Quantification of a PbClx Shell on the Surface of PbS Nanocrystals
Author(s)
Winslow, Samuel W.; Liu, Yun; Swan, James W; Tisdale, William
DownloadPublished version (1.712Mb)
Publisher Policy
Publisher Policy
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Terms of use
Metadata
Show full item recordAbstract
Differences between the properties of PbS nanocrystals prepared using a large excess of PbCl2 and those prepared using other Pb sources have led to speculation that a thin PbClx shell may be present on the surface of PbCl2-derived PbS nanocrystals. However, characterization of this chloride layer has proven to be challenging because of the poor contrast provided by electron and X-ray scattering probes. Here, we show that small-angle neutron scattering (SANS) provides the compositional sensitivity needed to unambiguously quantify the PbClx shell that is present on the surface of PbCl2-derived PbS nanocrystals. Using a charge-balanced structural model, the scattering contribution of a ∼0.3 nm thick surface PbClx layer is parsed separately from ligand carboxylate head groups and PbS in the core. Global fitting of the SANS data across a solvent deuteration series enables unique determination of the spatial distribution of each material. These results are corroborated by quantitative nuclear magnetic resonance (NMR) and energy-dispersive X-ray spectroscopy (EDS). This work resolves a discrepancy in reported sizing curves for PbS nanocrystals prepared by different syntheses and further demonstrates the power of SANS in resolving molecular structure in soft and hybrid nanomaterials. Keyword: Quantum dots; Ligands; Layers; Solvents Nanocrystals
Date issued
2019-06Department
Massachusetts Institute of Technology. Department of Chemical EngineeringJournal
ACS Materials Lettters
Publisher
American Chemical Society (ACS)
Citation
Winslow, Samuel W. et al. "Quantification of a PbClx Shell on the Surface of PbS Nanocrystals." ACS Materials Letters 1, 2, (June 2019): 209-216 © 2019 American Chemical Society
Version: Final published version
ISSN
2639-4979
2639-4979