Detection of luminescent single ultrasmall silicon nanoparticles using fluctuation correlation spectroscopy
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)
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. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20215787
- Journal Information:
- Applied Physics Letters, Vol. 76, Issue 14; Other Information: PBD: 3 Apr 2000; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
Similar Records
Stimulated blue emission in reconstituted films of ultrasmall silicon nanoparticles
Second harmonic generation in microcrystallite films of ultrasmall Si nanoparticles