Fluorescence line-narrowing difference spectra: Dependence of Huang-Rhys factor on excitation wavelength

- ΔFLN spectra are obtained using time-resolved fluorescence measurements.
- A peculiar dependence of the Huang-Rhys factor (S) on excitation wavelength is observed.
- The obtained fluorescence difference spectrum is almost homogeneous.
- Increase of Huang-Rhys factor on the blue edge is explained in terms of electrostatic interactions.