CdSe/CdS/CdTe Core/Barrier/Crown Nanoplatelets: Synthesis, Optoelectronic Properties, and Multiphoton Fluorescence Upconversion

Ali Hossain Khan, Guillaume H.V. Bertrand, Ayelet Teitelboim, Chandra Sekhar M, Anatolii Polovitsyn, Rosaria Brescia, Josep Planelles, Juan Ignacio Climente, Dan Oron, Iwan Moreels

Research output: Contribution to journalArticle

Abstract

Colloidal two-dimensional (2D) nanoplatelet heterostructures are particularly interesting as they combine strong confinement of excitons in 2D materials with a wide range of possible semiconductor junctions due to a template-free, solution-based growth. Here, we present the synthesis of a ternary 2D architecture consisting of a core of CdSe, laterally encapsulated by a type-I barrier of CdS, and finally a type-II outer layer of CdTe as so-called crown. The CdS acts as a tunneling barrier between CdSe- and CdTe-localized hole states, and through strain at the CdS/CdTe interface, it can induce a shallow electron barrier for CdTe-localized electrons as well. Consequently, next to an extended fluorescence lifetime, the barrier also yields emission from CdSe and CdTe direct transitions. The core/barrier/crown configuration further enables two-photon fluorescence upconversion and, due to a high nonlinear absorption cross section, even allows to upconvert three near-infrared photons into a single green photon. These results demonstrate the capability of 2D heterostructured nanoplatelets to combine weak and strong confinement regimes to engineer their optoelectronic properties.

Original languageEnglish
Pages (from-to)4206-4215
Number of pages10
JournalACS nano
Volume14
Issue number4
DOIs
Publication statusPublished - Apr 28 2020

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Keywords

  • fluorescence upconversion
  • k·p calculations
  • nanoplatelets
  • photoluminescence
  • ternary architecture

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Khan, A. H., Bertrand, G. H. V., Teitelboim, A., Sekhar M, C., Polovitsyn, A., Brescia, R., Planelles, J., Climente, J. I., Oron, D., & Moreels, I. (2020). CdSe/CdS/CdTe Core/Barrier/Crown Nanoplatelets: Synthesis, Optoelectronic Properties, and Multiphoton Fluorescence Upconversion. ACS nano, 14(4), 4206-4215. https://doi.org/10.1021/acsnano.9b09147