Charge transfer in fullerene - porphyrin-derived dyads studied with light-induced electron spin resonance

Dyads of fullerene-porphyrin type and adequate reference porphyrins were investigated with light-induced electron spin resonance (LESR) spectroscopy. Charge localization and photoinduced electron transfer in the dyads were studied in the dark and under light illumination. It was stated that the LESR signal increases stepwise with the incident light and decreases very slowly when the light is switched-off. Photogeneration of porphyrin cation-radicals was observed and analyzed. The principal parameters of the LESR lines of the ion-radicals are determined. It was stated that the main ESR parameters of the porphyrins are weakly dependent on number of involved porphyrin molecules; these parameters are not noticeably changed after the dyad formation.