Low temperature exciton‐exciton annihilation in amphi‐PIPE J‐aggregates

The mobility of optically excited excitons on J‐aggregates can be demonstrated by the phenomena of exciton‐exciton annihilation. In this intensity‐dependent process the collision of two excitons results in their annihilation and hence in a shortening of the mean excitation lifetime. By measuring the intensity‐dependent fluorescent lifetime in contrast to the predicted immobilization of the excitons at low temperature we could prove the excellent mobility of the excitons at a temperature (4K), which is far below their expected freezing point.