The influence of exposed surface on trap state of PbS quantum dots
The influence of exposed surface on trap state of PbS quantum dots
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暴露表面对PbS量子点陷阱态的影响
DOI：
10.1016/j.spmi.2020.106616
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发表时间：
2020-09-01
影响因子：
3.1
通讯作者：
Chen, Chunlan
中科院分区：
文献类型：
--
作者：
Hu, Jichao;He, Xiaomin;Chen, Chunlan
本文采用热注入法制备了PbS量子点（PbS QDs）。实验结果表明，PbS量子点的主要暴露面为（200）、（110）和（111），少量暴露面为（311）、（420）、（422）和（511）。采用第一性原理方法研究了PbS量子点的阱态能级与暴露表面之间的关系。投影态密度（PDOS）的讨论表明，化学计量PbS量子点不可能引入陷阱能级，而暴露在{110}和{111}表面的量子点将在带隙中引入陷阱能级。电荷分析表明，{111}和{110}表面的Pb原子是捕获态的主要来源。与{110}表面相比，11111表面的Pb原子更容易引入陷阱能级。密度分布结果表明，对于含有{110}表面的量子点，Pb原子的展宽电荷密度主要集中在{110}表面，而对于含有11111表面的量子点，Pb原子的展宽电荷密度主要集中在{111}表面。
In this work, the PbS quantum dots (PbS QDs) are successfully prepared by the hot-injection method. The experimental results show that the surfaces of PbS QDs mainly exposed are (200), (110), and (111) with some minor exposed surfaces (311), (420), (422), and (511). The firstprinciple method is carried out to study the relationship between the trap state levels of PbS QDs and the exposed surfaces. Projected density of states (PDOS) discussions imply that it is impossible for stoichiometric PbS QDs to introduce trap state levels, while the QDs with {110} and {111} surfaces exposed will introduce the trap energy levels in the bandgap. Charge analysis shows that the Pb atoms on the {111} and {110} surfaces are the main sources of trap states. In comparison with the {110} surface, the Pb atoms on the 11111 surface are easier to introduce the trap energy levels. The population distribution results indicate that the broadened charge densities of Pb atoms are mainly concentrated on the {110} surface for QDs containing {110} surface, while for QDs with 11111 surface, the broadened charge densities of Pb atoms are mainly located on the {111} surface.