Color-Switchable, Emission-Enhanced Fluorescence Realized by Engineering C-dot@C-dot Nanoparticles

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• 作者：Zhen Guo ; Zhiqiang Zhang ; Wei Zhang ; Lianqun Zhou ; Haiwen Li ; Hongmei Wang ; Caroline Andreazza-Vignolle ; Pascal Andreazza ; Dongxu Zhao ; Yihui Wu ; Quanlong Wang ; Tao Zhang ; Keming Jiang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：December 10, 2014
• 年：2014
• 卷：6
• 期：23
• 页码：20700-20708
• 全文大小：522K
• ISSN：1944-8252

文摘

This paper reports the preparation and properties of color-switchable fluorescent carbon nanodots (C-dots). C-dots that emit dark turquoise and green鈥搚ellow fluorescence under 365 nm UV illumination were obtained from the hydrothermal decomposition of citric acid. Dark green fluorescent C-dots were obtained by conjugating prepared C-dots to form C-dot@C-dot nanoparticles. After successful conjugation of the C-dots, the fluorescence emission undergoes a blue-shift of nearly 20 nm (鈭?.15 eV) under UV excitation at 370 nm. The C-dots emit goldenrod, green鈥搚ellow, and gold light under excitation at 455 nm, which shows that the prepared C-dots are color-switchable. Furthermore, conjugation of the C-dots results in enhanced, red-shifted absorption of the 蟺鈥撓€* transition of the aromatic spp>2p> domains due to the conjugated 蟺-electron system. N incorporation in the carbon structure leads to a degree of dipoles for all the aromatic spp>2p> bonds. The enhanced absorption in a wide range from 226 to 601 nm indicates extended conjugation in the C-dot@C-dot structure. The time-resolved average lifetimes for the three different types of C-dots prepared in this study are 7.10, 7.65, and 4.07 ns. The radiative rate (reduced decay lifetime) increases when the C-dots are conjugated in the C-dot@C-dot nanoparticles, leading to the enhanced fluorescence emission. The fluorescence emission of the C-dot@C-dot nanoparticles can be used in applications such as flow cytometry and cell imaging.

Keywords:

color switching; emission enhancement; fluorescent carbon nanodots; conjugating nanoparticles