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Updated: Jun 12, 2026

Observation and Analysis of Blinking Surface-enhanced Raman Scattering
Published on: January 11, 2018
Challenge to the charging model of semiconductor-nanocrystal fluorescence intermittency from off-state quantum yields
Jing Zhao1, Gautham Nair, Brent R Fisher
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Abstract:
Semiconductor nanocrystals emit light intermittently; i.e., they "blink," under steady illumination. The dark periods have been widely assumed to be due to photoluminescence (PL) quenching by an Auger-like process involving a single additional charge present in the nanocrystal. Our results challenge this long-standing assumption. Close examination of exciton PL intensity time traces of single CdSe(CdZnS) core(shell) nanocrystals reveals that the dark state PL quantum yield can be 10 times less than the biexciton PL quantum yield. In addition, we observe spectrally resolved multiexciton emission and find that it also blinks with an on/off ratio greater than 10:1. These results directly contradict the predictions of the charging model.
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