Influence of magnetic field on delayed fluorescence of coumarin dye in Langmuir-Blodgett films

► The triplet-triplet annihilation in mixed Langmuir-Blodgett films with coumarin dye. ► Thermal activation process of TTA. ► Time and temperature dependence of magnetic field effects on delayed fluorescence. ► Dominance into process of TTA of contribution of ordered clusters or randomly oriented molecules clusters.