Origin of the stabilization energy of perylene excimer as studied by fluorescence and near-IR transient absorption spectroscopy

TLDR: In this article, the origin of the stabilization energy of perylene excimer in toluene has been studied and photophysical parameters such as the formation rate constant, the peak position and the lifetime and the quantum yield of fluorescence can be obtained.

Abstract: The origin of the stabilization energy of perylene excimer in toluene has been studied. In order to measure the fluorescence spectra and its decay profiles under the condition free from the reabsorption effect, we designed a thin optical cell with a path length of about 10 μm. From the results, the photophysical parameters of perylene excimer such as the formation rate constant, the peak position and the lifetime and the quantum yield of fluorescence can be obtained. Using these values, the binding energy of perylene excimer can be evaluated as 0.44 eV from the temperature dependence of the transient absorption. By analyzing the band shape of the charge transfer absorption in near-IR wavelength range, the transfer integral V between a neutral excited state and an ion-pair state can be estimated as 0.37 eV. From these results, we conclude that the stabilization energy of perylene excimer consists of two components: exciton interaction (70%) and charge transfer interaction (30%). We also discuss the origin of the stabilization energy of other aromatic excimers on the basis of the results on perylene excimer.