Auger Ionization Beats Photo‐Oxidation of Semiconductor Quantum Dots: Extended Stability of Single‐Molecule Photoluminescence |
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| Authors: | Shin‐ichi Yamashita Morihiko Hamada Prof Shunsuke Nakanishi Hironobu Saito Prof Yoshio Nosaka Dr Shin‐ichi Wakida Dr Vasudevanpillai Biju |
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| Affiliation: | 1. Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2217‐14 Hayashi‐Cho, Takamatsu, Kagawa 761‐0395 (Japan);2. Department of Advanced Materials Science, Kagawa University, 2217‐20 Hayashi‐Cho, Takamatsu, Kagawa 761‐0395 (Japan);3. Department of Materials Science and Technology, Nagaoka Technological University, Kamitomioka, Nagaoka 940‐2188 (Japan) |
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| Abstract: | Despite the bright and tuneable photoluminescence (PL) of semiconductor quantum dots (QDs), the PL instability induced by Auger recombination and oxidation poses a major challenge in single‐molecule applications of QDs. The incomplete information about Auger recombination and oxidation is an obstacle in the resolution of this challenge. Here, we report for the first time that Auger‐ionized QDs beat self‐sensitized oxidation and the non‐digitized PL intensity loss. Although high‐intensity photoactivation insistently induces PL blinking, the transient escape of QDs into the ultrafast Auger recombination cycle prevents generation of singlet oxygen (1O2) and preserves the PL intensity. By the detection of the NIR phosphorescence of 1O2 and evaluation of the photostability of single QDs in aerobic, anaerobic, and 1O2 scavenger‐enriched environments, we disclose relations of Auger ionization and 1O2‐mediated oxidation to the PL stability of single QDs, which will be useful during the formulation of QD‐based single‐molecule imaging tools and single‐photon devices. |
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| Keywords: | Auger ionization photochemistry quantum dots single‐molecule studies singlet oxygen |
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