Credit: M. Fernée, unpublished
An example of spectral diffusion observed in colloidal quantum dots, where the diffusion rate is on the 1-second time scale. (Top) This time series of several hundred spectra from a single quantum dot at 5 K reveals significant variation among individual spectra. (The bright area indicates the most intense point on the spectrum.) (Bottom) The average spectrum (blue curve) is significantly broader than any single spectrum (red curve shows a typical example), and the peak frequency of each spectrum wanders back and forth.