Element doping plays a key role in achieving desired properties of semiconductor nanocrystals. In the energy-state landscape the doping-induced localized impurity states (LIS) can bring on significant modification of photoelectrochemical effects. It is difficult to retrieve information regarding the doping-induced LIS. Here we report on such information gleaned on a prototypical system of CdS nanocrystals slightly doped with In³⁺, through joint observations from photoluminescence (PL) and ultrafast transient absorption (TA) spectroscopy. The nonradiative nature of the In-doping induced LIS is revealed by PL. The TA observations, with a set of control experiments, enable us to capture a picture of the photoexcited electron dynamics and unravel the photoexcited electron reservoir (PEER) effect associated with the In-doping induced band gap LIS. This work establishes a fundamental, mechanistic understanding of the significant impact of element doping on the photoexcited electron dynamics in this model system, offering useful inputs for relevant material design and applications.

中文翻译：

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元素掺杂对CdS纳米晶体中光激发电子动力学的影响

元素掺杂在实现半导体纳米晶体的所需特性方面起着关键作用。在能态图中，掺杂引起的局部杂质态（LIS）可以显着改变光电化学效应。检索关于掺杂引起的LIS的信息是困难的。在这里，我们报道了这种信息，该信息收集在轻掺杂In ³⁺的CdS纳米晶体的原型系统中通过光致发光（PL）和超快速瞬态吸收（TA）光谱的联合观察。PL揭示了In-掺杂引起的LIS的非辐射性质。TA观察和一组对照实验使我们能够捕获光激发电子动力学的图片，并揭示与In掺杂引起的带隙LIS相关的光激发电子储层（PEER）效应。这项工作建立了对元素掺杂对该模型系统中光激发电子动力学的重大影响的基本的机械理解，为相关的材料设计和应用提供了有用的输入。