Fluorescence intermittency,or blinking, is the phenomena in which a single QD's fluorescence switches between a bright and a dark state. Although extensively researched throughout the past 15 years, the mechanism behind blinking is still far from being well understood. While a first explanation of blinking dynamics through a universal charging mechanism had given an explanation to many experimental results, recent developments in the field point out that blinking is a general name for a phenomena with many faces [1,2,3]. I will present two recent works which demonstrate the variety of dynamics that blinking encompasses. In the first it was found that blinking and damage in QDs are highly suppressed by allowing microsecond-scale interval between exciting pulses, leading to the conclusion that an intermediate state plays a roll in switching from "on" to "off" state [4]. In the second, I will present how a switching is at times between three states "on", "grey" and "off" and show how examining a complicated heterostructure can shed light on the nature of the "grey" state.

[1] - S Rosen, O Schwartz, D Oron - Phys. Rev. Lett. 157404 (2010)

[2] - C Galland, Y Ghosh, A Steinbruck, M Sykora, J A Hollingsworth, V I Klimov, H Htoon, Nature 479, 203-207 (2011)

[3] - W Qin, P Guyot-Sionnest - ACS Nano 6 (10) p. 9125-9132 (2012)

[4] - O Schwartz, R Tenne, J M Levitt, Z Deutsch, S Itshakov, D Oron - ACS Nano 6 (10) p. 8778-8782 (2012)