Temperature dependent fluorescence in disordered Frenkel chains: interplay of equilibration and local band-edge level structure

TL;DR

This paper models the temperature-dependent fluorescence in disordered Frenkel chains, revealing a nonmonotonic Stokes shift due to the interplay of local energy levels and thermal effects, with results fitting experimental data.

Contribution

It introduces a model that captures the temperature-dependent fluorescence behavior in disordered Frenkel chains, highlighting the role of local level structure and equilibration.

Findings

Fluorescence Stokes shift varies nonmonotonically with temperature.

Model accurately fits experimental fluorescence spectra.

Interplay of local levels and thermal effects explains observed behavior.

Abstract

We model the optical dynamics in linear Frenkel exciton systems governed by scattering on static disorder and lattice vibrations, and calculate the temperature dependent fluorescence spectrum and lifetime. The fluorescence Stokes shift shows a nonmonotonic behavior with temperature, which derives from the interplay of the local band-edge level structure and thermal equilibration. The model yields excellent fits to experiments performed on linear dye aggregates.