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Probing Dynamics of Lead(II) Sulfide Quantum Dots in Solution Ligand Exchange by Voltammetry
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2021-02-04 , DOI: 10.1021/acs.jpclett.0c03423
Jie Chen 1 , Chonglin Yuan 1 , Weili Liang 2 , Nanlin Zhang 2 , Xiaolin Zhang 1 , Zhiwei Wang 1 , Chengqun Wang 2 , Xiuting Li 1
Affiliation  

The ligand/quantum dots (QDs) ratio is crucial for the liquid state ligand exchange process to ensure a high-quality surface passivation and stable QDs ink. Herein we report an electrochemical method to investigate the ligand exchanged PbS-PbI2 QDs. It is found that the shell and core Pb(II) are distinguished by their reduction peak position in the cyclic voltammogram and the peak charge ratio gives the shell/core composition of the QDs. Combined with XPS analysis and UV–vis spectroscopy, it is further indicated that the shell/core ratio of PbS-PbI2 QDs varies as the ligand PbI2 concentration changes. Specifically, below a certain concentration, more PbI2 binds to the QD surface, leading to better passivation when the PbI2 concentration increases; however, beyond that concentration, decomposition of QDs likely occurs via an anion exchange process. The presented electrochemical method provides a new and powerful tool to investigate and optimize QD surface chemistry for boosting the scale up applications of QD devices.

中文翻译:

伏安法测定溶液配体中硫化铅(II)量子点的动力学

配体/量子点(QDs)比率对于液态配体交换过程至关重要,以确保高质量的表面钝化和稳定的QDs墨水。在这里,我们报告了一种电化学方法来研究配体交换的PbS-PbI 2 QDs。发现壳和核Pb(II)的区别在于它们在循环伏安图中的还原峰位置,并且峰电荷比给出了QD的壳/核组成。结合XPS分析和紫外-可见光谱,进一步表明PbS-PbI 2 QD的壳/核比随配体PbI 2浓度的变化而变化。具体而言,在一定浓度以下时,更多的PbI 2结合到QD表面,导致当PbI更好的钝化2浓度增加;但是,超过该浓度,QD的分解可能会通过阴离子交换过程发生。提出的电化学方法为研究和优化QD表面化学性质提供了一个新颖而强大的工具,以促进QD设备的大规模应用。
更新日期:2021-02-11
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