title: Colloidal quantum dots as saturable fluorophores.
abstract: Although colloidal quantum dots (QDs) exhibit excellent photostability under mild excitation, intense illumination makes their emission increasingly intermittent, eventually leading to photobleaching. We study fluorescence of two commonly used types of QDs under pulsed excitation with varying power and repetition rate. The photostability of QDs is found to improve dramatically at low repetition rates, allowing for prolonged optical saturation of QDs without apparent photodamage. This observation suggests that QD blinking is facilitated by absorption of light in a transient state with a microsecond decay time. Enhanced photostability of generic quantum dots under intense illumination opens up new prospects for fluorescence microscopy and spectroscopy.
authors.affiliation: Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel 76100. osip.schwarz@weizmann.ac.il
authors.forename: Osip
authors.initials: O
authors.lastname: Schwartz
authors.forename: Ron
authors.initials: R
authors.lastname: Tenne
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Levitt
authors.forename: Zvicka
authors.initials: Z
authors.lastname: Deutsch
authors.forename: Stella
authors.initials: S
authors.lastname: Itzhakov
authors.forename: Dan
authors.initials: D
authors.lastname: Oron
mesh_terms: D003102:Colloids / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008422:Materials Testing; D045663:Quantum Dots
chemical_list: D003102:Colloids