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Title: Electronic structure of cobalt doped CdSe quantum dots using soft X-ray spectroscopy

The electronic structure and magnetic properties of cobalt doped CdSe quantum dots (QDs) are studied using electron microscopy, soft X-ray spectroscopy, and magnetometry. Magnetometry measurements suggest these QDs are superparamagnetic, contrary to a spin-glass state observed in the bulk analogue. Moreover, the electron microscopy shows well formed QDs, but with cobalt existing as doped into the QD and as unreacted species not contained in the QD. X-ray absorption measurements at the Co L3-edge suggest that changes in spectra features as a function of particle size can be described considering combination of a cobalt ion in a tetrahedral crystal field and an octahedrally coordinated (impurity) phase. With decreasing particle sizes, the impurity phase increases, suggesting that small QDs can be difficult to dope.
;  [1] ;  [2] ;  [3]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. of Maine, Orono, ME (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 2050-7526; R&D Project: 16060; KC0403020
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Materials Chemistry. C; Journal Volume: 2; Journal Issue: 39
Royal Society of Chemistry
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
29 ENERGY PLANNING, POLICY, AND ECONOMY CdSe quantum dots; electron microscopy; soft X-ray spectroscopy; functional nanomaterials