An ensemble-based method to assess the quality of a sample of nanocrystals as single photon emitters

Colloidal semiconductor nanocrystals are among the best candidates for realizing a nano-structured single photon source at room temperature. In this paper we present a new and efficient optical method to assess the quality of a sample of nanocrystals as single-photon emitters, by an ensemble measurement of photoluminescence. We relate the ensemble photoluminescence measurements to the photon statistics of single emitters by a simple theoretical model. As an example we compare two different kinds of CdSe/CdS dot-in-rods, showing a similar degree of single photon emission when observed on a selection of single nanocrystals. The results are compared with anti-bunching measurements realized on single nanocrystals of the two kinds.