling electronically well-defined functional nanomaterials that foster fundamental science and motivate diverse fields of applications. While the exploitation of the strong confinement regime has been driving commercial and scientific interest in InP or CdSe QDs, such a regime has still not been thoroughly explored and exploited for lead-halide perovskite QDs, mainly due to a so far insufficient chemical stability and size monodispersity of perovskite QDs smaller than about 7 nm. Here, we demonstrate chemically stable strongly confined 5 nm CsPbBr3 colloidal QDs via a postsynthetic treatment employing didodecyldimethylammonium bromide ligands. The achieved high size monodispersity (7.5% ± 2.0%) and shape-uniformity enables the self-assembly of QD superlattices with exceptional long-range order, uniform thickness, an unusual rhombic packing with an obtuse angle of 104°, and narrow-band cyan emission. The enhanced chemical stability indicates the promise of strongly confined perovskite QDs for solution-processed single-photon sources, with single QDs showcasing a high single-photon purity of 73% and minimal blinking (78% "on" fraction), both at room temperature.

Description

Funder: University of Cambridge


Funder: Royal Society

Keywords

colloidal nanocrystals, excitons, perovskites, quantum confinement, self-assembly

Journal Title

ACS Nano

Conference Name

Journal ISSN

1936-0851
1936-086X

Volume Title

17

Publisher

American Chemical Society (ACS)
Sponsorship
European Research Council (756962)
Engineering and Physical Sciences Research Council (EP/R023980/1)