State Key Laboratory of Medicinal Chemical Biology, College of Chemistry, Nankai University, Tianjin, 300071, China.
Chemistry. 2013 May 10;19(20):6282-8. doi: 10.1002/chem.201204372. Epub 2013 Mar 22.
The study of the composition, morphology, and surface structure of carbon dots (Cdots) is critical to understanding their effect on the photo- and electrochemiluminescence (PL and ECL) of Cdots in selected applications. Herein, two kinds of Cdots were prepared with 3-(3,4-dihydroxyphenyl)-L-alanine (L-DOPA) as precursor. The Cdots prepared by using a carbonization-extraction strategy have a low oxidation level and are denoted as reduced Cdots (r-Cdots). The Cdots obtained with a carbonization-oxidation process are highly oxidized and are denoted as oxidized Cdots (o-Cdots). The o-Cdots have a carbon core and oxygen-containing loose shell, but the r-Cdots consist mainly of the carbon core. Whereas r-Cdots have a strong blue PL but no apparent ECL response, o-Cdots exhibit a relatively weak PL and strong ECL emission. These properties allow for selected applications of the Cdots. The r-Cdots were used in cell imaging with their high PL emission. The o-Cdots, with their high ECL efficiencies, were selected to sense Cu(2+) with Cu(2+) -inducing ECL quenching in the o-Cdots/K2 S2 O8 system. This work provides the possibility to control the composition of Cdots for selected applications and shows a good way to characterize surface traps of Cdots because ECL is characterized by the surface-state and PL is mainly related to the core-state in Cdots.
研究碳点（Cdots）的组成、形态和表面结构对于理解它们在某些应用中对 Cdots 的光致发光（PL）和电致发光（ECL）的影响至关重要。在此，我们使用 3-(3,4-二羟基苯基）-L-丙氨酸（L-DOPA）作为前驱体制备了两种 Cdots。采用碳化-萃取策略制备的 Cdots 氧化程度较低，被标记为还原型 Cdots（r-Cdots）。采用碳化-氧化法得到的 Cdots 氧化程度较高，被标记为氧化型 Cdots（o-Cdots）。o-Cdots 具有碳核和含氧疏松壳，而 r-Cdots 主要由碳核组成。r-Cdots 具有很强的蓝色 PL 但没有明显的 ECL 响应，而 o-Cdots 则表现出相对较弱的 PL 和很强的 ECL 发射。这些特性使得 Cdots 可以应用于某些特定领域。r-Cdots 因其高 PL 发射而被用于细胞成像。而 o-Cdots 因其高 ECL 效率，被选择用于在 o-Cdots/K2S2O8 体系中通过 Cu(2+)诱导的 ECL 猝灭来检测 Cu(2+)。这项工作为控制 Cdots 的组成以应用于某些特定领域提供了可能，并展示了一种很好的方法来表征 Cdots 的表面陷阱，因为 ECL 主要由表面态决定，而 PL 主要与 Cdots 的核态有关。
