Abstract 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 first-principle 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 {111} 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 {111} surface, the broadened charge densities of Pb atoms are mainly located on the {111} surface.

中文翻译：

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暴露表面对PbS量子点陷阱态的影响

摘要 本工作采用热注射法成功制备了PbS量子点(PbS QDs)。实验结果表明，PbS QDs 的主要暴露表面为（200）、（110）和（111），还有一些次要的暴露表面（311）、（420）、（422）和（511）。第一性原理方法用于研究 PbS QD 的陷阱态能级与暴露表面之间的关系。投影态密度 (PDOS) 讨论意味着化学计量的 PbS QD 不可能引入陷阱态能级，而 {110} 和 {111} 表面暴露的 QD 将在带隙中引入陷阱能级。电荷分析表明{111}和{110}表面的Pb原子是陷阱态的主要来源。与 {110} 表面相比，{111} 表面的 Pb 原子更容易引入陷阱能级。布居分布结果表明，对于含有{110}面的量子点，Pb原子的加宽电荷密度主要集中在{110}面上，而对于具有{111}面的量子点，Pb原子的加宽电荷密度主要集中在{110}面。 {111} 表面。