Photoinduced Electron Spin Polarization in a Fullerene-Azothiophene dyad.

Summary : Time Resolved EPR spectroscopy was applied to the investigation of photoinduced electron spin polarization in a molecular dyad. This is composed of a fullerene unit linked to a azothiophene dye. Compared to the separated components, spin polarization yield and lifetime were found to be strongly increased. This is discussed in terms of multiple energy transfer processes involving singlet and triplet excited states of the dyad components. Abstract : La sp\ue8ctroscopie de RPE a \ue9t\ue9 appliqu\ue9e \ue0 l'\ue9tude de la polarisation gener\ue8e par la lumi\ue8re dans une compos\ue9 mol\ue9culaire contenant une unit\ue9e de fullerene connect\ue9e \ue0 une azocolorant. Par rapport \ue0 ses composantes consid\ue9r\ue9es s\ue9parement, on a trouv\ue9 que la dur\ue9e et l\u2019intensit\ue9 de la polarisation ont \ue9t\ue9es fortement augment\ue9s. On analyse ce fenom\ue8ne en termes de proc\ue8s multiples de transfer d'energie faisant intervenire les \ue9tats excit\ue9s de singulet e de triplet des composantes