Hot electrons play a crucial role in enhancing the efficiency of photon-to-current conversion or photocatalytic reactions. In semiconductor nanocrystals, energetic hot electrons capable of photoemission can be generated via the upconversion process involving the dopant-originated intermediate state, currently known only in Mn-doped cadmium chalcogenide quantum dots. Here, we report that Mn-doped CsPbBr₃ nanocrystals are an excellent platform for generating hot electrons via upconversion that can benefit from various desirable exciton properties and the structural diversity of metal halide perovskites (MHPs). Two-dimensional Mn-doped CsPbBr₃ nanoplatelets are particularly advantageous for hot electron upconversion due to the strong exciton–dopant interaction mediating the upconversion process. Furthermore, nanoplatelets reveal evidence for the hot electron upconversion via long-lived dark excitons in addition to bright excitons that may enhance the upconversion efficiency. This study establishes the feasibility of hot electron upconversion in MHP hosts and demonstrates the potential merits of two-dimensional MHP nanocrystals in the upconversion process.

中文翻译：

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Mn 掺杂 CsPbBr3 纳米晶体中上转换热电子的光电发射

热电子在提高光子到电流转换或光催化反应的效率方面起着至关重要的作用。在半导体纳米晶体中，能够光发射的高能热电子可以通过涉及掺杂剂起源的中间态的上转换过程产生，目前仅在 Mn 掺杂的镉硫族化物量子点中已知。在这里，我们报告了 Mn 掺杂的 CsPbBr ₃纳米晶体是通过上转换产生热电子的绝佳平台，可以受益于各种理想的激子特性和金属卤化物钙钛矿 (MHP) 的结构多样性。二维Mn掺杂CsPbBr ₃由于介导上转换过程的强激子-掺杂剂相互作用，纳米片对于热电子上转换特别有利。此外，除了可以提高上转换效率的亮激子外，纳米片还揭示了通过长寿命暗激子进行热电子上转换的证据。本研究确立了在 MHP 主体中进行热电子上转换的可行性，并展示了二维 MHP 纳米晶体在上转换过程中的潜在优点。