Detection of luminescent single ultrasmall silicon nanoparticles using fluctuation correlation spectroscopy

O. Akcakir, J. Therrien, G. Belomoin, N. Barry, J. D. Muller, E. Gratton, M. Nayfeh

Research output: Contribution to journalArticle

Abstract

We dispersed electrochemical etched Si into a colloid of ultrasmall blue luminescent nanoparticles, observable with the naked eye, in room light. We use two-photon near-infrared femtosecond excitation at 780 nm to record the fluctuating time series of the luminescence, and determine the number density, brightness, and size of diffusing fluorescent particles. The luminescence efficiency of particles is high enough such that we are able to detect a single particle, in a focal volume, of 1 pcm3. The measurements yield a particle size of 1 nm, consistent with direct imaging by transmission electron microscopy. They also yield an excitation efficiency under two-photon excitation two to threefold larger than that of fluorescein. Detection of single particles paves the way for their use as labels in biosensing applications.

Original languageEnglish (US)
Pages (from-to)1857-1859
Number of pages3
JournalApplied Physics Letters
Volume76
Issue number14
DOIs
StatePublished - Apr 3 2000

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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