Jump to main content
Jump to site search

Issue 32, 2010
Previous Article Next Article

Shell and ligand-dependent blinking of CdSe-based core/shell nanocrystals

Author affiliations

Abstract

Blinking of zinc blende CdSe-based core/shell nanocrystals is studied as a function of shell materials and surface ligands. CdSe/ZnS, CdSe/ZnSe/ZnS and CdSe/CdS/ZnS core/shell nanocrystals are prepared by colloidal synthesis and six monolayers of larger bandgap shell materials are grown over the CdSe core. Organic-soluble nanocrystals covered with stearate are made water-soluble by ligand exchange with 3-mercaptopropionic acid. The light-emitting states of nanocrystals are characterized by absorption and emission spectroscopy as well as photoluminescence lifetime measurements in solution. The blinking time trace is recorded for single nanocrystals on a glass coverslip. Both on- and off-time distributions are fitted to the power law. The power-law exponents vary, depending on shell materials and surface ligands. The off-time exponents for organic and water-soluble nanocrystals are measured in the range of 1.36–1.55 and 1.25–1.37, respectively, while their on-time exponents are spread in the range of 1.53–1.86 and 1.85–2.17, respectively. Water-soluble surface passivation with thiolate prolongs the dark period regardless of shell materials and core/shell structures. Of the core/shell structures, CdSe/CdS/ZnS exhibits the longest bright state. The on/off-time exponents are inversely correlated, although the successive on/off events are not individually correlated. A two competing charge-tunneling model is presented to describe the variation of on- and off-time exponents with shell materials and surface ligands.

Graphical abstract: Shell and ligand-dependent blinking of CdSe-based core/shell nanocrystals

Back to tab navigation

Supplementary files

Publication details

The article was received on 26 Nov 2009, accepted on 06 May 2010 and first published on 07 Jul 2010


Article type: Paper
DOI: 10.1039/B924917F
Citation: Phys. Chem. Chem. Phys., 2010,12, 9312-9319
  •   Request permissions

    Shell and ligand-dependent blinking of CdSe-based core/shell nanocrystals

    B. Chon, S. J. Lim, W. Kim, J. Seo, H. Kang, T. Joo, J. Hwang and S. K. Shin, Phys. Chem. Chem. Phys., 2010, 12, 9312
    DOI: 10.1039/B924917F

Search articles by author

Spotlight

Advertisements