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Surface Properties of Nanocrystalline PbS Films Deposited at the Water-Oil Interface: A Study of Atmospheric Aging

På svenska

Author

  • David J. H. Cant
  • Karen L. Syres
  • Patrick J. B. Lunt
  • Hanna Radtke
  • Jon Treacy
  • P. John Thomas
  • Edward A. Lewis
  • Sarah J. Haigh
  • Paul O'Brien
  • Karina Schulte
  • Federica Bondino
  • Elena Magnano
  • Wendy R. Flavell
Show all

Summary, in English

Nanocrystalline thin films of PbS are obtained in a straightforward reaction by precipitation at the interface between toluene (containing a Pb precursor) and water (containing Na2S). Lead thiobiuret [Pb(SON(CN(i)Pr-2)(2))(2)] and lead diethyldithiocarbamate [Pb(S2CNEt2)(2)] precursors are used. The films are characterized by X-ray diffraction and electron microscopy, revealing typical particle sizes of 10-40 nm and preferred (200) orientation. Synchrotron-excited depth-profiling X-ray photoelectron spectroscopy (XPS) is used to determine the depth-dependent chemical composition as a function of surface aging in air for periods of up to 9 months. The as-synthesized films show a 1:1 Pb/S composition. Initial degradation occurs to form lead hydroxide and small quantities of surface-adsorbed -SH species. A lead-deficient Pb1-xS phase is produced as the aging proceeds. Oxidation of the sulfur occurs later to form sulfite and sulfate products that are highly localized at the surface layers of the nanocrystals. These species show logarithmic growth kinetics, demonstrating that the sulfite/sulfate layer acts to passivate the nanocrystals. Our results demonstrate that the initial reaction of the PbS nanocrystals (forming lead hydroxide) is incongruent. The results are discussed in the context of the use of PbS nanocrystals as light-harvesting elements in next-generation solar technology.

Department/s

Publishing year

2015

Language

English

Pages

1445-1453

Publication/Series

Langmuir

Volume

31

Issue

4

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Natural Sciences
  • Physical Sciences

Status

Published

ISBN/ISSN/Other

  • ISSN: 0743-7463