Imaging the fluorescence decay lifetime of a conjugated-polymer blend by using a scanning near-field optical microscope

A conjugated polymer blend is studied by time-resolved scanning near-field optical microscopy. The blend undergoes strong phase separation on spin-casting. The fluorescence lifetime of the F8BT emission is strongly dependent on the relative phase in which it is located (see figure and cover). This effect is manifested by a significant concentration-dependent variation in the overall photolummescence quantum efficiency of the film.