A quantitative model of multi-scale single quantum dot blinking

In spite of decades of comprehensive studies, the phenomenon of photoluminescence (PL) blinking in single semiconductor colloidal quantum dots (QDs) still requires theoretical retreatment. Here we present an enhanced model which proposes that the blinking phenomenon is caused by fluctuations in the rate of nonradiative relaxation due to temporal variations in the electron-phonon interaction coupling. This model quantitatively reproduces the results of single CdSeS/ZnS core/shell QD spectroscopy experiments. In order to analyze the temporal properties of blinking, a new method of power spectral density estimation is proposed, based on the second-order cross-correlation function of the PL intensity, obtained experimentally. The proposed method extends the frequency range up to 5-6 orders of magnitude.