Controlled Dopant Migration in CdS/ZnS Core/Shell Quantum Dots
Controlled Dopant Migration in CdS/ZnS Core/Shell Quantum Dots
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DOI：
10.1021/jacs.7b02320
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发表时间：
2017-07-05
影响因子：
15
通讯作者：
Zheng, Weiwei
中科院分区：
文献类型：
--
作者：
Hofman, Elan;Robinson, Richard John;Zheng, Weiwei
掺杂量子点 (QD) 的物理性质受到主晶格内的掺杂剂位点的强烈影响，这决定了主晶格的掺杂剂和激子波函数之间的重叠的主掺杂剂耦合。尽管已经开发了几种在尺寸受限的半导体纳米晶体内部引入掺杂剂的合成方法，但通过掺杂剂迁移控制的掺杂剂-主体晶格耦合仍未得到探索。在这项工作中，研究了 CdS/ZnS 核/壳量子点的晶格失配对 Mn(II) 掺杂行为的影响。研究发现，掺杂剂向核/壳量子点合金界面的迁移是一个热力学驱动的过程，可以最大限度地减少纳米晶体内的晶格应变。掺杂剂迁移速率可以用阿伦尼乌斯方程表示，因此可以通过温度和晶格失配来控制。此外，在ZnS壳钝化过程中，通过掺杂剂向合金界面的迁移，主体CdS量子点和掺杂剂之间的能量转移可以在很宽的范围内精细地转变，这提供了一种有效的方法来控制发射带的数量以及主体晶格和掺杂剂离子的发射比率。
The physical properties of a doped quantum dot (QD) are strongly influenced by the dopant site inside the host lattice, which determines the host dopant coupling from the overlap between the dopant and exciton wave functions of the host lattice. Although several synthetic methodologies have been developed for introducing dopants inside the size-confined semiconductor nanocrystals, the controlled dopant-host lattice coupling by dopant migration is still unexplored. In this work, the effect of lattice mismatch of CdS/ZnS core/shell QDs on Mn(II) dopant behavior was studied. It was found that the dopant migration toward the alloyed interface of core/shell QDs is a thermodynamically driven process to minimize the lattice strain within the nanocrystals. The dopant migration rate could be represented by the Arrhenius equation and therefore can be controlled by the temperature and lattice mismatch. Furthermore, the energy transfer between host CdS QDs and dopants can be finely turned in a wide range by dopant migration toward the alloyed interface during ZnS shell passivation, which provides an efficient method to control both the number of the emission band and the ratio of the emission from the host lattice and dopant ions.