Shell and ligand-dependent blinking of CdSe-based core/shell nanocrystals
SCIE
SCOPUS
- Title
- Shell and ligand-dependent blinking of CdSe-based core/shell nanocrystals
- Authors
- Chon, B; Lim, SJ; Kim, W; SEO, JONGCHEOL; Kang, H; Joo, T; Hwang, J; Shin, SK
- Date Issued
- 2010-01
- Publisher
- ROYAL SOC CHEMISTRY
- 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.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/25510
- DOI
- 10.1039/B924917F
- ISSN
- 1463-9076
- Article Type
- Article
- Citation
- PHYSICAL CHEMISTRY CHEMICAL PHYSICS, vol. 12, no. 32, page. 9312 - 9319, 2010-01
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