Influence of Dopant Distribution on the Plasmonic Properties of Indium Tin Oxide Nanocrystals

Journal Article · Wed May 14 00:00:00 EDT 2014 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja502541z· OSTI ID:1211171

Lounis, SD; Runnerstrom, EL; Bergerud, A; Nordlund, D; Milliron, DJ

Doped metal oxide nanocrystals represent an exciting frontier for colloidal synthesis of plasmonic materials, displaying unique optoelectronic properties and showing promise for a variety of applications. However, fundamental questions about the nature of doping in these materials remain. In this article, the strong influence of radial dopant distribution on the optoelectronic properties of colloidal indium tin oxide nanocrystals is reported. Comparing elemental depth-profiling by X-ray photoelectron spectroscopy (XPS) with detailed modeling and simulation of the optical extinction of these nanocrystals using the Drude model for free electrons, a correlation between surface segregation of tin ions and the average activation of dopants is observed. A strong influence of surface segregation of tin on the line shape of the localized surface plasmon resonance (LSPR) is also reported. Samples with tin segregated near the surface show a symmetric line shape that suggests weak or no damping of the plasmon by ionized impurities. It is suggested that segregation of tin near the surface facilitates compensation of the dopant ions by electronic defects and oxygen interstitials, thus reducing activation. A core shell model is proposed to explain the observed differences in line shape. These results demonstrate the nuanced role of dopant distribution in determining the optoelectronic properties of semiconductor nanocrystals and suggest that more detailed study of the distribution and structure of defects in plasmonic colloidal nanocrystals is warranted.

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• OSTI ID: 1211171
• Journal Information: Journal of the American Chemical Society, Vol. 136, Issue 19; ISSN 0002-7863
• Country of Publication: United States
• Language: English