Hot electron lifetime exceeds 300 nanoseconds in quantum dots with high quantum efficiency
Abstract
Hot electrons are theoretically predicted to be long-lived in strongly confined quantum dots, which could play vital roles in quantum dot-based optoelectronics; however, existing photoexcitation transient spectroscopy investigations reveal that their lifetime is less than 1 ps in well-passivated quantum dots because of the ultrafast electron-hole Auger-assisted cooling. Therefore, they are generally considered absent in quantum dot optoelectronic devices. Here, by using our newly developed electrically excited transient absorption spectroscopy, we surprisingly observed abundant hot electrons in both II-VI and III-VI compound quantum dot light-emitting diodes at elevated bias (>4 V), of which the lifetimes reach 59 to 371 ns, lengthened by more than 5 orders of magnitude compared with the photoexcited hot electrons. These results experimentally prove the presence of a strong phonon bottleneck effect, refreshing our understanding of the role of hot electrons in quantum dot optoelectronics.
Keywords
Cite
@article{arxiv.2410.05818,
title = {Hot electron lifetime exceeds 300 nanoseconds in quantum dots with high quantum efficiency},
author = {Beibei Tang and Bo Li and Yingying Sun and Jianshun Li and Yanheng Guo and Jiaojiao Song and Xiaohan Yan and Huimin Zhang and Xiaosuo Wang and Fei Chen and Lei Wang and Jiangfeng Du and Huaibin Shen and Fengjia Fan},
journal= {arXiv preprint arXiv:2410.05818},
year = {2024}
}