Intensified blinking, continuous memory loss, and fluorescence enhancement of interacting light-emission quantum dots

We propose a microscopic quantum-mechanical model for describing the nonstochastic dynamics of the nanoscopic light-emissive quantum dot. The model is extended beyond a single quantum dot to consider the Coulomb repulsion between neighboring quantum dots in the ionic states caused by the random fluctuations of charge carriers. We find that the interaction gives rise to intensified blinking intermittency, continuous memory loss of the dynamics, and fluorescence enhancement in an ensemble of light-emissive quantum dots, which explains the recent experimental results. Our findings clarify the nature of the interaction underlying in the ensemble.

Figure 1

(Color online) (a) Schematics of the three-state model for a single QD. (b) Unnormalized probability of the “on” sojourn time. A change from the power-law to the exponential behavior is clearly illustrated; the inset is a semilog plot. $\theta =1.15$ and $\Gamma =0.18$ are obtained. $v_0=1$ is used.

Figure 2

(Color online) Probability of the on sojourn time $P\left({\tau }_{\text{on}}\right)$ with respect to $v_0$. Inset: crossover time ${\tau }_C$ shows a linear behavior with $1/v_0$, except for $v_0⪢1$.

Figure 3

(Color online) Fluorescence intensity $\mathcal{I}\left(\tau \right)$ from the weakly or strongly interacting QDs. The blinking becomes faster and more intensified for $U=1$ than $U=0.1$. $v_0=1$ is used.

Figure 4

(Color online) Probability of the “on” sojourn time $P\left({\tau }_{\text{on}}\right)$ with respect to the interacting strength $U$. $v_0=1$ is used.

Figure 5

(Color online) Correlation function $g\left(\tau \right)$ with respect to the interacting strength $U$. $v_0=1$ is used.

Figure 6

(Color online) Integrated fluorescence intensity $\overline{\mathcal{I}}$ with respect to $U$. $v_0=1$ is used.