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 journalArticlepeer-review


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
Issue number4
Early online date15 Apr 2020
StatePublished - 28 Apr 2020

All Science Journal Classification (ASJC) codes

  • General Engineering
  • General Materials Science
  • General Physics and Astronomy


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