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Shell-dependent Blinking of CdSe-Based Core/Shell Nanocrystals



Seung Koo Shin, Bonghwan Chon, Sung Jun Lim, Wonjung Kim, Hyeong G. Kang, Taiha Joo, Jeeseong C. Hwang


Blinking of zinc-blende CdSe-based core/shell nanocrystals are studied as a function of shell materials. CdSe/ZnS, CdSe/ZnSe/ZnS, and CdSe/CdS/ZnS core/shell nanocrystals are prepared by epitaxial growth of two-to-six monolayers (MLs) of shell materials over the same green-emitting CdSe core. The time trace of blinking is recorded for single nanocrystals on a borosilicate cover glass. Both on- and off-time distributions are fit to the power law. The off-time exponents are grouped in the range of 1.45-1.70, whereas the on-time exponents are spread in the range of 1.84-2.11. The on-time duration significantly varies with shell material and thickness. As the thickness of ZnS shell increases from four-to-six MLs in CdSe/ZnS nanocrystals, the on-time duration decreases with concomitant increases in the off-time duration. On the other hand, as the shell composition and structure are changed to CdS(2ML)/ZnS(4ML), the power-law statistics remains almost identical to that of CdSe/ZnS(4ML) nanocrystals; on the contrary, the ZnSe(2ML)/ZnS(4ML) double shell over the CdSe core shortens the on-time duration. The shell-dependent power-law exponents suggest that blinking of single nanocrystals can be suppressed by reducing interfacial defects and extending the conduction band to the shell.
Physical Chemistry Chemical Physics


quantum dot, nanocrystal, core-shell


Shin, S. , Chon, B. , Lim, S. , Kim, W. , Kang, H. , Joo, T. and Hwang, J. (2010), Shell-dependent Blinking of CdSe-Based Core/Shell Nanocrystals, Physical Chemistry Chemical Physics, [online], (Accessed February 21, 2024)
Created May 9, 2010, Updated October 12, 2021