Issue 32, 2010
From the journal:

Physical Chemistry Chemical Physics

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

Bonghwan Chon,a   Sung Jun Lim,a   Wonjung Kim,a   Jongcheol Seo,a   Hyeonggon Kang,b   Taiha Joo,a   Jeeseong Hwangb  and  Seung Koo Shin*a  

* Corresponding authors

a Bio-Nanotechnology Center, Department of Chemistry, Pohang University of Science and Technology, San31 Hyoja-dong Nam-gu, Pohang, Kyungbuk 790-784, Korea
E-mail: skshin@postech.ac.kr
Fax: +82 (0)54 279 3399
Tel: +82 (0)54 279 2123

b National Institute of Standards and Technology, Physics Laboratory, Optical Technology Division, 100 Bureau Drive, Gaithersburg, USA
Fax: +1 301 975 4580
Tel: +1 307 975 6991

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

About
Cited by
Related
Download options Please wait...

Supplementary files

Article information

DOI
https://doi.org/10.1039/B924917F
Article type
Paper
Submitted
26 Nov 2009
Accepted
06 May 2010
First published
07 Jul 2010

Phys. Chem. Chem. Phys., 2010,12, 9312-9319

Permissions

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

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements