Impurity incorporation and exchange interactions in Co2+-doped CdSe/CdS core/shell nanoplatelets
Author
Fainblat, R.
Delikanlı, Savaş
Spee, L.
Czerny, T.
Işık, Furkan
Sharma, V. K.
Demir, Hilmi Volkan
Bacher, G.
Date
2019Source Title
Journal of Chemical Physics
Print ISSN
0021-9606
Publisher
American Institute of Physics
Volume
151
Issue
22
Pages
224708-1 - 224708-10
Language
English
Type
ArticleItem Usage Stats
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Abstract
The intentional incorporation of transition metal impurities into colloidal semiconductor nanocrystals allows an extension of the host material’s functionality. While dopant incorporation has been extensively investigated in zero-dimensional quantum dots, the substitutional replacement of atoms in two-dimensional (2D) nanostructures by magnetic dopants has been reported only recently. Here, we demonstrate the successful incorporation of Co2+ ions into the shell of CdSe/CdS core/shell nanoplatelets, using these ions (i) as microscopic probes for gaining distinct structural insights and (ii) to enhance the magneto-optical functionality of the host material. Analyzing interatomic Co2+ ligand field transitions, we conclude that Co2+ is incorporated into lattice sites of the CdS shell, and effects such as diffusion of dopants into the CdSe core or diffusion of the dopants out of the heterostructure causing self-purification play a minor role. Taking advantage of the absorption-based technique of magnetic circular dichroism, we directly prove the presence of sp-d exchange interactions between the dopants and the band charge carriers in CdSe/Co2+:CdS heteronanoplatelets. Thus, our study not only demonstrates magneto-optical functionality in 2D nanocrystals by Co2+ doping but also shows that a careful choice of the dopant type paves the way for a more detailed understanding of the impurity incorporation process into these novel 2D colloidal materials.
Keywords
DopingNanocrystals
Exchange interactions
Ligand fields
Atomic layer deposition
Heterostructures
Nanoplatelet
Magnetic circular dichroism spectroscopy