Fluorescence blinking statistics from single CdSe nanorods

We report that room temperature fluorescence from single colloidally synthesized CdSe nanorods exhibits intermittency (blinking) with truncated power-law off-time and on-time statistics. The nanorods have cross-sectional diameter 5 nm and length 20 nm and are deposited on mica substrates. The aggregated off-time statistics from 67 single nanorods follow a power law: $P(t_{off})\sim t_{off}^{-\alpha }$, with $\alpha \approx $1.1. Power-law behavior extends to off-times of roughly 10 s; longer-time probabilities fall below the best-fit power law. Individual nanorods also show power-law off-time statistics with 1$\le \alpha \le $1.3. On-time probabilities drop below a power law after only $\sim $0.6 s; no on-times longer than $\sim $3 s are observed. These results differ somewhat from those observed with spherical CdSe or CdSe/ZnS core-shell nanocrystals, for which power-law statistics persist to much longer on- and off-times.