Chemical insight into the origin of red and blue photoluminescence arising from freestanding silicon nanocrystals

Mita Dasog, Zhenyu Yang, Sarah Regli, Tonya M. Atkins, Angelique Faramus, Mani P. Singh, Elayaraja Muthuswamy, Susan M. Kauzlarich, Richard D. Tilley, Jonathan G C Veinot

Research output: Contribution to journalArticlepeer-review

224 Scopus citations


Silicon nanocrystals (Si NCs) are attractive functional materials. They are compatible with standard electronics and communications platforms and are biocompatible. Numerous methods have been developed to realize size-controlled Si NC synthesis. While these procedures produce Si NCs that appear identical, their optical responses can differ dramatically. Si NCs prepared using high-temperature methods routinely exhibit photoluminescence agreeing with the effective mass approximation (EMA), while those prepared via solution methods exhibit blue emission that is somewhat independent of particle size. Despite many proposals, a definitive explanation for this difference has been elusive for no less than a decade. This apparent dichotomy brings into question our understanding of Si NC properties and potentially limits the scope of their application. The present contribution takes a substantial step forward toward identifying the origin of the blue emission that is not expected based upon EMA predictions. It describes a detailed comparison of Si NCs obtained from three of the most widely cited procedures as well as the conversion of red-emitting Si NCs to blue emitters upon exposure to nitrogen-containing reagents. Analysis of the evidence is consistent with the hypothesis that the presence of trace nitrogen and oxygen even at the parts per million level in Si NCs gives rise to the blue emission.

Original languageEnglish (US)
Pages (from-to)2676-2685
Number of pages10
JournalACS Nano
Issue number3
StatePublished - Mar 26 2013


  • nitrogen
  • photoluminescence
  • silicon nanocrystals
  • surface functionalization

ASJC Scopus subject areas

  • Engineering(all)
  • Materials Science(all)
  • Physics and Astronomy(all)


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