Photoemission of the Upconverted Hot Electrons in Mn-doped CsPbBr$_3$ Nanocrystals

TL;DR

This paper demonstrates that Mn-doped CsPbBr3 nanocrystals, especially 2D nanoplatelets, can generate hot electrons via upconversion, highlighting their potential for improved photon-to-current conversion and photocatalysis.

Contribution

It introduces Mn-doped CsPbBr3 nanocrystals as a new platform for hot electron upconversion, emphasizing the advantages of 2D nanostructures and dark exciton involvement.

Findings

Hot electrons can be generated via upconversion in Mn-doped CsPbBr3 nanocrystals.

2D nanoplatelets enhance hot electron upconversion due to strong exciton-dopant interactions.

Long-lived dark excitons contribute to the hot electron upconversion process.

Abstract

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 (MHP). 2-dimensional Mn-doped CsPbBr$_3$ 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 exciton in addition to bright exciton that may enhance the upconversion efficiency. This study not only establishes the feasibility of hot electron upconversion in MHP host but also demonstrates the potential merits of 2-dimensional MHP nanocrystals in hot electron upconversion.