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Proceedings Paper

Effects of surface ligands and solvents on quantum dot photostability under pulsed UV laser irradiation
Author(s): Victor A. Krivenkov; Pavel S. Samokhvalov; Pavel A. Linkov; Sergey D. Prokhorov; Igor L. Martynov; Alexander A. Chistyakov; Igor R. Nabiev
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Paper Abstract

The organic ligands passivating the surface of semiconductor quantum dots (QDs) and the solvents used strongly determine the photostability of QD solutions. Highly purified QD solutions in chloroform have been shown to photodegrade upon pulsed ultraviolet (UV) irradiation, irrespectively of the type of surface ligand. However, the photostability of QDs dissolved in n-octane, a more photochemically inert solvent, strongly depends on the ligands passivating their surface. In n-octane, hexadecylamine-coated QDs are completely stable and display no photochemical response to pulsed UV laser irradiation. In solutions of octanethiol-capped QDs, the photoluminescence intensity slightly decreases under irradiation. QDs coated with trioctylphosphine oxide exhibit a more complex pattern of photobleaching, which depends on the initial value of fluorescence quantum yield of QDs. This complex pattern may be accounted for by two competing processes: (1) ligand photodesorption accompanied by photobleaching due to specific alignment of the band levels of QDs and highest occupied molecular orbital of the ligand and (2) photoinduced decrease in the population of trapping states. Furthermore, practically no thermodynamic degradation of QD solutions has been observed for the micromolar QD concentration used in the study, in contrast to lower concentrations, thus confirming the photoinduced origin of the changes caused by UV irradiation. Obtained results show that the photostability of QDs may be strongly increased by careful selection of the ligands passivating their surface and the solvents used in the experiments.

Paper Details

Date Published: 7 May 2015
PDF: 7 pages
Proc. SPIE 9505, Quantum Optics and Quantum Information Transfer and Processing 2015, 95050U (7 May 2015); doi: 10.1117/12.2179240
Show Author Affiliations
Victor A. Krivenkov, National Research Nuclear Univ. MEPhI (Russian Federation)
Pavel S. Samokhvalov, National Research Nuclear Univ. MEPhI (Russian Federation)
Pavel A. Linkov, National Research Nuclear Univ. MEPhI (Russian Federation)
Lab. de Recherche en Nanosciences, Univ. de Reims Champagne-Ardenne (France)
Sergey D. Prokhorov, National Research Nuclear Univ. MEPhI (Russian Federation)
Igor L. Martynov, National Research Nuclear Univ. MEPhI (Russian Federation)
Alexander A. Chistyakov, National Research Nuclear Univ. MEPhI (Russian Federation)
Igor R. Nabiev, National Research Nuclear Univ. MEPhI (Russian Federation)
Univ. de Reims Champagne-Ardenne (France)


Published in SPIE Proceedings Vol. 9505:
Quantum Optics and Quantum Information Transfer and Processing 2015
Konrad Banaszek; Christine Silberhorn, Editor(s)

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