Organic-to-Aqueous Phase Transfer of Cadmium Chalcogenide Quantum Dots using a Sulfur-Free Ligand for Enhanced Photoluminescence and Oxidative Stability.
Organic-to-Aqueous Phase Transfer of Cadmium Chalcogenide Quantum Dots using a Sulfur-Free Ligand for Enhanced Photoluminescence and Oxidative Stability.
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DOI：
10.1021/acs.chemmater.6b03106
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发表时间：
2016-09-27
期刊：
影响因子：
--
通讯作者：
Weiss EA
中科院分区：
文献类型：
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作者：
Calzada R;Thompson CM;Westmoreland DE;Edme K;Weiss EA
本文介绍了一种将胶体CD和CDSE量子点（QD）（QD）从有机溶剂转移到水的程序，通过将其天然疏水配体换成磷酸丙酸（PPA）配体，这些配体通过磷酸组结合与QD表面结合。为了生产含含硫配体的高质量水溶性QD的高质量水溶性QD的开发，该方法使用二甲基甲酰胺作为中间转移溶剂，也不是聚合物的封装层，它们在QDS对光催化和生物成像的应用中都有缺陷。 CDS（CDSE）QD使用PPA以43％（48％）的产量转移到水中。 PPA限制的CDSE QD的光致发光（PL）量子产率大于用类似的含硫硫的配体（MPA）限制的QD，在pH 7处的光致发光QD量（MPA）的光致发光量（MPA）的光致发光量（MPA）限制为QD。 MPA限制的QD中的MPA配体在EOX〜+1.7 V vs. SCE上氧化，而PPA胶囊QDS的环状伏安图显示，在高达+2.5 V vs. SCE的施加电势处没有可见的氧化峰。即使在O2的存在下，PPA限制的QD在黑暗中至少稳定了至少五天，并且在排除氧气时连续照明五天，并且存在牺牲性还原剂以捕获光生孔的孔。
This paper describes a procedure for transferring colloidal CdS and CdSe quantum dots (QDs) from organic solvents to water by exchanging their native hydrophobic ligands for phosphonopropionic acid (PPA) ligands, which bind to the QD surface through the phosphonate group. This method, which uses dimethylformamide as an intermediate transfer solvent, was developed in order to produce high-quality water soluble QDs with neither a sulfur-containing ligand nor a polymer encapsulation layer, both of which have disadvantages in applications of QDs to photocatalysis and biological imaging. CdS (CdSe) QDs were transferred to water with a 43% (48%) yield using PPA. The photoluminescence (PL) quantum yield for PPA-capped CdSe QDs is larger than that for QDs capped with the analogous sulfur-containing ligand, mercaptopropionic acid (MPA), by a factor of four at pH 7, and by up to a factor of 100 under basic conditions. The MPA ligands within MPA-capped QDs oxidize at Eox ~ +1.7 V vs. SCE, whereas cyclic voltammograms of PPA-capped QDs show no discerible oxidation peaks at applied potentials up to +2.5 V vs. SCE. The PPA-capped QDs are chemically and colloidally stable for at least five days in the dark, even in the presence of O2, and are stable when continuously illuminated for five days, when oxygen is excluded and a sacrificial reductant is present to capture photogenerated holes.