Manganese(II)-doped perovskite nanocrystals (NCs), because of their unique dual-color (from host excitons and Mn-dopants) emission property, are promising materials for various optical applications. Because the excited state at Mn²⁺ is extremely long-lived, one or more host excitons coexisting with an excited Mn²⁺ can be generated in the same NC under continuous excitation, and the behavior of exciton in the presence of excited Mn²⁺ can determine the optical property of Mn-doped NCs. Herein, by using pump–pump–probe transient absorption spectroscopy, we show that, in Mn-doped CsPbCl₃ NCs, the host exciton can undergo ultrafast nonradiative Auger-like recombination (τ_Aug ≈ 12 ps) when coexisting with the excited state at Mn²⁺. Such fast Auger-like process competes with the exciton-to-dopant energy transfer (τ_IET ≈ 303 ps) and, thus, allows the Mn-dopant emission from only one Mn²⁺ site per NC at a time. This dopant-induced Auger-like recombination should correspond to the broadly observed excitation-dependent saturation of dopant emission in Mn-doped NCs, and also makes the Mn-doped NC a potential single photon emitter.

中文翻译：

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锰掺杂钙钛矿纳米晶体中超快掺杂物诱导的激子似俄格复合。

锰（II）掺杂的钙钛矿纳米晶体（NCs）由于其独特的双色（来自主体激子和Mn掺杂剂）的发射特性，是用于各种光学应用的有前途的材料。由于Mn ²⁺处的激发态非常长寿，因此在连续激发下的同一NC中可以生成与激发的Mn ²⁺共存的一种或多种主体激子，并且在激发的Mn ²⁺存在下激子的行为可以确定Mn掺杂NC的光学性质。在本文中，通过使用泵-泵-探针瞬态吸收光谱，我们表明，在Mn掺杂CsPbCl ₃ NCS，主机激子可以经历非辐射超快俄歇状重组（τ_八月当与Mn ²⁺的激发态共存时（≈12 ps）。这种快速的俄歇式过程与激子到掺杂剂的能量转移（_τIET≈303 ps）竞争，因此，每个NC一次只能从一个Mn ²⁺位点发射Mn掺杂剂。这种掺杂剂诱导的俄歇样重组应该对应于在Mn掺杂的NCs中广泛观察到的激发依赖的掺杂剂发射饱和，并且还使Mn掺杂的NC成为潜在的单光子发射体。