Fluorescence millisecond oscillation in polar solvents regulates fluorescence intensity of colloidal quantum dots' solution
Fluorescence millisecond oscillation in polar solvents regulates fluorescence intensity of colloidal quantum dots' solution
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DOI：
10.1117/1.2767608
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发表时间：
2007-01-01
影响因子：
1.5
通讯作者：
Yamamoto, Kenji
中科院分区：
文献类型：
--
作者：
Hoshino, Akiyoshi;Omata, Kazumi;Yamamoto, Kenji
量子点由于具有较高的发光性能和光稳定性而被广泛应用于生命科学研究中。虽然量子点的物理化学和生物学性质的变化显着的量子点的表面修饰，很少知道的原因是量子点的光致发光强度（PLI）的表面修饰改变。我们报道了量子点集体荧光振荡的脉冲光强度在毫秒范围内的变化。添加NaN3后，表面带有羧酸和羟基的量子点的PLI增强，而表面带有胺的量子点的PLI减弱，去除NaN3后，增强的PLI消失。此外，对倏逝场的观察表明，抗氧化剂的加入增强了量子点的振荡。此外，通过添加抗氧化剂，一毫秒的眨眼次数也增加了。然而，在水溶液和极性有机溶剂中观察到振荡增强，而在非极性有机溶剂中没有观察到，表明量子点与其环境溶剂之间的相互作用改变了量子点的PLI。这些毫秒振荡机制独立于传统上称为"闪烁"的"开"和"关"事件。总而言之，胶体量子点的荧光发射受到表面覆盖的胶体分子和外部溶剂在毫秒级相互作用的影响。
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.