Carrier doping is important for semiconductor nanocrystals (NCs) as it offers a new knob to tune NCs’ functionalities, in addition to size and shape control. Also, extensive studies on NC devices have revealed that under operating conditions NCs are often unintentionally doped with electrons or holes. Thus, it is essential to be able to control the doping of NCs and study the carrier dynamics of doped NCs. The extension of previously reported redox-doping methods to chemically sensitive materials, such as recently introduced perovskite NCs, has remained challenging. We introduce an “intact” carrier-doping method by performing pump–pump–probe transient absorption spectroscopy on NC–acceptor complexes. The first pump pulse is used to trigger charge transfer from the NC to the acceptor, leading to NCs doped with a band edge carrier; the following pump–probe pulses measure the dynamics of carrier-doped NCs. We performed this measurement on CsPbBr₃ NCs and deduced positive and negative trion lifetimes of 220 ± 50 and 150 ± 40 ps, respectively, for 10 nm diameter NCs, both dominated by Auger recombination. It also allowed us to identify randomly photocharged excitons in CsPbBr₃ NCs as positive trions.

中文翻译：

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通过泵-泵-探针光谱结合界面电荷转移进行“完整”载流子掺杂：以CsPbBr ₃纳米晶体为例

载流子掺杂对于半导体纳米晶体（NC）很重要，因为它提供了一个新的旋钮来调节NC的功能，此外还可以控制尺寸和形状。同样，对NC设备的大量研究表明，在工作条件下，NC通常无意中被电子或空穴掺杂。因此，必须能够控制NC的掺杂并研究掺杂NC的载流子动力学。将先前报道的氧化还原掺杂方法扩展到对化学敏感的材料（例如最近推出的钙钛矿NC）的研究仍然具有挑战性。我们通过对NC-受体复合物执行泵-泵-探针瞬态吸收光谱法，引入了“完整的”载流子掺杂方法。第一个泵浦脉冲用于触发电荷从NC转移到受体，从而导致NC掺杂有带边沿载流子。随后的泵浦探测脉冲可测量载流子掺杂NC的动力学。我们在CsPbBr上执行了此测量对于直径为10 nm的NC，有_3个NC以及推论的正子和负Trion寿命分别为220±50和150±40 ps，二者均由俄歇复合法控制。它还使我们能够将CsPbBr ₃ NC中的随机带电激子识别为正三子。