@article{Bieniek2024, 
author = {Jan Bieniek and Woonhyuk Baek and Severin Lorenz and Franziska Muckel and Rachel Fainblat and Taeghwan Hyeon and Gerd Bacher},
title = {Impact of exciton fine structure on the energy transfer in magic-sized (CdSe)13 clusters},
year = {2024},
journal = {Nano Research},
volume = {17},
number = {12},
pages = {10669-10676},
keywords = {surface defects, energy transfer, Mn-doping, magic-sized cluster, excitonic fine structure},
url = {https://www.sciopen.com/article/10.1007/s12274-024-7108-1},
doi = {10.1007/s12274-024-7108-1},
abstract = {Magic-sized (CdSe)13 clusters (MSCs) represent a material class at the boundary between molecules and quantum dots that exhibit a pronounced and well separated excitonic fine structure. The characteristic photoluminescence is composed of exciton bandgap emission and a spectrally broad mid-gap emission related to surface defects. Here, we report on a thermally activated energy transfer from fine-structure split exciton states to surface states by using temperature dependent photoluminescence excitation spectroscopy. We demonstrate that the broad mid-gap emission can be suppressed by a targeted Mn-doping of the MSC leading to the characteristic orange luminescence of the 4T1 → 6A1 Mn2+ transition. The energy transfer to the Mn2+ states is found to be significantly different than the transfer to the surface defect states, as the activation of the dopant emission requires a spin-conserving charge carrier transfer that only dark excitons can provide.}
}