Chem
Volume 8, Issue 11, 10 November 2022, Pages 2978-2989
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Article
Structure of a subnanometer-sized semiconductor Cd14Se13 cluster

https://doi.org/10.1016/j.chempr.2022.06.025Get rights and content
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Highlights

  • Nonsupertetrahedral arrangement is unveiled in the stoichiometric CdSe clusters

  • Ligand-exchange-induced growth pathway of magic-sized clusters is identified

  • Site-specific Mn2+ doping is realized in Cd14Se13 cluster

  • Nanoclusters exhibit size-dependent optical and photophysical properties

The bigger picture

The size-controlled colloidal semiconductor nanocrystals promise applications in optoelectronics and catalysis. However, the atomic-level understanding of the evolution of the properties of nanocrystals is still lacking, largely due to challenges in the synthesis of atomically monodisperse nanocrystals and subsequent structural characterization. In this work, by the judicious choice of a tertiary diamine ligand, we have synthesized a single-sized Cd14Se13 cluster, the first example of a nearly stoichiometric semiconductor cluster. Its single-crystal structure reveals a nonsupertetrahedral arrangement of CdSe, which is in sharp contrast to the typical supertetrahedral structure of CdSe quantum dots. Furthermore, growth and size-conversion pathways of Cd14Se13 and Cd34Se33 clusters are mapped out. The Cd14Se13 cluster is found to be susceptible to site-specific Mn substitution, forming atomically precise dilute magnetic semiconductors for futuristic applications.

Summary

Atomic-level structure characterization is central to the science and engineering of materials. However, the crystal structure determination of magic-sized nanoclusters (MSCs), typical nuclei of the semiconductor nanocrystals, is impeded by challenges in obtaining phase-pure MSCs. Herein, we report on the synthesis and X-ray crystal structure of ∼0.9-nanometer-sized 27-atom semiconductor MSC, Cd14Se13. Its structure has a central Se atom encapsulated by a Cd14Se12 cage with an adamantane-like CdSe arrangement. Two chloride ions released in situ from the dichloromethane solvent stabilize and linearly self-assemble the clusters. The formation and growth pathways of Cd14Se13 clusters provide vital insights into the size-structure-property relationships in MSCs. Furthermore, potential sites for magnetic dopants are identified in Cd14Se13 MSC, enabling research on atomically precise dilute magnetic semiconductors.

Keywords

magic-sized clusters
colloidal semiconductors
Cd14Se13 clusters
Cd34Se33 clusters
size conversion
photoluminescence
dilute magnetic semiconductors
ligand exchange

UN Sustainable Development Goals

Other
SDG7: Affordable and clean energy

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