Blinking fluorescence of single semiconductor nanocrystals: basic experimental facts and the theoretical models of blinking
I.S. Osad’ko Lebedev Physical Institute, Russian Academy of Sciences, Leninsky prosp. 53, Moscow, 119991, Russian Federation
Various theoretical models for blinking fluorescence from a single semiconductor core-shell nanocrystal (NC) are discussed in terms of consistency with new experimental data, with most emphasis placed on the charging model and multiple recombination center model. The advantages and disadvantages of each are analyzed, and their recently proposed combination using the advantages of both is examined, which is capable of accounting for the recently observed properties of the A- and B-type NCs. (The two types differ by whether or not the fluorescence quantum yield of a single NC correlates with its fluorescence lifetime). It is shown that the Auger neutralization of the NC core results in the anticorrelation of the off-interval duration and the grey emission lifetime in the off-interval. It is also shown that the exponent in the tm power-law distribution of on and off intervals in the fluorescence of single NCs characterizes the concentration of traps and localized NC core excitations on the core-shell interface.