Direct coating of quantum dots with silica shell

Yoshio Kobayashi; Takuya Nozawa; Tomohiko Nakagawa; Kohsuke Gonda; Motohiro Takeda; Noriaki Ohuchi; Atsuo Kasuya

doi:10.1007/s10971-010-2218-5

Direct coating of quantum dots with silica shell

Yoshio Kobayashi, Takuya Nozawa, Tomohiko Nakagawa, Kohsuke Gonda, Motohiro Takeda, Noriaki Ohuchi, Atsuo Kasuya

MED - Health Sciences

Research output: Contribution to journal › Article › peer-review

26 Citations (Scopus)

Abstract

This paper describes a method for direct coating of fluorescent semiconductor nanoparticles with silica shell. The fluorescent semiconductor nanoparticles used were CdSe _x Te_1-x nanoparticles coated with ZnS and succeedingly surface-modified with carboxyl groups, or quantum dots (Q-dots). The Q-dots were silica-coated by performing sol-gel reaction of tetraethyl orthosilicate (TEOS) using NaOH as a catalyst in the presence of the Q-dots. Quasi-perfect Q-dots/silica core-shell particles were formed at 5.0 M H₂O and 4.0 × 10^-4 M NaOH. Under these concentrations of H₂O and NaOH, the particle size of Q-dots/silica particles could be varied from 20.1 to 38.1 nm as the TEOS concentration increased from 2.5 × 10^-4 to 50 × 10^-4 M. The Q-dots/silica particles showed fluorescence as well as the uncoated Q-dots.

Original language	English
Pages (from-to)	79-85
Number of pages	7
Journal	Journal of Sol-Gel Science and Technology
Volume	55
Issue number	1
DOIs	https://doi.org/10.1007/s10971-010-2218-5
Publication status	Published - 2010 Jul

Keywords

Core-shell
Nanoparticle
Quantum dots
Silica-coating
Sol-gel
Stöber method

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10.1007/s10971-010-2218-5

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title = "Direct coating of quantum dots with silica shell",

abstract = "This paper describes a method for direct coating of fluorescent semiconductor nanoparticles with silica shell. The fluorescent semiconductor nanoparticles used were CdSe x Te1-x nanoparticles coated with ZnS and succeedingly surface-modified with carboxyl groups, or quantum dots (Q-dots). The Q-dots were silica-coated by performing sol-gel reaction of tetraethyl orthosilicate (TEOS) using NaOH as a catalyst in the presence of the Q-dots. Quasi-perfect Q-dots/silica core-shell particles were formed at 5.0 M H2O and 4.0 × 10-4 M NaOH. Under these concentrations of H2O and NaOH, the particle size of Q-dots/silica particles could be varied from 20.1 to 38.1 nm as the TEOS concentration increased from 2.5 × 10-4 to 50 × 10-4 M. The Q-dots/silica particles showed fluorescence as well as the uncoated Q-dots.",

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author = "Yoshio Kobayashi and Takuya Nozawa and Tomohiko Nakagawa and Kohsuke Gonda and Motohiro Takeda and Noriaki Ohuchi and Atsuo Kasuya",

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AU - Kobayashi, Yoshio

AU - Nozawa, Takuya

AU - Nakagawa, Tomohiko

AU - Gonda, Kohsuke

AU - Takeda, Motohiro

AU - Ohuchi, Noriaki

AU - Kasuya, Atsuo

PY - 2010/7

Y1 - 2010/7

N2 - This paper describes a method for direct coating of fluorescent semiconductor nanoparticles with silica shell. The fluorescent semiconductor nanoparticles used were CdSe x Te1-x nanoparticles coated with ZnS and succeedingly surface-modified with carboxyl groups, or quantum dots (Q-dots). The Q-dots were silica-coated by performing sol-gel reaction of tetraethyl orthosilicate (TEOS) using NaOH as a catalyst in the presence of the Q-dots. Quasi-perfect Q-dots/silica core-shell particles were formed at 5.0 M H2O and 4.0 × 10-4 M NaOH. Under these concentrations of H2O and NaOH, the particle size of Q-dots/silica particles could be varied from 20.1 to 38.1 nm as the TEOS concentration increased from 2.5 × 10-4 to 50 × 10-4 M. The Q-dots/silica particles showed fluorescence as well as the uncoated Q-dots.

AB - This paper describes a method for direct coating of fluorescent semiconductor nanoparticles with silica shell. The fluorescent semiconductor nanoparticles used were CdSe x Te1-x nanoparticles coated with ZnS and succeedingly surface-modified with carboxyl groups, or quantum dots (Q-dots). The Q-dots were silica-coated by performing sol-gel reaction of tetraethyl orthosilicate (TEOS) using NaOH as a catalyst in the presence of the Q-dots. Quasi-perfect Q-dots/silica core-shell particles were formed at 5.0 M H2O and 4.0 × 10-4 M NaOH. Under these concentrations of H2O and NaOH, the particle size of Q-dots/silica particles could be varied from 20.1 to 38.1 nm as the TEOS concentration increased from 2.5 × 10-4 to 50 × 10-4 M. The Q-dots/silica particles showed fluorescence as well as the uncoated Q-dots.

KW - Core-shell

KW - Nanoparticle

KW - Quantum dots

KW - Silica-coating

KW - Sol-gel

KW - Stöber method

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Direct coating of quantum dots with silica shell

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Keywords

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