Abstract In this work, ZnSe and ZnSe/ZnS quantum-dots (QDs) stabilized by 3-mercaptopropionic acid (MPA) were synthesized by an electrochemical method, in aqueous medium (pH 7). A paired electrolysis (i = 30 mA) of elemental selenium and zinc rod sacrificial anode was carried out in an electrochemical cavity cell, simultaneously producing Se2− (cathode) and Zn2+ (anode), which reacts in the central compartment of the cell, in a controlled way. Nanoparticles were characterized by UV–vis and fluorescence spectroscopy, XRD, and HRTEM; hydrodynamic diameter and zeta potential were also determined. ZnSe-MPA nanoparticles of 3.2 nm average diameter were obtained with a zinc blend crystal structure and luminescence QY of 4.8%. The same electrochemical procedure was carried out to synthesize ZnS-MPA, which was used in the preparation of core/shell QDs. The ZnSe/ZnS-MPA nanoparticle were prepared with diameter of 4.8 nm, and the luminescence quantum yield was increased to 9.8% due to the decrease on the number of surface defects of the ZnSe core. ZnSe/ZnS-MPA presented efficiency for Cu2+ sensing by fluorescence quenching method, showing good sensitivity with LoD = 0.17 μmol L−1. A static quenching mechanism was proposed, based on the quenching rate constant (Kq).

中文翻译：

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ZnSe/ZnS 量子点的配对电合成和 Cu2+ 荧光猝灭检测

摘要 在这项工作中，通过电化学方法在水性介质 (pH 7) 中合成了由 3-巯基丙酸 (MPA) 稳定的 ZnSe 和 ZnSe/ZnS 量子点 (QD)。在电化学空腔电池中进行元素硒和锌棒牺牲阳极的配对电解 (i = 30 mA)，同时产生 Se2−（阴极）和 Zn2+（阳极），它们在电池的中央隔室中反应，在一种受控的方式。通过紫外-可见光和荧光光谱、XRD 和 HRTEM 对纳米颗粒进行表征；还测定了流体动力学直径和zeta电位。获得平均直径为 3.2 nm 的 ZnSe-MPA 纳米粒子，具有锌混合晶体结构和 4.8% 的发光 QY。进行相同的电化学过程以合成用于制备核/壳量子点的 ZnS-MPA。制备出直径为4.8 nm的ZnSe/ZnS-MPA纳米粒子，由于ZnSe核表面缺陷数量的减少，发光量子产率提高到9.8%。ZnSe/ZnS-MPA 通过荧光猝灭法展示了 Cu2+ 传感的效率，显示出良好的灵敏度，LoD = 0.17 μmol L−1。基于猝灭速率常数 (Kq) 提出了一种静态猝灭机制。