Ensemble Effects in the Temperature-Dependent Photoluminescence of Silicon Nanocrystals

Matthias Jakob, Morteza Javadi, Jonathan G.C. Veinot, Al Meldrum, Aras Kartouzian, Ulrich Heiz

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


In this work the temperature-dependent photoluminescence of alkyl-capped silicon nanocrystals with mean diameters of between 3 and 9 nm has been investigated. The nanocrystals were characterized extensively by FTIR, TEM, powder XRD, and X-ray photoelectron spectroscopy prior to low-temperature and time-resolved photoluminescence spectroscopy experiments. The photoluminescence (PL) properties were evaluated in the temperature range of 41–300 K. We found that the well-known temperature-dependent blueshift of the PL maximum decreases with increasing nanocrystal diameter and eventually becomes a redshift for nanocrystal diameters larger than 6 nm. This implies that the observed shifts cannot be explained solely by band-gap widening, as is commonly assumed. We propose that the luminescence of drop-cast silicon nanocrystals is affected by particle ensemble effects, which can explain the otherwise surprising temperature dependence of the luminescence peak.

Original languageEnglish
Pages (from-to)3061-3067
Number of pages7
JournalChemistry - A European Journal
Issue number12
StatePublished - 26 Feb 2019
Externally publishedYes


  • ensemble effects
  • luminescence
  • nanocrystals
  • silicon
  • time-resolved spectroscopy


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