Auger ionization beats photo-oxidation of semiconductor quantum dots: extended stability of single-molecule photoluminescence.
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 ((1) O2 ) and preserves the PL intensity. By the detection of the NIR phosphorescence of (1) O2 and evaluation of the photostability of single QDs in aerobic, anaerobic, and (1) O2 scavenger-enriched environments, we disclose relations of Auger ionization and (1) O2 -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.
Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2217-14 Hayashi-Cho, Takamatsu, Kagawa 761-0395 (Japan); Department of Advanced Materials Science, Kagawa University, 2217-20 Hayashi-Cho, Takamatsu, Kagawa 761-0395 (Japan).
Shin-Ichi
S
Yamashita
Morihiko
M
Hamada
Shunsuke
S
Nakanishi
Hironobu
H
Saito
Yoshio
Y
Nosaka
Shin-Ichi
S
Wakida
Vasudevanpillai
V
Biju
D016166:Free Radical Scavengers; D049449:Luminescence; D036103:Nanotechnology; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D055668:Photochemical Processes; D045663:Quantum Dots; D017382:Reactive Oxygen Species; D012666:Semiconductors; D019265:Spectroscopy, Near-Infrared
D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D010100:Oxygen
Auger ionization; photochemistry; quantum dots; single-molecule studies; singlet oxygen