Research Papers

Fluorescence millisecond oscillation in polar solvents regulates fluorescence intensity of colloidal quantum dots' solution

[+] Author Affiliations
Akiyoshi Hoshino, Kazumi Omata

Research Institute,International Medical Center of Japan

Seiichi Takami, Tadafumi Adschiri

Tohoku University Graduate School of Engineering,

Naofumi Terada, Takashi Funatsu

Graduate School of Pharmaceutical Sciences, The University of Tokyo

Masato Yasuhara

Tokyo Medical and Dental University Graduate School of Medicine

Kenji Yamamoto

Research Institute,International Medical Center of Japan

J. Nanophoton. 1(1), 013516 (July 10, 2007). doi:10.1117/1.2767608
History: Received April 18, 2007; Revised June 26, 2007; Accepted July 4, 2007; July 10, 2007; Online July 10, 2007
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Abstract

Quantum Dots (QDs) have been used in life science study because of their higher emission and photostability. Although physicochemical and biological properties of QDs were varied dramatically by the surface modification of QDs, little is known about the reason why the photoluminescence intensity (PLI) of QDs was changed by surface modification. We report on the millisecond-span change of PLI of QD's collective fluorescence oscillation. QDs covered with carboxylic acid and hydroxyl groups show enhanced PLI by adding NaN3, whereas QDs with amine showed less. Removal of NaN3 from QD solution abrogated the enhanced PLI. In addition, observation on evanescent field revealed that addition of antioxidants induced enhanced oscillation of QDs. Furthermore, the blinking count at one millisecond was also increased by addition of antioxidants. However the oscillation enhancement is observed in both aqueous solution and polar organic solvents but not in nonpolar organic solvents, indicating that PLI of QD was varied by the interaction between QDs and their environmental solvents. These millisecond oscillation mechanism was independent of "on" and "off" events which were conventionally known as "blinking". Taken together, the fluorescent emission of colloidal QDs is affected by both surface-covered colloidal molecules and external solvents around at millisecond span interaction.

© 2007 Society of Photo-Optical Instrumentation Engineers

Citation

Akiyoshi Hoshino ; Kazumi Omata ; Seiichi Takami ; Tadafumi Adschiri ; Naofumi Terada, et al.
"Fluorescence millisecond oscillation in polar solvents regulates fluorescence intensity of colloidal quantum dots' solution", J. Nanophoton. 1(1), 013516 (July 10, 2007). ; http://dx.doi.org/10.1117/1.2767608


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