Excitation Spectra and Stokes Shift Measurements of Single Organic Dyes at Room Temperature

Abstract

We report measurements of excitation and emission spectra of single, polymer-embedded, perylene dye molecules at room temperature. From these measurements, we can derive the Stokes shift for each single molecule. We determined the distribution of excitation and emission peak energies and, thus, the distribution of single molecule Stokes shifts. Single molecule Stokes shifts have not been recorded to date, and the Stokes shift has often been assumed to be constant in single molecule studies. Our data show that the observed spectral heterogeneity in single molecule emission originates not only from synchronous energetic shifts of the excitation and the emission spectra but also from variations in the Stokes shift, speaking against the assumption of constant Stokes shift.

Broadband single-molecule excitation spectroscopy

“…Previously, Stopel et al . 26 determined the Stokes shift of individual molecules recording both excitation and emission spectrum at room temperature. Against the general believe, they found that the Stokes shift varies between individual molecules.…”

Dynamics of Single-Molecule Stokes Shifts: Influence of Conformation and Environment

“…The experimentally determined Stokes shifts formed a broad distribution. 19 In the most recent study by Piatkowski et al, excitation spectra were acquired for about two minutes by a broadband Fourier approach. 20 The method's advantage is the robustness against blinking and bleaching of the observed molecule.…”

Photoluminescent PEG based comacromers as excitation dependent fluorophores for biomedical applications

“…which shows that the stokes shift value of PLM was considerably higher than that of polymer embedded organic dyes like perylene having stokes shift of 50 nm [30] .…”