Single Fluorophore Blinking

Synonyms

Fluorescent intermittency; Photoblinking; Photoswitch

Definition

Light-emitting species, including organic dye molecules, fluorescent proteins and semiconductor particles, are prone to enter transient dark states, collectively referred to as “blinking” events. Depending on the nature of the fluorophore species, the illumination source and intensity, as well as the environmental conditions, blinking events can range from rare to frequent and last from microseconds to minutes. Blinking events are distinguished from photobleaching, the irreversible loss of fluorescence, by their temporary nature.

Temporary dark states can arise for a variety of reasons. In the case of organic fluorophores, transient dark states may occur due to reversible isomerization of the conjugated π orbital system, resulting in temporary formation of a low-fluorescent isomer and thus cycles of bright and dark states. Organic fluorophores may also undergo intersystem crossing, a low probability electronic...